Biology 2001 - Exam 1

all the offspring of a cross between a green-eyed cat and an orange-eyed cat have orange eyes. what is the expected phenotypic ratio of a cross between two of these second-generation orange-eyed cats?

1 green-eyed: 3 orange-eyed

color-blindness is an x-linked recessive trait. a color-blind woman marries a man who is not color-blind. which of the following would you expect to see in the children of this couple?

100% of the sons and no daughters will be color-blind

assuming that the probability of having a female child is 50% and the probability of having a male child is also 50% what is the probability that a couple's first-born child will be male and that their second-born child will be male?

25%

how many hydrogen bonds connect a guanine base to a cytosine base on opposite strands of a DNA molecule?

3

what is the reverse complement of the DNA sequence 5' AGGCTATGC 3'?

3' TCCGATACG 5'

cytosine makes up 15% of the nucleotides in a sample of DNA from an organism. approximately what percentage of the nucleotides in this sample will be in thymine?

35%

how many different gametes can be produced from a cell with the following genotype: AaBbCc?

8

in blood type alleles, A is dominant to O, B is dominant to O, and A and B are co-dominant alleles. a man who has type B and a woman who has type A could have child of which of the following blood types?

A, B, AB, or O

mr. smith's oarents have normal hearing. however, mr. smith has an inherited form of deafness. deafness is a recessive trait that is associated with the abnormal allele d. the normal allele at this locus, associated with normal hearing, is D. mr. smith's parents could only have which of the following genotypes?

Dd and Dd

what sex chromosome(s) are present in a human egg cell?

X

which of the following types of cells in dogs contain the gene for eye color?

all cells

which of the following statements regarding genotypes and phenotypes is false?

an organism with two different alleles for a single trait is said to be homozygous for that trait

sister chromatids...

are joined together at the centromere

a carrier of a genetic disorder who does not show symptoms is most likely ______ to transmit it to offspring

heterozygous for the trait and able

crossing over occurs between which of the following?

homologous chromosomes

beak color in a finch species is controlled by a single gene. you mate a finch homozygous for orange (pigmented) beak with a finch homozygous for ivory (unpigmented) beak and get numerous offspring, all of which have a light ivory-orange beak. this pattern of color expression is most likely to be an example of

incomplete dominance

which of the following terms refers to a situation where a single phenotypic character, such as skin color, is determined by the additive effects of two or more genes?

polygenic inheritance

all the offspring of a cross between a green-eyed cat and an orange-eyed cat have orange eyes. this means that the allele for green eyes is _______ the allele for orange eyes

recessive to

which of the following is NOT a major change in chromosomal structure in a cell?

recombination of a chromsomal segment

the alleles of a gene are found at ______ chromosomes.

the same location on homologous

which of the following is TRUE about genes found in the mitochondrial genome?

they are inherited through the maternal line

which of the following statements about telomeres is FALSE?

they cannot be increased in length

a complete non-disjunction event in meiosis results in a gamete that recieved both homologous chromosomes for each pair. if this gamete combines with a normal gamete during fertilization, the resulting zygote will be:

triploid

DNA replication

uses each strand of a DNA molecule as a template for the creation of a new strand