Cell Cycle (Mitosis and Protein Synthesis)
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1. The term “chromatin” would be used in reference to which of the following?
A. Genetic substance
B. Cellular energy
C. Membrane support
D. Nuclear membrane
Answer is A: Chromatin is DNA and the associated proteins so pertains to genetic material.
2. In protein synthesis, where does translation occur?
A. Cytoplasm between ribosomes, tRNA and mRNA
B. Nucleus between ribosomes, tRNA and mRNA
C. Nucleus between DNA and mRNA
D. Cytoplasm between DNA and mRNA
Answer is A: Translation occurs in the cytoplasm (transcription occurs in the nucleus). DNA does not exist in the cytoplasm.
3. If the DNA strand sequence of bases is CTT AGA CTA ATA, what would the tRNA read?
A. GAA TCT GAT TAT
B. CUU AGA CUA AUA
C. GAA UCU GAU UAU
D. GUU ACA GUA AUA
Answer is C: Guanine (G) must be matched to cytosine (C) and vice versa. Adenine
(A) must match with thymine (T). In RNA, uracil (U) replaces thymine; hence, U must be matched to A.
4. Which one of the following statements best describes DNA?
A. Single-stranded, deoxyribonucleic acid
B. Single-stranded, ribonucleic acid
C. Double-stranded, deoxyribonucleic acid
D. Double-stranded, ribonucleic acid
Answer is C: DNA is double-stranded, while the “D” refers to “deoxy-”.
5. In which phase of mitosis would chromosomes line up at the centre of the spindle?
A. Anaphase
B. Interphase
C. Prophase
D. Metaphase
Answer is D: Remember the metaphase plate occupies the middle of the cell.
6. In a cell cycle, which phase takes the longest time to complete?
A. Anaphase
B. Interphase
C. Prophase
D. Telophase
Answer is B: Interphase is the time when the cell is performing its normal function and not dividing.
7. What is the purpose of meiosis? To produce:
A. DNA
B. Somatic cells
C. Diploid cells
D. Haploid cells
Answer is D: Meiosis produces sperm or egg, so these must have half the complement of chromosomes (be haploid) to allow for the full complement to be present (and not more!) when sperm combines with egg.
8. What results from the events that occur during the metaphase of mitosis?
A. The nuclear membranes form around two nuclei.
B. The chromosomes are aligned on a plane in the centre of the cell.
C. The chromosomes become visible and attach to the spindle fibres.
D. The chromatids from each chromosome separate and move to opposite sides of the cell.
Answer is B: During metaphase, chromosomes are arranged on a plane (the metaphase plate) in the middle of the cell, attached to microtubules of the spindle.
9. What is the name of the process of division of a somatic cell’s nucleus into two daughter nuclei?
A. Prophase
B. Cytokinesis
C. Mitosis
D. Meiosis
Answer is C: Mitosis involves somatic cells. Meiosis refers to the production of the sex cells.
10. In a strand of DNA, what is the combination of deoxyribose and phosphate and base is known as?
A. A ribosome
B. A chromatid
C. A codon
D. A nucleotide
Answer is D: Three nucleotides form a codon, and many codons form a chromatid.
11. What happens during the anaphase of mitosis?
A. Spindle fibres pull each chromatid to opposite sides of the cell.
B. The sense and non-sense strands “unzip” along their hydrogen bonds.
C. RNA polymerase forms a complementary strand by reading the sense strand.
D. The cell cytoplasm divides into two cells.
Answer is A: Separation of the two chromatids of a chromosome occurs at anaphase.
Choice D is cytokinesis and begins in late anaphase and continues into telophase.
12. The process by which information is read from DNA, encoded and transported outside the nucleus is known as:
A. Translation
B. Transcription
C. Encoding
D. Catalysis
Answer is B: To “transcribe” is to record the information from a source and to
record it at another place (onto mRNA). Then messenger RNA moves out of the nucleus.
13. How many nucleotides are required to code for a single amino acid?
A. Twenty
B. Five
C. Three
D. One
Answer is C: A sequence of three nucleotides constitutes a codon. Each codon is specific for one of the 20 amino acids.
14. The combination of sugar, a base and at least one phosphate group is given the general term of:
A. Nucleoside
B. Amino acid
C. Polypeptide
D. Nucleotide
Answer is D: A nucleoside is a nucleotide without a phosphate group.
15. The nucleus of the cell contains the master nucleic acid:
A. DNA
B. RNA
C. mRNA
D. tRNA
Answer is A: DNA exists in the nucleus. The other three are ribonucleic acids.
16. Which of the following is the correct combination of the components for the nucleic acid DNA?
A. Phosphate, ribose, uracil
B. Phosphate, deoxyribose, proline
C. Phosphate, ribose, thymine
D. Phosphate, deoxyribose, adenine
Answer is D: DNA has the sugar deoxyribose, and proline is an amino acid that does not occur in DNA.
17. In the ribosome of a cell, the mRNA is read to produce the particular amino acid sequence for the formation of a protein. What is this process called?
A. Translation
B. Transcription
C. Transportation
D. Transmutation
Answer is A: Translation occurs in the cytoplasm of a cell with a ribosome. It is when the information in mRNA is read to produce the sequence of amino acids needed to form a protein.
18. Which of the base pairings in DNA would be correct?
A. A–T pair
B. A–G pair
C. C–T pair
D. C–A pair
Answer is A: A pairs with T, while C pairs with G.
