Description : The most important mechanism by which tetracycline antibiotics exert antiimicrobial action is (a) They chelate Ca2+ ions and alter permeability of bacterial cell membrane (b) They bind to 30S ribosomes ... peptide chain in the bacteria (d) They interfere with DNA mediated RNA synthesis in bacteria
Last Answer : Ans: B
Description : The most important mechanism by which tetracycline antibiotics exert antimicrobial action is: A. They chelate Ca2+ ions and alter permeability of bacterial cell membrane B. They bind to 30S ribosomes ... peptide chain in the bacteria D. They interfere with DNA mediated RNA synthesis in bacteria
Last Answer : B. They bind to 30S ribosomes and inhibit bacterial protein synthesis
Description : Most viruses that infect plant possess (a) single-stranded DNA (b) single-stranded RNA (c) double-stranded DNA and RNA (d) double - stranded RNA only
Last Answer : Ans:(b)
Description : Which one of the following statements about viruses is correct? (a) Viruses possess their own metabolic system. (b) All viruses contain both RNA and DNA. (c) Viruses are obligate parasites. (d) Nucleic acid of viruses is known as capsid.
Last Answer : (c) Viruses are obligate parasites.
Description : The mechanism of antibacterial action of tetracycline involves (a) Binding to a component of the 50S ribosomal subunit (b) Inhibition of translocase activity (c) Blockade of binding of ... (d) Selective inhibition of ribosomal peptidyl transferases (e) Inhibition of DNA-dependent RNA polymerase
Last Answer : Ans: C
Description : Ribosomes are chemically composed of (A) Protein (B) Only DNA (C) RNA (D) Both A + C
Last Answer : (D) Both A + C
Description : Viruses have (a) DNA enclosed in a protein coat (b) prokaryotic nucleus (c) single chromosome (d) both DNA and RNA.
Last Answer : (a) DNA enclosed in a protein coat
Description : .Viroids differ from viruses in having (a) DNA molecules without protein coat (b) RNA molecules with protein coat (c) RNA molecules without protein coat (d) DNA molecules with protein coat
Last Answer : (c) RNA molecules without protein coat
Description : Viroids differ from viruses in having; (1) DNA molecules without protein coat (2) RNA molecules with protein coat (3) RNA molecules without protein coat (4) DNA molecules with protein coat
Last Answer : (3) RNA molecules without protein coat
Description : Ribosomes help to synthesize a. carbohydrates b. proteins c. lipids d. minerals
Last Answer : proteins
Description : The genome of a virus may contain either ______ or ______. a. DNA; protein b. protein; carbohydrate c. carbohydrate; RNA d. RNA; DNA
Last Answer : d. RNA; DNA
Description : Which statement is wrong for viruses? (a) All are parasites. (b) All of them have helical symmetry. (c) They have ability to synthesize nucleic acids and proteins. (d) Antibiotics have no effect on them
Last Answer : (b) All of them have helical symmetry
Description : 100. Which statement is wrong for viruses ? (1) Antibiotics have no effect on them (2) All are parasites (3) All of them have helical symmetry (4) They have ability to synthesize nucleic acids and proteins
Last Answer : All of them have helical symmetry
Description : The role of molecular chaperones is to A-facilitate binding of ribosomes to mRNA B-degrade newly synthesized polypeptides that contain inaccurate sequences C-.facilitate binding of RNA polymerase to DNA D-aid a newly synthesized polypeptide in folding to its proper shape
Last Answer : -aid a newly synthesized polypeptide in folding to its proper shape
Last Answer : aid a newly synthesized polypeptide in folding to its proper shape
Description : Transfer RNA transfers (A) Information from DNA to ribosomes (B) Information from mRNA to cytosol (C) Amino acids from cytosol to ribosomes (D) Proteins from ribosomes to cytosol
Last Answer : Answer : C
Description : Nissl’s bodies are mainly composed of (a) proteins and lipids (b) DNA and RNA (c) nucleic acids and SER (d) free ribosomes and RER.
Last Answer : (d) free ribosomes and RER.
