ANATOMY
CELL CYCLE
MITOSIS AND PROTEIN
SYNTHESIS
QUESTIONS AND ANSWERS
, CELL CYCLE {MITOSIS AND PROTEIN SYNTHESIS}
The cell nucleus contains chromosomes which are composed of molecules of DNA. DNA is composed of units called
nucleotides which consist of a sugar (deoxyribose) attached to a phosphoric acid group (PO 3O H) and one of four
bases. Chromosomes contain the code for the sequence of amino acids used to construct different proteins. Each amino
acid is coded for by a particular sequence of three of the four bases (adenine, guanine, cytosine & thymine). This
sequence is called a “codon”. mRNA “transcribes” this code then moves from the nucleus to a ribosome in the
cytoplasm where it is “translated” and the protein is assembled by joining the required amino acids in the appropriate
sequence.
M itosis is the process by which a somatic cell divides to produce two cells with identical DNA. In this way an
organism can grow. Before mitosis, the DNA must be duplicated. Hence the chromosomes (consisting of one strand
or “chromatid”) double up by becoming two chromatids. Then during mitosis the two chromatids separate and move
into the two daughter cells.
Meiosis occurs only in the gonads. This process results in four daughter cells. Human cells have two copies of each
of 23 chromosomes, one copy being inherited from the father and the other copy from the mother. The gametes need
to have only one copy of each of the 23 chromosomes, so that when the sperm fuses with the ovum, the “diploid”
number of 46 (two copies of each chromosome) is restored. Meiosis is the process by which cells reduce their number
of chromosomes from 46 to 23 different chromosomes. Of the 23 chromosomes in a sperm (or ovum), some (between
0 and 23) will have come from the sperm owner’s mother and the rest from the sperm owner’s father. The same can
be said of the 23 chromosomes in the ovum. In this way the resulting children will be genetically different from each
of their parents (and siblings) as each sperm/ovum will have a different assortment of the 23 available chromosomes.
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 & the associated proteins so pertains to genetic material.
2. In protein synthesis, where dose 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
A nswer is A: translation occurs in the cytoplasm (transcription occurs in the nucleus). DNA does not exist in the
cytoplasm.
3 . I f 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, while both bind to adenine. 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:
CELL CYCLE
MITOSIS AND PROTEIN
SYNTHESIS
QUESTIONS AND ANSWERS
, CELL CYCLE {MITOSIS AND PROTEIN SYNTHESIS}
The cell nucleus contains chromosomes which are composed of molecules of DNA. DNA is composed of units called
nucleotides which consist of a sugar (deoxyribose) attached to a phosphoric acid group (PO 3O H) and one of four
bases. Chromosomes contain the code for the sequence of amino acids used to construct different proteins. Each amino
acid is coded for by a particular sequence of three of the four bases (adenine, guanine, cytosine & thymine). This
sequence is called a “codon”. mRNA “transcribes” this code then moves from the nucleus to a ribosome in the
cytoplasm where it is “translated” and the protein is assembled by joining the required amino acids in the appropriate
sequence.
M itosis is the process by which a somatic cell divides to produce two cells with identical DNA. In this way an
organism can grow. Before mitosis, the DNA must be duplicated. Hence the chromosomes (consisting of one strand
or “chromatid”) double up by becoming two chromatids. Then during mitosis the two chromatids separate and move
into the two daughter cells.
Meiosis occurs only in the gonads. This process results in four daughter cells. Human cells have two copies of each
of 23 chromosomes, one copy being inherited from the father and the other copy from the mother. The gametes need
to have only one copy of each of the 23 chromosomes, so that when the sperm fuses with the ovum, the “diploid”
number of 46 (two copies of each chromosome) is restored. Meiosis is the process by which cells reduce their number
of chromosomes from 46 to 23 different chromosomes. Of the 23 chromosomes in a sperm (or ovum), some (between
0 and 23) will have come from the sperm owner’s mother and the rest from the sperm owner’s father. The same can
be said of the 23 chromosomes in the ovum. In this way the resulting children will be genetically different from each
of their parents (and siblings) as each sperm/ovum will have a different assortment of the 23 available chromosomes.
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 & the associated proteins so pertains to genetic material.
2. In protein synthesis, where dose 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
A nswer is A: translation occurs in the cytoplasm (transcription occurs in the nucleus). DNA does not exist in the
cytoplasm.
3 . I f 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, while both bind to adenine. 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:
