2.2- DNA REPLICATION

Question 1

How are all cells formed?

Answer 1

cellular fusion

Question 2

What is not formed by cellular fusion?

Answer 2

zygotes

Question 3

How are all cells that make up a multicellular organisms derived and by what process?

Answer 3

derived from existing cells by process of division

Question 4

In what two main stages does cell division occur?

Answer 4

nuclear division

cytokinesis

Question 5

What is nuclear division?

Answer 5

process by which nucleus divides

Question 6

what are the two types of nuclear division?

Answer 6

mitosis

meiosis

Question 7

What is cytokinesis?

Answer 7

follows nuclear division and is process by which whole cell divides

Question 8

What must happen before a nucleus divides?

Answer 8

its DNA must be replicated (copied)

Question 9

Why must the DNA be replicated before the nucleus divides?

Answer 9

ensure that all the daughter cells have the same genetic information to produce enzymes + other proteins they need

Question 10

What model of DNA replication is universally accepted?

Answer 10

semi-conservative model

Question 11

What are the four requirements for semi-conservative replication to take place?

Answer 11

four types of nucleotide, each with their bases must be present

both strands of DNA molecule acts as template for attachment of nucleotides

enzyme DNA polymerase

source of chemical energy required to drive process

Question 12

Process of semi-conservative replication #1

Answer 12

enzyme DNA helicase breaks hydrogen bonds linking base pairs of DNA

Question 13

Process of semi-conservative replication #2

Answer 13

so double helix separates into its two strands + unwinds

Question 14

Process of semi-conservative replication #3

Answer 14

each exposed polynucleotide stand then acts as a template to which complementary free nucleotides bind by specific base pairing

Question 15

Process of semi-conservative replication #4

Answer 15

nucleotides joined together in condensation reaction by enzyme DNA polymerase to form “missing” polynucleotide strand on each of the two original polynucleotide strands of DNA

Question 16

Process of semi-conservative replication #5

Answer 16

each of the new DNA molecules contains one of the original DNA strands, that is, half the original DNA has been saved and built into each of the new DNA molecules. Process termed as “semi-conservative replication”