Description : Leucine zipper motif is seen in some helical proteins when leucine residues appear at every (A) 3rd position (B) 5th position (C) 7th position (D) 9th position
Last Answer : Answer : C
Description : Zinc finger motif is formed in some proteins by binding of zinc to (A) Two cysteine residues (B) Two histidine residues (C) Two arginine residues (D) Two cysteine and two histidine residues or two pairs of two cysteine residues each
Last Answer : Answer : D
Description : An important step in protein synthesis is transcription. Which of the following statement(s) is/are true concerning this process? a. The first step in gene transcription involves separating the double helix ... nucleus to the cytoplasm d. Only one protein can be produced from an initial mRNA strand
Last Answer : Answer: c Transcription of a gene begins at an initiation site associated with a specific DNA sequence, termed a promoter region. After binding to DNA, the RNA polymerase opens up a short ... different proteins from the same gene. mRNA is exported from the nucleus only after processing is complete
Description : The structural stability of the double helix of DNA is as cribbed largely to (A) Hydrogen bonding between adjacent purine bases (B) Hydrophobic bonding between staked purine and ... Hydrogen bonding between adjacent pyrimidine bases (E) Hydrogen bonding between purine and pyrimidine bases
Description : The structure of DNA is a double helix formed by two strands of DNA sequence. This sequence consists of 4 different nucleotides- Adenine, Thymine, Cytosine and Guanine. How do the nucleotides on one strand interact with the nucleotides on the second strand to maintain the helical shape of DNA?
Last Answer : Complementary Base Pairing. Adenine complementary base pairs with Thymine and Guanine complementary base pairs with Cytosine.
Description : Name the enzyme that facilitates opening of DNA helix during transcription. (a) DNA ligase (b) DNA helicase (c) DNA polymerase (d) RNA polymerase
Last Answer : b) DNA helicase
Description : The association of histone H1 with a nucleosome indicates that (a) DNA replication is occurring (b) the DNA is condensed into a chromatin fibre (c) the DNA double helix is exposed (d) transcription is occurring.
Last Answer : (b) the DNA is condensed into a chromatin fibre
Description : The association of histone H1 with a nucleosome indicates: (1) DNA replication is occurring. (2) The DNA is condensed into a Chromatin Fibre. (3) The DNA double helix is exposed. (4) Transcription is occurring.
Last Answer : (2) The DNA is condensed into a Chromatin Fibre.
Description : The double helix is a structural arrangement associated with _____. a. A Polysaccharide. b. The DNA Molecule. c. Glucose Molecules In Starch. d. A Protein.
Last Answer : b. The DNA Molecule.
Description : Ten base pairs are present in one turn of the helix in (A) A-DNA (B) B-DNA (C) C-DNA (D) Z-DNA
Last Answer : Answer : B
Description : Which one of the following is wrongly matched? (a) Transcription - Writing information from DNA to tRNA. (b) Translation - Using information in mRNA to make protein. (c) Repressor protein - Binds to operator to stop enzyme synthesis. (d) Operon - Structural genes, operator and promoter.
Last Answer : (c) Repressor protein - Binds to operator to stop enzyme synthesis.
Description : Which one of the following is not a part of a transcription unit in DNA? (a) The inducer (b) A terminator (c) A promoter (d) The structural gene
Last Answer : (c) A promoter
Last Answer : (d) Operon - Structural genes, operator and promoter
Last Answer : (a) The inducer
Description : Which one of the following is not a part of a transcription unit in DNA ? (1) The structural gene (2) The inducer (3) A terminator (4) A promoter
Last Answer : (2) The inducer
Description : Besides structural genes that encode proteins, DNA contains some regulatory sequences which are known as (A) Operons (B) Cistrons (C) Cis-acting elements (D) Trans-acting factors
Description : There are special proteins that help to open up DNA double helix in front of the replication fork. These proteins are (a) DNA ligase (b) DNA topoisomerase I (c) DNA gyrase (d) DNA polymerase I.
