sexual reproduction

Question 1

sexual reproduction (eukaryotes)

Answer 1

sperm (n) / egg (n) = sex cells / gametes

fusing of sperm (n) and egg (n)= fertilisation/ syngamy
sperm and egg fuse into = zygote (2n)

precurers of sex cells –> meiosis –> 1 chromosome out of each pair gets randomly removed (~8 mill combinations)

haploid cell (n) - only 1 set of chromosomes
diploid cell (2n) - 2 sets (redundant - protects us against the effects of mutations)
- gametes have (n) chromosomes
- humans: n=23
- zygotes (and most cells of the body) have 2n chromosome

Question 2

sources of randomness

Answer 2

1. mutations
   - random errors during DNA replication
   - in all organisms

2.sexual reproduction
- random reassortment of homologous chromosomes into gametes
- random crossing over of chromosomes
- random mating (choice of partner)
- only in eukaryotes

Question 3

asexual reproduction

Answer 3

singular, circular chromosome (long piece of DNA)
mitosis
daughter cells are copies of each other

Question 4

isogamy

Answer 4

sexual reproduction without sexes
original form
still in some fung

Question 5

amisogamy

Answer 5

2 gametes fuse together with one gamete being significantly larger (female) than the other (small)