genetics homework 2

Question 1

The spread of a complete metaphase chromosome set presented for diagnostic purposes is called a ______.

Answer 1

karyotype

Question 2

Of all cases of primary Down syndrome, 92% are due to ______ of Chromosome 21.

Answer 2

trisomy

Question 3

______ is a type of polyploidy that arises from the hybridization between two different species.

Answer 3

Allopolyploidy

Question 4

What does diagram A in Figure 8.3 represent?

Answer 4

chromosome duplication

Question 5

Which statement about aneuploidy is true?

Answer 5

One form of aneuploidy is a loss of both members of a homologous pair of chromosomes.

Question 6

Which statement about polyploidy is not true?

Answer 6

Polyploidy is possible only between the members of the same species.

Question 7

Which method of gene transfer in bacteria requires physical contact between donor and recipient cells?

Answer 7

conjugation

Question 8

Mutant bacterial strains that lack one or more enzymes needed to make essential molecules are called:

Answer 8

auxotrophs

Question 9

Which statement best describes an F′ bacterial cell?

Answer 9

It contains an F plasmid that includes some bacterial genes.

Question 10

What is the process called in which a virus has undergone major changes in its genome through the reassortment of genetic material from different strains of the virus?

Answer 10

antigenic shift

Question 11

A phage cross is made with phage T2. One of the parents was h⁺r⁻ and the other parent was h⁻r⁺. What would be the two recombinant classes of progeny from this cross?

Answer 11

h⁺r⁺ and h⁻r⁻

Question 12

When two genes show a high frequency of cotransduction, it can be assumed that:

Answer 12

The two genes are located close to each other.

Question 13

Which of the types of bacterial cells would normally be able to undergo conjugation with an F⁺ cell?

Answer 13

an F⁻ cell

Question 14

What characteristic is not necessary for a molecule that is the genetic material?

Answer 14

It must perform the action associated with the phenotype.

Question 15

A key discovery leading to the structure of DNA was done by Chargaff. He found that:

Answer 15

the amount of A equals the amount of T, and the amount of G equals the amount of C; the tetranucleotide hypothesis was false

Question 16

What did Griffith discover with his experiments?

Answer 16

the transforming principle in bacteria

Question 17

What does the term antiparallel mean?

Answer 17

The strands run in opposite directions; the 5′ end of one strand is opposite the 3′ end of the second strand.

Question 18

A left-handed form of DNA is the

Answer 18

Z DNA

Question 19

A structure formed by a single-stranded DNA or RNA molecule that has complementary sequences is:

Answer 19

a hairpin

Question 20

In Avery, MacLeod, and McCarty’s experiments, under which condition would transformation not occur?

Answer 20

treatment with DNase

Question 21

The major contribution of Franklin and Wilkins to the study of DNA was

Answer 21

an X-ray diffraction pattern

Question 22

The number of hydrogen bonds between complementary G−C pairs is:

Answer 22

three

Question 23

In experiments involving tobacco mosaic virus, Fraenkel-Conrat and Singer demonstrated:

Answer 23

that in some cases, RNA can be the genetic material

Question 24

Bacteria have acquired genes from other species of bacteria and sometimes from eukaryotic cells. The processes by which this occurs are known collectively as:

Answer 24

horizontal gene transfer

Question 25

Which statement about retroviruses is not true?

Answer 25

They replicate their DNA genomes in the cytoplasm of host animal cells.