Biology Exam 2

An allele that appears more frequently in males is MOST likely

.sex-linked.

Mendel used ________ as his research organism to study patterns of genetic inheritance.

a. garden peas

The two strands of a DNA molecule are held together by ________ bonds between their base pairs.

a.hydrogen

In a genetic cross of Gg with Gg guinea pigs, none of the four offspring were gg. This

b. neither supports nor disproves Mendel's law of independent assortment.

Which of the following statements would indicate a pedigree that shows the inheritance pattern of a recessive X-linked disease?

b.Most affected individuals are males.

Most human genetic characters are

c.controlled by more than one gene.

DNA polymerase is used by the cell to

c.make copies of a DNA sequence.

A Thoroughbred racehorse could have at most ________ alleles of the same gene.

d. 2

In a strand of double-stranded DNA, cytosine (C) will always be bound with

d.G.

The sex of a human child is determined by the

d.presence or absence of the Y chromosome.

The sequence of DNA differs among individuals within a species. This is the reason for

d.variations in phenotypes.

If one strand of DNA has the sequence CGATT, the sequence of the other strand of the same molecule will be

.GCTAA.

Autosomal dominant diseases are exhibited by anyone who carries at least one dominant allele for that gene. How is it that dominant lethal genes, such as the one that causes Huntington disease, can persist in a population?

These diseases usually take effect later in life after people have had children.

Which of the following statements explains how genetically identical plant clones can exhibit dramatic phenotypic variation?

a.Environmental conditions under which plants are grown can cause variations in phenotypes.

Which of the following did Gregor Mendel notice in garden peas?

a.Some plants always produced offspring with flowers that were the same color as the parent plants' flowers.

The source of the gene needed for gene therapy treatment of the sex-linked adrenoleukodystrophy (ALD) would be a(n) ________ chromosome with a ________ copy of the ALD gene.

a.X; functional

If two different alleles for the same trait have an equal effect on the phenotype, the alleles are

a.codominant.

A female carrier of the X-linked recessive gene for red-green color blindness will display a phenotype of

a.normal color vision.

The coat color in a Siamese cat is determined by a temperature-sensitive allele that allows the brownish pigment melanin to be produced in extremities of the body. What might explain this phenomenon?

b.Alleles are used to produce proteins that function best in specific temperature ranges.

Because an individual with an XX genotype is a female, is an individual with an XO (no second sex chromosome) a male?

b.No, because the Y chromosome contains the gene that makes an embryo male.

Replication of DNA cannot begin until ________ bonds between ________ are broken.a.phosphate; nucleotides

b.hydrogen; complementary bases

40. According to the infographic below, the number of references to CRISPR in the PubMed database ________ between 2014 and 2016.

b.more than tripled

DNA replication

b.occurs before mitosis in the cell cycle.

In Mendel's controlled mating experiments, the individuals produced by crossing two true-breeding parents are referred to as

b.the F1 generation.

The pleiotropy that occurs when a single gene controls multiple skeletal traits in dogs, such as leg bone length and skull size, may be explained because

b.the skeletal traits are related in the overall function of the dog.

In a karyotype of a male, which of the following would indicate an abnormality?

b.three copies of chromosome 22

The adenine bases in a DNA molecule are radioactively labeled. The DNA is then placed in a solution containing unlabeled nucleotides and the enzymes needed for DNA replication. The DNA molecule is allowed to replicate twice, forming four new DNA molecules. The radioactively labeled adenine would be found in

b.two of the eight strands.

A pea plant that is heterozygous for the flower color gene makes gametes. What is the probability that a specific gamete contains the recessive allele for flower color?

c.50 percent

If a female who carries the X-linked recessive gene for hemophilia mates with a male who does not have hemophilia, what is the chance that their daughter will be a carrier of the gene?

c.50 percent

Sickle-cell disease is an inherited chronic blood disease caused by an autosomal recessive allele. Suppose a man with sickle-cell disease fathers a child by a woman who is a carrier for sickle-cell disease. What are the chances their children will exhibit the disease?

c.50 percent

Suppose D were dominant and d were recessive, and you could label the D allele in the P generation with a radioactive substance that could be inherited over several generations. You create hybrids by mating your radioactive DD individuals to dd individuals. Finally, you cross two F1 individuals (with the Dd genotype). In 1,000 offspring, how many would you predict would be radioactive?

c.750

What information in a pedigree would indicate a condition is likely dominant?

c.None of the affected individuals have unaffected parents.

If a recessive allele causes a fatal disease that kills the affected individual before he or she can reproduce, why doesn't that allele quickly become extinct in the population?

c.The recessive allele is carried in the genome of heterozygotes, who do not suffer from the disease.

A karyotype from an adult male indicates a chromosomal abnormality, which does not affect his health. Which of the following abnormalities is MOST likely seen?

c.a translocation between chromosome 14 and chromosome 15

In the Punnett square shown below, the lettered circles on the top and left of the square (indicated by the arrows) represent the

c.gametes that may be produced by each parent involved in the cross.

Which of the following would explain two chromosomes in an individual cell that contain some, but not all, of the same genes at the same loci?

d.A chromosomal alteration has occurred.

During cell division a piece of a chromosome breaks off and reattaches to the same chromosome, but the piece is now in reverse order. How would this abnormality affect the chromosome?

d.Genes in the section that was inverted could lose normal function.

If the male in generation II of the figure below was affected, what would the pattern of inheritance MOST likely be?

d.autosomal dominant

The karyotype shown below is from a(n)

d.individual with a genetic disorder.

Which of the following is NOT a base found in DNA?

d.uracil