University:
The University Of Western Ontario
Course:
Biology 2290F | Scientific Method in Biology
Academic year:

2022
Views:

242

Pages:

3
Author:

Kyuwon J.

Chromosome counting ● The coefficient of N would only change if the number of chromosomes changes ● In order to count how many chromosomes we have, we count the number of centromeres → # of centromeres = # of chromosomes ● In the first picture we have 2 centromeres, representing 2 homologous chromosomes ● In the second picture ○ Human still have 2 chromosome at this point ○ We still only have 2 centromeres ○ Coefficient of N does not change ● coefficient is the number in front of a variable ○ multiplied with the variable ● Ex. in humans: ○ N = 23 chromosome ○ Before replication 2N = 46 chromosome ○ After replication we still have 46 chromosomes meaning we still have 2N - - - - The C value is the amount of dna you have (genome size), and the coefficient of C represents how many copies of your genome you have When we replicate our DNA for mitosis, we replicate the whole genome (all chromosomes are replicated) This means that the coefficient of C does change - This is not just C values We go from 2C to 4C (in humans) Continuous vs Discontinuous ● Polymerase can only add nucleotide on continuous ○ One direction only ○ Anti parallel nature ○ Semi discontinuous replication ● Leading strands ○ Continuous replication ○ Moves towards replication fork ● Lagging strands ○ Discontinuous replication moving away from replication fork ○ Okazaki fragment ● Anti parallel DNA = DNA polymerase 3 can add nucleotide continuously ○ One direction in replication fork ● Leading strand synthesize continuously in one direction ● Okazaki fragment are sealed Replication bubble ● Multiple origin increases replication efficiency ● Origin has 2 replication forks traveling ○ Each moves in opposite directions ○ Bi-directional ● DNA replicated continuously at one fork ● Discontinous in the other fork