Free Chromosomes MCQs with Answers
633 Chromosomes MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Chromosomes are DNA-protein structures that carry genes and become visible during cell division. Coverage includes chromatin, centromeres, sister chromatids, homologous chromosomes, chromosome number, and the distinction between diploid and haploid cells, with links to DNA replication, mitosis and meiosis.
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633 questions · page 18 of 32
- A. UGA
- B. UAU
- C. CAU
- D. GAU
Explanation: Stop codons are also called nonsense codons because they do not code for an amino acid and instead signal the end of protein synthesis.
Correct answer: UGA- A. Somatic Mutation
- B. Hereditary mutation
- C. Germ line mutation
- D. De novo mutation
Explanation: De navo mutation is A genetic alteration that is present for the first time in one family member as a result of a variant (or mutation) in…
Correct answer: De novo mutation- A. Change in Phenotype
- B. No change in Phenotype
- C. Synthesis of 3 amino acids.
- D. Synthesis of 4 amino acids.
Explanation: A deletion changes the DNA sequence by removing at least one nucleotide in a gene.Phenotypic effects of deletions depend on the size and…
Correct answer: Change in Phenotype344. Identify in which of the following the genetic information is catalyzed using reverse transcription;
- A. Protein→DNA
- B. RNA →DNA
- C. DNA→RNA
- D. RNA Protein
Explanation: A reverse transcriptase(RT) is an enzyme used to generate complementary DNA(cDNA) from an RNA template, a process termed reverse…
Correct answer: RNA →DNA345. If an α-helix of a polypeptide consist of 360 amino acids, how many turns does the helix contain?
- A. 3.6 turns
- B. 100 turns
- C. 360 turns
- D. The number of turns can not be determind
Explanation: An alpha(α) helix contains 3.6 amino acids per turn of the helix. If a polypeptide consists of 360 amino acids, the turns in the helix…
Correct answer: 100 turns- A. PKU
- B. Alkaptunuria
- C. Anuria
- D. Dluria
Explanation: Phenylketonuria occurs when parents pass the defective phenylalanine hydroxylase (PAH) gene that causes this disorder on to their…
Correct answer: PKU- A. Klinefelter's Syndrome
- B. Down's Syndrome
- C. Turner's Syndrome
- D. Jacob's Syndrome
Explanation: Down's Syndrome involves a child receiving an extra copy of their 21st chromosome.Klinefelter's syndrome is a genetic disorder that occurs…
Correct answer: Down's Syndrome- A. Both are due to a quantitative defect in globin chain synthesis
- B. Thalassemia is due to less synthesis of globin molecules
- C. Sickle cell anaemia is due to a quantitative problem of globin molecules
- D. Both are due to a qualitative defect in globin chain synthesis
Explanation: Sickle cell anemia is caused due to point mutation in which at the 6th position of the beta-globin chain, glutamic acid is replaced by…
Correct answer: Thalassemia is due to less synthesis of globin molecules349. A molecule that can act as a genetic material must NOT fulfill which of the the traits given below?
- A. It should be able to express itself in the form of 'Mendelian characters'
- B. It should be able to generate its replica
- C. It should be unstable structurally and chemically
- D. It should provide the scope for slow changes that are required for evolution
Explanation: Genetic material should be structurally and chemically stable otherwise its expression will change.
Correct answer: It should be unstable structurally and chemically- A. Lactose
- B. Lactose and Galactose
- C. Glucose
- D. Galactose
Explanation: In Lac operon, lactose is an inducer. It binds with a suppressor and inactivates it.
Correct answer: Lactose- A. The inducer
- B. A terminator
- C. A promoter
- D. The structural gene
Explanation: A transcription unit is a part of DNA that is able to transcribe a complete RNA.
Correct answer: The inducer- A. One strand turns clockwise
- B. One strand turns anti-clockwise
- C. The phosphate groups of two DNA strands, at their ends, share the same position
- D. The phosphate groups at the start of two DNA strands are in opposite positions (poles)
Explanation: DNA is a type of nucleic acid that forms genetic material in many organisms.
Correct answer: The phosphate groups at the start of two DNA strands are in opposite positions (poles)- A. A polypeptide of 24 amino acids will be formed.
- B. Two polypeptides of 24 and 25 amino acids will be formed.
- C. A polypeptide of 49 amino acids will be formed.
- D. A polypeptide of 25 amino acids will be formed.
Explanation: UGA, UAG and UAA are three non sense (or termination) codons which do not code for any amino acid.
Correct answer: A polypeptide of 24 amino acids will be formed.- A. Ligase
- B. Primase
- C. DNA polymerase
- D. Endonuclease
Explanation: DNA ligase is a type of enzyme that catalyses the formation of a phosphodiester bond between two DNA molecules.
Correct answer: Ligase- A. repetitive DNA
- B. RNA
- C. single copy DNA
- D. none of these
Explanation: Single copy DNA - because most protein-coding genes are present in the unique (single-copy) regions of the genome, while repetitive DNA…
Correct answer: single copy DNA- A. F. Sanger
- B. Beadle
- C. Tatum
- D. Ingram
Explanation: Ingram because Vernon Ingram discovered that sickle cell anaemia results from a single amino acid substitution (glutamic acid → valine) in…
Correct answer: Ingram- A. GGGAUCUC
- B. GGGATCTC
- C. GGAAUCUC
- D. GGGGTCTC
Explanation: C pairs with G, A pairs with T in DNA, while A pairs with U in RNA. The question asks for the corresponding mRNA sequence after…
Correct answer: GGGAUCUC- A. DNA polymerase
- B. DNA ligase
- C. Reverse transcriptase
- D. All of these
Explanation: Reverse Transcriptase is an enzyme that uses single-stranded RNA as a template to synthesize complementary double-stranded DNA (cDNA).This…
Correct answer: Reverse transcriptase- A. Chromatic body
- B. Nuclear region
- C. Nuclear Body
- D. All of above
Explanation: Nucleotides are present in chromosomes that are located in the nucleus.
Correct answer: All of above- A. Haploid
- B. Diploid
- C. Single nucleus
- D. None of these
Explanation: Diploid organisms have cells with two sets of chromosomes (2n), one set inherited from each parent.
Correct answer: Diploid