Description : At a chromosome replication fork, the lagging strand consists of__ That is joined by___. a. RNA sequences; DNA ligase b. Okazaki Fragments; RNA Polymerase c. RNA sequences; ribosomes d. Okazaki fragments; DNA ligase
Last Answer : d. Okazaki fragments; DNA ligase
Description : Nissl bodies are mainly composed of (1) Proteins and lipids (2) DNA and RNA (3) Nucleic acids and SER (4) Free ribosomes and RER
Last Answer : (4) Free ribosomes and RER
Description : Which of the following statements is wrong for viroids? (a) They cause infections. (b) Their RNA is of high molecular weight. (c) They lack a protein coat. (d) They are smaller than viruses
Last Answer : (b) Their RNA is of high molecular weight.
Description : Which organelle does assemble ribosomes? (a) Nuclear envelope (b) Nucleolus (c) Chromosomes (d) Nucleoplasm
Description : Which of the following organelle of the cell contain their own genetic material? (1) Mitochondria (2) Ribosomes (3) Golgi complex (4) None of the above
Last Answer : (1) Mitochondria Explanation: Nucleus is the central organelle of the cell which encloses the DNA. Apart from the nucleus, there are few other organelles which have their own DNA.
Description : ______ is the cell organelle, in which the biochemical processes of respiration and energy production occur. (1) Mitochondria (2) Chloroplast (3) Ribosomes (4) Nucleus
Last Answer : (1) Mitochondria Explanation: Mitochondria is an organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur.
Description : Cell Organelle found only in plants are— (A) Mitochondria (B) Golgi complex (C) Ribosomes (D) Plastids
Last Answer : (D) Plastids
Description : Which of the following organelle lack membrane? (a) Mitochondria (b) Ribosomes (c) Microtubules(d) Peroxisomes
Last Answer : (b) Ribosomes
Description : Template-directed DNA synthesis occurs in all the following except (A) The replication fork (B) Polymerase chain reaction (C) Growth of RNA tumor viruses (D) Expression of oncogenes
Description : Template-directed DNA synthesis occurs in all the following except (A) The replication fork (B) Polymerase chain reaction (C) Growth of RNA tumor viruses (D) Expression of oneogenes
Description : The only correct statement about oncoviruses is (A) All the oncoviruses are RNA viruses (B) Reverse transcriptase is present in all oncoviruses (C) Viral oncogenes are identical to human protooncogens (D) Both DNA and RNA viruses can be oncoviruses
Last Answer : Answer : D
Description : All of the following statements about RNA-dependent DNA polymerase are true except: (A) It synthesizes DNA using RNA as a template (B) It is also known as reverse transcriptase (C) It synthesizes DNA in 5’→3’ direction (D) It is present in all the viruses
Description : Some viruses have RNA but no DNA. This would indicate that – (1) these viruses cannot replicate (2) these viruses have no heritable information (3) RNA transmits the hereditary information in these viruses (4) their nucleic acids can be crystallised
Last Answer : (2) these viruses have no heritable information Explanation: DNA is an informational molecule encoding the genetic instructions Along with RNA and proteins, it is one of the three major macromolecules that are ... guanine, adenine, thymine, and cytosine) recorded using the letters G, A, T, and C.
Description : Which of the following is true? (1) DNA is the genetic material in most of the organism (2) RNA is the genetic material in most viruses and bacteria (3) DNA is the genetic material in all the viruses (4) RNA is the genetic material in all the viruses
Last Answer : (1) DNA is the genetic material in most of the organism Explanation: Deoxyribonucleic acid (DNA) molecules are informational molecules encoding the genetic instructions used in the development and functioning of all ... letters. G, A, T, and C. DNA is well-suited for biological information storage.
Description : The chemical component that is invariably found in all viruses is (1) proteins (2) lipids (3) DNA (4) RNA
Last Answer : (1) proteins Explanation: All viruses contain the following two components: a nucleic acid genome and a protein capsid that covers the genome. Together this is called the nucleocapsid. The proteinous ... , many animal viruses contain a lipid envelope. The entire intact virus is called the virion.
