1.02 DNA Replication & The Cell Cycle

Question 1

What is chromatin?

Answer 1

DNA coiled around histones

Question 2

What is heterochromatin?

Answer 2

Tightly packed chromatin and is A-T rich

Question 3

What is euchromatin?

Answer 3

Loosely packed chromatin and is G-C rich/gene rich

Question 4

How many chromosomes are there in the cell nucleus

Answer 4

46. 2x22 autosomes + 2 sex chromosomes
    Diploid: 2n = 46

Question 5

What is DNA replication?

Answer 5

The process of producing an exact copy of the genetic material from a template

Question 6

What are the four main proteins involved in DNA replication and what do they do?

Answer 6

DNA Polymerase: produces complementary strands in a 5’ to 3’ direction. Performs two functions, Extension (addition of new bases) and Excision/Proofreading (Monitoring of addition of nucleotides)
Helicase: Move along the DNA and separate the two strands
Primase: adds a primer to the DNA to allow replication
DNA Ligase: Facilitate the joining of two DNA strands

Question 7

What is Mitosis?

Answer 7

It is the replication division of normal (somatic) cells.

Question 8

What is Meiosis?

Answer 8

Is the reduction division of sex cells (gametes). End up with ‘n’ rather than 2n.

Question 9

What are the phases of the cell cycle and what occurs at each stage?

Answer 9

G0: Cells that have left the cell cycle (stopped dividing)
G1: RNA synthesis
S: DNA replication
G2: Chromatin condense into chromosomes
M: Cell division

Question 10

Define: Gene Expression

Answer 10

It is the process by which information from a gene is used in the synthesis of a functional gene product