Bio 110 Practice exam 5

Why is color-blindness more common in males than in females?

Because color-blindness is an Y-linked trait.

Which of the following adds new nucleotides to a growing DNA chain?

DNA polymerase

Why is DNA able to store large amounts of information?

Its nucleotides can be arranged in a large number of possible sequences.

The kinetochore serves which of the following functions?

Kinetochores attach to microtubules during mitosis.

Which of the following statements concerning the cell cycle is FALSE?

M-Cdk inhibits mitosis.

Which of the following best describes semiconservative replication?

a DNA molecule consists of one parental strand and one new strand e

To prevent disastrous consequences, the eukaryotic cell cycle is controlled by:

a series of cell cycle checkpoints.

During prophase I, each chiasma represents:

a site of crossing-over

Mating an individual expressing a dominant phenotype, but whose genotype is unknown, with an individual expressing the corresponding recessive phenotype is an example of:

a test cross.

The sources of genetic variation during meiosis are:

crossing-over and the random assortment of maternal and paternal chromosomes.

Hydrogen bonds can form between guanine and __________, and between adenine and __________.

cytosine; thymine

What evolutionary advantage is provided by sexual reproduction?

increased genetic diversity

The cell cycle of a typical somatic cell consists of __________ and M phase.

interphase

A replication fork:

is a Y-shaped structure where both DNA strands are replicated simultaneously.

In DNA replication, the lagging strand:

is synthesized as a series of Okazaki fragments.

If a cell is in G2:

it has twice the amount of DNA present in a telophase nucleus.

The chromosome makeup of an individual organism is called a:

karyotype

The DNA strand that is replicated smoothly and continuously is called the:

leading strand

Eukaryotic chromosomes consist of:

linear DNA molecules complexed with positively charged histone proteins

The principle of independent assortment is not true for:

linked genes.

The correct number of chromosomes is maintained during sexual reproduction by:

meiosis, which reduces the chromosome number by half.

The mitotic spindle is made of:

microtubules.

The __________ is responsible for the separation of the chromosomes during __________ of mitosis

mitotic spindle; anaphase

The term "dominant" means that:

one allele can mask the expression of another in a hybrid.

The formation of female gametes is termed:

oogenesis

The physical appearance of an organism for a given trait is termed:

phenotype.

Which of the following represents the overall sequence of events during mitosis?

prophase - metaphase - anaphase - telophase

During which phase does crossing-over occur?

prophase I

Homologous chromosomes undergo synapsis during:

prophase I

The information carried by DNA is incorporated in a code specified by the:

specific nucleotide sequence of the DNA molecule.

If a cell is dividing by binary fission then you know that:

the cell is prokaryotic.

A cell is in metaphase if:

the chromosomes are aligned at the midplane of the cell

The probability that two genes will be separated by crossing-over is related to:

the distance between the two genes on the chromosome

The main reason scientists thought that proteins, rather than DNA, were the carriers of genetic material in the cell was

the large number of possible amino acid combinations.

The sex of a human is determined by

the presence of a Y chromosome

Generation time refers to:

the time it takes to complete one cell cycle.

Using standard conventions for naming alleles, which of the following pairs is correct?

tt-homozygous

The genotype for a pea plant that is homozygous recessive for both height and pea color would be:

ttyy.

Calico cats are never male because:

two different X chromosomes are needed for the expression of the calico phenotype.

A __________ is best used to demonstrate the linkage of two genes

two-point test cross

In the experiments of Griffith, the conversion of nonlethal R-strain bacteria to lethal S-strain bacteria:

was an example of the genetic exchange known as transformation.

Which of the following nucleotide sequences represents the complement to the DNA strand 5'- AGATCCG- 3'?

3' TCTAGGC- 5'

__________ are alternative forms of a gene that govern the same feature, such as eye color, and occupy corresponding positions on homologous chromosomes.

Alleles

Which of the following represents the possible genotype(s) resulting from a cross between an individual homozygous (BB) and one heterozygous (Bb) individual?

BB and Bb

Which of the following represents the possible genotype(s) resulting from a cross between two individuals that are heterozygous (Bb)?

BB, Bb, and bb

Why does DNA synthesis only proceed in the 5' to 3' direction?

Because DNA polymerases can only add nucleotides to the 3 end of a polynucleotide strand.

The bacteriophages used in Alfred Hershey's and Martha Chase's experiments showed that:

DNA was injected into bacteria.

Chromosomes are duplicated during __________ of the cell cycle.

S phase

__________ contain identical DNA sequences and are held together by __________ during mitosis.

Sister chromatids; centromeres

During which of the following stages of meiosis do the sister chromatids separate?

anaphase II

Two chains of DNA must run in __________ direction(s) and must be __________ if they are to bond with each other.

antiparallel; complementary

If meiosis did not occur in sexually reproducing organisms, then:

chromosome number would double in each generation

Meselson and Stahl separated DNA from different generations using:

density gradient centrifugation.

A zygote contains the __________ complement of chromosomes

diploid

Most human somatic cells are:

diploid.

A pear plant with the genotype Aa can produce gametes containing:

either A or a.