Today Quiz date 30/12/2018

Biology Test Date 30/12/2018

1. Micronutrients

A. Are less important in nutrition than macronutrients

B. Are as important in nutrition as macronutrients

C. May be omitted from culture media without any detrimental effects on plants

D. Are called micro because they play only a minor role in nutrition

2. Which hormone influences contraction of gall bladder and secretion of pancreatic juice?

A. Enterogastrone
B. Gastrin
C. Cholecystokinin-pancreozymin
D. All of the above

3. The cells of the epithelial lining in the vertebrate stomach are not damaged by HCl because of

A. Mucus secretion covering the epithelium
B. Neutralization of HCl by alkaline gastric juice
C. HCl being too dilute
D. Epithelium being resistant to HCl

4. Pancreatic juice is

A. Acidic
B. Enzyme
C. Alkaline
D. None of the above

5. Emulsification of fats by bile takes place in

A. Duodenum
B. Intestine
C. Stomach
D. Liver

6. Ptyalin does not digest food in stomach because

A. Its quantity is small
B. It is carbohydrate digesting enzyme
C. It is secreted from salivary glands
D. HCl makes it inert

7. Which amino acid produces hexose by decarboxylation?

A. Arginine
B. Tryptophan
C. Guanine
D. Cysteine

8. Trypsin enzyme

A. Breaks proteins in alkaline medium of duodenum

B. Digests proteins in acidic medium of stomach

C. Digests proteins in acidic medium of duodenum

D. None of the above

9. Maltase enzyme in human gut acts on food at pH

A. Less than 7 to change maltose into fructose

B. More than 7 to change maltose into glucose

C. More than 7 to change starch into maltose

D. Less than 7 to change starch into maltose

Biology Test

Biology today Quiz. Date 29/12/2018

1. Palindromic DNA was discovered by

A. J. D. Watson
B. Khorana
C. Sanger
D. Wilson and Thomas

2. PROKARYOTES genetic system

A. DNA but no histones
B. Histones
C. DNA with histones
D. None of the above

3. Histone is rich in

A. Alanine
B. Methionine
C. Histidine
D. Arginine

4. Which of the gene is transcribed but not translated?

A. Histone gene
B. Keratin gene
C. t-RNA gene
D. r-RNA gene

5. mRNA is complementary to

A. Structural gene in the sense strand
B. Structural gene in the non-sense strand
C. Operator gene in the sense strand
D. Regulatory sequence of the sense strand

6. Cap in eukaryotic mRNA consists of

A. Methylated guanine residue
B. Methylated thymine residue
C. Methylated cytosine residue
D. Non- methylated adenine residues

7. Cap in the eukaryotic mRNA occurs in

A. 5'-end
B. 3'-end
C. Both A and B
D. Middle

8. tRNA reacts only with

A. Activated amino acids
B. Unactivated adenine
C. Ribosomes
D. ATP

9. Anti-codon is present on

A. rRNA
B. Ribosomal protein part
C. tRNA
D. mRNA

10. Defective gene in Amylotropic lateral sclerosis is

A. Rb
B. P53
C. bC12
D. TGF

11. Genetic disorder Xeroderma pigmentosum is due to error in

A. Base excision repair mechanism
B. Nucleotide excision repair mechanism
C. Direct repair mechanism
D. DNA replication mechanism
Answer-
1 - D
2 - A
3 - D
4 - C
5 - A
6 - A
7 - A
8 - A
9 - C
10 - C
11 - B

SET life science Question

1. The highest concentration of cystine can be found in
(A) Myosin
(B) Keratin
(C) Collagen
(D) Spectrin

2. A membrane bound enzyme that catalyses
the formation of cAMP from ATP is
(A) MAP Kinase
(B) Receptor Kinase
(C) ATP phosphorylase
(D) Adenyl cyclase

3. Assertion (A) : Quarum sensing is the ability of bacteria to communicate and coordinate behaviour.
Reason (R) : Bacteria those use Quarum sensing to producer and secrete a signaling chemical called
as “Inducer”.
(A) Both A and R are true and R is the correct explanation
(B) Both A and R are true, but R is the false explanation
(C) A is true, but R is false
(D) A is false, but R is true

4. Assertion (A) : Interferons are produced by the host against viral infection.
Reason (R) : Interferons are essential for viral replication.
(A) Both A and R are true and R is the correct explanation
(B) Both A and R are true, but R is the false explanation
(C) A is true, but R is false
(D) A is false, but R is true

5. Chylomicrons, Intermediate density lipoproteins (IDL), Low density Lipoproteins (LDL) and very low density Lipoproteins all are serum Lipoproteins.
What is correct ordering of these particles from the lowest to the greatest density ?
(A) LDL, IDL, VLDL, Chylomicra
(B) Chylomicra, VLDL, IDL, LDL
(C) VLDL, IDL, LDL, Chylomicra
(D) Chylomicra, IDL, VLDL, LDL

6. The sequence of the steps involved in the viral replication
I) Attachment
II) Penetration
III) Genome replication and Expression
IV) Uncoating
Arrange the above steps in chronologically
(A) I, II, III, IV
(B) III, II, I, IV
(C) II, III, IV, I
(D) I, II, IV, III

7. In the area of desmosome the adjacent cells have
I) Intercellular thickening material
II) Cilia
III) Transmembrane linkers
IV) Protein sheath

(A) I and IV are correct
(B) II and IV are correct
(C) I, II and III are correct
(D) I and III are correct

8. Viruses contain the following
I) Genome
II) Capsid
III) Capsule
IV) Enzyme

(A) I, II, III are correct
(B) I, II, III, IV are correct
(C) I, II, IV are correct
(D) II, III, IV are correct

9. DNA polymerase I are multifunctional enzymes because it promotes
I) Polymerisation reaction
II) Removal of nucleotides from 3′
terminus in DNA
III) Removal of nucleotides from 5′
terminus in DNA
IV) Joining of ends of DNA fragments

(A) I & IV are correct
(B) II & IV are correct
(C) III & IV are correct
(D) I, II & III are correct

10. Most of DNA binding proteins insert the following structure into the major groove of DNA during binding
(A) Beta-sheet
(B) Alpha-helix
(C) Beta-Turn
(D) Triple-helix

11. Coding region of an mRNA is 336 nucleotides long, including the initiator and termination codons. What is the number of amino acids in the protein translated from this mRNA ?
(A) 109
(B) 110
(C) 111
(D) 112

12. Origin of replication in E.coli consists of
I) Repetitive elements
II) GC rich regions
III) AT rich regions
IV) Series of U residues

