DNA

Question 1

What is DNA?

Answer 1

DNA is found in the nucleus of animal and plant cells in really long molecules called CHROMSOMES.

DNA contains all the instructions to make the cell and organism work

Question 2

Whatis a gene?

Answer 2

A gene is a section of DNA - it contains the instructions to make a specific protein.

This in turn determines what type of cell is produced - red blood cell, skin cell etc.

Question 3

How do cells make protein?

Answer 3

They do so by stringing amino acids together in a particular order.

There are only 20 amino acids but they make up thousands of different proteins

Question 4

Is DNA the same for everyone?

Answer 4

No everyone’s DNA is different unless you are identical twins or a clone

Question 5

What is DNA fingerprinting?

Answer 5

This is where a person’s DNA is cut up into small sections and then separating them.

Every person’s genetic fingerprint has a unique pattern which means you can tell people apart by comparing samples of their DNA.

Question 6

Give two examples of where the use of DNA fingerprinting is used

Answer 6

1. Forensic science - crime scene

2. Paternity testing

Question 7

Should we have a genetic database where everyone’s DNA is stored

Answer 7

The argument for is that this was assist criminal investigations but others say this is an invasion of privacy.

There is also the scientific problems - FALSE POSITIVES which can occur if errors are made in the procedure or if the data is mininterpreted.

Question 8

What does MITOSIS do?

Answer 8

Mitosis makes new cells for growth and repair

Question 9

Explain mitosis works

Answer 9

1. Body cells normally have two copies of each chromosome - one from the organism’s mother and one from its father.
2. So humans have two copies of chromosome 1, two copies of chromosome 2.
3. There are 23 pairs of chromosomes from a human cell.
4. When a body cell divides it needs to make new cells identical to the original cell.
5. This type of cell division is called Mitosis

Question 10

Give a detailed explanation of how Mitosis works

Answer 10

1. In a cell not dividing the DNA is spreadd out like a long string.
2. If the cell gets a signal to divide, it duplicates the DNA so there’s one copy for each cell.
3. The DNA is copied and forms X shaped chromosomes. Each arm of the chromosome is an identical duplicate of the other.
4. The chromosomes then line up in the centre of the cell and cell fibres pull them apart. The two arms of each chromosome go to opposite ends of the cell.
5. Membranes form around each of the sets of chromosomes. These become nuclei of the two new cells.
6. Lastly the cytoplams divides.

Question 11

Does Asexual reporduction use Mitosis?

Answer 11

Yes. some organisms such as strawberry plants form runners in this way.