19. The combination of sugar and a base is given the general term of:
A. Nucleoside
B. Amino acid
C. Polypeptide
D. Nucleotide
Answer is A: A nucleotide is formed from a nucleoside and a phosphate group.
20. The nucleic acid carries the information for protein synthesis from the cell nucleus to the ribosomes is:
A. DNA
B. RNA
C. mRNA
D. tRNA
Answer is C: “Messenger” RNA carries the data (the message) from the chromosomes in the nucleus to the ribosomes in the cytoplasm.
21. Which of the following is the correct combination of the components for the nucleic acid RNA?
A. Phosphate, ribose, uracil
B. Phosphate, deoxyribose, proline
C. Phosphate, ribose, thymine
D. Phosphate, deoxyribose, adenine
Answer is A: RNA must have the sugar ribose. Thymine exists in DNA but not RNA, where it is replaced with uracil.
22. In the nucleus of the cell, DNA is used as a template to form mRNA. What is the process called?
A. Translation
B. Transcription
C. Transportation
D. Transmutation
Answer is B: Transcription refers to the conversion of information on DNA into the form of mRNA.
23. Which of the following describes the translation step of protein synthesis?
A. DNA unwinds to expose the “sense” strand.
B. mRNA reads the sense strand.
C. Amino acids are split from tRNA and join to make the protein.
D. Amino acids are split form mRNA and join to form the protein.
Answer is C: The tRNA molecule carries an amino acid to the mRNA molecule. As each amino acid splits from its transfer RNA molecule, the amino acids assemble to form the protein. Choice B describes transcription.
24. Which statement about the triplets of bases on a nucleic acid is correct?
A. A gene is a triplet found on DNA.
B. A codon is a triplet found of DNA.
C. An anticodon is a triplet found on mRNA.
D. A codon is a triplet found on tRNA.
Answer is B: A triplet of three consecutive bases along a strand of DNA is called a codon. An anticodon is a triplet found on the anti-sense strand of DNA (and on tRNA). The three bases on mRNA are also called a codon but with the U in DNA replaced with T in RNA.
25. If the following code “GTA CGT GAG AAG CAG” is found on the DNA sense strand, what is found on the DNA anti-sense strand?
A. GTA CGT GAG AAG CAG
B. CAT GCA CTC TTC GTC
C. CAU GCA CUC UUC GUC
D. GUA CGU GAG AAG CAG
Answer is B: Looking at the first codon, G binds to C so either choice B or C is correct. T binds to A and A binds to T, so the anticodon we are looking for is CAT, hence choice B. (The amino acid sequence is: valine, arginine, glutamic acid, lysine, and glutamine.)
26. From the DNA codon sequence of question 25 above, what would be the sequence of the tRNA?
A. GTA CGT GAG AAG CAG
B. CAT GCA CTC TTC GTC
C. CAU GCA CUC UUC GUC
D. GUA CGU GAG AAG CAG
Answer is D: As we are now focussing on RNA, the T is replaced with U, which
eliminates choices A and B. mRNA TRANSCRIBES the DNA so where G and T
appears on DNA, C and A (respectively) will appear on RNA and where C and A
appear on the DNA, G and U will be on the RNA. Hence, GTA will be CAU on
RNA so choice C is how the mRNA will appear. The tRNA TRANSLATES so is
complementary to the mRNA and will be GUA.
27. What is the sequence of amino acids corresponding to the following codon
sequence “GTA CGT GAG AAG CAG”?
A. his, ala, phe, val
B. thr, arg, phe, cys
C. val, arg, glu, lys, gln
D. ser, thr, arg, lys, thr
Answer is C: By consulting a DNA codon chart: GTA = valine; CGT = arginine; GAG = glutamic acid; AAG = lysine; GAG = glutamine.
28. During which phase of the cell cycle does DNA replication occur?
A. G1 stage
B. G2 stage
C. S phase
D. The resting phase
Answer is C: The cell cycle passes through phases G0, G1, S, G2, and mitosis. S for the synthesis phase is when DNA replicates. At this stage, chromosomes that consist of one chromatid become two chromatids.
29. Which of the following events occur in the stated phase of mitosis?
A. Chromosomes shorten and thicken in interphase.
B. Chromosomes line up at the cell equator at prophase.
C. Chromosomes split into single chromatids at anaphase.
D. Chromatin material duplicates a second chromatid at telophase.
Answer is C: This ensures that each daughter cell has one chromatid of each chromosome. Shortening and thickening happen in early prophase; assembling at the equator (metaphase plate) happens in metaphase; the cell begins to cleave at interphase which is the end of mitosis; chromosome duplication occurs if the S phase of interphase, not during mitosis.
30. What is the end result of meiosis?
A. Two haploid cells
B. Two diploid cells
C. Four diploid cells
D. Four haploid cells
Answer is D: Meiosis prepares the sex cells which must have half the number of chromosomes of somatic cells so that when the sperm fuses with the egg, the correct (diploid) number is present. In humans, meiosis results in four haploid sperm cells and one oocyte, with three polar bodies.
31. Which of the following is NOT found in DNA?
A. Thymine
B. A double helix
C. Phosphate
D. Ribose
Answer is D: Deoxyribose (not ribose) is found in DNA. Ribose sugar is found in RNA (ribonucleic acid).