(A) III is correct
(B) I and III are correct
(C) I, III and IV are correct
(D) IV is correct

13. Bt Cotton contains
(A) dry gene
(B) Cry gene
(C) Nif gene
(D) AmpR gene

14. Choose the correct signal transduction pathway.
(A) Hormone → 7 TM Receptor →G Protein → cAMP → PKA
(B) Hormone → G protein → 7 TM Receptor → cAMP → PKA
(C) Hormone → 7 TM Receptor → G protein → PKA → cAMP
(D) Hormone → 7 TM Receptor → cAMP → G protein → PKA

15. Which of the following can form a part of a Biosensor ?
I) Enzyme
II) Antibody
III) Lipid
IV) Vitamin

(A) III and IV are correct
(B) II and IV are correct
(C) I and II are correct
(D) I, II and III are correct

16. Name the enzyme act as Intracellular mediator for growth factor receptor
(A) MAP Kinases
(B) Phosphodiesterases (PDE)
(C) JAK Kinases
(D) β – adrenergic receptor Kinase (BARK)

17. DNA can be radiolabelled with
I) P32
II) I125
III) P33
IV) S35

(A) I, II and III are correct
(B) I and III are correct
(C) I, III and IV are correct
(D) II and IV are correct

18. Electrophoresis of a purified protein called X in the presence of SDS and beta-Mercaptoethanol shows a single band of 60 KDa. In gel filtration experiment protein X elutes between alcohol dehydrogenase (160 KDa) and beta-amylase (190 KDa).
How many identical subunits in the protein X composed of ?
(A) 1
(B) 2
(C) 3
(D) 4

19. Branched hydrophobic amino acids are
I) Valine
II) Leucine
III) Isoleucine
IV) Threonine

(A) I & IV are correct
(B) I, II & III are correct
(C) I & II are correct
(D) Only I is correct

20. Assertion (A) : Olfaction and taste are important sensory modalities for insects, particularly in mating, oviposition and food selection.
Reason (R) : Chaemo reception in insects is well established than the other animals.
(A) Both (A) and (R) are true and (R) is the correct explanation
(B) Both (A) and (R) are true and (R) is not the correct explanation
(C) (A) is true, but (R) is false
(D) (A) is false, but (R) is true

21. Match the Jaw suspension type in various organisms.
         List – I                                 List – II
I) Autodiastylic                  1) elasmobranchs
II) Amphistylic                  2) mammals
III) Hyostylic                     3) bony fishes
IV) Autostylic                   4) shark
       I II III IV
(A) 1 2 3 4
(B) 2 1 4 3
(C) 3 4 1 2
(D) 4 2 1 3

22. Arrange the transport pigments in the order of evolutionary origin from more recent
(A) Haemoglobin, Myoglobin, Chlorocruorin, Haemocyanin
(B) Myoglobin, Chlorocrcruorin, Haemoglobin, Haemocyanin
(C) Haemocyanin, Chlorocrcruorin, Myoglobin, Haemoglobin
(D) Haemocyanin, Haemoglobin,Myoglobin, Chlorocruorin

23. Match List I (genes) with List II (character) and select the correct answer using thecodes given below the Lists :
            List – I                                       List – II
I) Incomplete dominance             1) Human skin colour
II) Codominance                          2) Purple colour in maize due to anthocyanin
III) Polygenes                               3) Human being belonging to AB blood group
IV) Complementary genes           4) Pink colour in 4 O’ clock plant

Code :
       I II III IV
(A) 4 3 1 2
(B) 3 4 2 1
(C) 4 3 2 1
(D) 3 4 1 2

24. The cross over percentage between linked genes J and M is 20%, J and L is 35%, J and
N is 70%, L and K is 15%, M and N 50%.
Thus the sequence of genes on the chromosome is
(A) J, N, M, L, K
(B) J, M, L, N, K
(C) J, M, L, K, N
(D) M, J, L, K, N

25. Mammals and birds were originated in which of the following era/epoch/period ?
(A) Jurassic period
(B) Eocene and Oligocene
(C) Carboniferous and permian
(D) All of these

26. The Hardy-Weinberg law is expressed as (p+q)2, where ‘p’ and ‘q’ stands for
(A) Frequency of heterozygotes
(B) Frequency of alleles in population
(C) Gene frequencies in population
(D) Genotype frequencies in population

27. Assertion (A) : Autonomous specification gives rise to a pattern of embryogenesis referred
to as mosaic development. If particular blastomere is removed early in its development, that isolated
blastomere will produce the same type of cells that it would have made if it were still part of the embryo.
Reason (R) : The embryo appears to be constructed like a file mosaic of independent, self differentiating parts.
(A) Both (A) and (R) are true and (R) is the correct explanation of (A)
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A)
(C) (A) is true, but (R) is false
(D) (A) is false, but (R) is true

28. Assertion (A) : Structures of globular proteins are accurately determined with X-ray diffraction.
Reason (R) : Wave length of X-rays is less than 2°A and the resolution of structural information achievable is around 2°A.
(A) A & R are correct. R is explanation for A
(B) A is false, but R is correct
(C) A is correct, but R is false
(D) Both A and R are false

29. Given below are two statements : Assertion (A) : Foreign genes can be cloned into plasmid
cloning vectors.
Reason (R) : Cloning vectors can be used for expressing the foreign genes in bacterial systems.
Which of these statements is correct ?
(A) Both A and R are correct
(B) Both A and R are wrong
(C) A is correct, R is wrong
(D) A is wrong, R is correct

30. Given below are two statements
Assertion (A) : Plant breeders have an advantage over the animal breeders.
Reason (R) : Plant breeders can employ clonal propagation.
Which of the statements are correct ?
(A) A and R are correct and R is the explanation for A
(B) A and R are correct and R is not the explanation for A
(C) A is wrong, but R is correct
(D) Both A and R are wrong

31. Identify the correct statement
(A) Went’s theory explains the reasons for geotropism
(B) Thigmotropic movements are shown by Desmodium gyrans
(C) Coiling of tendrils around a hard stem are nyctinastic movements
(D) Movements of tentacles of Drosera are chemotropic movements

32. Given below are two statements, one labeled as Assertion (A), and the other labeled as Reason (R) :
Assertion (A) : Several factors are responsible for seed dormancy. One of the factors is immature
embryo.
Reason (R) : Seed dormancy caused by immature embryo can be overcome by scarification.
In the context of the above two statements which one of the following is correct ?
Codes :
(A) A is correct, R is also correct
(B) A is wrong, R is correct
(C) A is correct, R is wrong
(D) A is wrong and R is also wrong

