Free Cell Structure and Function MCQs with Answers
2,478 Cell Structure and Function MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Animal, plant, prokaryotic and eukaryotic cells are compared through their membranes, cell walls, nuclei and cytoplasmic organelles. The work includes the structures and functions of mitochondria, chloroplasts, ribosomes, endoplasmic reticulum, Golgi apparatus and lysosomes, as well as chromosome organization and the distinction between chromatin and chromosomes.
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Read the Cell Structure and Function notesFree MDCAT chapter notes with key terms2,478 questions · page 99 of 124
- A. Looping
- B. Inducing
- C. Slicing
- D. Splicing
Explanation: Introns, which mainly occur in eukaryotes, are transcribed into messenger RNA (mRNA) but are then removed from the transcript before…
Correct answer: Splicing- A. TTAGU
- B. UAGAC
- C. AACTG
- D. ATCGU
Explanation: In RNA, thymine is substituted with uracil; thus, the RNA strand complementary to the DNA strand ATCTG will be UAGAC.
Correct answer: UAGAC- A. Lysosomes
- B. Nucleolus
- C. Nucleoplasm
- D. Ribosomes
Explanation: The nucleolus is the centre for the synthesis of ribosomal RNA (rRNA) that forms ribosomal subunits.
Correct answer: Nucleolus- A. tRNA
- B. hnRNA
- C. mRNA
- D. rRNA
Explanation: In eukaryotes, RNA polymerase enzymes (Type I, II, III) catalyse the synthesis of RNA using as a template either an existing DNA strand or…
Correct answer: tRNA- A. Bacterium
- B. Fungus
- C. Viroid
- D. Bacterial virus
Explanation: Avery, MacLeod, and McCarty first established that DNA was the genetic material by working on the same bacteria as Griffith.
Correct answer: Bacterial virus- A. Pea
- B. Mucor
- C. Chlamydomonas
- D. HIV
Explanation: The oneway flow of information from DNA to mRNA and then to protein is known as the central dogma of molecular biology by F.H.C.
Correct answer: HIV- A. (ii) and (iii)
- B. (i) and (iii)
- C. (ii) and (iv)
- D. (i) and (ii)
Explanation: The two French scientists, Jacob and Monod, proposed the lac operon of E.coli.
Correct answer: (ii) and (iv)- A. Ribosomes
- B. Nucleus
- C. Dictyosomes
- D. Endoplasmic Reticulum
Explanation: Unlike in prokaryotes, where transcription and translation take place in the same compartment, in eukaryotes, the primary transcript is…
Correct answer: Nucleus1969. Whose experiments cracked the DNA and discovered unequivocally that the genetic code is a "triplet"?
- A. Hershey and Chase
- B. Morgan and Sturtevant
- C. Beadle and Tatum
- D. Nirenberg and Mathaei
Explanation: Marshall Nirenberg and J. Heinrich Matthaei were pioneering scientists who, in 1961, performed a landmark experiment that cracked the…
Correct answer: Nirenberg and Mathaei- 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 coli1971. Removal of introns and joining the exons in a defined order in a transcription unit is called:
- 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: Splicing1972. 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 transcriptase1980. Which one of the following hydrolyses internal phosphodiester bonds in a polynucleotide chain?
- 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