Cell Cycle Control + Replication

Question 1

Helicase

Answer 1

unwinds the double helix to separate strands and make each accessible to be copied

Question 2

DNA polymerase III (and II)

Answer 2

can ‘read’ a DNA strand and add complementary bases on to the other strand

Question 3

What does DNA polymerase need to work?

Answer 3

a free 3’ OH to add on to

Question 4

Primase

Answer 4

can ‘read’ a DNA strand and add complementary RNA bases on to the other strand

can only add to the 3’ end, but can start a new chain

Question 5

DNA polymerase I

Answer 5

can remove RNA bases and replace them with DNA bases

can only add to a 3’ OH

Question 6

Ligase

Answer 6

can form bond between 5’P group and 3’ OH group for bases next to each other

connects fragments

used in both leading and lagging strands, but more in lagging strand

Question 7

Why do cells need gap phase?

Answer 7

Single and multicellular organisms both need to ensure there are enough materials to support two cells after division

Multicellular organisms need to tightly regulate number of each cell type

Question 8

Before replication what needs to be checked at G1 checkpoint?

Answer 8

Cell size

nutrients/resources

DNA is in good shape

Growth/social signals

Question 9

Before entering mitosis, what needs to be checked at G2 checkpoint?

Answer 9

DNA properly and completely replicated

Enough organelles to support 2 cells

Question 10

During mitosis, what needs to be checked at M checkpoint

Answer 10

All chromosomes are attached to spindle

All chromatids are separated

Question 11

Kinase

Answer 11

enzyme that phosphorylates substrates

often obtain the phosphate from ATP

Question 12

Cyclin-dependent kinase (CDK)

Answer 12

kinase that is only active when cyclin is bound to it

work to regulate different parts of the cell cycle