Meiosis
during which phase of meiosis do homologous chromosomes separate?
anaphase I
What is a dominant allele?
an allele that expresses its trait even when only one copy is present
what is the function of a viral capsid?
to protect the viral genetic material
what is evolution?
change in a population’s genetic makeup over time
what is the biological species concept?
a species is a group of populations that can interbreed in nature and produce viable, fertile offspring
what is a zygote?
a diploid cell formed by the fusion of two gametes
what is the difference between genotype and phenotype?
genotype is the genetic makeup (e.g., Aa)
phenotype is the observable trait (e.g., tall)
what type of virus infects bacteria?
bacteriophage
what is population genetics?
the dynamics of genes in populations
what is the difference between a pre- and post-zygotic barrier?
Prezygotic barrier- impede fertilization
Postzygotic barrier- impede development
of viable, fertile offspring
in humans, how many chromosomes are in a typical gamete?
23
why did Mendel choose pea plants for his experiments?
had easily observable traits, grew quickly, and could self- or cross-pollinate
what is a virus made of?
protein and RNA or DNA
what is natural selection?
the process where organisms with favorable traits survive and reproduce
what is allopatric vs. sympatric speciation?
a population is isolated geographically vs. a reproductive barrier that isolates
what is a tetrad?
a pair of homologous chromosomes, each made of two sister chromatids
If two heterozygous tall pea plants (Tt × Tt) are crossed, what percent of offspring are expected to be short?
25%
what do we call the range of species and cell types a virus can infect?
the host range
what is the difference between micro vs. macroevolution?
change in allele frequencies in a population over generations vs. multiple small changes over time lead to new species
what is Punctuated Equilibrium?
periods of little change followed by periods of
rapid evolution
which stage of meiosis is responsible for reducing the chromosome number from diploid to haploid?
meiosis I
what is a test cross, and why is it used?
a cross between an organism with an unknown genotype and a homozygous recessive to determine the unknown genotype.
what enzyme do retroviruses use to make DNA from RNA?
reverse transcriptase
What are the 5 conditions to satisfy the Hardy-Weinberg Theorem?
1. No mutation. No new alleles are generated by mutation, nor are genes duplicated or deleted.
2. Random mating.
3. No gene flow. ...
4. Very large population size.
5. No natural selection.
what is speciation?
The appearance of a new species