33. List I consists of some terms and List II includes their corresponding definitions.
Select the code showing correct matching
            List – I                                  List – II
               (Terms)                              (Definitions)
I) Photooxidation                1) Influence of duration of day and night on flowering of plants
II) Photoperiodism              2) Splitting of water molecule by light
III) Photolysis                     3) Damage of cells under high intensity of light
IV) Photorespiration           4) Respiration in chloroplasts during day time

Codes :
      I II III IV
(A) 4 3 1 2
(B) 3 4 2 1
(C) 2 1 4 3
(D) 3 1 2 4

34. The light sensitive plant pigment phytochrome was first isolated by
(A) Borthwick and Coworders
(B) Garner and Allard
(C) Butler and his colleagues
(D) Hammer and Bonner

35. Which one of the following is NOT a correct statement ?
(A) Calcium is a component of chlorophyll
(B) Iron is a structural component of porphyrin molecules
(C) Boron plays an important role in translocation of sugars
(D) Molybdenum plays active role in nitrogen fixation

36. List I consists of some terms and List II includes corresponding definitions. Select the code showing correct matching
                     List – I                           List – II
                    (Terms)                         (Definitions)
I) Nitrification                                1) Conversion of nitrates to gaseous nitrogen
II) Denitrification                           2) Conversion of NH3 to NO3
III) Nitrogen fixation                     3) Conversion of proteins to ammonia
IV) Ammonification                      4) Conversion of gaseous nitrogen to ammonia

Codes :
      I II III IV
(A) 1 2 3 4
(B) 2 1 4 3
(C) 3 4 2 1
(D) 4 1 2 3

37. The following proteins are involved in protein synthesis on ribosomes
1) EF-TU
2) RF1
3) RRF
4) EF-G
5) IF2
What is the sequence of their involvent in the translation process ?
(A) 1, 5, 2, 3, 4
(B) 2, 3, 1, 4, 5
(C) 5, 2, 3, 1, 4
(D) 5, 1, 4, 2, 3

38. Choose the correct sequence of the following tools applied in proteomic
I) MALDI – TOF
II) IEF
III) SDS-PAGE
IV) Isolation of proteins

(A) III, II, I, IV
(B) II, III, IV, I
(C) IV, II, III, I
(D) I, III, IV, II

39. Five proteins with the following PI values were separated by isoelectric focusing
1) 3.6
2) 2.9
3) 7.2
4) 6.5
5) 8.5
What is the order of their migration from
the anode (closest to farthest) ?
(A) 5, 3, 4, 1, 2
(B) 3, 4, 5, 1, 2
(C) 2, 1, 4, 3, 5
(D) 5, 2, 3, 1, 4

Unit 1 Biochemistry (Amino Acid)

Terms in this set (20)Amino Acid,∆∆∆∆

Glycine

Not Chiral
Nonessential
Nonpolar
(Structure) High Conformational Flexibility
(Function) Sidechain-less backbone (bind to phosphates)

Alanine

Nonessential
Nonpolar
Structure (Present in most non-critical protein contexts)
Function (Very non-reactive, substrate recognition or specificity)

Proline

Nonessential
Nonpolar
Side chain connected to backbone twice
Secondary Amine (Imino acid) (S stereochemistry)
(Structure) Very limited in conformations, usually found on the protein surface
(Function) Important roles in molecular recognition

Valine

Essential
Nonpolar
(Structure) Bulkiness near the protein backbone. Hydrophobic: prefers to be buried in protein hydrophobic cores
(Function) Very non-reactive, substrate recognition in hydrophobic amino acids and lipids

Leucine

Essential
Nonpolar
(Structure): Hydrophobic prefers to be buried in protein hydrophobic cores. Preference for a helices more than in B strands
(Function) Very non-reactive, substrate recognition

Isoleucine

Essential
Nonpolar
(Structure) Bulkiness near to the protein backbone. Hydrophobic prefers to be buried in hydrophobic cores
(Function) Very non-reactive, substrate recognition

Methionine

Essential, sulfur atom
Nonpolar
(Structure) Slightly nonpolar thioester group. Prefers to be buried in a protein hydrophobic cores
(Function) Fairly non reactive; first amino acid in proteins
Substrate recognition, Can be involved in binding to atoms such as metals

Phenylaline

Aromatic
Essential
Nonpolar
(Structure) Prefers to be buried in protein hydrophobic cores, aromatic side chain can also mean that is involved in stacking interactions with other aromatic side chains
(Function) Fairly non-reactive, substrate recognition, Interactions with non-protein ligands

Tryosine

Aromatic
Nonessential
Polar
(Structure) Prefers to be buried in protein hydrophobic cores. Aromatic side chain can also mean that it is involved in stacking interactions with other aromatic side chains.
(Function) Reactive hydroxyl group. Substrate recognition

Tryptophan

Aromatic
Essential
Hydrophobic
(Structure) Prefers to be buried in protein hydrophobic cores. Aromatic side chain can also mean that is involved in stacking interactions with other aromatic side chains.
(Function) Nitrogen in aromatic system. Substrate recognition

Serine

Polar
Nonessential 
Small
(Structure) Conformationally versatile
(Function) The hydroxyl group is fairly reactive. Common in functional centers (for catalysis), catalytic triad found in many hydrolyses, site of phosphorylation

Threonine

Polar
Essential 
Small
2 chiral centers
(Structure) Conformationally versatile
(Function) The hydroxyl group is fairly reactive, common in functional centers, site of phosphorylation and or glycosylation

Cysteine

Polar
Semi-essential
Small
(Structure) Extracellular proteins: frequently involved in disulphide bonds (pairs of cysteines are oxidized to form a covalent bond). Intracellular: Sulfydryl side-chain is excellent for binding to metals, such as zinc
(Function) The sulfur group is reactive (nucleophile)

Asparagine

Polar
Nonessential
Amido of aspartate
(Structure) Surface of proteins, exposed to an aqueous environment 
(Function) Frequently involved in protein active or binding sites

Glutamine

Polar
Nonessential
Amido of glutamate
(Structure) Surface of proteins; exposed to an aqueous environment
(Function) Frequently involved in protein active or binding sites

Lysine

Positively Charged
Essential
(Structure) Prefers to be on the outside of proteins, hydrophobic side chains, terminated with positive charge
(Function) Involved in salt bridges, binds nucleic acids, site of post-translational modifications

Arginine

Positively Charged
Semi-essential
(Structure) Generally prefer to be on the outside of proteins. Hydrophobic side chain, terminated with positive charge.
(Function) Frequently involved in salt bridges, binds nucleic acids, complex quanidinium group