Description : Virions are (a) DNA viruses (b) RNA viruses (c) Naked DNA viruses (d) Naked RNA viruses
Last Answer : (d) Naked RNA viruses
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 : Viruses are no more “alive” than isolated chromosomes because (a) they require both RNA and DNA (b) they both need food molecules (c) they both require oxygen for respiration (d) both require the environment of a cell to replicate.
Last Answer : (d) both require the environment of a cell to replicate.
Description : Retroviruses are so-named because their reverse transcriptase _____. a. reverses the flow of genetic information by stimulating information to proceed from RNA to DNA. b. reverses the normal ... the action of drugs on viruses and allows them to continue multiplying in living cells.
Last Answer : a. reverses the flow of genetic information by stimulating information to proceed from RNA to DNA.
Description : 9 In some viruses DNA is synthesized by using RNA as a template. Such a DNA is called............ a. r-DNA b. C-DNA c. B- DNA d. A- DNA
Last Answer : Ans. b C-DNA
Description : The chemical component that is invariably found in all viruses is : (1) proteins (2) lipids (3) DNA (4) RNA
Description : Some viruses have RNA but no DNA. This would indicate that– (1) these viruses cannot replicate (2) these viruses have no heritable information (3) RNA transmits the hereditary information in these viruses (4) their nucleic acids can be crystallised
Last Answer : these viruses have no heritable information
Description : Which of the following is true ? (1) DNA is the genetic material in most of the organism (2) RNA is the genetic material in most viruses and bacteria (3) DNA is the genetic material in all the viruses (4) RNA is the genetic material in all the viruses
Last Answer : DNA is the genetic material in most of the organism
Description : Production of a human protein in bacteria by genetic engineering is possible because (a) the human chromosome can replicate in bacterial cell (b) the mechanism of gene regulation is identical in ... ) bacterial cell can carry out the RNA splicing reactions (d) the genetic code is universal.
Last Answer : (d) the genetic code is universal.
Description : The mechanism of synthesis of DNA and RNA are similar to all the following ways except (A) They involve release of pyrophosphate from each nucleotide added (B) They require activated nucleotide precursor and Mg2+ (C) The direction of synthesis is (D) They require a primer
Description : The mechanism of synthesis of DNA and RNA are similar in all the following ways except (A) They involve release of pyrophosphate from each nucleotide added (B) They require activated nucleotide precursor and Mg2+ (C) The direction of synthesis is 5’ → 3’ (D) They require a primer
Last Answer : Answer : A
Description : In human body, the cell growth and differentiation are highly controlled and regulated, but in cancer cells. (a) there is breakdown of these regulatory mechanism leading to formation of benign and malignant ... is mutated and produced in less amount (d) DNA is mutated and produced in less amount
Last Answer : Ans:(a)
Description : Thermococcus, Methanococcus and Methano- bacterium exemplify (a) bacteria whose DNA is relaxed or positively supercoiled but which have a cytoskeleton as well as mitochondria (b) bacteria that ... that lack any histones resembling those found in eukaryotes but whose DNA is negatively supercoiled
Last Answer : (c) archaebacteria that contain protein homologous to eukaryotic core histones
Description : Which of the following act as the blueprint or template for the process of protein synthesis that takes place on ribosomes? A.rRNA B.DNA C.tRNA D.mRNA
Last Answer : mRNA
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 : Where do plants synthesize protein from?
Last Answer : Amino Acids
Description : Where do plants synthesize protein from? (1) Fatty Acids (2) Sugar (3) Amino Acids (4) Starch
Last Answer : (3) Amino Acids Explanation: Amino acids are the molecular building blocks of proteins. So proteins are synthesized from them. Essential ami acids are histidine, isoleucine, leucine, methionine, phenyl lanine, threonine, tryptophan, valine, and lysine.
Description : Living cells have the unique ability to synthesize only _________ the form of optical isomer due to _________. (A) ‘d’ form, stereospecific enzymes (B) ‘l’ form stereospecific enzymes (C) ‘d’ form, DNA (D) ‘L’ form, DNA
Last Answer : Answer : B