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 21 of 32
- A. Escherichia coli
- B. Streptococcus pneumoniae
- C. Salmonella typhimurium
- D. Drosophila melanogaster
Explanation: The semi-conservative replication of DNA was first experimentally demonstrated by Matthew Meselson and Franklin Stahl in 1958.
Correct answer: Escherichia coli- A. Tailing
- B. Transformation
- C. Capping
- D. Splicing
Explanation: mRNA is not made directly in a eukaryotic cell. It is transcribed as heterogeneous nuclear RNA (hnRNA) in the nucleus.
Correct answer: Splicing403. In the DNA molecule:
- A. The proportion of adenine in relation to thymine varies with the organism
- B. There are two strands which run antiparallel; one in the 5' ➡ 3' direction and the other in 3' ➡ 5' direction
- C. The total amount of purine nucleotides and pyrimidine nucleotides is not always equal
- D. There are two strands which run parallel in the 5' ➡ 3' direction
Explanation: A DNA molecule has two unbranched complementary strands, which are spirally coiled.
Correct answer: There are two strands which run antiparallel; one in the 5' ➡ 3' direction and the other in 3' ➡ 5' direction- A. Guanine, Adenine-Purines
- B. Adenine, Thymine-Purines
- C. Thymine, Uracil-Pyrimdines
- D. Uracil, Cytosine-Pyrimidines
Explanation: Adenine and Guanine are the purine bases, while Cytosine, Thymine and Uracil are pyrimidine bases.
Correct answer: Adenine, Thymine-Purines- A. AUG, ACG -Start/methionine
- B. UUA, UCA -Leucine
- C. GUU, GCU -Alanine
- D. UAG, UGA -Stop
Explanation: AUG codes for methionine and is the initiation or start codon that starts the synthesis of the polypeptide.
Correct answer: UAG, UGA -Stop- A. 2 nm
- B. 20 nm
- C. 0.34 nm
- D. 3.4 nm
Explanation: DNA is the largest macromolecule made of helically twisted two antiparallel polydeoxyribonucleotide strands held together by hydrogen…
Correct answer: 3.4 nm- A. Beadle and Tatum
- B. R. Franklin
- C. Hershey and Chase
- D. A. Garrod
Explanation: In 1948, Beadle and Tatum proposed the one gene one enzyme hypothesis, which states that a gene controls the metabolic machinery of the…
Correct answer: Beadle and Tatum- A. rRNA
- B. tRNA
- C. mRNA
- D. cDNA
Explanation: Messenger RNA or mRNA has been named so because it carries the coded information from DNA for the synthesis of proteins.
Correct answer: mRNA- A. Only on the ribosomes present in cytoplasm
- B. Only on the ribosomes attached to the nuclear envelope and endoplasmic reticulum
- C. On the ribosomes present in the nucleolus as well as the cytoplasm
- D. On ribosomes present in the cytoplasm as well as mitochondria
Explanation: Protein synthesis is the process by which an mRNA is read by ribosomes to synthesise a polymer of amino acids known as a protein.
Correct answer: On ribosomes present in the cytoplasm as well as mitochondria- A. DNA polymerase
- B. RNA polymerase
- C. Reverse transcriptase
- D. DNA dependant RNA polymerase
Explanation: The answer to this question is reverse transcriptase. Reverse transcriptase is an enzyme that uses an RNA template to synthesise DNA.
Correct answer: Reverse transcriptase- A. Lipase
- B. Protease
- C. Endonuclease
- D. Exonuclease
Explanation: The answer is endonuclease. Endonucleases are enzymes that hydrolyze internal phosphodiester bonds in a polynucleotide chain.
Correct answer: Endonuclease- A. AAAT box
- B. TATA box
- C. GGTT box
- D. CAAT box
Explanation: The DNA sequence that holoenzyme RNA polymerase binds to during transcription, and the DNA assumes a saddle-like structure at that point…
Correct answer: TATA box- A. Protein structure
- B. DNA replication
- C. Protein synthesis pattern
- D. RNA transcription pattern
Explanation: After a mutation at a genetic locus, the character of an organism changes due to a change in protein structure.
Correct answer: Protein structure- A. rRNA
- B. hnRNA
- C. mRNA
- D. tRNA
Explanation: The form of RNA that has a structure resembling the cloverleaf is tRNA (transfer RNA).
Correct answer: tRNA- A. TATGC
- B. TCTGG
- C. UAUGC
- D. UATGC
Explanation: During transcription, the nucleotide sequence of the mRNA is complementary to the nucleotide sequence of the DNA template strand, with the…
Correct answer: UAUGC- A. Frame shift mutation
- B. Transcription
- C. Transition
- D. Transversion
Explanation: When adenine replaces guanine because of a mutation, it is called a transition.
Correct answer: Transition- A. A + G / C + T
- B. T + C / G + A
- C. G + C / A + T
- D. A + C / T + G
Explanation: According to Chargaff's rules:A = T and G = CThe GC content (G + C) and AT content (A + T) vary between species but are constant within a…
Correct answer: G + C / A + T- A. Lactose
- B. Lactase
- C. Lac insect
- D. The number 1,00,000
Explanation: In the lac operon, lac refers to lactose. The lac operator is a part of the structural genes (lac Z, lac Y, lac A, and lac I).
Correct answer: Lactose- A. UCG - start
- B. UUU - stop
- C. UGU - leucine
- D. UAC - tyrosine
Explanation: Codon UAC is correctly matched as it codes for the amino acid tyrosine.
Correct answer: UAC - tyrosine- A. Promoter
- B. Regulator
- C. Receptor
- D. Enhancer
Explanation: The DNA site at which RNA polymerase binds during transcription is called the promoter.
Correct answer: Promoter