Cell division & Mitosis Flashcards
What is mitosis
Cell division that produces genetically identical cells
Sum up mitosis
Parent cell divides to produce two identical daughter cells (exact copy of DNA)
What are 3 needs for mitosis
Growth of multicellular organisms - Repairing damaged tissue - Asexual reproduction
Define gametes
Male/female sex cells
What is the process that joins gametes
Fertilisation
What does fertilisation produce
A zygote
How many chromosomes do normal cells have
46 (set of 23 from each parent)
How many chromosomes do gametes have
One set (23)
Name 4 key parts of ovum structure
- Cell (plasma) membrane
- Follicle cells
- Zona pellucida
- Nucleus
Function of follicle cells?
Form protective coating
Function of Zona pellucida
Protective glycoprotein layer (sperm have to penetrate)
Why is there lots of mitochondria in sperm
Releases energy in from of ATP, which sperm use to swim
5 main parts of sperm structure
-Nucleus
-Cell (plasma) membrane
-Acrosome
-Flagellum
-Lots of
Mitochondria
Function of acrosome
Contains digestive enzymes to break done Zona pellucida
Function of flagellum
Allows sperm to swim toward egg cell
Where does the sperm have to go to?
Through the cervix and uterus into one of the oviducts
Where does fertilisation occur
The oviduct
What is meiosis
A type of cell division that happens in the reproduce organs
How many chromosomes do cells that divide by mitosis have?
The full number (46) to start with
How many chromosomes do cells that are formed from meiosis have
Half the number (23)
What is the main difference between meiosis and mitosis
Meiosis produces cells that are genetics different
How does genetic variation occur?
Independent assortment of chromosomes
Describe G1 of interphase
Cell grows:
- more cytoplasm
- more organelles
- larger energy store
Describe S stage of interphase
DNA replicates