DNA Replication, Mitosis, Meiosis Flashcards
In what stage of the cell cycle does cell checking and repair occur?
G2
In what stage of the cell cycle does DNA replication occur?
S
In what stage of the cell cycle does cell division occur?
M
What enzyme is used to catalyse DNA replication?
DNA polymerase
In what direction does the new chain in DNA replication grow?
5’ to 3’
What is required for DNA replication to start?
Primase- to create a primer strand
In what stage of the cell cycle does cell content replication occur?
G1
What are the names of the 2 newly formed strands of DNA in replication?
Leading strand
Lagging strand
Why is the lagging strand not continuous and what is the name given to the fragments?
DNA is made from 5’ to 3’. As the DNA unwinds, small chains of DNA are made. These are called Ozazaki fragments.
Which enzyme connects Ozazaki fragments?
DNA ligase
Which enzyme unwinds the DNA alpha helix?
DNA helicase
How many DNA molecules are in a chromosome?
1
What is mitosis?
Cell division in somatic cells to produce 2 identical daughter cells
What happens in prophase?
The nuclear membrane breaks down and spindle fibres appear
What happens in Prometaphase?
A kinetochore attached to the centromere is attached to the spindle fibres
What happens in Metaphase?
The chromosomes line up randomly in the centre of the cell. The spindle fibres are polar.
What happens in Anaphase?
The chromatids separate as they are pulled by the spindle fibres
What happens in Telophase?
2 nuclear membranes form around each group of chromosomes. The cytoplasm starts to split.
What is meiosis?
A special type of cell division for germ line cells. It produces 4 non-identical, haploid cells.
In meiosis, at what stage does crossing over occur?
Metaphase I
Name the products at the 4 steps of spermatogenesis
1 Spermatogonium
1 Primary spermatocyte
4 Spermatids
4 Mature sperm
Name the products at the 3 stages of oogenesis
1 Oogonium
1 Primary Oocyte
3 Polar bodies + 1 Mature Ovum
