BIOLOGY
100 EXAM KEY
(EXAM II)
- DNA replication is completed by the end of:
S phase
- Which of the following (phases of mitosis) are arranged in the correct order?
Prophase ŕ metaphase ŕ anaphase ŕ cytokinesis
- During which phase are cellular organelles replicated?
G1
- When two chromosomes resemble each other in size, shape and the kinds of hereditary information carried, they are said to be:
Homologous
5. Alternative forms of the same genes are known as:
Alleles
6. In anaphase I of mitosis, _____________ are separated; in anaphase II of meiosis, ______________ are separated.
My apologies! I meant to write: In anaphase I of meiosis (Not Mitosis!!!)…..There is no correct answer listed for the way the question is written, therefore everyone will receive credit for this question.
7. What type of information can be obtained from a human karyotype?
A & B
8. At the completion of meiosis, each new nucleus has received:
One member of each pair of homologous chromosomes
9. After telophase I of meiosis, what is the chromosomal makeup of each daughter cell?
Haploid, and the chromosomes are composed of two chromatids
10. What proportion of the sperm cells of a human male carry an X chromosome?
50%
11. Each sperm cell of a horse contains 32 chromosomes. How many chromosomes are in each of the horse’s somatic cells?
64
12. Consider a cell that has 20 homologous pairs of chromosomes and is just starting to go through meiosis. After meiosis is complete, there will be ____________cells that each contain a total of ____________ chromosomes.
4; 20
13. Shown above are two cells, each containing 2 pairs of homologous chromosomes (homologs are identifiable here by size). Both cells are shown at metaphase, but Cell A is undergoing ____________ while Cell B is undergoing __________________.
Mitosis; meiosis
14. Refer to the diagram above. Which of the following statements is true?
Both Cell A and Cell B are diploid
15. Gregor Mendel used __________to model patterns of inheritance.
Garden peas
16. A man and a woman both show the normal phenotype for pigmentation but both have one parent who is albino. Albinism is an autosomal recessive trait. What is the probability that their first child will be an albino?
25%
17. The Law of Independent Assortment assumes that:
Genes separate independently during gamete formation
18. A testcross is a mating of an individual expressing a dominant phenotype (genotype unknown) with:
A homozygous recessive individual
19. A cross between a white seeded plant and a black seeded plant produces offspring that all bear grey seeds. Upon crossing the F1 generation, you observe black, white and grey seeded offspring (F2). You conclude that you are observing:
Incomplete dominance between the white and black alleles
20. In pea plants, yellow color (Y) is dominant to green (y) and smooth (S) is dominant to wrinkled (s). Determine the parental genotypes given the information below.
Parental
Phenotype Offspring
Phenotype_____________
Yellow/Smooth x
Green/Wrinkled Yellow Yellow Green Green
Smooth Wrinkled Smooth Wrinkled 4 4 4 4
YySs x yyss
21. In mice, the dominant allele C must be present for brown hair. White hair is produced by the recessive allele c. A brown mouse is crossed with a white mouse. Half the offspring are brown and half are white. What is the genotype of the brown (parent) mouse?
Cc
22. Hemophilia is an X-linked recessive disease that involves failure of the blood to clot normally. What are the chances that the daughter of a normal man and a heterozygous woman will have hemophilia?
zero
23. Five genes are located on one chromosome in the order A, B, C, D, and E. Assume there is identical map distances between neighboring genes. Crossover is least likely to occur between:
A and B
24. The crossover frequency between genes 1 and 2 is 20%, between 2 and 3 is 20%, between 3 and 4 is 10%, and between 4 and 1 is 30%. What is the sequence of these genes on the chromosome?
1,2,4,3
25. There is a mix-up of babies at the University of Maryland’s hospital maternity ward.
Mr. Smith Type A Baby 1 Type O
Mrs. Smith Type A Baby 2 Type B
Mr. Jones Type AB Baby 3 Type A
Mrs. Jones Type A Baby
4 Type AB
Which of the following is possible with regards to the babies and parents?
Baby 1 belongs to the Smiths
26. Huntington disease is a dominant autosomal disease. Unfortunately, the onset of symptoms usually occurs after a person has reproduced. What are the chances that a heterozygous person with the disease will produce a child with the disease if he mates with a normal homozygous person?
50%
27. Which of the following is true for an X chromosome sex-linked trait?
All the above are correct
28. Muscular dystrophy is a sex-linked recessive trait. A normal man marries a woman who is a carrier for muscular dystrophy. What percentage of their male offspring will develop hemophilia?
50%
29. Using Neurospora (bread mold), Beadle and Tatum were able to propose that:
The role of a gene is to produce a specific enzyme
30. The direction of transfer of genetic information (The Central Dogma) in most living organisms is:
DNA ŕ RNA ŕ protein
31. Which of the following is FALSE with regards to DNA synthesis?
RNA polymerase is responsible for catalyzing the synthesis of DNA
32. In the DNA triplet code, which of the following is true?
Each amino acid in a protein is coded for by three bases in DNA
33. A protein is 300 amino acids long. Which of the following could be the number of nucleotides in the DNA that codes for the protein?
900
34. A gene is best defined as:
A sequence of DNA nucleotides that codes for a protein
35. RNA contains ______________whereas DNA contains __________________.
Uracil; thymine
36. How many amino acids would be coded for by this sequence?
-ACUACCGGCCCCCGG-
5
37. Which of the following is FALSE with regards to the experiments conducted by Hershey & Chase on bacteriophage?
The biochemical basis of hereditary diseases was uncovered
38. Regarding the genetic code:
Multiple codons may code for the same amino acid
39. What is the initiator triplet in both prokaryotes and eukaryotes? What amino acid corresponds to this codon?
AUG, methionine
40. The process of DNA replication is said to be ______________because each new molecule of DNA consists of one old and one new strand.
Semiconservative
41. In prokaryotes, mismatched bases are recognized and removed by way of repair enzymes. These enzymes remove and replace mismatched bases from:
Unmethylated strands of DNA only
42. Pyrimidine dimer formation, such as the thymine-thymine dimer discussed in class, usually occurs in DNA after exposure to:
UV radiation
43. At the replication fork, new DNA is synthesized on both strands of the parent DNA molecule. How is the replication processes on the two strands different?
On one strand, DNA is replicated continuously whereas the other DNA is replicated discontinuously
44. A chemical change to one or a few base pairs in a sequence of DNA is called:
Point mutation
45. __________________is the enzyme responsible for repairing the gaps between Okazaki fragments and _______________is the enzyme responsible for opening (unwinding) DNA at the replication fork.
Ligase; helicase
46. Which of the following does not occur after eukaryotic transcription?
Splicing out exons
1.
DNA RNA Protein
2. 3.
47. The figure above describes the central dogma of molecular biology as described in class. The three numbered arrows represent three major processes. The arrows represent:
1= replication;
2=transcription; 3=translation
48. The process of transcription and translation can occur simultaneously in a bacterial cell.
True
49. During the process of acylation (i.e. “charging”), a(n) _____________ is attached to a(n) ____________ molecule.
amino acid; tRNA
50. Which types of bonds are formed during translation?
Hydrogen bonds between the codon and anticodon regions and peptide bonds between amino acids