fall 2011 midterm exam

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bio 286 second exam


Biology 105Midterm Examination II Version AFall 2011

This was the second midterm examination of the course in the Fall of 2011. Be mindful that one instructor was different, and the materials covered and emphasized were slightly different. Some questions here may concern areas not discussed in the current semester.

1. Bacteria typically have _______, whereas eukaryotes have _______.a. one chromosome that is circular; many chromosomes that are linear.b. several chromosomes that are circular; many chromosomes that are linear.c. one chromosome that is linear; many chromosomes that are circular.d. two chromosomes that are circular; eight chromosomes that are linear.e. None of the above.

2. Mature nerve cells, which are incapable of cell division, are most likely in:a. G1.b. the S phase.c. G2.d. mitosis.e. meiosis.

3. A typical cell cycle consists of:a. mitosis and meiosis.b. G1, the S phase, and G2.c. prophase, metaphase, anaphase, and telophase.d. interphase, mitosis, and cytokinesis.e. meiosis and fertilization.

4. The molecules that make up a chromosome are _______ and _______.a. DNA; RNAb. DNA; proteinsc. proteins; lipidsd. nucleotides; nucleosidese. proteins; phospholipids

5. The basic structure of chromatin has sometimes been referred to as beads on a string of DNA. These beads are called:a. chromosomes.b. chromatids.c. supercoils.d. interphases.e. nucleosomes.

6. The products of mitosis are:a. one nucleus containing twice as much DNA as the parent nucleus.b. two genetically identical cells.c. four nuclei containing half as much DNA as the parent nucleus.d. four genetically identical nuclei.e. two genetically identical nuclei.

7. Many chromosome abnormalities (trisomies and monosomies) are not observed in the human population because:a. they are lethal and cause spontaneous abortion of the embryo early in development.b. all trisomies and monosomies are lethal early in childhood.c. meiosis distributes chromosomes to daughter cells with great precision.d. they are so difficult to count.e. the human meiotic spindle is self-correcting.

8. Different forms of a gene are called:a. traits.b. phenotypes.c. genotypes.d. alleles.e. None of the above

9. In a(n) _______ cross, genes for two different characters separate.a. monohybridb. dihybridc. trihybridd. F1e. F2

10. Classical albinism results from a recessive allele. Which of the following is the expected ratio for the progeny when a normal pigmented male with an albino father has children with an albino woman?a. 34normal; 14 albinob. 34albino; 14 normalc. 12normal; 12 albinod. All normale. All albino

11. A pea plant with red flowers is test crossed, and one-half of the resulting progeny have red flowers, while the other half has white flowers. Therefore, the genotype of the test-crossed parent was:a. RR.b.Rr.c. rr.d. eitherRR orRr.e. This cannot be answered without more information.

12. The genetic disease blue sclera is determined by an autosomal dominant allele. The eyes of individuals with this allele have bluish sclera. These same individuals may also suffer from fragile bones and deafness. This is an example of:a. incomplete dominance.b. pleiotropy.c. epistasis.d. codominance.e. linkage.

13. A linkage group corresponds to:a. a group of genes on different chromosomes.b. the linear order of centromeres on a chromosome.c. the length of a chromosome.d. a group of genes on the same chromosome.e. None of the above

14. What is the pattern of inheritance for a rare dominant allele?a. Every affected person has an affected parent.b. Unaffected parents can produce children who are affected.c. Affected parents do not produce affected children.d. Unaffected mothers have affected sons and daughters who are carriers.e. None of the above

15. Chargaffs rule states that:a. DNA must be replicated before a cell can divide.b. viruses enter cells without their protein coat.c. only protein from the infecting phage can also be detected in progeny phage.d. only nucleic acids enter the cell during infection.e. the amount of cytosine equals the amount of guanine.

16. The strands that make up DNA are antiparallel. This means that:a. one strand is positively charged, and the other is negatively charged.b. the base pairings create unequal spacing between the two DNA strands.c. the 5-to-3 direction of one strand is counter to the 5-to-3 direction of the other strand.d. the twisting of the DNA molecule has shifted the two strands.e. purines bond with purines and pyrimidines bond with pyrimidines.

17. Mutations are:a. heritable changes in the sequence of DNA bases that produce an observable phenotype.b. heritable changes in the sequence of DNA bases.c. mistakes in the incorporation of amino acids into proteins.d. heritable changes in the mRNA of an organism.e. None of the above

18. At the end of DNA replication, two DNA molecules are produced, each one consisting of a parental DNA strand and a new DNA strand. This process is known as:a. semiconservative replication.b. conservative replication.c. dispersive replication.d. fission.e. the transforming principle.

