T3L7 Gametes Flashcards
What are gametes
Haploid cells with half the number off chromosomes
Through what process are gametes created
Meiosis
Name the parts of the mammalian egg
Follicle cells from ovary
Cell membrane
Zona pellucida
Cytoplasm
Lysosomes
Lipid droplets
Nucleus
Describe the purpose of follicle cells
They secrete chemicals to stimulate the acrosome reaction
Describe the purpose of the zona pellucida
Hardens once a sperm nucleus has fused with the egg nucleus to stop further sperm from entering
Describe the purpose of
Cytoplasm in egg
Large so zygote can divide easily
Describe the purpose of lysosomes in egg
Cortical granule - contain enzymes that cause the zp to harden
Describe the purpose of lipid droplets
Provide a source of energy for further division
Describe the parts of a mammalian sperm
Acrosome, nucleus, mitochondrion, tail
Describe the acrosome
An adapted lysosome.
The acrosome swells and bursts when the sperm embeds in the zp (caused by chemicals secreted by the follicle cells)
The enzymes digest f cells and zp so the gamete nuclei fuse
Describe the mitochondrion in sperm
In in the middle body make ATP - aerobic respiration
Describe the tail in sperm
Made from motor proteins and uses ATP to propel the sperm to the egg
Describe the acrosome reaction
Acrosomes are lysosomes found in the sperm ehad
Follicle cells release chemicals that trigger the acrosome to swell and fuse with the cell membrane
A bursts and enzymes released by exocytosis
Enzymes breakdown the zp so that the cell membranes can fuse
Describe the Cortical reaction
When the sperm has penetrated the ovum’s membrane, the ovum releases chemicals that thicken the zp.
There is also a change in charge across the membrane (Ovum)
This prevents entry of further sperm
