Meiosis
4 haploid gametes
What is a different version of a gene called?
Allele
In what phase of Meiosis does first division nondisjunction occur?
Anaphase 1
What is the protein coat of a virus called?
Capsid
What are the 2 main sources of genetic variation?
- Mutation
- Recombination
During which phase do homologous chromosomes pair up?
Prophase 1
What term describes a genotype of two identical alleles?
Homozygous
How does first division nondisjunction affect chromosome number in gametes?
Produces gametes with extra or missing chromosomes.
What is a virus outside a host cell called?
Virion
What does an environment in Hardy-Weinberg equilibrium mean?
No change in allele frequencies
If nondisjunction occurs in Meiosis 1, how many normal gametes are produced?
0
What is a testcross?
A testcross is the mating of an individual with an unknown genotype with a homozygous recessive individual to determine the unknown genotype.
What chromosomal condition is described by 2n + 1?
Trisomy
Which viral cycle results in immediate destruction of the host cell?
Lytic cycle
True or False: Individuals evolve.
False!
- Populations evolve, not individuals.
What structure is formed when homologous chromosomes pair during Prophase 1?
Bivalent
What fraction of offspring from Aa x Aa will show the dominant phenotype?
3/4
A zygote has 3 copies of chromosome 21. What is the condition called?
Down syndrome
What is viral DNA integrated into a bacterial genome called?
Prophage
What type of selection favors extreme traits over intermediate ones?
Disruptive selection
Describe what happens in Prophase 1
Homologous chromosomes condense, bivalent forms, nuclear envelope begins to break down.
If both alleles are fully expressed in the phenotype, what inheritance pattern is this?
If sister chromatids fail to separate, which division was affected?
Meiosis 2
What enzyme do retroviruses use to make DNA from RNA?
Reverse transcriptase
Contrast genetic drift vs. shift
- Genetic shift: A sudden major genetic change.