BIOL 182: Biology II Assignment 3 - Cell Division, Genetics and Molecular Biology
BIOL 182: Biology II Assignment 3 - Cell Division, Genetics and Molecular Biology
BIOL 182: Biology II Assignment 3 - Cell Division, Genetics and Molecular Biology
Name: _______________
ID Number: _______________
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Section I – Cell Division, Genetics and Molecular Biology (29 marks)
1. Describe the process of protein synthesis. You answer must include the two major steps,
all major enzymes and molecules involved, where each step occurs in the cell and a
summary of what happens in each step. (4 marks)
Protein is synthesized through transcription and translation. Transcription occurs in
the nucleus and this is the process of copying DNA of a gene into mRNA. The DNA unwinds
and RNA polymerase copies base sequence in RNA nucleotides. The RNA primary transcript,
which contains exons and introns is ‘edited’ and introns are cut out and produce the final
mRNA. The second step translation occurs in the cytoplasm. An initiator tRNA which carries
methionine, binds to the ribosome unit and to the start codon of mRNA and the larger
ribosome joins. Then tRNA brings specific amino acids to the protein chain and it elongates
one amino acid at a time. Once a stop codon is reached the protein is release from the
ribosome.
2. Compare and contrast mitosis and meiosis by filling in the table: (5 marks)
Mitosis Meiosis
Type of cells in which this Somatic Germ
process occurs
Number of daughter cells 2 4
produced
Are daughter cells diploid or diploid haploid
haploid?
Number of cell divisions that 1 2
occur
Does crossing over occur? No Yes, in prophase 1
And if so, at what stage?
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4. Explain what the term “nondisjunction” means and provide the names of two diseases
caused by nondisjunction. (2 marks)
Nondisjunction is a homologous chromosome fails to separate during meiosis
this will result in one daughter cell with too many chromosomes and the other with less.
Two diseases this is caused by is trisomy and monosomy.
5. A unique type of fox was discovered. It has a very shiny grey coat. In an attempt to
figure out how this trait is inherited, a series of grey fox matings were analyzed. The
resulting offspring were:
75 grey foxes
39 white foxes
37 black foxes
a) What is the mode of inheritance of coat coloration among these foxes? Explain how
you determined your answer. (2 marks)
Incomplete dominance because the expression of the alleles in the heterozygote
produces an intermediate phenotype.
b) Draw a Punnett square for these crosses (between grey foxes) and indicate the
genotypic and phenotypic percentages of the offspring. (2 marks)
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6. In house cats, the polydactyl trait (more than five digits on paws) is dominant to having
five digits (recessive trait). A five-digit female cat was mated to a male of unknown
genotype/phenotype. They had nine offspring; five of the offspring were polydactyl,
while the other four had five digits.
a. From the information above, clearly indicate what the genotypes of each of the
parents are. (2 marks)
The genotype of the female is ff and the male is Pf
b. Draw a Punnett square for this cross and indicate the genotypic and phenotypic
percentages of the offspring. (2 marks)
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c. If
two
of
the
polydactyl F1 offspring were crossed, what would be the expected genotypic and
phenotypic percentages of this F2 generation of offspring? Draw the Punnett
square for this mating. (3 marks)
a. During the diploid generation, the body consists of diploid cells called the germ
cells (1 mark)
b. Is the dominant stage in the life cycle of a fern haploid or diploid? (1 mark)
Diploid
d. In the life cycle of a fern, are spores haploid or diploid? Are spores produced by
mitosis or meiosis? (2 marks)
Spores are haploid and are produced by meiosis
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Section II – Virtual Lab Component (6 marks)
Using the DNA sequence provided, determine the corresponding mRNA sequence, the amino
acid sequence of the protein, and tRNA anti-codons.
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Partially developed from the Biology Life on Earth 9th Edition and Companion Website (Instructor Resources)
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