Histidine

Positively Charged
Essential
Imidazole
(Structure) pKa near to that of physiological pH
(Function) Relatively small shifts in pH change its average charge
• Most common amino acids in active or binding sites
• Common in metal binding sites (e.g. zinc)
• Charge relay systems (such as catalytic triads in proteases)

Glutamate

Negatively charged
Non-essential 
(Structure) Prefer to be on the surface of proteins
• When buried in protein: salt-bridges (Arg)
(Function) Frequently involved in protein active or binding sites
• Interact with positively charged atoms (e.g. zinc

Aspartate

Negatively charged 
Non-essential
(Structure) Prefer to be on the surface of proteins
• When buried in protein: salt-bridges (Arg)
(Function) Frequently involved in protein active or binding sites
• Interact with positively charged atoms (e.g. zinc)

Unit 1Biochemistry(Protien)

Proteins

A protein molecule is made up of a long chain of amino acids each linked to its neighbor through a covalent peptide bond. They are therefore referred to as polypeptides.

Amino Acids

Amino acids are the building blocks of proteins. The structure of amino acids consists of a central carbon atom that is bonded to:

one carboxylic acid group

one amino group

a side group (side-chain)

The side group is responsible for the uniqueness of an amino acid since it affects its:

shape

size

composition

pH

charge

A protein is universally accepted to have four levels of structural organization:

Primary Structure

The primary structure of proteins is the specific linear sequence of amino acids that make up the polypeptide chain.

It constitutes the covalent peptide bonds that join the amino acids together.

The sequence of the amino acids will ultimately decide the nature of the proteins function.

Secondary Structure

The secondary structure of proteins describes certain portions or stretches of the polypeptide chain and refers to the three-dimensional arrangement of atoms in the molecule.

What causes secondary structures?

Secondary structure is caused by the need for neutralization of the polar groups  in the main chain via hydrogen bonds. This allows the hydrophobic regions of the protein to settle into the interior.

Constituents of secondary structures:

(1) Alpha Helices

Alpha helices (α-helices) are repeating, twisted spiral or coiled structures stabilized by hydrogen bonds that generally form between the carboxyl oxygen of each amino acid residue and amide nitrogen of the amino acid situated four residues away (i.e. they are perpendicular to the polypeptide chain). The side-chains radiate outward and are staggered to minimize steric hindrance.

The average length of an α-helix is approximately ten residues = three helical turns. α-helices are either left-handed or right-handedwith the latter being most often observed.

Net dipole moment is also for an α-helix is as follows:

partial positive at N-terminus

partial negative at C-terminus

This favors the bonding of negatively charged groups (such as phosphates, etc.)

α-helices are the major structural componentsin many proteins. Some globular proteins contain mostly α-helices connected by turns or loops. A few examples are:

Hemoglobin --> about 7% are α-helices

small DNA binding helices

membrane-spanning helices

amphipathic helices

coiled coils (super-secondary structures)

*An interesting feature of the side-chain of Proline that makes it bad for α-helices is that the side-chain is bonded to the N atom eliminating any chances of hydrogen bonding and makes the polypeptide chain rigid.

On the other hand, the small side-chain of Glycine generates a wide array of Ψ and Φ angles. Hence both Proline and Glycine are often found at the boundaries of α-helices and in turns.

(2) Beta Sheets

Beta sheets (β-sheets) are segments of polypeptides that lie side by side. This causes the backbone of each segment to adopt a pleated conformation. Hydrogen bonds are formed  between the carboxyl oxygen of one strand and the amide nitrogen of the adjacent strand (i.e. they are parallel to the sheets). Their highly extended form results in resistance to tensile forces.

The side-chains are perpendicular to the sheet and jut out on either side of the sheet giving each face a unique property (i.e. polarity)

β-sheets are typically found in the interior of proteins and are generally of three types:

parallel β-strands

anti-parallel β-strands

parallel - adjacent β-strands run in same direction

anti-parallel - adjacent β-strands run in opposite direction

mixed

β-barrels are large β-sheets that are twisted and coiled in the form of a closed structure in which the hydrophobic side-chains line the outer surface to interact with the lipid bilayer. 

**β-sheets cannot be transmembrane unless they are part of a β-barrel structure.

β-sandwiches are structures in which β-sheets are stacked upon one another; side chains are often hydrophobic and complementary. 

(3) Hinges, Turns, Loops or Finger-like Extensions

These are the most flexible portions of the polypeptide chain and sites where the majority of biological activity takes place.

Super secondary structures

These are folding motifs composed of different combinations of secondary structures formed by interactions between the side-chains in order to solve the folding requirements by minimizing energy. 

Motifs

Motifs are entities containing specific combinations of secondary structures having a particular topology. Some examples are:

coiled coils = alpha helices wrap around one another and form a structure that is thermodynamically stable; found in myosin

β-barrels = found in enzymes

zinc-finger motifs = DNA binding (found in transcription factors)

helix-turn-helix = DNA binding (found in transcription factors); calcium binding

Domains and Modules

Domains are parts of the polypeptide chain that are able to fold independently of one another into stable, compact substructures and usually key out a certain function. 

Throughout the course of evolution, proteins with unique combinations of activities have been generated through shuffling of the domains.

Tertiary Structure

Tertiary structure of the protein describes the three-dimensional conformation of the entire polypeptide.

It is stabilized by non-covalent interactionsbetween the side-chains of proteins and leads a protein to attain the most thermodynamically stable conformation.

Quaternary Structure

Quaternary structure of a protein describes the relationship of the different polypeptide chainsthat make up a multiple subunit protein or a protein complex.

UNIT 1 Biochemistry (Non Standard Amino Acid)

NON STANDARD AMINO ACIDS

Apart from the 20 standard amino acids, all the rest amino acids are called as ‘non-standard’ amino acids. These include both proteinogenic as well as non-proteinogenic amino acids.  

Amino acid derivatives as proteins (Proteinogenic)

4-hydroxyproline = found in plant cell wall proteins, also  in collagen.

5-hydroxylysine= found in collagen

6-N-methyllysine= found in myosin, a muscle protein

γ-carboxyglutamate = found in prothrombin  and certain other proteins that bind Ca₂⁺ ions.

Desmosine= found in fibrous protein elastin

N-Formylmethionine= It is initially the N-terminal residue of all prokaryotic proteins.

 D-amino acid residues form polypeptides that are generally found to constitute bacterial cell walls. Apart from this, certain bacterially produced peptide antibiotics also contain D amino acids like valinomycin, gramicidin A and actinomycin D. 

