Meiosis Flashcards
(19 cards)
Define sister chromatids.
Replicated (identical) chromosomes.
What are homologous chromosomes?
A pair of chromosomes which contain genes for the same traits but are not identical.
What occurs during Meiosis I?
Separates homologous chromosomes.
What happens in interphase I of meiosis?
Chromosomes duplicate.
What is synapsis?
Synaptonemal complex (a protein) holds homologs together.
What is chiasmata?
Crossing of non-sister chromatids.
What happens during anaphase I?
Pairs of homologous chromosomes split up.
What is the outcome of telophase I and cytokinesis in meiosis?
Two haploid cells form, chromosomes are still double.
What is the main difference between meiosis I and meiosis II?
Meiosis I separates homologous pairs of chromosomes, not sister chromatids.
How does meiosis II compare to mitosis?
Meiosis II is similar to mitosis, but chromosomes do not replicate between meiosis I and II.
What is independent assortment of chromosomes?
The random distribution of homologous chromosomes during gamete formation.
What is crossing over?
Produces recombinant chromosomes, which are not entirely inherited from either parent. Crossing over is visible as chiasmata
When does crossing over begin?
In prophase I.
On average, how many crossovers occur per chromosome pair in humans?
2-3 crossovers.
What is random fertilization?
A zygote is formed from an ova and a sperm, greatly increasing the number of possible combinations.
How does genetic variation contribute to evolutionary adaptation?
A population evolves through differential reproductive success of its members.
What is natural selection?
Individuals best suited to an environment leave the most offspring, transmitting their genes.
Why is heritable variation important for evolution?
It allows different combinations of genes to compete, enabling some combinations to function better than others.
What does comparative genomics help us understand?
How our own genome functions and how we evolved.
