DNA, DNA Replication and Cell Division

Question 1

What is DNA?

Answer 1

A molecule that carries genetic instructions used in the development, functioning, growth, and reproduction of all living organisms

Question 2

Describe the structure of DNA

Answer 2

Made of two linked strands that wind around each other to resemble a twisted ladder, a shape known as a double helix

Contains four types of nucleotides (ATGC)

Question 3

State the role of detergent in DNA extraction

Answer 3

Helps to dissolve the phospholipid bilayers of the cell membrane and organelles

Question 4

State the role of salt in DNA extraction

Answer 4

Used to break up protein chains that bind around the nucleic acids

Question 5

State the role of Ethanol in DNA extraction

Answer 5

Used to precipitate the DNA

Question 6

Describe the process of DNA replication.

Answer 6

1. Double helix/complementary base pairing
2. Double helix unwound and unzipped by helicase, forming the replication fork
3. Polyermase synthesis new complimentary nucleotide strand based on complimentary base pairing
4. There are now two genetically identical pairs

Question 7

State that DNA is a semi-conservative process

Answer 7

During DNA replication, each original DNA molecule separates into two strands. Each of these strands act as a template for the new synthesis of a new complementary strand

This is a semi-conservative process because it conserves oone of the original DNA strands in each new molecule.

Question 8

State the changes of DNA during interphase

Answer 8

The period of the cell cycle where the cell grows and makes a copy of its DNA, preparing the cell for division

Question 9

State the changes of DNA during mitosis

Answer 9

During the mitotic phase, the cell separates its DNA into two sets and divides its cytoplasm, forming two new cells.

Question 10

State the mitotic index formula

Answer 10

Cells in mitosis / Total number of cells

Question 11

State the difference between meiosis and mitosis.

Answer 11

Mitosis - process where a single cells divides into two identical daughter cells (cell division)

Meiosis - Process where a single cell divides twice to produce four cells that contain half the original amount of genetic information.

Question 12

What does PCR stand for?

Answer 12

Polymerase chain reaction

Question 13

Outline the process of DNA replication to amplify viral DNA using PCR.

Answer 13

1. Double-stranded DNA is heated to separate the two strands and resulting in a single-stranded DNA
2. Temperature is lowered, allowing short DNA primers to bind to specific regions of the single-stranded DNA.
3. A heat-stable DNA polymerase enzyme synthesised new DNA strands from the primers, using the single-stranded DNA as a template.

Question 14

Complementary base pairing

Answer 14

Refers to the specific pairing of nitrogenous bases in the DNA

Hydrogen bonding between that always occurs T and A; G and C

Question 15

Pentose

Answer 15

The sugar found in a nucleotide (of DNA)

Question 16

Nitrogenous base

Answer 16

A molecule found in DNA that encodes genetic information in cells.

Question 17

Hydrogen bond

Answer 17

The attraction between nitrogenous bases of two strands of DNA.

Question 18

Covalent bond

Answer 18

The attraction between pentose and phosphate between nucleotides of a single strand of DNA

Question 19

State the function of DNA polymerase

Answer 19

An enzyme that plays a crucial role in DNA replication.

Adds nucleotides to the growing new strand of DNA, using the
existing template as a guide

Also checks for and corrects errors to make sure the new DNA strand is
accurate