Genetics HW 2

Genetics at Virginia Tech BIOL 2004 Kamran

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

karyotype

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

trisomy

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

Allopolyploidy

Which statement about aneuploidy is true?

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

Which statement about polyploidy is not true?

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

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

conjugation

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

auxotrophs

Which statement best describes an F' bacterial cell?

It contains an F plasmid that includes some bacterial genes.

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?

antigenic shift

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?

h+r+ and h−r−

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

The two genes are located close to each other.

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

an F– cell

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

It must perform the action associated with the phenotype.

A key discovery leading to the structure of DNA was done by Chargaff. He found that: (Select all that apply)

the amount of A equals the amount of T, and the amount of G equals the amount of C

the tetranucleotide hypothesis was false

What did Griffith discover with his experiments?

the transforming principle in bacteria

What does the term antiparallel mean?

The 5' end of one strand is opposite the 3' end of the second strand.

The strands run in opposite directions.

A left‑handed form of DNA is the

Z DNA.

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

a hairpin

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

treatment with DNase

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

an X-ray diffraction pattern

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

three

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

that in some cases, RNA can be the genetic material

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

horizontal gene transfer

Which statement about retroviruses is NOT true?

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