Question 1

What does it mean to say that a person has a heterozygous genotype for a disease and no disease phenotype?

Accepted Answer

A)  It means that the person has two copies of the disease allele. 
B)  It means that the person has two copies of the normal allele. 
C)  It means that the person exhibits the symptoms of the disease if the disease allele is recessive. 
D)  It means that the person does not show symptoms of the disease if the disease allele is recessive. 
E)  It means that the person is a carrier who has already sired children who show symptoms of the disease.

Question 2

A disease caused by gene X is an autosomal dominant disease but is modified by expression of a gene on another chromosome gene Y.If gene Y has two recessive alleles,then the disease is mild.If there is a dominant allele present for gene Y,then the disease is aggressive.What are the chances the child will have the aggressive form of the disease?

Accepted Answer

A)  9:16 chance 
B)  4:16 chance 
C)  3:16 chance 
D)  1:16 chance 
E)  16:16 chance

Question 3

Would a change in the nucleotide sequence of DNA change the structure of a protein?

Accepted Answer

A)  One base equals one amino acid,so if there is a change in a base,it changes the amino acid,too. 
B)  A change in the DNA could lead to a change in the protein's amino acid sequence.This could lead to improper folding of the protein. 
C)  It wouldn't affect the protein;a change in the DNA sequence doesn't change the protein sequence. 
D)  A change in the DNA would only be caused by a change in the protein first. 
E)  None of the above.

Question 4

If two individuals were heterozygous for freckles,which is a dominant trait,what percentage of their progeny would have freckles?

Accepted Answer

A)  25% 
B)  50% 
C)  75% 
D)  100% 
E)  0%

Question 5

What are gametes?

Accepted Answer

A)  in humans,the egg and sperm 
B)  reproductive cells that carry only one copy of each chromosome 
C)  haploid cells 
D)  gametes are diploid cells with chromosomes from the mother and father 
E)  A,B,and C

Question 6

How many chromosomes are in a gamete?

Accepted Answer

A)  46 
B)  23 
C)  12 
D)  1 
E)  92

Question 7

You have two parental varieties of peas: tall plants with axial flowers and short plants with terminal flowers.When the short plants with terminal flowers variety were crossed with the tall plants with axial flowers variety,all of the offspring were tall plants and axial flowers.What characteristics are recessive?

Accepted Answer

A)  None.This is an example of incomplete dominance. 
B)  None.This is an example of codominance. 
C)  tall and short 
D)  tall and terminal 
E)  short and terminal

Question 8

How can someone get two different alleles of the same gene?

Accepted Answer

A)  A mutation can cause a second form of a gene to be created. 
B)  One allele can be inherited from mom and a different allele inherited from dad. 
C)  They can inherit two different alleles from mom. 
D)  They can inherit two different alleles from dad. 
E)  A and B

Question 9

A carrier is someone who

Accepted Answer

A)  expresses a recessive disease. 
B)  expresses a dominant disease. 
C)  has two copies of a recessive allele. 
D)  will pass on a recessive disease to all of their children. 
E)  has one copy of a recessive allele and one copy of a dominant allele for a particular gene.

Question 10

One of the purposes of meiosis is to _____.

Accepted Answer

A)  produce four zygotes instead of only two (as produced in mitosis) 
B)  reduce the chromosome number in each resulting cell by half 
C)  increase genetic diversity in the diploid-starting cells 
D)  increase the number of embryos per fertilization 
E)  double the number of chromosomes per gamete

Question 11

A human female has _____ chromosomes in each skin cell and _____ chromosomes in each egg.

Accepted Answer

A)  46;46 
B)  23;46 
C)  46;23 
D)  23;23 
E)  92;46

Question 12

The CFTR protein controls

Accepted Answer

A)  a potassium and chloride ion channel. 
B)  a sodium and potassium channel. 
C)  a sodium and chloride ion channel. 
D)  the phosphorus balance of the cell. 
E)  the regulation of pH in the cell.

Question 13

During the process of genetic recombination,

Accepted Answer

A)  maternal and paternal chromosomes pair and physically exchange DNA segments. 
B)  crossing over occurs between two nonsister chromatids. 
C)  DNA segments are exchanged between two nonsister chromatids during meiosis I. 
D)  None of the above. 
E)  All of the above.

Question 14

Which term would represent the trait cystic fibrosis?

Accepted Answer

A)  heterozygous recessive 
B)  homozygous recessive 
C)  homozygous dominant 
D)  heterozygous 
E)  heterozygous dominant

Question 15

All of the following are true of recessive alleles,EXCEPT

Accepted Answer

A)  they are never transcribed and therefore never produce protein. 
B)  they are designated by lowercase letters. 
C)  the phenotype encoded by the recessive allele will only be noticeable when in the homozygous state. 
D)  a person heterozygous for a recessively inherited disease has one normal allele and one disease allele and is called a "carrier." 
E)  not all recessive alleles cause disease.

Question 16

Humans have 23 pairs of chromosomes.How many possible ways can these be sorted out during independent assortment?

Accepted Answer

A)  more than 8 million ways 
B)  46 ways 
C)  23 ways 
D)  about 100 million ways 
E)  529 ways (23 × 23 ways)

Question 17

How are the X and Y chromosomes in males different from other diploid cells?

Accepted Answer

A)  Genes on the X and Y chromosome do not have a second copy. 
B)  Genes on the X and Y chromosome express an extra copy of each gene. 
C)  The X and Y chromosome in males preferentially express specific genes while silencing others. 
D)  A and C. 
E)  None of the above

Question 18

A mutation in a DNA coding region of a protein can cause

Accepted Answer

A)  a different amino acid at that position. 
B)  altered bonding between amino acids in the protein. 
C)  a change in the 3D shape of the protein. 
D)  no change in protein functionality. 
E)  All of the above.

Question 19

A human male has how many pairs of homologous chromosomes?

Accepted Answer

A)  46 
B)  23 
C)  22 
D)  44 
E)  48

Question 20

A duplicated homologous chromosome pair contains how many possible alleles?

Accepted Answer

A)  2 
B)  4 
C)  8 
D)  16 
E)  32

Exam 11: Simple Inheritance and Meiosis