Biology 1081 Exam 3
Terms in this set (32)
Final result of mitosis in a human:
genetically identical 2n somatic cells
In human and many other eukaryotic species' cells, the nuclear membrane has to disappear to permit:
the attachment of microtubules to kinetochores
Kinetochore microtubules assist in the process of splitting centromeres by:
creating tension by pulling toward opposite poles
Some cells have several nuclei per cell. How could such multinucleated cells be explained:
The cell underwent repeated mitosis, but cytokinesis did not occur
Movement of the chromosomes during anaphase would be most affected by a drug that prevents:
shortening of microtubules
How is plant cell cytokinesis different from animal cell cytokinesis
Plant cells deposit vesicles containing cell-wall building blocks on the metaphase plate; animal cells form a cleavage furrow
During which phase of mitosis do the chromatids become chromosomes?
Cyclin-dependent kinase (Cdk) is
an enzyme that attaches phosphate groups to other proteins
Which of the following is a true statement about sexual vs. asexual reproduction
In sexual reproduction, individuals transmit half of their nuclear genes to each of their offspring
carry information for the same traits
Which of the following happens at the conclusion of meiosis I?
Homologous chromosomes of a pair are separated from each other
If meiosis produces haploid cells, how is the diploid number restored for those organisms that spend most of their life cycle in the diploid state
If a cell has completed meiosis I and is just beginning meiosis II, which of the following is an appropriate description of its contents
It has half the amount of DNA as the cell that began meiosis
Sister chromatids separate from each other during
mitosis and meiosis II
Which of the following occurs in meiosis but not in mitosis?
synapsis of chromosomes
What do we mean when we use the terms monohybrid cross and dihybrid cross
A dihybrid cross involves organisms that are heterozygous for two characters that are being studied, and a monohybrid cross involves organisms that are heterozygous for only one character being studied
The individual with genotype AaBbCCDdEE can make many kinds of gametes. Which of the following is the major reason?
different possible assortment of chromosomes into gametes
Mendel accounted for the observation that traits that had disappeared in the F1 generation reappeared in the F2 generation by proposing that _____.
traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1
Albinism is an autosomal (not sex-linked) recessive trait. A man and woman are both of normal pigmentation, but both have one parent who is albino (without melanin pigmentation). What is the probability that their first child will be an albino?
Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of crosses BbTt × BBtt will be expected to have black fur and long tails?
When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?
The gene involved is on the X chromosome
Sex determination in mammals is due to the SRY gene. Which of the following could allow a person with an XX karyotype to develop a male phenotype
translocation of SRY to a X chromosome
In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male
tortoiseshell females; black males
Normally, only female cats have the tortoiseshell phenotype because _____.
a male inherits only one allele of the X-linked gene controlling hair color
Which of the following statements is true of linkage?
The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them.
A recessive allele on the X chromosome is responsible for red-green color blindness in humans. A woman with normal vision whose father is color blind marries a color-blind male. What is the probability that this couple's first son will be color blind?
One possible result of chromosomal breakage is for a fragment to join a nonhomologous chromosome. What is this alteration called?
In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts?
DNA contains phosphorus, whereas protein does not
Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?
Singer and Nicolson's fluid mosaic model of the membrane proposed that membranes
consist of protein molecules embedded in a fluid bilayer of phospholipids
When oxygen is released as a result of photosynthesis, it is a direct by-product of
splitting water molecules
Phospholipids and triglycerides both
have a glycerol backbone