Question 1

Under what circumstances can Down syndrome occur?

Accepted Answer

A) as a result of translocation during mitosis 
B) because of nondisjunction,which yields an extra chromosome 
C) most frequently in the offspring of women under the age of 40 
D) most frequently in the offspring of men under the age of 40

Question 2

What determines human ABO blood types?

Accepted Answer

A) regulatory genes 
B) multiple alleles 
C) multiple genes 
D) homeotic genes

Question 3

What does DNA replication produce?

Accepted Answer

A) four identical daughter cells 
B) two identical copies of itself 
C) two single strands of DNA 
D) four single strands of DNA

Question 4

Which of the following are complementary bases in DNA?

Accepted Answer

A) adenine and thymine 
B) adenine and cytosine 
C) guanine and thymine 
D) guanine and uracil

Question 5

In what way is the presence of a recessive allele related to the phenotype?

Accepted Answer

A) It can always be determined from the phenotype. 
B) It can be masked in the phenotype. 
C) It is expressed in the phenotype alongside a dominant allele. 
D) It can never be expressed in the phenotype.

Question 6

Which of the following is a characteristic of somatic cells?

Accepted Answer

A) Each includes a nucleus at some stage of their development and contains a complete copy of all of an organism's DNA. 
B) They only comprise a few specialized tissues in the body but contain a complete copy of all of an organism's DNA. 
C) Each contains half a copy of an organism's DNA. 
D) They only comprise the gametes.

Question 7

A trait's heritability is the proportion of its variation that:

Accepted Answer

A) is genetic. 
B) cannot be explained. 
C) is the product of genes and environment. 
D) results from the environment alone.

Question 8

A cell containing a gene for blond hair and blue eyes as well as genes for brown hair and brown eyes goes through meiosis.What is the chance that each of these gametes will have a combination of brown hair and blue eyes?

Accepted Answer

A) There is no chance this will happen. 
B) There is the same chance as blond hair and brown eyes. 
C) Brown hair and blue eyes is the only outcome because of recombination. 
D) There is a 5% chance this will happen.

Question 9

________ DNA is heteroplasmic,meaning it can differ among different parts of a person's body.

Accepted Answer

A) Nuclear 
B) All 
C) Ribosomal 
D) Mitochondrial

Question 10

An individual that is homozygous at the locus that determines ABO blood type may have type ________ blood:

Accepted Answer

A) O,A,or B 
B) A,B,or AB 
C) A,AB,or O 
D) AB

Question 11

Why is Transfer RNA important to the production of proteins?

Accepted Answer

A) It seeks complementary triplet strands of mRNA codons and contains codons that correspond to specific amino acids. 
B) It forms in the nucleus of a cell during the process of transcription,while mRNA is being created in the cytoplasm. 
C) It stops the formation of polypeptide chains. 
D) It is just like DNA but does not contain the nitrogen base uracil.

Question 12

Why do microsatellites mark a key discovery in DNA research?

Accepted Answer

A) They comprise small satellite transmitters. 
B) They determine group but not individual identification. 
C) They are highly individualized repetitive stretches of nuclear DNA. 
D) They were used as the basis of Watson and Crick's work in the 1950s.

Question 13

During which process is chromosome number reduced?

Accepted Answer

A) mitosis 
B) recombination 
C) translation 
D) meiosis

Question 14

A doctor finds that the mammary glands of a woman are not functioning due to a genetic abnormality that influences the structural design of the thoracic cavity.This is likely the result of a mutation:

Accepted Answer

A) on the sex chromosomes. 
B) in a Hox gene. 
C) in HSV-1. 
D) in an antibody.

Question 15

Why is nuclear DNA important for protein synthesis?

Accepted Answer

A) It forms sequences that are templates for production of proteins or parts of proteins. 
B) It serves as a template to which amino acids are attached in protein production. 
C) It provides the code to produce tRNA. 
D) It transfers information from RNA to proteins.

Question 16

When did Prokaryotes first appear?

Accepted Answer

A) 10,000 years ago 
B) 1 mya 
C) 3.5 bya 
D) 65 mya

Question 17

Which of the following types of cells in humans have fewer chromosomes than somatic cells do?

Accepted Answer

A) lung cells 
B) gametes 
C) skin cells 
D) neurons

Question 18

Why do the blood types of a person providing blood for a transfusion,and the person receiving the blood,have to be of a compatible ABO type?

Accepted Answer

A) This assures that the DNA matches between the two individuals,thus avoiding problems with genetic conflict later in life. 
B) This assures that there will not be an antibody-antigen reaction,in which the red blood cells with the "dominant" A or B alleles engulf the red blood cells with the "recessive" (O)alleles. 
C) This assures that antigens of one type of blood cell do not attract the notice of the antibodies in the recipient's blood stream. 
D) This assures that a methylation effect will not occur between the two sets of blood cells.

Question 19

Define polygenic and pleiotropic traits and explain their significance for researchers' efforts to link human genotypes to phenotypes.

Accepted Answer

The answer of Define polygenic and pleiotropic traits and explain...

Question 20

What does meiosis produce?

Accepted Answer

A) two gametes 
B) four gametes 
C) a single gamete 
D) identical somatic cells

Exam 3: Genetics: Reproducing Life and Producing Variation