19. Ideally, PCR _______ increases the amount of DNA during additional cycles.a. additivelyb. graduallyc. linearlyd. systematicallye. exponentially

20. One strand of DNA has the sequence 5-ATTCCG-3 The complementary strand for this is:a. 5-TAAGGC-3b. 5-ATTCCG-3c. 5-ACCTTA-3d. 5-CGGAAT-3e. 5-GCCTTA-3

21. After irradiating Neurospora, Beadle and Tatum collected mutants that would:a. not grow on a minimal medium but would grow on a minimal medium with arginine.b. grow on any minimal medium.c. not grow on any minimal medium.d. grow on a minimal medium but would not grow on a minimal medium with arginine.e. None of the above

22. The central dogma of molecular biology states that:a. information flow between DNA, RNA, and protein is reversible.b. information flow in the cell is unidirectional, from protein to RNA to DNA.c. information flow in the cell is unidirectional, from DNA to RNA to protein.d. the DNA sequence of a gene can be predicted if we know the amino acid sequence of the protein it encodes.e. the genetic code is ambiguous but not degenerate.

23. Imagine that a novel life-form is found deep within Earths crust. Evaluation of its DNA yields no surprises. However, it is found that a codon for this life-form is just two bases in length. How many different amino acids could this organism be composed of?a. 4b. 8c. 16d. 32e. 64

24. Exons are:a. spliced out of the original transcript.b. spliced together from the original transcript.c. spliced to introns to form the final transcript.d. much larger than introns.e. larger than the original coding region.

25. The binding of snRNPs to consensus sequences is necessary for:a. gene duplication.b. the addition of a poly A tail.c. capping an hnRNA.d. RNA splicing.e. transcription.

26. What events must take place to ensure that the protein made is the one specified by mRNA?a. tRNA must read mRNA correctly.b. tRNA must carry the amino acid that is correct for its reading of the mRNA.c. Covalent bonding between the base pairs must occur.d. Both a and be. All of the above

27. mRNA is synthesized in the _______ direction, which corresponds to the _______ of the protein.a. 5 to 3; N terminus to C terminusb. 3 to 5; C terminus to N terminusc. 5 to 3; C terminus to N terminusd. 3 to 5; N terminus to C terminuse. Examples of all of the above have been found.

28. The three basic parts of an operon are the:a. promoter, the operator, and two or more structural genes.b. promoter, the structural genes, and the termination codons.c. promoter, the mRNA, and the termination codons.d. structural genes, the mRNA, and the tRNAs.e. None of the above

29. Which operon is turned off in response to molecules present in the environment of the cell?a. Repressibleb. Suppressiblec. Impressibled. Induciblee. Degraded

30. Which of the following is not a DNA binding motif?a. Helix-straight-helixb. Helix-turn-helixc. Helix-loop-helixd. Leucine zippere. Zinc finger

31. The drought stress response in plants is an example of:a. a transcription factor.b. coordinated gene expression.c. a way to increase water intake.d. Both a and be. None of the above

32. The interphase cells of normal female mammals have a stainable nuclear body called a Barr body. This body is:a. an inactive X chromosome.b. made of fat droplets.c. made of fragments of mRNA.d. made of extra chromosomal pieces.e. None of the above

33. A chemical modification that adds methyl groups to cytosine residues in some genes acts to:a. enhance transcription.b. amplify the gene.c. inactivate the gene.d. stabilize the mRNA.e. None of the above

34. What would happen initially to cells that lack a functional ubiquitin?a. Nothing would happen.b. Transcriptional initiation would increase.c. Protein degradation would decrease.d. Histone modifications would increase.e. Translation of proteins would be more efficient.

35. Which of the following is the correct ranking of stem cells with respect to the number of cell types into which they can differentiate (from greatest to least)?a. Multipotent> pluripotent > totipotentb. Pluripotent > totipotent >multipotentc. Pluripotent >multipotent> totipotentd. Totipotent > pluripotent >multipotente. Totipotent >multipotent> pluripotent

36. The process by which signaling molecules from one tissue (or group of cells) affect the development of adjacent tissue is called:a. determination.b. morphogenesis.c. placode.d. differentiation.e. induction.

37. The large amount of yolk in birds eggs results in:a. gradual metamorphosis.b. complete metamorphosis.c. incomplete cleavage.d. incomplete mitosis during cleavage.e. bic