Genetics

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1

The genetic variation represented by plants and animals is known as ________.

A) biodiversity

B) conservation

C) evolutionary heterosis

D) contract digression

E) None of the answers listed is correct.

A

2

At which levels do most scientists examine genetic diversity?

A) species and kingdom

B) female and male

C) interspecific and intraspecific

D) species A and species B

E) higher and lower forms

C

3

The Food and Agriculture Organization (FAO) estimated that since 1900, ________ percent of the genetic diversity in agricultural crops has been lost.

A) 20

B) 30

C) 50

D) 75

E) 90

D

4

Interspecific diversity refers to diversity ________.

A) between species

B) within species

C) within a particular population

D) within an individual

E) within an isolated population

A

5

The shrinking of available habitat reduces populations of wild species and often also isolates them from one another. Individual populations become trapped in pockets of undeveloped land surrounded by areas of agriculture. This process is called ________.

A) isolation

B) stagnation

C) overdevelopment

D) underdevelopment

E) population fragmentation

E

6

Which experimental technique employs the "obscure" bacterium Thermus aquaticus that was first discovered in a thermal pool in Yellowstone National Park?

A) centrifugation

B) complementation

C) northern blotting

D) PCR

E) electrophoresis

D

7

Predominantly inbreeding species, such as those that self-fertilize, tend to have greater levels of ________ than ________ diversity.

A) interpopulation; intrapopulation

B) isopopulation; gametopopulation

C) intrapopulation; interpopulation

D) specific; interspecific

E) nonmutant; mutant

A

8

What are allozymes?

A) multiple versions of a single enzyme in a species

B) multiple genes in a chromosome

C) variations that are lethal in homozygotes

D) variations that give a selective advantage in the heterozygous state

E) multiple forms of mitochondrial DNA

A

9

Driver mutations provide a growth advantage to a tumor cell. Which type of mutation is known to accumulate in cancer cells but has no direct contribution to the cancer phenotype?

A) alteration mutations

B) passenger mutations

C) carrier mutations

D) indirect mutations

E) insignificant mutations

B

10

Which of the following three general mechanisms appear to be involved in the conversion of proto-oncogenes to oncogenes?

A) point mutations, translocations, overexpression

B) inversions, translocations, methylation

C) familial, sporadic, phosphorylation

D) transdetermination, mutation, allosteric interactions

E) suppression, tabulation, projection

A

11

Which protein combines with cyclins to exert local control of the cell cycle?

A) cyclin-dependent kinase

B) phosphatase

C) ATPase

D) integrase

E) hexokinase

A

12

A protein that functions as a cell-cycle regulator causes cell death (apoptosis) under high sunlight exposure. Which symbol given to this protein?

A) p34

B) p102

C) cyclin

D) p53

E) phosphokinase

D

13

The retinoblastoma protein (pRB), like p53, serves as a(n) ________ in regulating the cell cycle.

A) tumor suppressor

B) tumor enhancer

C) up regulator

D) oncogene

E) pseudooncogene

A

14

Mutant versions of genes that are normally involved in promoting the cell cycle are known as ________.

A) tumor suppressors

B) proto-oncogenes

C) oncogenes

D) malignant genes

E) attenuators

C

15

In sporadic cases of retinoblastoma, how many gene mutations are thought to be necessary in the same cell for a tumor to develop?

A) one

B) two

C) four

D) six

E) insufficient information to answer this question

B

16

Which protein appears to regulate the entry of cells into an S phase? This protein is also known as the "guardian of the genome."

A) p34

B) p102

C) cyclin

D) p53

E) phosphokinase

D

17

1) The Human Genome Project, which got underway in 1990, is an international effort to ________.

A) construct a physical map of the billions of base pairs in the human genome

B) collect samples of cells from all parts of the world in order to preserve human genetic diversity

C) collect plant seeds in order to reduce the impact of human activity on plant extinction

D) clone deleterious genes from humans and study their mode of action

E) clone beneficial genes from humans for eventual use in gene therapy

A

18

Numerous scientists around the world have proposed to sequence 10,000 vertebrate genomes in five years. What is the name of this plan?