Last Answer : (c) DNA gyrase
Description : Which of the following is not required for any of the techniques of DNA fingerprinting available at present? (a) Restriction enzymes (b) DNA-DNA hybridisation (c) Polymerase chain reaction (d) Zinc finger analysis
Last Answer : (d) Zinc finger analysis
Description : The region of the Lac operon which must be free from structural gene transcription to occur is (A) The operator locus (B) The promoter site (C) The ‘a’ gene (D) The ‘i’ gene
Last Answer : Answer : A
Description : Mutations in promoter regions of genes can cause (A) Premature termination of translation (B) Change in reading frame of downstream structural gene (C) Decreased efficiency of transcription (D) All of these
Description : Transcription of structural genes of lac operon is prevented by binding of the repressor tetramer to (A) i gene (B) Operator locus (C) Promoter (D) z gene
Description : All of the following statements about eukaryotic promoters are true except (A) They may be located upstream or down stream from the structural gene (B) They have two consensus sequences ( ... (D) Mutations in promoter region can decrease the efficiency of transcription of the structural gene
Description : To commence structural gene transcription the region which should be free on lac operation is (A) Promoter site (B) Operator locus (C) Y gene (D) A gene
Description : The function of a repressor protein in an operon system is to prevent synthesis by binding to (A) The ribosome (B) A specific region of the operon preventing transcription of structural genes (C) The RNA polymerase (D) A specific region of the mRNA preventing translation to protein
Description : In many proteins the hydrogen bonding produces a regular coiled arrangement which is called as (A) β-Helix (B) α-Helix (C) Both (A) and (B) (D) Spiral
Description : In many proteins the hydrogen bonding produces a regular coiled arrangement called (A) α-helix (B) β-helix (C) Both (A) and (B) (D) None of these
Description : Both α-helix and β-pleated sheet conformation of proteins were proposed by (A) Watson and Crick (B) Pauling and Corey (C) Waugh and King (D) Y.S.Rao
Description : The a-helix of proteins is (A) A pleated structure (B) Made periodic by disulphide bridges (C) A non-periodic structure (D) Stabilised by hydrogen bonds between NH and CO groups of the main chain
Description : In proteins the α-helix and β-pleated sheet are examples of (A) Primary structure (B) Secondary structure (C) Tertiary structure (D) Quaternary structure
Description : $ DNA helix to 20Å wide. One complete turn of DNA is 34Å long.
Last Answer : $ DNA helix to 20Å wide. One complete turn of DNA is 34Å long. A. If both As and R are correct and R ... , R is wrong D. If both As and R are wrong.
Description : One turn of the helix in a B-form DNA is approximately (a) 2 nm (b) 20 nm (c) 0.34 nm (d) 3.4 nm.
Last Answer : ) 3.4 nm.
Description : Which is wrong about nucleic acids? (a) DNA is single stranded in some viruses. (b) RNA is double stranded occasionally. (c) Length of one helix is 45 Å in B-DNA. (d) One turn of Z-DNA has 12 bases
Last Answer : (c) Length of one helix is 45 Å in B-DNA
Description : The proteins destined to be transported out of the cell have all the following features except (A) They possess a signal sequence (B) Ribosomes synthesizing them are bound to endoplasmic reticulum (C) After synthesis, they are delivered into Golgi apparatus (D) They are tagged with ubiquitin
Description : Hormone receptors possess all the following properties except (A) All of them are proteins (B) They possess a recognition domain (C) They bind hormones with a high degree of specificity (D) Number of receptors in a target cell is constant
Description : Bence-Jones proteins possess all the following properties except (A) They are dimers of light chains (B) Their amino acids sequences are identical (C) Their N-terminal halves have variable amino acid sequences (D) Their C-terminal halves have constant amino acid sequences
Description : The major fibrous proteins are: a) peptone and edestin b) glutelin and leucine c) valine and lysine d) myosin and actin
Last Answer : ANSWER: D -- Myosin and Actin
Description : Melting temperature of DNA is the temperature at which (A) Solid DNA becomes liquid (B) Liquid DNA evaporates (C) DNA changes from double helix into supercoiled DNA (D) Native double helical DNA is denatured
Description : DNA topoisomerase I of E. coli catalyses (A) Relaxation of negatively supercoiled DNA (B) Relaxation of positively supercoiled DNA (C) Conversion of negatively supercoiled DNA into positively supercoiled DNA (D) Conversion of double helix into supercoiled DNA
Description : Left handed double helix is present in (A) Z-DNA (B) A-DNA (C) B-DNA (D) None of these
Description : The enzyme DNA ligase (A) Introduces superhelical twists (B) Connects the end of two DNA chains (C) Unwinds the double helix (D) Synthesises RNA primers
Description : The width (helical diameter) of the double helix in B-form DNA in nm is (A) 1 (B) 2 (C) 3 (D) 4
Description : Mitochondrial DNA is (A) Circular double stranded (B) Circular single stranded (C) Linear double helix (D) None of these
Last Answer : A
Description : STAT proteins are (A) Thermostat proteins of brain (B) Glucostat proteins of hepatocyte cell membrane (C) Short term activators of translation (D) Signal transduction and activators of transcription
Description : The distance travelled per turn of α-helix in nm is (A) 0.34 (B) 0.44 (C) 0.54 (D) 0.64
Description : Each turn of α-helix contains the number of amino acids (A) 2.8 (B) 3.2 (C) 3.4 (D) 3.6
Description : Each turn of α-helix contains the amino acid residues (number): (A) 3.6 (B) 3.0 (C) 4.2 (D) 4.5
Description : Which one of the following best defines the word allotropes ? A Different structural forms of an element B A pair of substances that differ by H+ C Elements that possess properties intermediate between ... a specific number of neutrons E The different phases (solid, liquid or gas) of a substance
Last Answer : A Different structural forms of an element
Description : Genes that are involved in turning on or off the transcription of a set of structural genes are called (a) redundant genes (b) regulatory genes (c) polymorphic genes (d) operator genes.
Last Answer : (d) operator genes.
Description : Silencer elements (A) Are trans-acting factors (B) Are present between promoters and the structural genes (C) Decrease the expression of some structural genes (D) Encode specific repressor proteins