Chapter 2 - Meiosis Flashcards
What is sexual reproduction?
Combines genetic material from 2 parents to form a gentically unique individual
What is one advantage of sexual reproduction
Increases genetic diversity
Increases survival chances
What are the two disadvantages of sexual reproduction?
Takes time and energy to find a mate
Lower rate of offspring production
What are body cells/somatic cells called?
Diploid cells (2n)
What are haploid cells?
Haploid cells are our gametes/sex cells and only contain one copy of a chromosome (n)
What is the total number of chromosome is one somatic cell?
46
(22 pairs of autosomes - non sex chromosome)
(1 pair of sex chromosomes)
What is a homolog/homologous pair?
A pair of chromosomes which contain the genetic code for the same features
What is Meiosis?
Producing four haploid gametes from a single parent cell
Where does Meiosis occur?
Gonads
What differentiates Meiosis from Mitosis?
Meiosis has two deparate division events rather than one because they are producing four haploid gametes.
What happens before meiosis begins?
DNA replication occurs during the S phase to produce identical sister chromatids
What does Meiosis 1 involve?
Separation of homologous chromosome from 2n to n
How many stages are there in total for Meiosis?
8 (Meiosis stage 1 = 4 phases. Meiosis stage 2 = 4 phases)
What is a parent cell called?
Germline cell - diploid (2n)
Describe the events at prophase 1
- replicated DNA condenses
- centrioles start to produce spindle fibres
- Nuclear envelope breaks down
- Spindle fibres attach at centromeres and move to opposite ends