Other amino acids (Non-proteinogenic) 

Besides their role in protein synthesis, amino acids also serve various other important functions.

Some amino acids act as neurotransmitters like γ-aminobutyric acid (GABA) that’s formed as a result of glutamate decarboxylation and dopamine that’s a tyrosine derivative.

         Histamine which is formed as a result of decarboxylation of histidine is a local mediator of allergic reactions

 Tyrosine derivative thyroxine is a thyroid hormone.

Ornithine and citrulline are intermediates in the biosynthesis of arginine and urea cycle.

 Homocysteine is an intermediate in amino acid metabolism.

S-adenosylmethionine is a biological methylating reagent.

Azaserine is a medically useful antibiotic.

UNIT 8 GENETICS(Genomic Imprinting)

Genomic imprinting

Genomic imprinting is an epigenetic (study of changes in organisms caused by modification of gene expression rather than alternation of the genetic code itself )phenomenon which in most cases is belived to occur in gametogenesis.

 It occurs when both maternal and paternal alleles are present ,but one allele will be expressed while the other remains inactive.This process is necessary for development and may somehow regulate growth in the embryo .

Evidence - It came from experiments with androgenotes ( embryos with two paternal genomes ) and gynogenotes ( embryos with two maternal genomes ) , which were produced by nucler transplantation .These zygotes are formed , but neither type was able to undergoes further development.

Example -
1. Gene Igf2 is an imprinted gene being expressed only from the paternal chromosome .
2. H19 gene is an imprinted gene expressed only from the maternal chromosome .  

                                                       Image source credit-http://curekatelyn.com/how-close-are-we-to-a-cure/

It is also called as uniparental disomy as only one allele is expressed either from father or from mother .

Genomic imprinting is rare in mammalsbecause most of the genes are not imprinted. From a nuclear transplantation experiment in mouse during  1980 s it was confirmed that foe normal mammalian development both the maternal and paternal genomes are required.

In case of flowering plants some genes are found to be expressed from maternal genomes while some others are expressed exclusively from the alone paternal copy .( In case of Sweetbay -Magnolia virginiana )

In case of insects like honeybees and  ants can reproduce either through fertilized eggs or unfertilized eggs. This sex determining system develops males from unfertilized eggs and females develop from fertilized eggs. The queen honey bee decides whether to fertilize an egg or to leave it unfertilized .

Improper imprinting in humans leads to some developmental abnormalities-
1.Prader-Willi-syndrome (when fathers copy is missing or there are 2 maternal parents.)
2.Angelman syndrome( when mothers copy is missing and there are 2 paternal parents .)

Unit 1 Biochemistry (Collagen)

Collagen

It is a type of structural protein which is most abundant protein in the human body . It is found throughout the body . It is the main fibrous component of skin , tendon,bone and cartilage. Normal collagen denatures at 39 c and on boiling they yield gelatin .Vertebrates have 46 genetically distinct polypeptide chains comprising 28 distinct collagen types . it is a secreted protein and therefore occurs outside cells. They are hydrolyzed by pepsin Enzyme. 

Structure -triple helix structure (3.3  aminoacids residues per turn )

Collagens are made up of 3 polypeptide alpha chains which are left handed and coiled around each other to form a right alpha helix confirmation . 

Each such helix is around 1.4 nm in diameter and 300 nm in length . The rise of the collagen helix (superhelix) is 2.9 Å (0.29 nm) per residue. 

Glycine occupies every third position in the repeating amino acid sequence. (Gly-X-Y). X is often proline. Proline makes up about 17% of collagen.

Collagen contains two uncommon derivative amino acids . These amino acids are found at specific locations relative to glycine and are modified post-translationally by different enzymes, both of which require vitamin-C as a co-factor-

1.Hydroxyproline derived from proline .    2. Hydroxylysine derived from lysine.

Proline and hydroxyproline residues permit sharp twisting of collagen helix.Only glycine residues can be accomodated at tight junctions between chains.

Formation of fibril -

1.After the formation of alpha chain the sequence facilitate binding of ribosomes to the rough ER and direct the alpha chain into the lumen of the RER.

2.This sequence is cleaved and precurser of collagen Pro- alpha chain is formed.
3.Proline and lysine are hydrolysed and modified by glycosylation with glucose or galactose residues.

4.After hydroxylation and glycosylation pro alpha chains are converted to pro -collagen .

5.Pro collagens are translocated to Golgi - apparatus .

6.In the golgi apparatus they are packaged in secretory vesicles or transport vesicles (Exocytosis).

7.Vesicles fuse with the membrane and release the pro- collagen into extracellular space.

8. Procollagen molecules are cleaved by N and C pro collagen peptides.

9.Triple helical structure is released as Tropocollagen .

10.Tropocollagen spontaneously associate with each other and form collagen fibrils .

Today Quiz

Biology

1. Which one of the following theories does not explain crossing over?

A. Torsion Theory
B. Chiasma type theory
C. Breaking first theory
D. Coupling and repulsion theory

2. Chromosomal theory of heredity is

A. Genes composed of chromosomes
B. A chromosome is made up of DNA and histone protein
C. Genes are found on chromosomes
D. Each and every living organism must have a set of chromosomes

3. Artificial mutation is

A. Induced mutation
B. Chemical mutation
C. Desired mutation
D. All of the above

4. Starting codon

A. AUG
B. AGA
C. AGU
D. GUG

5. Non-sense codon

A. UAA
B. UGA
C. UAG
D. All of the above

6. Not a pyridine base

A. Thymine
B. Guanine
C. Uracil
D. Cytosine

7. Operon concept was given by

A. Jacob and Monod
B. Watson and Crick
C. Schleiden and Schwann
D. Morgan and Beadle

8. Who first established the fact that DNA is the GENETIC MATERIAL by his experiments with Streptococcus pneumoniae?

A. Fred Griffith
B. O.T. Avery
C. Marshall Nirenberg
D. Robert W. Holley

9. Nucleoside?

A. Base + Sugar
B. Base + Phosphate
C. Sugar + Phosphate
D. Base + Sugar + Phosphate

10. Chargaff's Rule?

A. A + G = T + C
B. A + T = G + C
C. A/T = G/C
D. A = T = C = G

11. The cell DNA mainly exists in the form of

A. Left handed alpha - helix
B .Left handed beta - helix
C. Right handed alpha helix
D. Right handed beta helix

12. Z-DNA is

A. Double stranded DNA
B. Left handed helix
C. 12 residues per turn
D. All of the above

Unit 2 Cell Biology(Euchromatin and Hetrochromatin

Heterochromatin And Euchromatin

Heterochormatin - It is a region of chromosome whose properties are as follows-

It is highly condensed.

