Name: __________________________

Bio 105 Exam 3 November 21, 2011

Mark your answers on the answer sheet provided. Turn in both this exam and your answer sheet. The answers to the exam will be posted on the course website later today and your score will be posted on Sakai once the exams are graded and scores entered.

1. Genetically identical cells are produced during cell division called:

a. Mitosis b. Meiosis c. DNA replication d. Fertilization

2. Gametes such as eggs and sperm are produced during cell division called:

a. Mitosis b. Meiosis c. DNA replication d. Fertilization

3. In mitosis __ new daughter cells are produced and in meiosis __ new daughter cells are produced.

a. 1 / 2 b. 2 /4 c. 4 / 2 d. 2 / 2

4. Which is true of homologous chromosomes?

a. They are similar in size and shape

b. One comes from one parent and the other from the other parent of an organism

c. They separate during the first cell division in meiosis

d. All of these

5. Humans have ___ homologous pairs of chromosomes.

a. 12 b. 23 c. 46 d. 92

6. In human males (but not females) ___ chromosomes do not have a match in the form of another chromosome of similar size and shape.

a. 7 b. 46 c. 23 d. 2

7. The largest scale or level at which genetic information is copied prior to cell division is:

a. Genes b. DNA c. Alleles d. Chromosomes

8. Hereditary units that code for synthesis of a particular protein are:

a. Genes b. DNA c. Traits d. Chromosomes

9. Identical genes contributed to an offspring from two parents are ____ alleles.

a. Homologous pairs c. Homozygous

b. Sister alleles d. Heterozygous

10. Different versions of a gene are referred to as:

a. Homologous pairs c. Sister chromatids

b. Alleles d. Homozygous

11. Rats have 60 chromosomes; therefore rat cells produced during meiosis will have ___ chromosomes.

a. 60 b. 30 c. 15 d. 120

12. The Austrian monk that pioneered the study of heredity through his work on inheritance in pea plants was:

a. Joseph Biden b. Charles Darwin c. Gregor Mendel d. Gregory Peck

13. The genotype of a pea plant that is homozygous recessive for two traits would be:

a. Tt b. YY c. TytY d. ttyy

14. The height that a pea plant attains is an example of its _____ for this particular trait:

a. Expression of both types of alleles in a population c. Genotype

b. Possession of only recessive homozygous alleles d. Phenotype

15. A pea plant with the genotype Tt can produce gametes containing:

a. TT, Tt or tt c. Only T

b. Either T or t d. Only Tt

16. A pea plant with the genotype TT is crossed with a plant with the genotype tt. The possible genotypes of offspring of this cross are:

a. Tt only c. TT, Tt or tt

b. TT only d. Tt or tt only

17. In humans assume that brown eye color is dominant over blue eye color. If two brown-eyed individuals have a child with blue eyes, that means:

a. Both parents are homozygous for brown eye color

b. One parent has to have blue eyes and must wear colored contact lenses

c. Both parents are heterozygous for eye color

d. None of the above

18. The best description of a gene is:

a. A strand of DNA coiled around proteins in the nucleus of all cells

b. A hereditary trait

c. A version of a genetic trait that may or may not be expressed in the genotype

d. A section of DNA that contains information for synthesizing a particular protein

19. All deoxyribonucleotides (found in DNA) are similar except for:

a. The phosphate group

b. The presence of nitrogen

c. The hydroxyl groups present in sugars

d. The type of base included

20. If a double-stranded DNA molecule contains 30% T, it contains ___% A?

a. 20% b. 30% c. 40% d. 70%

21. The central dogma of molecular biology states that information in ________ is transcribed into ________ which is then translated to form _______.

a. Genes/polypeptides/gene products c. Proteins/DNA/RNA

b. DNA/RNA/proteins d. DNA/mRNA/rRNA

22. During DNA replication a sequence of bases G-C-A-T would be paired with:

a. C-G-T-A b. C-C-G-T c. G-G-C-A d. C-G-T-U

23. RNA and DNA differ by:

a. The number of phosphate and sugar chains

b. The structure of the sugar molecule

c. The nitrogenous bases

d. All of these

24. During translation (the second part of protein synthesis):

a. RNA polymerase binds ribonucleotides

b. Genetic information is converted from one nucleic acid to another

c. Amino acids are assembled to form proteins

d. Both a & b

25. The amount of adenine in DNA is equal to the amount of:

a. Guanine b. Thymine c. Cytosine d. Uracil

26. The fact that DNA structure is based on pairs of bases implies that it:

a. Cannot replicate to form identical molecules

b. Can only be used as a template for RNA formation

c. Consists of two strands that contain complementary but not identical information

