2.2 Cell Cycle (Mitosis and Protein Synthesis)

Question 1

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 1

Answer is A: Chromatin is DNA and the associated proteins so it pertains to genetic material.

Question 2

2. In protein synthesis, where does translation occur? In the:
   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 2

Answer is A: Translation occurs in the cytoplasm (transcription occurs in the nucleus). DNA does not exist in the cytoplasm.

Question 3

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 3

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.

Question 4

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 4

Answer is C: DNA is double-stranded, while the “D” refers to “deoxy-”.

Question 5

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 5

Answer is D: Remember the metaphase plate occupies the middle of the cell.

Question 6

6. In a cell cycle, which phase takes the longest time to complete?
   A. Anaphase
   B. Interphase
   C. Prophase
   D. Telophase

Answer 6

Answer is B: Interphase is the time when the cell is performing its normal function and not dividing.

Question 7

7. What is the purpose of meiosis? To produce:
   A. DNA
   B. Somatic cells
   C. Diploid cells
   D. Haploid cells

Answer 7

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.

Question 8

8. What results from the events that occur during 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 8

Answer is B: During metaphase, chromosomes are arranged on a plane (the meta- phase plate) in the middle of the cell, attached to microtubules of the spindle.

Question 9

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 9

Answer is C: Mitosis involves somatic cells. Meiosis refers to the production of the sex cells.

Question 10

10. In a strand of DNA, what is the combination of deoxyribose and phosphate and base known as?
    A. A ribosome
    B. A chromatid
    C. A codon
    D. A nucleotide

Answer 10

Answer is D: Three nucleotides form a codon, and many codons form a chromatid.

Question 11

11. What happens during anaphase of mitosis?
    A. Spindle fibres pull each chromatid to opposite sides of the cell.
    B. The sense and nonsense 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 11

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.

Question 12

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 12

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.

Question 13

13. How many nucleotides are required to code for a single amino acid?
    A. Twenty
    B. Five
    C. Three
    D. One

Answer 13

Answer is C: A sequence of three nucleotides constitutes a codon. Each codon is specific for one of the 20 amino acids.

Question 14

14. The combination of a 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 14

Answer is D: A nucleoside is a nucleotide without a phosphate group.

Question 15

15. The nucleus of the cell contains the master nucleic acid:
    A. DNA
    B. RNA
    C. mRNA
    D. tRNA

Answer 15

Answer is A: DNA exists in the nucleus. The other three are ribonucleic acids.

Question 16

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 16

Answer is D: DNA has the sugar deoxyribose; proline is an amino acid that does not occur in DNA.

Question 17

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 17

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.

Question 18

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 18

Answer is A: A pairs with T, while C pairs with G.

Question 19

19. The combination of a sugar and a base is given the general term of:
    A. Nucleoside
    B. Amino acid
    C. Polypeptide
    D. Nucleotide

Answer 19

Answer is A: A nucleotide is formed from a nucleoside and a phosphate group.

Question 20

20. The nucleic acid which carries the information for protein synthesis from the cell nucleus to the ribosomes is:
    A. DNA
    B. RNA
    C. mRNA
    D. tRNA

Answer 20

Answer is C: “Messenger” RNA carries the data (the message) from the chromo- somes in the nucleus to the ribosomes in the cytoplasm.

Question 21

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 21

Answer is A: RNA must have the sugar ribose. Thymine exists in DNA but not RNA, where it is replaced with uracil.

Question 22

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 22

Answer is B: Transcription refers to the conversion of information on DNA into the form of mRNA.

Question 23

23. Which statement is true of the 23 chromosomes within a sperm?

A. 23 chromosomes is the diploid number.
B. 11 chromosomes came from the father, 11 chromosomes came from the mother, while one of either the Y or the X came from the father or mother, respectively.
C. Some of the 23 came from the father, and the rest came from the mother.
D. 11 chromosomes and the Y came from the father, while 11 chromosomes came from the mother.

Answer 23

Answer is C: A sperm has 23 chromosomes which is the haploid number. The male that produced the sperm has 46 chromosomes (23 pairs) in their somatic cells – 23 each from the man’s father and mother. When sperm are produced, the 46 chromosome assemble and pair up. The man’s X and Y chromosomes pair up. Each pair of chromosomes then separates so that only one of each pair moves into a new sperm. Which one of the pair ends up in which sperm is a random process. It is possible that an individual sperm has any number of chromosomes between 0 and 23 that originated from the father.