It is found in centromere and telomere region .

It contains long stretches of repetitive sequences called satellite DNA.

Replication occours in late s- phase .

Meiotic recombination is absent .

Heterochomatin Dna is not very active.

Transcriptionally silent and silences adjecent genes .

Types of heterochromatin -

1.Constitutive Heterochromatin - It remains always as heterochromatin untill no change due to mutation hence also called as obligate heterochromatin. It is usually repetitive and forms structural functions such as centromere or telomers.

e.gCentromeric heterochromatin,telomeric heterochromatin, Retrotransposons

2.Facultative Heterochromatin -It may convert to euchromatin depending upon the requirement .It is the result of genes that are silenced through a mechanisms such as Histone methylation or sirna by RNAi.

e.g Barr body in Mammalian female and female Drosophila 

                                    Image source credit -http://www.discoveryandinnovation.com/BIOL202/notes/lecture18.html

Euchromatin -

It is less condensed ,loosely packed regions of chromatin .

It is lightly stained.

Replication occours in throughout  s- phase .

Meiotic recombination is present.

Euchomatin Dna is very active.

Transcriptionally  not silent, very active .

MCQs.
1.In eukaryotes, transcription is generally associated with 
A) euchromatin only. 
B) heterochromatin only. 
C) very tightly packed DNA only. 
D) both euchromatin and histone acetylation

Ans. d

2.Some of the heterochromatin region can convert into euchromatic regions ,in different cell cycle stages. They are called -
a.Constitutive heterochromatin
b.Facultative heterochromatin
c.Euchromatin 
d.None of the above 

Ans. b

Unit 4 Devolopmental Biology (Stem Cell)

Stem cells

The cells that  have the capability to give rise to any kind of other cells. It have  totipotent nature that means as in the tissue culture a single explant is able to give rise a new plant the stem cells  can differentiated into other cells and the classification includes -

Totipotent - the ability to differentiate into all possible cell types.

Pluripotent - the ability to differentiate into almost all cell types. (include embryonic stem cells and cells that are derived from the mesoderm, endoderm, and ectoderm germ layers that are formed in the beginning stages of embryonic stem cell differentiation.)

Multipotent - the ability to differentiate into a closely related family of cells.( include hematopoietic (adult) stem cells that can become red and white blood cells or platelets.)

Oligopotent - the ability to differentiate into a few cells. Examples include (adult) lymphoid or myeloid stem cells.

Unipotent - the ability to only produce cells of their own type, but have the property of self-renewal required to be labeled a stem cell. Examples include (adult) muscle stem cells.

Stem cells can be preserved from the birth time of a baby. Human stem cells are currently being used to test new drugs. New medications are tested for safety on differentiated cells generated from human pluripotent cell lines. 

It can be adult stem cell or embryonic stem cell.

Embryonic stem cells can become all cell types of the body because they are pluripotent. Adult stem cells are thought to be limited to differentiating into different cell types of their tissue of origin.

Embryonic stem cells can be grown relatively easily in culture. Adult stem cells are rare in mature tissues, so isolating these cells from an adult tissue is challenging, and methods to expand their numbers in cell culture have not yet been worked out. This is an important distinction, as large numbers of cells are needed for stem cell replacement therapies. 

UNIT 6 PLANT Physiology(Senescence)

Senescence

The gradual deteriotion of cell division and growth that lead to death is termed as senescence. Telomeres ends serve to protect the coding DNA of the genome. When a telomeres shorten to critical lengths, the cell senescence and die off. It may affect the whole organism or some parts , cells and tissues. In case of leaf it may be seasonal leaf senescence or sequential leaf senescence.

Role of hormones -

Cytokinin is a plant growth regulator which delays leaf senescence by delaying the degradation of chloroplasts . In the leaf it starts from margin and move towards the interior.

ABA(Abscissic acid ) induces senescence resulting in chlorosis and necrosis.

Types of senescence-

1.Whole plant senescence - Found in  monocarpic plants .Whose are flower only once in their life cycle .(Annuals and bienneals)In this the senescence process begins with reproductive phase and the whole plant dies after seed formation .(Bamboos)

2.Shoot senescence- The upper part of shoot only undergoes senescence. The underground shoot remains as it is . It is seen in perennialplants . Examples zinger ,Musa paradisica 

3.Organ senescence- Occur only in the lateral organs like leaves and fruits . It is of 2 types -

Simultaneous senescence - Seen in deciduousplants where all leaves senesce at a particular season . It is also called as seasonal or deciduous senescence. It is controlled by environmental factors. Example is maple .

Sequential senescence (Progressive) -(Example coleus plant)   As the name indicates the senescence occurs in a sequential manner depending upon the age of leaf. The progressive older and lower leaves senesce while the new ones are added to the shoot .

                        Image source credit -http://biology4isc.weebly.com/7-plant-hormones-and-photomorphogenesis.html

Today Quiz's BIOLOGY DATE 27/12/2018

Biology

1. Which one is a SEX LINKED TRAIT?

A. Blindness
B. Deafness
C. Hemophilia
D. Myxodema

2. Number of autosomes in human sperms

A. 11
B. 22
C. 44
D. 45

3. Which one is a TEST CROSS?

A. Tt × Tt
B. TT × Tt
C. TT × TT
D. Tt × tt

3. The term 'gene' refers to

A. Sequence of amino acids in protein
B. A linkage group
C. A part of RNA
D. A portion of DNA

4. Gene mutation is caused by

A. Reproduction
B. Linkage
C. Change in the sequence of nitrogenous base
D. Change in the sequence of genes in DNA

5. Which of the following diseases is sex linked?

A. Colour blindness
B. Malignancy
C. Hepatitis
D. Leukemia

6. The character of organisms is said to be sex linked when its gene is carried on

A. Y - chromosomes
B. X - chromosome of male or female
C. X and Y chromosomes
D. A particular autosome

7. Two allelic genes are located on

A. The same chromosomes
B. Two homologous chromosomes
C. Two non - homologous chromosomes
D. Any two chromosomes

8. The genetic code was discovered by

A. G. Gamow
B. H. G. Khorana
C. Watson and Crick
D. M. Nirenberg

9. A colour blind man marries the daughter of a colour blind person. Then in their progeny

A. None of their daughters are colour blind
B. All the sons are colour blind
C. All the daughters are colour blind
D. 50% sons are colour blind

