DNA and Genetics

Question 1

TOPIC 1 - Mitosis

What are the 5 phases of Mitosis?

Answer 1

Interphase
Prophase
Metaphase
Anaphase
Telephase

Question 2

TOPIC 1 - Mitosis

What is mitosis?

Answer 2

the cell division which occurs in all cells and results in two cells which have identical nuclei.

Question 3

TOPIC 1 - Mitosis

Describe what happens in Interphase

Answer 3

The cell grows in size
The chromosomes are still large strands of DNA
The chromosomes replicate
Now two chromatids are inside the nucleus joined by centromeres.

Question 4

TOPIC 1 -Mitosis

Describe what happens in Prophase

Answer 4

The nuclear membrane disappears
The centriole divides and moves to the poles of the cell and releases spindle fibres which attach to the centromeres of the chromatids

Question 5

TOPIC 1 - Mitosis

Describe what happens in Metaphase

Answer 5

The chromatids line up in the middle of the cell

Question 6

TOPIC 1 - Mitosis

Describe what happens in Anaphase

Answer 6

The centromeres break as the spindle fibres contract, pulling the now separated chromatids to the poles of the cell
The chromatids are now called chromosomes again

Question 7

TOPIC 1 - Mitosis

Describe what happens in Telophase

Answer 7

The chromosomes form 2 sets
Nuclear membranes form around each set
The cells start to divide

Question 8

TOPIC 1 - Mitosis

Describe what happens in Cytokinesis

Answer 8

The cytoplasm splits and the cell membrane reforms

Result is two new cells

Question 9

TOPIC 2 - Cancer

What is cancer?

Answer 9

Cancer is uncontrolled cell division which interferes with normals cells and competes for nutrients and space.

Question 10

TOPIC 2 - Cancer

Why do cancer cells keep growing to form tumours?

Answer 10

Cancer cells do not exhibit CONTACT INHIBITION, where they stop growing when they touch another cell. Rather they ignore the contact and continue to divide.

Question 11

TOPIC 2 - Cancer

What is it called when cancer cells spread around the body?

Answer 11

When cancer cells spread in the blood of lymph it is called METASTASIS.

Question 12

TOPIC 2 - Cancer

What is the gene that controls cell division called? What happens if a mutation occurs in these genes?

Answer 12

The genes that control cell division are the PROTO-ONCO genes and are activated by hormones. If a mutation occurs the mutated gene is then called a ONCO gene and do not deactivate, leading to uncontrolled cell division.

Question 13

TOPIC 2 - Cancer

Can mutations be caused by outside factors?

Answer 13

Yes, they can be caused by many things which are called carcinogens.

Question 14

TOPIC 3 - Cancer cells vs. normal cells

What are the differences between cancerous cells and normal cells?

Answer 14

NORMAL CELLS

• contact inhibition
• divide at a normal rate
• will stay in mapped cell place
• function normally
• fit together and don’t compete for nutrients

CANCER CELLS

• no contact inhibition
• divide at a rapid rate
• can easily break away and spread
• do not carry out their functions
• compete with normal calls for space and nutrients

Question 15

TOPIC 4 - The structure of DNA

What are the names of the four nitrogenous bases?

Answer 15

Adenine
Thymine
Cytosine
Guanine

Question 16

TOPIC 4 - The structure of DNA

What is the structure of a nucleotide?

Answer 16

A phosphate connected to a sugar (deoxyribose) connected to a nitrogenous base (adenine, thymie, cytosine, guanine)

Question 17

TOPIC 4 - The structure of DNA

What is the shape and structure of DNA?

Answer 17

DNA is in the shape of a double helix. It has a sugar-phosphate back bone with nitrogenous base pairs.

Question 18

TOPIC 5 - DNA replication

What are the 5 steps to DNA replication?

Answer 18

1. The original DNA
2. The bonds between the DNA chains break
3. There are now two separate strands of DNA
4. Each chain attracts single complimentary DNA nucleotides found in the nucleus
5. The single nucleotides join the strands of DNA to form two identical molecules of DNA

Question 19

TOPIC 6 - Protein Synthesis

What is step 1 of protein synthesis?

Answer 19

The original DNA molecule in the Nucleus unzips.

Question 20

TOPIC 6 - Protein Synthesis

What is step 2 of protein synthesis?

Answer 20

The unzipped DNA strand attracts RNA nucleotides that form the complimentary base pairs of the DNA. This is called m-RNA, and the process is called TRANSCRIPTION.

Question 21

TOPIC 6 - Protein Synthesis

What is step 3 of protein synthesis?

Answer 21

The m-RNA moves out of the nucleus and attaches to a ribosome with the bases facing outwards. A set of the 3 bases is called a codon.

Question 22

TOPIC 6 - Protein Synthesis

What is step 4 of protein synthesis?

Answer 22

Transfer RNA’s (t-RNA) anti-codons are attracted to the codons on the m-RNA. The t-RNA have a amino acid attached the other side of each anti-codon.

Question 23

TOPIC 6 - Protein Synthesis

What is step 5 of protein synthesis?

Answer 23

The amino acids on the opposite end of each anti-codon are lined up in a particular order and are then joined together by enzymes. This results in a protein. This process is called TRANSLATION.

Question 24

TOPIC 7 - Mutations

What are the two types of Mutations?

Answer 24

Point mutations and frameshift mutations

Question 25

TOPIC 7 - Mutations

What is a Point mutation?

Answer 25

A point mutation occurs when a single base is substituted for another. This change can effect the amino acid produced.

Question 26

TOPIC 7 - Mutations

What is a Frameshift mutation?

Answer 26

A frameshift mutation occurs when a base is either added or deleted from a base sequence of DNA. This is worse than a point mutation as it can change a whole strand of DNA rather than just one base.

Question 27

TOPIC 8 - Genetic engineering and restriction enzymes

What is a restriction enzyme?

Answer 27

A restriction enzyme is a special enzymes used to cut DNA at a particular code.