A) Genome 10K

B) Bigger Than Life Plan

C) 10K or Bust

D) Vertebrate Beginnings

E) Vertebrate Enlightenment

A

19

Compared with eukaryotic chromosomes, bacterial chromosomes are ________.

A) large, mainly organized in single gene transcription units without introns

B) small, mainly organized in single gene transcription units with introns

C) large, mainly organized in polygenic transcription units without introns

D) small, with high gene density

E) large, triple-helix, Z-DNA, organized in single gene units with introns

D

20

Compared with prokaryotic chromosomes, eukaryotic chromosomes are ________.

A) large, mainly organized in single gene transcription units without introns

B) small, mainly organized in single gene transcription units with introns

C) large, mainly organized in polygenic transcription units without introns

D) small, mainly organized in polygenic transcription units without introns

E) large, linear, less densely packed with protein-coding genes, mainly organized in single gene units with introns

E

21

Most of the bacterial genomes described in the text have fewer than ________.

A) 10,000 genes

B) 5000 base pairs

C) 500 genes

D) 10,000 base pairs

E) 50 genes

A

22

A bacterial polygenic transcription unit ________.

A) contains information for one protein product

B) contains information for more than one protein product

C) is capped at the 5' end and carries a poly-A tail at the 3' end

D) is void of start (AUG) and termination (UAA, UGA, UAG) triplets

E) None of the answers listed is correct.

B

23

Mycoplasma are among the smallest and perhaps the simplest self-replicating prokaryotes known. M. genitalium contains a genome of 0.58 Mb. Approximately how many genes does this bacterium contain?

A) 426,000

B) 3000

C) 1200

D) between 400 and 550

E) 12

D

24

In general, the organization of genes in bacteria is different from that in eukaryotes. In E. coli, approximately 27 percent of all genes are organized into contiguous, functionally related units containing multiple genes under coordinate control that are transcribed as a single unit. Such contiguous gene families are called ________.

A) transcriptomes

B) proteomes

C) contigs

D) operons

E) pseudogenes

D

25

The human genome contains approximately 20,000 protein-coding genes, yet it has the capacity to produce several hundred thousand gene products. What can account for the vast difference in gene number and product number?

A) Alternative splicing occurs.

B) There are more introns than exons.

C) There are more exons than introns.

D) Much of the DNA is in the form of trinucleotide repeats, thus allowing multiple start sites for different genes.

E) Every gene can be read in both directions, and each gene can have inversions and translocations.

A

26

What is one major limitation of two-dimensional gel electrophoresis (2DGE)?

A) It is extremely costly to execute in a typical molecular biology laboratory.

B) When products are separated, they tend to leach out of the gel matrix.

C) Only the most abundant products are detected.

D) 2DGE can be run only on nucleic acids.

E) 2DGE is useful only in separating eukaryotic gene products.

C

27

Proteomics is the ________.

A) process of defining the complete set of proteins encoded by a genome

B) harvesting of proteins from a cell to determine their economic value

C) manipulation of amino acid sequences in proteins to alter their function

D) changing of the terminal sequences of proteins to alter their function

E) rational design of drugs based on protein structure

A

28

The discipline within evolutionary biology that studies changes in allele frequencies is known as ________.

A) population genetics

B) consanguinity

C) hybrid vigor

D) genetics

E) cytogenetics

A

29

Which term is given to the total genetic information carried by all members of a population?

A) gene pool

B) genome

C) chromosome complement

D) breeding unit

E) race

A

30

A number of mechanisms operate to maintain genetic diversity in a population. Why is such diversity favored?

A) Homozygosity is an evolutionary advantage.

B) Diversity leads to inbreeding advantages.

C) Genetic diversity may better adapt a population to inevitable changes in the environment.

