3.4 Genetics and Variation Flashcards
What are the four stages of cell eukaryotic cell division?
Prophase, metaphase, anaphase, telophase
What is chromatin
The unravelled form of chromosomes
What is a chromosome?
A long DNA molecule associated with another protein (usually a histone protein)
How many centromeres in one chromosome?
1
What is a homologous pair of chromosomes?
Unidentical chromosomes with DNA that codes for the same features in the same place.
What are the 4 stages of the cell cycle (not PMAT) and what do they stand for?
G1,growth phase 1
S, synthesis phase
G2, growth phase
M, mitosis
What happens in the four stages of the cell cycle (G1, S, G2, M)
G1- cell grows, normal processes occur
S- chromatids replicate
G2- cells build up ATP, DNA is screened
M- PMAT
What are the 4 stages of mitosis
Prophase
Metaphase
Anaphase
Telophase
What happens in Prophase? (4)
1- chromosomes condense
2- centromeres move to poles
3- spindle fibres form
4- nuclear envelope breaks down
What happens in Metaphase? (3)
1- centrosomes arrive at opposite poles
2-chromosomes line up at equator
3- spindle fibres attach to centromeres
What happens in Anaphase? (2)
1- sister chromatids separate at centromere
2- spindle pulls chromatids to opposite ends of cell
What happens in Telophase?(3)
1- chromosomes decondense back into chromatin
2- nuclear envelope & nucleolus reform
3- spindle breaks down
What happens after Mitosis? (Name and what actually happens)
Cytokinesis, the cytoplasm divides
What controls cell division?
Proteins called cyclins
What controls cell division?
Proteins called cyclins