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 : 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 of the following is correct about viroids? (a) They have RNA with protein coat. (b) They have free RNA without protein coat. (c) They have DNA with protein coat. (d) They have free DNA without protein coa
Last Answer : (b) They have free RNA without protein coat.
Description : Which of the following statements is incorrect? (a) Prions consist of abnormally folded proteins. (b) Viroids lack a protein coat. (c) Viruses are obligate parasites. (d) Infective constituent in viruses is the protein coat.
Last Answer : (d) Infective constituent in viruses is the protein coat.
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 : .Mad cow disease in cattle is caused by an organism which has (a) inert crystalline structure (b) abnormally folded protein (c) free RNA without protein coat (d) free DNA without protein coat.
Last Answer : (b) abnormally folded protein
Description : Viroids and prions differ in that viroids are believed to contain only ______, while prions are believed to contain only _______. a. carbohydrate; amino acids b. nucleic acid; protein c. amino acids; carbohydrate d. protein; nucleic acid
Last Answer : b. nucleic acid; protein
Description : Viroids contain a. RNA and DNA. b. Only RNA. c. DNA and a capsid. d. RNA and an envelope.
Last Answer : b. Only RNA.
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 : Human immuno deficiency virus (HIV) has a protein coat and a genetic material which is (a) double stranded RNA (b) double stranded DNA (c) single stranded DNA (d) single stranded RNA
Last Answer : (d) single stranded RNA.
Description : .Viruses possess (a) ribosomes to synthesize protein (b) organelle for its vital mechanism (c) either DNA or RNA (d) none of these.
Last Answer : (c) either DNA or RNA
Description : How are viroids different from viruses? -Biology
Last Answer : answer:
Description : Select the wrong statement. (a) The term ‘contagium vivum fluidum’ was coined by M. W. Beijerinck. (b) Mosaic disease in tobacco and AIDS in human being are caused by viruses. (c) The viroids were discovered by D.J. Ivanowsky. (d) W.M. Stanley showed that viruses could be crystallised.
Last Answer : (c) The viroids were discovered by D.J. Ivanowsky
Description : Attenuated viruses are those that _____. a. can be used to treat viral disease. b. give rise to viroids and prions. c. multiply in cells but at a low rate. d. have been treated with chemicals such as formaldehyde.
Last Answer : c. multiply in cells but at a low rate.
Description : .Which one of the following pairs is wrongly matched? (a) Ginkgo – Archegonia (b) Salvinia – Prothallus (c) Viroids – RNA (d) Mustard – Synergids
Last Answer : (b) Salvinia – Prothallus
Description : _____ are infectious RNA particles a. Viroids b. Prions c. Virions d. A-C are correct
Last Answer : a. Viroids
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
Last Answer : Answer : C
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 : 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 : 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 : 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 : 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
Last Answer : proteins
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 : RNA molecules can be broken up into three classes-which type of RNA molecule is translated into a protein sequence?
Last Answer : Messenger RNA (mRNA). mRNAs are the RNA transcripts that contain protein coding sequences which are translated into protein.
Description : Labelled-D contains :- (i) A few RNA molecules (ii) 70s ribosome (iii) Enzymes (iv) Circular DNA
Last Answer : Labelled-D contains :- (i) A few RNA molecules (ii) 70s ribosome (iii) Enzymes (iv) Circular DNA A. ii, iv B. ... iv, C. ii, iii, iv D. i, ii, iii, iv
Description : What are the smaller repeating molecules that make up a DNA or RNA molecule called?
Last Answer : Need answer
Description : What is true about viruses without exception? (1) They contain a core of RNA (2) They can infect bacteria (3) They cannot produce antibodies (4) They can multiply only in host cells
Last Answer : (4) They can multiply only in host cells Explanation: Viruses do not contain enzymes for energy production or protein synthesis. For a virus to multiply, it must invade a host cell and direct the host ... proteins, and copies of its nucleic acid, using the host cell's ATP to power the reactions.
Last Answer : They can multiply only in host cells
Description : In the process of transcription, the flow of genetic information is from (A) DNA to DNA (B) DNA to protein (C) RNA to protein (D) DNA to RNA
Description : Translocase is an enzyme required in the process of (A) DNA replication (B) RNA synthesis (C) Initiation of protein synthesis (D) Elongation of peptides
Description : DNA is (A) Usually present in tissues as a nucleo protein and cannot be separated from its protein component (B) A long chain polymer in which the internucleotide linkages are of the diester type between C-3 ... linkages are between C-2' and C-5' (D) Hydrolyzed by weal alkali (pH9 to 100°C)
Last Answer : Answer : B
Description : The genetic code operates through (A) The protein moiety of DNA (B) Cistrom of DNA (C) Nucleotide sequence of m RNA (D) The anticodons of tRNA
Description : From a DNA-RNA hybrid, DNA can be obtained by addition of (A) DNA B protein and ATP (B) Helicase and ATP (C) DNA topoisomerase I (D) Alkali
Description : Restriction endonucleases recognize and cut a certain sequence of (A) Single stranded DNA (B) Double stranded DNA (C) RNA (D) Protein
Description : Termination of the synthesis of the RNA molecule is signaled by a sequence in the template strand of the DNA molecule, a signal that is recognized by a termination protein, the (A) Rho (ρ) factor (B) σ factor (C) δ factor (D) ε factor
Last Answer : Answer : A
Description : The process through which the amount of DNA, RNA and protein can be known at a time is called (a) Autoradiography (b) Tissue culture (c) Cellular fractioning (d) Phase contrast microscopy
Last Answer : Ans. ((c))
Description : The process by which the amount of DNA, RNA and protein can be known at a time is: (a) Cell fractionation (b) Autoradiography (c) Phase-contrast microscopy (d) Tissue culture
Last Answer : Ans. ((b))
Description : Francis Crick’s seminal concept that in nature genetic information generally flows from DNA to RNA to protein.
Last Answer : Ans. Central Dogma
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 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