10. Conjoined twins are also known as

A. Fraternal twins
B. Siamese twins
C. Dizygotic twins
D. None of the above

11. Difference in the twins suggest

A. Incomplete dominance

B. That phenotype is influenced by many genes

C. That single gene may produce multiple effects

D. That they develop from two different eggs

12. Inheritance of ABO blood group system is an example of

A. Multiple allelism
B. Partial dominance
C. Epistasis
D. Dominance
Answer-:
1 - C

Hemophilia A, also called factor VIII deficiency or classic hemophilia, is a genetic disorder caused by missing or defective factor VIII, a clotting protein

The X and Y chromosomes are called sex chromosomes. The gene for hemophilia is carried on the X chromosome

Hemophilia is inherited in an X-linked recessive manner

2 - B
3 - D (Pehla)
3 - D (Doosra)
4 - D

5 - A

Colour blindness is not a form of blindness

It is inability to differentiate between some specific colours

Most common form of colour blindness is known as red/green colour blindness and most colour blind people suffer from this

6 - B
7 - B

8 - D

Nirenberg was awarded NOBEK PRIZE along with HAR GOVIND KHORANA, ROBERT HOLLEY for "GENETIC CODE INTERPRETATION"

9 - D
10 - B
11 - D
12 - A

UNIT 4 Devolopmental Biology CSIR NET exam

BLOCKS OF POLYSPERMY (DEVELOPMENTAL BIOLOGY )

Two mechanisms are used by animals to ensure that only one sperm will fertilize the egg to prevent the polyspermy condition .
1.FAST BLOCK - ( In sea urchins and Frogs) No fast block polyspermy are identified in mammals .

 (It happens immediately after fertilization )Depolarization of membrane so it is the change in potential of the plasma membrane. Sperm binding causes Na+ influx. 

STEPS-   a. Opening of Na+ channels in the egg plasma membrane .

                          b.Flow of Na+ into the egg cell(Na+ influx) .

                          c.Depolarization of the membrane .

                          d. As a result of that it prevents the additional sperm entry to the egg plasma membrane .

                          e. The egg plasma membrane restored to its normal -70 Mv resting potential within minutes of fusion as the Na+ channels  close  and Na+ is pumped out .

          (IF DEPOLARIZATION IS PREVENTED IT WOULD RESULTS IN POLYSPERMY )

2.SLOW BLOCK -(CHEMICAL AND MECHANICAL BLOCK)
Upon sperm entry the cortical granules fuse with the egg plasma membrane and  exocytosis of cortical granules occurs which  releases zonal inhibiting proteins like  serine proteases(which digest the connection between vitelline membrane and plasma membrane .) ,mucopolysaccharides ( It produce osmotic gradient and water rushes to perivitelline space),peroxidases ( oxidizes and cross links tyrosine )going to harden the fertilization envelope and in case of Humans it is zona Pellucida ) andhyaline which provides support during cleavage by formimg a coat around the egg called hyaline layer  .
STEPS - (In most of the species)

Inositol triphosphate -(IP3) causes the release of  Ca2+ from intracellular stores in the egg Endoplasmic Reticulum .

At the site of sperm entry ca2+ is released and it passes to the egg .

This ca2+ results in the fusion of cortical vesices with the egg plasma membrane releasing their contents into the space surrounding the egg called the perivitelline space. which is presnt in between cell membrane and vitelline envelope .

This raises the vitelline envelope and inactivates or destroys  the bindin receptor.

So, any additional sperm cannot bind which in turn prevents polyspermy .  Image source credit -http://slideplayer.com/slide/6364295/

NOTE -SOME ORGANISMS DO NOT BLOCK POLYSPERMY MANY SPERM ENTER ONLY ONE SURVIVE AND THE REST ARE DEGRADED.

What would be the reason to block polyspermy ?
Ans.       It leads to polyploidy and eventually death ..

BIOCHEMISTRY FLASH CARD

BIOCHEMISTRY FLASH CARD

1.GLYCOGEN AND STARCH ------- Alpha (1 -4)glucose (Branched and unbranched)

2.CELLULOSE--------Beta(1-4)glycosidic bond of  glucose (unbranched )

3.Insulin ---------------- 21 and 30 amino acids

4. Chitin ---------------------- N-acetyl glucosamine with alpha (1--4 ) linkage

5. Hemicellulose -------------D galactose

6.ADP ribosylation----------- Arginine

7. Uridylytion -----------------Tyrosine

8. Mg2+ is an inorganic activator of ---------Phosphatase enzyme

9. Zn2+ is an inorganic activator of ---------Carbonic anhydrase

10.Penicillin -------------Block the active site of enzyme that many bacteria used to make cell walls.

11. Phosphofructokinase allosterically regulated ---------------by ATP

12. Phosphorylation and Glycosylation---------Serresidue involved

13.Tyrosine --------------------------------Dopamine

14.Methylation and Acetylation ------------------------------lysine

15.Isocitrate lyase -------------------------------------------Synthesis of glucose from acetate

16.PEP  Carboxylase --------------------------------------Conversion of aminoacid into glucose

17.Pyruvate dehydrogenase complex-------------------Lipoic acid

18.Phosphofructokinase -------------------------------An allosteric enzyme

19.Pyruvate carboxylase ------------------------------Biotin

20.Uronic acid-----------------------------------------Dermatan sulphate ,Chondroitin sulphate ,Heparin sulphate

21.1,1-----Glucoside linkage -----------------------Trehalose

22.Invert sugar --------------------------------------Hydrolytic product of sucrose

23.Hyaluronic acid ---------------------------------Glucurnic acid and N- acetyl D- galactosamine

24.Diasteromers------------------------------------Isoleucine and threonine (Also have 2 chiral centers)

25.Non polar amino acids -----------------------In the core of proteins

26.Arginine--------------------------------------Imidazole group

27.Histidine-----------------------------------Guanidine group

28.Name of test - a. Histidine and tyrosine ----------------------Pauly
                             b.Tryptophan------------------------(glyoxylic acid reaction)Hopkins cole
                             c.Arginine---------------------Milon
                             d.Cysteine--------------------Nitroprusside
29.Spingosine------------------------------------Ceramide ,Cerebrosides,Gangliosides,Spingomyelin

30.Tay-Sachs disease -----------------------------Genetic defect in the metabolism of gangliosides

31.Alpha keratin -----------------------------Mammals and Beta keratin-------Birds and Reptiles

32.Major polysaccharide components of extracellular matrix----------------Glycosaminoglycans

33.Lipids -------------Fatty acid ,spingolipid,glycerophospholipid ,triglecerides,chlesterol

34.Transfatty acids--------------------By fermentation in the rumen of diary animals.

