Question 1

What does a frequency of recombination of 50% indicate?

Accepted Answer

A) The two genes are likely to be located on different chromosomes. 
B) All of the offspring have combinations of traits that match one of the two parents. 
C) The genes are located on sex chromosomes. 
D) Abnormal meiosis has occurred. 
E) Independent assortment is hindered. 
A) The two genes are likely to be located on different chromosomes. 
B) All of the offspring have combinations of traits that match one of the two parents. 
C) The genes are located on sex chromosomes. 
D) Abnormal meiosis has occurred. 
E) Independent assortment is hindered.

Question 2

If a pair of homologous chromosomes fails to separate during meiosis I,select the choice
That shows the chromosome number of the four resulting gametes with respect to the normal haploid number (n)?

Accepted Answer

A) n+1; n+1; n-1; n-1 
B) n+1; n-1; n; n 
C) n+1; n-1; n-1; n-1 
D) n+1; n+1; n; n 
E) n+2; n-1; n-1; n 
A) n+1; n+1; n-1; n-1 
B) n+1; n-1; n; n 
C) n+1; n-1; n-1; n-1 
D) n+1; n+1; n; n 
E) n+2; n-1; n-1; n

Question 3

A woman is found to have 47 chromosomes,including three X chromosomes.Which of the following describes her expected phenotype?

Accepted Answer

A) masculine characteristics such as facial hair 
B) enlarged genital structures 
C) excessive emotional instability 
D) normal female, slightly taller than average 
E) sterile female 
A) masculine characteristics such as facial hair 
B) enlarged genital structures 
C) excessive emotional instability 
D) normal female, slightly taller than average 
E) sterile female

Question 4

The greatest distance among the three genes is between a and c.What does this mean?

Accepted Answer

A) Gene a is closest to b. 
B) Genes are in the order: a-b-c. 
C) Gene a is not recombining with c. 
D) Gene a is between b and c. 
E) Distance a-b is equal to distance a-c. 
A) Gene a is closest to b. 
B) Genes are in the order: a-b-c. 
C) Gene a is not recombining with c. 
D) Gene a is between b and c. 
E) Distance a-b is equal to distance a-c.

Question 5

A certain kind of snail can have a right-handed direction of shell coiling (D)or left-handed coiling (d).If direction of coiling is due to a protein deposited by the mother in the egg cytoplasm,then a Dd egg-producing snail and a dd sperm-producing snail will have offspring of which genotype(s)and phenotype(s)?

Accepted Answer

A) 1/2 Dd:1/2 dd; all right coiling 
B) all Dd; all right coiling 
C) 1/2 Dd:1/2 dd; half right and half left coiling 
D) all Dd; all left coiling 
E) all Dd; half right and half left coiling 
A) 1/2 Dd:1/2 dd; all right coiling 
B) all Dd; all right coiling 
C) 1/2 Dd:1/2 dd; half right and half left coiling 
D) all Dd; all left coiling 
E) all Dd; half right and half left coiling

Question 6

Use the following information to answer the questions below.
The following is a map of four genes on a chromosome.
  
-Which two genes would you likely find inherited together?

Accepted Answer

A) A and W 
B) W and E 
C) E and G 
D) A and E 
E) A and G 
A) A and W 
B) W and E 
C) E and G 
D) A and E 
E) A and G

Question 7

Chimpanzees,gorillas,and orangutans have DNA sequences that are almost identical to those of humans; however,these genes are found on 24 pairs of chromosomes in apes,while humans have 23 pairs.The C2 chromosome in humans is a large chromosome with similar banding pattern and DNA sequences to two smaller chromosomes in apes (C2 and C4).In addition it appears to have both a vestigial second centromere and telomere sequences in the middle of the strand.
-Why do,in general,do only female cats have the tortoiseshell phenotype?

Accepted Answer

A) a male inherits only one allele of the X-linked gene controlling hair color 
B) the Y chromosome has a gene blocking orange coloration 
C) only males can have Barr bodies 
D) multiple crossovers on the Y chromosome prevent orange pigment production 
E) two tortoiseshell genes located on the X chromosome are required 
A) a male inherits only one allele of the X-linked gene controlling hair color 
B) the Y chromosome has a gene blocking orange coloration 
C) only males can have Barr bodies 
D) multiple crossovers on the Y chromosome prevent orange pigment production 
E) two tortoiseshell genes located on the X chromosome are required

Question 8

An inversion in a human chromosome often results in no demonstrable phenotypic effect in the individual.What else may occur?

Accepted Answer

A) There may be deletions later in life. 
B) Some abnormal gametes may be formed. 
C) There is an increased frequency of mutation. 
D) All inverted chromosomes are deleted. 
E) The individual is more likely to get cancer. 
A) There may be deletions later in life. 
B) Some abnormal gametes may be formed. 
C) There is an increased frequency of mutation. 
D) All inverted chromosomes are deleted. 
E) The individual is more likely to get cancer.

Question 9

Use the following information to answer the questions below.
A plant-like organism on the planet Pandora has three recessive genetic traits: bluish leaves,due to an allele (a)of gene A; a feathered stem,due to an allele (b)of gene B; and hollow roots due to an allele (c)of gene C.The three genes are linked and,when a geneticist did a testcross with an organism that had been found to be heterozygous for the three recessive traits,she was able to identify progeny with the following phenotypic distribution (+ = wild type):
  
-Which of the following are the phenotypes of the parents in this cross?

