During which stage can cells either exit the cell cycle or become committed to completing the cell cycle?
G1
What is the longest and shortest phase of interphase?
Longest --> S
Shortest --> G2
What condition is evaluated at the G2/M checkpoint?
Precise replication of DNA
Which list of steps in the eukaryotic cell cycle is given in the correct order?
G1, S, G2, M, G1
Do haploid cells undergo mitosis?
Yes and so do diploid cells
Each of the following events occur during mitosis except
polar microtubules contract, pulling attached chromosomes toward the poles
Cell Cycle consists of two phases
Mitosis is the shorter phase
What structure is not found in all mitotic cells?
Centriole
What is the arrangement of chromosomes during metaphase?
Sister chromatids are aligned along the equatorial plane of the cell
Separation of sister chromatids occur
at anaphase in mitosis and anaphase II at meiosis
The end result of meiosis is four haploid cells
True
Novel combinations of genes can arise from:
reciprocal exchange of DNA between homologs during prophase I
What is a dyad?
A dyad is composed of two sister chromatids joined at a common centromere
A cell has 16 chromosomes. How many chromosomes would its daughter cells have after meiosis?
Meiosis reduced the number of chromosomes passed on to daughter cells by one-half so 8
Which of the following statements about meiosis is true?
The second meiotic division is also call an equational division and involves the separation of sister chromatids, similar to what occurs in mitosis
During what phase of prophase 1 does crossing over take place?
Pachynema
Is a tetrad composed of one pair of homologous chromosomes at synapsis of prophase 1?
True; chromosomes are duplicated after interphase; at synapsis of prophase 1, one chromosome in a tetrad is paternally inherited while the other is maternally inherited
When do sister chromatids separate during meiosis?
Anaphase
What does the law of independent assortment state?
During gamete formation, segregating pairs of unit factors assort independently of each other; the law says nothing about dominance
Independent assortment explains
Why a collection of meiotic products that includes gametes of genotype Ab will also include gametes of genotype AB in roughly the same proportion
Which term describes the individual in a pedigree whose phenotype was first brought to the attention of a medical researcher?
Proband
Which of the following statements about autosomal recessive traits is true?
If neither parents expresses the trait, but the offspring does, both parents must be heterozygous for the trait
What is the most likely mode of transmission for a trait that is not expressed in parents but is expressed by one half of the sons?
Rare X-linked recessive (mother must have been heterozygous)
How many different types are possible in a one gene/three allele system that displays co-dominance to each other?
Six
Which of the following is the most likely example of co-dominance?
A pure-breeding plant with red flowers is crossed to a pure-breeding plant with white flowers. All there progeny have flowers with some red patches and some white patches. Heterozygotes express BOTH alleles
The color dilution gene in horses is an example of incomplete dominance. True of false?
True
Which of the following is an example of a meristic trait?
Number of bristles on a fruit fly
Which term is defined as "a measure of variation in phenotypes due to genetic factors"?
Broad-sense heritability
Which of the following statements about twins and twin studies is FALSE?
Fraternal twins are as close genetically to each other as are monozygotic twins
Of the human traits, which are likely to be under the control of a polygenic mode of inheritance?
Intelligence
Skin color
Height
(all can change due to environmental factors)
What is transduction?
Exchange of genetic material using a bacteriophage
What is conjugation?
Dependent on the F factor, which, by a variety of mechanisms, can direct genetic exchange between two bacterial cells
What is transformation?
Uptake of exogeneous DNA by cells
What is true about barr bodies?
They ensure that males and females have equal "doses" of the genes on the X chromosome
What are pseudoautosomal regions on the sex chromosomes?
Homologous regions of the X and Y chromosomes
What is true about XYY males?
They are generally taller than average
Which of the following statements about co-transformation is true?
A bacterial cell receives two adjacent genes on a single piece of DNA from the medium
What is virus-mediated bacterial recombination?
Transduction
Why is it easier to identify spontaneous mutations in bacteria than in most eukaryotes?
They are expressed directly in descendent cells because bacteria are haploid