35.The pentose sugar present mainly in the
heart muscle is                                              -------------------------------------- Lyxose

36.Dietary fats are transported as ----------------------------------------------------Chylomicrons

37.Neurotransmitters ----------------------------------------Dopamine, serotonin,GABA,epinephrine 

38.Energy related metabolites-----------------------------Creatine, citrulline ,carnitine 

39.Carboxyglutamate-------------------------------Blood clotting proteins and Ca 2+ binding proteins 

40.Methyllysine--------------------------.    
constituent of  myosin

41.Pyroglutamate---------------------Bacteriorhodopsin

42.Ornithine and Citrulline--------------------Intermediates in biosynthesis of arginine and urea cycle

43.Ketogenic amino acids ---------------------leucine and lysine

Important Point For CSIR NET Exam

CSIR-UGC-JRF-NET Life Sciences-Notes (Syllabus wise) 

•Bio molecules (Carbohydrates, Lipids, Proteins, Nucleic acids and Vitamins).

We have given GRE practice tests for Bio molecules, the pattern of GRE is somewhat similar to CSIR. Go through that questions also.

• Stabilizing interactions
• pH, buffer, molarity, normality  
• Membrane structure and function
• Operon
• Cell organelles
• Cell division, checkpoints, cyclins involved and cell cycle
• Cellular communications: Tight junction, Gap Junctions ..
• DNA replication enzymes involved
• Transcription- translation Enzymes involved
• Inhibitors, mode of action of antibiotics
• Post- translational modification of proteins
• Cell signalling: Hormones and their receptors, cell surface receptor, signalling through G- protein coupled receptors.
• Oncology: Mode of action of tumor suppressor genes like p53, rB etc
• Anticancer drugs source & mode of action example: tamoxifen is an estrogen receptor blocker, Methotrexate
• Specific immune cells affected by diseases eg: HIV virus attacks T helper cells, Mycobacterium tuberculosis attacks macrophages
• Different types of immunoglobulinsand its importance
• MHCs
• Autoimmune disorders
• Cell signalling: Hormones and their receptors, cell surface receptor, signalling through G- protein coupled receptors.
• Photosynthesis - C3 , C4 and CAM pathways.
• Respiration
• Nitrogen metabolism
• Plant hormones :Precursors and functions
• Phytochromes, Secondary metabolites synthesis, pathways
• Flowering genes in plants
• Mendelian ratio + statistics.
• Extra chromosomal inheritance: Inheritance of Mitochondrial and chloroplast genes, maternal inheritance.
• Microbial genetics:  transformation, conjugation, transduction especially Hfr prophage.
• Cot curve analysis
• Human genetics : Pedigree analysis, genetic disorders. (Genetics Problems)
• ABO blood group
• Structural and numerical alterations of chromosomes : Deletion, duplication, inversion, translocation, ploidy and their genetic implications.
• Mitotic and meiotic Non-disjunction 
  
  
• Darwinisms; The evolutionary synthesis.
• Origin of cells and unicellular evolution: endosymbiotic theory. Concept of Oparin and Haldane; Experiment of Miller (1953); 
  
  
• Rule’s In ecology (Allens’ rule, Bergman’s rule, Gloger’s rule, Yoda’s Law)
• Geological time scale (make some codes in order to remember).
• Gene pool, Gene frequency; Hardy-Weinberg Law; concepts and rate of change in gene frequency through natural selection. (Genetics Problems)
• Speciation, allpatry and sympatry, convergent, divergent and parallel evolution.
• Major Biomes of the World
• Biosphere Reserve and Sanctuaries
• Endangered: plants, animals and birds (In India)

• Techniques in molecular biology and its applications 
• Microscopic Techniques

CSIR Unit 6 Plant physiology

SOME IMPORTANT POINTS ABOUT PLANT HORMONES

ABA -

DREB1 and DREB2 are two independent families of DREB proteins, which function as
trans-acting factors in two separate signal transaction pathways under low temperature
and dehydration. The ABA-responsive element (ABREs) contains the palindromic motif CACGTC with the G-box ACGT core element and A 9-bp conserved sequence,TACGACAT,termed dehydration responsive element (DRE), is essential for regulation of dehydration-responsive gene expression. The DRE has been reported to function as a cis- acting element involved in the induction of rd29A expression by low temperature stress.

GIBBERLLIN-

 Gibberllin (GA) regulate gene expressions by promoting degradation of the transcriptional regulator DELLA proteins, is essential for GA action that form a subgroup of the GRAS family of proteins. DELLA proteins are named for a conserved domain within the N terminus that is unique to this
subgroup and is necessary for GA-induced degradation.Binding of GA to its soluble, nuclear receptor,GID1, causes a conformational change in the protein that promotes its association with the
N-terminal domain of the DELLA protein, enabling, in turn, interaction with an SCF ubiquitin ligase, such that the DELLA is ubiquitinated, and thus targeted for degradation via the 26S proteasome.

ETHYLENE -

 There are many different types of receptor for ethylene like ETR1, ETR2, and ETHYLENE
INSENSITIVE4 (EIN4). ETR1 show the histidine kinase activity.  Any mutation in EIN2 will
lead to the loss of ethylene responsiveness throughout plant development.

ABA -

DREB1 and DREB2 are two independent families of DREB proteins, which function as
trans-acting factors in two separate signal transaction pathways under low temperature
and dehydration. The ABA-responsive element (ABREs) contains the palindromic motif CACGTC with the G-box ACGT core element and A 9-bp conserved sequence,TACGACAT,termed dehydration responsive element (DRE), is essential for regulation of dehydration-responsive gene expression. The DRE has been reported to function as a cis- acting element involved in the induction of rd29A expression by low temperature stress.

GIBBERLLIN-

 Gibberllin (GA) regulate gene expressions by promoting degradation of the transcriptional regulator DELLA proteins, is essential for GA action that form a subgroup of the GRAS family of proteins. DELLA proteins are named for a conserved domain within the N terminus that is unique to this
subgroup and is necessary for GA-induced degradation.Binding of GA to its soluble, nuclear receptor,GID1, causes a conformational change in the protein that promotes its association with the
N-terminal domain of the DELLA protein, jenabling, in turn, interaction with an SCF ubiquitin ligase, such that the DELLA is ubiquitinated, and thus targeted for degradation via the 26S proteasome.

ETHYLENE -

 There are many different types of receptor for ethylene like ETR1, ETR2, and ETHYLENE
INSENSITIVE4 (EIN4). ETR1 show the histidine kinase activity.  Any mutation in EIN2 will
lead to the loss of ethylene responsiveness throughout plant development.