D) Greater genetic diversity increases the chances of haploidy.

E) Genetic diversity helps populations avoid diploidy

C

31

In a population of 100 individuals, 49 percent are of the NN blood type. What percentage is expected to be MN assuming Hardy-Weinberg equilibrium conditions?

A) 9 percent

B) 21 percent

C) 42 percent

D) 51 percent

E) There is insufficient information to answer this

C

32

Albinism is an autosomal recessive trait in humans. Assume that there are 100 albinos (aa) in a population of 1 million. How many individuals would be expected to be homozygous normal (AA) under equilibrium conditions?

A) 100

B) 10,000

C) 19,800

D) 980,100

E) 999,900

D

33

Which method is often used to analyze proteins and nucleic acids by physical separation when estimating genetic variation in populations?

A) electrophoresis

B) centrifugation

C) absorption spectrophotometry

D) fluorometry

E) in situ hybridization

A

34

In small isolated populations, gene frequencies can fluctuate considerably. The term that applies to this circumstance is ________.

A) genetic isolation

B) allelic separation

C) natural selection

D) stabilizing selection

E) genetic drift

E

35

Which general term is used to group various biological and behavioral properties of organisms that act to prevent or reduce interbreeding?

A) phyletic evolution

B) allopatric speciation

C) reproductive isolating mechanisms

D) inbreeding

E) genetic divergence

C

36

Nutritional mutations can be defined as ________.

A) those mutations that do not allow a bacterium or fungus to grow on minimal medium but do allow growth on complete medium

B) those mutations that change the composition of the medium

C) those mutations belonging to the group called prototrophs

D) those mutations caused by site-specific mutagenesis

E) all strains that are not auxotrophic

A

37

Conditional mutations are more likely to result from a mutation caused by which of the following alterations to the coding region of a gene?

A) four bases added within a short region of a gene

B) base addition

C) X rays

D) deletion

E) tautomeric shift

E

38

A class of mutations that results in multiple contiguous amino acid changes in proteins is likely to be which of the following?

A) base analog

B) transversion

C) transition

D) frameshift

E) recombinant

D

39

Two formal terms used to describe categories of mutational nucleotide substitutions in DNA are ________.

A) base analogs and frameshift

B) error prone and spontaneous

C) transversions and transitions

D) euchromatic and heterochromatic

E) sense and antisense

C

40

) Mutations that arise in nature, from no particular artificial agent, are called ________.

A) oblique mutations

B) induced mutations

C) spontaneous mutations

D) chromosomal aberrations

E) cosmic mutations

C

41

Which of the following name two mutagens that would be classified as base analogs?

A) acridine orange and proflavin

B) ethylmethane sulfonate and ethylmethylketone peroxide

C) ultraviolet light and cosmic radiation

D) 5-bromouracil and 2-amino purine

E) hydroxyurea and peroxidase

D

42

Ultraviolet light causes pyrimidine dimers to form in DNA. Some individuals are genetically incapable of repairing some dimers at "normal" rates. Such individuals are likely to suffer from ________.

A) xeroderma pigmentosum

B) SCID

C) phenylketonuria

D) muscular dystrophy

E) Huntington disease

A

43

Transposons, or jumping genes, are DNA elements that move within the genome. In which organismic groups are transposons found?

A) bacteria

B) eukaryotes

C) mammals

D) ancient bacteria

E) all organismic groups

E

44

All insertion sequences (IS elements) contain two features that are essential for their movement. What are these two elements?

A) transposase and inverted terminal repeats

B) integrase and pseudogenes

C) integrase and oncogenes

D) proto-oncogenes and oncogenes

E) transposase and oncogenes

A

45

Some bacterial transposons, known as Tn elements, are larger than insertion sequences (IS elements) and contain protein-coding genes that have human health significance. What might such a bacterial transposon contain?

A) drug resistance

B) oncogene

C) pseudogene

D) proto-oncogene

E) dissociation element

A