Mitosis and DNA Flashcards
Describe purpose of mitosis
To replicate DNA in new somatic cells in order for an organism to grow and repair
Why is DNA replication semi-conservative?
Each DNA molecule produced is comprised of an old, conservative strand and a new strand.
How does DNA replication occur?
The enzyme helicase unzips parent strand of DNA, resulting in a replication fork. The enzyme DNA polymerase allows free DNA bases to attach to the corresponding base in either strand, forming two identical strands of DNA - each semi-conservative.
Describe the importance of base pairing rule for DNA replication
A pairs with T in opposite strand. C pairs with G in opposite strand. When anti-parallel polymers are unzipped, the complementary base-pairing rule determines the new RNA bases that will pair with the conserved strand of DNA. Thus, effective DNA replication can occur as two identical DNA molecules can be created, so when cell splits, both cells will contain the identical genetic information.
How does surface area to volume ratio change as the cell grows larger?
Surface area to volume ratio decreases as cell grows larger. (1:2 —- 1:4). There becomes a greater need for cell to split by mitosis to facilitate excess nutrients, enzymes, ions etc.
