genetic information (meiosis) Flashcards
what are gametes?
sex cells- sperm or egg
what is a zygote?
diploid cell resulting from the fusion of 2 gametes in fertilisation
what type of cells are diploid?
normal body cells
what is a diploid cell?
cell containing two complete sets of chromosomes
what type of cells are haploid?
gametes
what is a haploid cell?
contains a single set of chromosomes
how are gametes formed?
by meiosis
where does meiosis occur?
in the reproductive organs
what is produced in meiosis?
4 haploid cells (gametes) that are genetically different from eachother
what happens in meiosis 1?
prophase 1:
DNA replication
homologous chromosomes pair
DNA crosses over
metaphase 1:
chromosomes align on the cell equator
anaphase 1:
chromosome pairs separate
telophase 1:
nuclear envelopes reform
what happens in meiosis 2?
prophase 2:
chromosomes move towards the cell equator
metaphase 2:
line up on the equator
microtubules attach
anaphase 2:
chromosomes pull apart at the centromere
telophase 2:
new cell membranes and gametes form
what type of reproduction is mitosis/meiosis?
mitosis= asexual meiosis= sexual
is there variation in mitosis/meiosis?
mitosis= no variation meiosis= variation
when does crossing over occur?
meiosis 1
how does crossing over lead to genetic variation?
each of the daughter cells contains chromatids with different alleles
