11 Jun Biology 204 Principles of Biology -I Assignment 2A
Question
Biology 204
Principles of Biology I
Assignment 2A
For students with first names starting with the letters A to G.
This assignment is graded out of 110 points, and is worth 10% of your
final mark. Please submit this assignment after you have completed
Chapter 16 and before you write the final exam. A. Definition/Comparison Questions
Instructions: In your own words, define the pairs of terms given below.
Write in complete sentences, stating the differences and relationships
between the two terms, and give specific examples where appropriate. A
complete answer usually requires four to eight sentences.
Each question is worth four marks, for a total of 40 marks.
1. histones / chromatin
2. linkage / independent assortment
3. autosomes / Y chromosome
4. phosphodiester linkage / double helix
5. adenine / thymine
6. exons / pre-mRNA
7. PCR / cloning
8. Posttranscriptional regulation / translational regulation (re:
eukaryotes)
9. tRNA / rRNA
10. lysogenic cycle / lytic cycle Principles of Biology I 1 B. Short Answer/Short Essay Questions
Instructions: Answer each of the questions given below in your own
words. Write in complete sentences where appropriate. A complete
answer usually requires one to two sentences per mark, so a three-mark
question would be answered in three to six sentences. This section is
worth a total of 40 marks.
(7 marks) 1. Describe the major phases of the cell cycle in a typical eukaryote. (2 marks) 2. Which major event during meiosis is most likely to produce
deviations from Mendel’s laws? (6 marks) 3. Explain, with examples, the concept of jumping genes in prokaryotes. (5 marks) 4. Explain the variation of blood types in humans. (2 marks) 5. Compare prokaryotes and eukaryotes with regard to DNA that is
NOT part of the nucleus/nucleoid. (4 marks) 6. Explain what it means that the genetic code is “universal” and
“degenerate.” (6 marks) 7. Using the following DNA template strand sequence, answer the
questions that follow:
3?–TACCAGCATGACTAA–5?
a. What is the complementary DNA sequence?
b. What is the final sequence of amino acids in the peptide
produced?
c. If the sequence is mutated so that an adenine is inserted before
position 11, how will the peptide be affected? What kind of a
mutation is this? (8 marks) 2 8. In fruit flies, grey colour is dominant over black colour and normal
sized wings are dominant over vestigial wings. Suppose a true
breeding line of grey fruit flies with vestigial wings is mated with a
true breeding line of black fruit flies with normal wings. The F 1
generation is then crossed. Draw a Punnett square to show the
genotypes of the F 2 generation, and give the phenotypic ratio for the
F 2 generation. Biology 204 C. Multiple Choice Questions
Instructions: Select the single best answer to each of the questions given
below. Each question is worth one mark, for a total of 30 marks.
1. Breeding a yellow dog with a brown dog produced puppies with
yellow and brown hairs intermixed. This is an example of
a. pleiotropy.
b. codominance.
c. incomplete dominance.
d. epistasis.
e. a polygenic trait.
2. Chromosomes of eukaryotes consist of
a. DNA only.
b. DNA and RNA.
c. DNA and proteins.
d. RNA only.
e. proteins, DNA, and RNA.
3. Tay-Sachs disease is a(n) ________ disease that results in blindness,
mental retardation, and death due to ________.
a. sex-linked; the absence of one of the sex chromosomes
b. autosomal recessive; the accumulation of lipids in brain cells
c. X-linked; the accumulation of lipase in the cells of sweat glands
d. autosomal; the inability to break down amylase in the intestines
e. autosomal dominant; accumulation of mucus in the lungs
4. Genes that tend to be inherited together are said to be
a. associated.
b. related.
c. similar.
d. linked.
e. alleles. Principles of Biology I 3 5. The mitotic spindle is made of
a. collagen.
b. condensin.
c. histones.
d. keratin.
e. microtubules.
6. If meiosis did not occur in sexually reproducing organisms, then
a. growth of the zygote would be halted.
b. mitosis would be sufficient.
c. gametes would remain haploid.
d. chromosome number would double in each generation.
e. eggs would be haploid, but sperm would be diploid.
7. A Barr body in a mammalian female cell is
a. an inactivated oocyte.
b. a polar body.
c. a degenerate nucleus.
d. an inactivated X chromosome.
e. an inactivated Y chromosome.
8. After the S phase of mitosis, a replicated chromosome consists of
a. a chromosome tetrad. b. four sister chromatids.
c. two sister chromatids.
d. four homologous chromosomes.
e. two homologous chromosomes.
9. Which of the following cause the unwinding of the DNA double
helix?
a. DNA polymerase
b. DNA helicase
c. RNA primer
d. primosome
e. RNA polymerase 4 Biology 204 10. Restriction enzymes have the following properties:
a. they produce sticky ends on DNA fragments.
b. they help DNA to replicate.
c. they are involved in translation.
d. they are found in most eukaryotes.
e. all of the above.