Accepted Answer

A) 2 and 5 
B) 1 and 6 
C) 4 and 8 
D) 3 and 7 
E) 1 and 2 
A) 2 and 5 
B) 1 and 6 
C) 4 and 8 
D) 3 and 7 
E) 1 and 2

Question 10

An organism with three sets of complete chromosomes is

Accepted Answer

A) aneuploid. 
B) diploid. 
C) trisomic. 
D) triassic. 
E) triploid. 
A) aneuploid. 
B) diploid. 
C) trisomic. 
D) triassic. 
E) triploid.

Question 11

-In a Drosophila experiment,a cross was made between homozygous wild-type females and yellow-bodied males.All of the resulting F₁s were phenotypically wild type.However,adult flies of the F₂ generation (resulting from matings of the F₁s)had the characteristics shown in the figure above.Consider the following questions:
(a)Is the mutant allele for yellow body recessive or dominant?
(b)Is the yellow locus autosomal or X-linked?

Accepted Answer

A) (a)recessive; (b)X-linked 
B) (a)recessive; (b)autosomal 
C) (a)dominant; (b)X-linked 
D) (a)dominant; (b)autosomal 
E) (a)co-dominant; (b)X-linked 
A) (a)recessive; (b)X-linked 
B) (a)recessive; (b)autosomal 
C) (a)dominant; (b)X-linked 
D) (a)dominant; (b)autosomal 
E) (a)co-dominant; (b)X-linked

Question 12

Chimpanzees,gorillas,and orangutans have DNA sequences that are almost identical to those of humans; however,these genes are found on 24 pairs of chromosomes in apes,while humans have 23 pairs.The C2 chromosome in humans is a large chromosome with similar banding pattern and DNA sequences to two smaller chromosomes in apes (C2 and C4).In addition it appears to have both a vestigial second centromere and telomere sequences in the middle of the strand.
-What could explain these observations?

Accepted Answer

A) The human ancestor originally had 24 pairs but complete fusion of C2 and C4 occurred, reducing the total number of chromosomes. 
B) A nondisjunction event must have occurred in the human ancestor, increasing the overall ploidy. 
C) The loss of a chromosome is due to a deletion event in the human ancestor. 
D) C2 must have undergone an inversion with C4. 
E) There is not enough information to speculate. 
A) The human ancestor originally had 24 pairs but complete fusion of C2 and C4 occurred, reducing the total number of chromosomes. 
B) A nondisjunction event must have occurred in the human ancestor, increasing the overall ploidy. 
C) The loss of a chromosome is due to a deletion event in the human ancestor. 
D) C2 must have undergone an inversion with C4. 
E) There is not enough information to speculate.

Question 13

Why does recombination between linked genes continue to occur?

Accepted Answer

A) Recombination is a requirement for independent assortment. 
B) Recombination must occur or genes will not assort independently. 
C) New allele combinations are acted upon by natural selection. 
D) The forces on the cell during meiosis II always result in recombination. 
E) Without recombination there would be an insufficient number of gametes. 
A) Recombination is a requirement for independent assortment. 
B) Recombination must occur or genes will not assort independently. 
C) New allele combinations are acted upon by natural selection. 
D) The forces on the cell during meiosis II always result in recombination. 
E) Without recombination there would be an insufficient number of gametes.

Question 14

Mitochondrial DNA is primarily involved in coding for proteins needed for electron transport.Therefore,in which body systems would you expect most mitochondrial gene mutations to be exhibited?

Accepted Answer

A) the immune system and the blood 
B) the excretory and respiratory systems 
C) the skin and senses 
D) the nervous and muscular systems 
E) the circulation system 
A) the immune system and the blood 
B) the excretory and respiratory systems 
C) the skin and senses 
D) the nervous and muscular systems 
E) the circulation system

Question 15

Which of the following is an example of monosomy?

Accepted Answer

A) Turner's syndrome 
B) Klinefelter's syndrome 
C) Down syndrome 
D) Philadelphia syndrome 
E) chronic myelogenous leukemia 
A) Turner's syndrome 
B) Klinefelter's syndrome 
C) Down syndrome 
D) Philadelphia syndrome 
E) chronic myelogenous leukemia

Exam 15: The Chromosomal Basis of Inheritance

What does a frequency of recombination of 50% indicate?

If a pair of homologous chromosomes fails to separate during meiosis I,select the choice That shows the chromosome number of the four resulting gametes with respect to the normal haploid number (n)?

A woman is found to have 47 chromosomes,including three X chromosomes.Which of the following describes her expected phenotype?

The greatest distance among the three genes is between a and c.What does this mean?

Use the following information to answer the questions below. The following is a map of four genes on a chromosome. -Which two genes would you likely find inherited together?

An inversion in a human chromosome often results in no demonstrable phenotypic effect in the individual.What else may occur?

An organism with three sets of complete chromosomes is

Why does recombination between linked genes continue to occur?

Mitochondrial DNA is primarily involved in coding for proteins needed for electron transport.Therefore,in which body systems would you expect most mitochondrial gene mutations to be exhibited?

Which of the following is an example of monosomy?

Introduction: Evolution and Themes of Biology

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Molecular Basis of Inheritance

From Gene to Protein

Regulation of Gene Expression

Viruses

DNA Tools and Biotechnology

Genomes and Their Evolution

Descent with Modification: A Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity II: The Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure,Growth,and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons,Synapses,and Signalling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behaviour

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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