d. Has a maximum of only five different types of bases

27. During DNA replication

a. One DNA strand must be degraded so that the other can be copied

b. The parental DNA strands must separate so that both can be copied

c. The parental DNA strands come back together after passage of a replication enzyme

d. Two strands divide, but only one is copied

28. A deoxyribose nucleotide (in DNA) consists of:

a. Deoxyribose sugar plus a nitrogenous base

b. Sugar and a phosphate

c. Deoxyribose sugar, a nitrogenous base and a phosphate

d. Ribose sugar plus a nitrogenous base

29. A codon in mRNA with the sequence C-A-U would be recognized by the anticodon in tRNA of:

a. G-U-A b. G-T-A c. C-U-A d. C-A-T

30. Double-stranded DNA looks a little like a ladder that has been twisted into a helix, or spiral. The rungs of the ladder are:

a. Individual nitrogenous bases

b. Pairs of nitrogenous bases

c. Alternating sugars and phosphates

d. Alternating bases, sugars and phosphates

31. Which of the following statements about the flow of genetic information is true?

a. Proteins encode information that is used to produce other proteins of the same amino acid sequence

b. RNA encodes information that is translated into DNA, and DNA encodes information that is translated into proteins

c. Proteins encode information that can be translated into RNA, and RNA encodes information that can be transcribed into DNA

d. DNA encodes information that is translated into RNA, and RNA encodes information that is translated into proteins

32. The importance of DNA lies in its ability to:

a. Make copies of itself

b. Encode information

c. Control cell function

d. All of these

33. The role that RNA plays in cell function could best be described as:

a. An intermediate between DNA and proteins

b. Long-term storage of information

c. Ability to turn enzymes off and on

d. All of these

34. Which is NOT a nitrogenous base found in DNA?

a. Uracil b. Thymine c. Guanine d. Adenine

35. Which is true of variability in DNA?

a. DNA structure varies within an individual depending on which cell is examined

b. Phosphates and sugars of DNA vary among organisms

c. DNA diversity lies in differences among bases in nucleotides

d. No two DNA molecules are identical

36. About ___% of cancers are caused by genetic mutations.

a. 35 b. 50 c. 85 d. 99

37. Tumors consisting of cells that resemble parent cells and remain localized are:

a. Malignant b. Mutations c. Benign d. Sarcomas

38. Alteration of the sequence of nitrogenous base pairs in DNA is known as:

a. Cloning b. Transcription c. Tetrad crossover d. A Mutation

39. A tumor suppressor:

a. Is a gene that controls cell division

b. Is a gene that stimulates cell division

c. A drug used to treat cancer

d. A drug that stimulates production of stem cells

40. A mutation that involves a single gene or sometimes a single nucleotide is called a:

a. Chromosomal mutation c. Point mutation

b. Diversion d. Any of these

41. The only source of completely brand new genetic material into a population is:

a. Immigration of new individuals c. Natural selection

b. Mutations d. Crossing over

42. 85% of all human tumors involve epithelial cells and are called:

a. Sarcomas b. Leukemias c. Carcinomas d. Malignant

43. Uncontrolled cell division is:

a. Angiogenesis b. A benign tumor c. Cancer d. All of these

44. Which is true of a mutation?

a. May involve a single nucleotide out of the millions of nucleotides in DNA

b. May involve a whole chromosome

c. May involve entire sets of chromosomes

d. All of these

45. Environmental agents that may cause mutations and genetic disorders that affect DNA and lead to cancer are known as:

a. Nondisjunctions c. Carcinomas

b. Polyploidy inducers d. Carcinogens

46. Which is true of epithelial cells in terms of their relation with cancer?

a. Most tumors involve epithelial cells

b. Epithelial cells affected at a high rate because of their rapid cell division

c. Associated with carcinomas

d. All of these

47. As a result of the nature of a mutation:

a. The DNA of a cell is permanently altered

b. In division of somatic (non-gamete) cells the mutation will be passed on to all daughter cells produced by mitosis

c. In division of sex cells (gametes) the mutation may be passed on to offspring

d. All of these

48. Without mutations there would essentially be no:

a. Cancer b. Evolution c. Gene therapy d. Tumors

49. A mass of cancerous cells is referred to as a:

a. Cellular mass b. Metastasis c. Benign d. Tumor

50. A genetic disorder that results in one missing amino acid in a protein that forms part of hemoglobin molecules is wide-spread in the human population and is associated with the disease:

a. Cystic fibrosis c. Sickle cell anemia

b. Hemophilia d. Muscular dystrophy

Extra Credit Question (5 points)

Explain how information stored in DNA is used to synthesize a chain of amino acids (a protein).