11. Which of the following diseases (left) does NOT match its descriptors
(right)?
a. sickle cell anemia: abnormal RBC; tissue damage due to a lack of
oxygen; autosomal recessive trait
b. Tay-Sachs disease: blindness; membrane lipids accumulate in
lysosomes; autosomal recessive trait
c. Huntington’s disease: muscle spasms; develops late in life;
autosomal recessive trait
d. hemophilia A: internal bleeding; affects mostly males; X-linked
recessive trait
e. cystic fibrosis: lung disease; defective membrane protein;
autosomal recessive trait
12. Most human somatic cells are
a. polyploid.
b. diploid.
c. aneuploid.
d. tetraploid.
e. haploid.
13. The presence of detectable variation in the genomes of different
individuals of a population is termed
a. DNA sequencing.
b. DNA electrophoresis.
c. DNA tandem repeats.
d. polymorphism.
e. DNA profiling. Principles of Biology I 5 14. The lactose repressor blocks transcription of the lactose operon by
a. “turning off” the appropriate genes in the intron. b. regulating the activity of the enzymes that the operon codes for.
c. binding allosterically to the appropriate genes. d. slowing the uptake of lactose into the cell.
e. binding to the operator. 15. In producing a genomic library, human DNA and plasmid DNA must
first be treated with
a. the same restriction enzyme.
b. different restriction enzymes.
c. the same DNA ligase.
d. different DNA ligases.
e. none of the above.
16. Autosomal aneuploidies arise by
a. chromosome breakage and rejoining.
b. nondisjunction.
c. errors in crossing-over.
d. mistakes in chromosome replication.
e. single-gene mutations.
17. The primer that is used during DNA replication
a. is called an Okazaki fragment.
b. is used only once on the lagging strand.
c. is a short RNA strand that is added to the 3’ end.
d. is used once on the leading strand.
e. all of the above apply 18. The 3’ end of a eukaryotic pre-mRNA is changed by
a. removing the last phosphate group.
b. adding a “cap.”
c. copying the last few bases so that it can form a duplex structure.
d. cutting and adding 100-250 adenine nucleotides.
e. phosphorylation of the mRNA molecule. 6 Biology 204 19. Nucleosomes
a. are groups of ribosomes.
b. play a role in translation.
c. are groups of chromosomes. d. are histones surrounded by DNA.
e. contain RNA.
20. An egg cell of a human was found to contain 22 chromosomes. From
this information, you can conclude that
a. it is a normal egg cell.
b. non-disjunction occurred during mitosis.
c. non-disjunction occurred during meiosis.
d. egg cells commonly have unusual chromosome numbers.
e. the cell was diploid.
21. ________ are alternative forms of a gene that govern the same
feature, such as flower colour, and occupy corresponding positions
on homologous chromosomes.
a. Alleles
b. Loci
c. Homozygotes
d. Coupled traits
e. None of these
22. Epistasis means that
a. gene frequency will not change.
b. there are no mutations.
c. a particular gene has more than two alleles.
d. a gene may influence the effect of another gene.
e. linked genes have no effect on a particular phenotype. Principles of Biology I 7 23. Eukaryotic chromosomes consist of
a. circular DNA molecules complexed with positively-charged
nonhistone proteins.
b. circular DNA molecules complexed with negatively-charged
histone proteins.
c. linear DNA molecules complexed with positively-charged histone
proteins.
d. linear DNA molecules complexed with negatively-charged histone
proteins.
e. circular DNA molecules.
24. In the tryptophan operon, the repressor actively binds to the operator
when
a. tryptophan binds to an allosteric site on the repressor.
b. tryptophan levels are low.
c. lactose levels are low.
d. there is a great need for proteins.
e. allotryptophan levels are low.
25. The probability of a couple having a child affected with an autosomal
recessive condition would be
a. 0.5, or 50%, if both parents were homozygous normal.
b. 0.5, or 50%, if both parents were heterozygous.
c. 0.25, or 25%, if both parents were homozygous normal.
d. 0.25, or 25%, if both parents were heterozygous.
e. 0%, if both parents were heterozygous.
26. A human female is homozygous for a particular allele. Which of the
following statements is NOT always true?
a. She can pass the allele to her offspring.
b. Her gametes have one copy of the allele.
c. She has two copies of the allele in her somatic cells.
d. She is true-breeding for that allele.
e. Both of her parents must have been homozygous for the allele. 8 Biology 204 27. RNA interference inhibits
a. translation in general. b. translation of specific mRNAs.
c. transcription of specific genes. d. DNA replication.
e. the operator of a gene.
28. Which of the following is FALSE about transposons?
a. They are mobile DNA segments that can insert into genetic
sequences and inactivate genes.
b. They can spontaneously turn genes on and off.
c. They are found only in bacteria.
d. They can cause frameshift mutations in the genetic code.
e. Some can replicate using reverse transcriptase.
29. ________ is a technique that can be used to separate DNA molecules
on the basis of their size.
a. Separation gradient
b. Electrophoresis
c. Selective sorting
d. Cloning
e. PCR
30. Which of the following nucleotide sequences represents the
complement to the DNA strand 5’–AGATCCG–3’?
a. 5’–AGATCCG–3’
b. 3’–AGATCCG–5’
c. 5’–CTCGAAT–3’
d. 3’–CTCGAAT–5’
e. 3’–TCTAGGC–5’
— End of Assignment 2A — Principles of Biology I 9
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