exAM practice

X-linked recessive traits in humans (or in Drosophila) are observed ________.

• 1. in more males than females

• 1. in more females than males

• 1. in males and females equally

• 1. in different distributions depending on the trait

The first suggestion that chromosomes may physically exchange segments came from the microscopic identification of ________.

• 1. synapsis

• 1. sister chromatids

• 1. chiasmata

• 1. alleles

Which recombination frequency corresponds to independent assortment and the absence of linkage?

• 0

• 0.25

• 0.50

• 0.75

Which of the following codes describes position 12 on the long arm of chromosome 13?

1. 
   

• 1. 13p12

• 1. 13q12

• 1. 12p13

• 1. 12q13

In agriculture, polyploid crops (like coffee, strawberries, or bananas) tend to produce ________.

• 1. more uniformity

• 1. more variety

• 1. larger yields

• 1. smaller yields

The genotype XXY corresponds to

• 1. Klinefelter syndrome

• 1. Turner syndrome

• 1. Triplo-X

• 1. Jacob syndrome

Abnormalities in the number of X chromosomes tends to have milder phenotypic effects than the same abnormalities in autosomes because of ________.

• 1. deletions

• 1. nonhomologous recombination

• 1. synapsis

• 1. X inactivation

You isolate a cell strain in which the joining of Okazaki fragments is impaired and suspect that a mutation has occurred in an enzyme found at the replication fork. Which enzyme is most likely to be mutated?

• DNA ligase

• fragments

• strands

• biology

If DNA of a particular species was analyzed and it was found that it contains 27 percent A, what would be the percentage of C?

• 1. 27 percent

• 1. 30 percent

• 1. 23 percent

• 1. 54 percent

The experiments by Hershey and Chase helped confirm that DNA was the hereditary material on the basis of the finding that:

• 1. radioactive phage were found in the pellet

• 1. radioactive cells were found in the supernatant

• 1. radioactive sulfur was found inside the cell

• 1. radioactive phosphorus was found in the cell