Mitosis, Meiosis, Clones, Stem cells

Question 1

What is meant by mitosis?

Answer 1

Cell division.

Question 2

What is meant by a diploid cell?

Answer 2

A cell that has 2 sets of chromosomes.

Question 3

Before the parent cell divides what occurs?

Answer 3

DNA replication.

Question 4

What happens after DNA replication?

Answer 4

The parent cell divides and forms TWO genetically identical DIPLOID cells.

Question 5

Name three situations where mitosis is used to produce new cells?

Answer 5

• Growth
• Repair
• Asexual reproduction

Question 6

Give 2 examples of asexual reproduction.

Answer 6

• Bacteria splitting into two.

- A plant making new plantlet to split off from the parent plant to grow on their own.

Question 7

True or false:

Asexual reproduction produces genetically identical offspring.

Answer 7

Truuuuuuuuuuuu

Question 8

What is fertilisation?

Answer 8

When a male gamete combines with a female gamete to produce a zygote.

Question 9

What’s meant by a haploid cell?

Answer 9

A cell that only has 23 chromosomes (remember HAploid is HAlf).

Question 10

What is meant by meiosis?

Answer 10

Cell division, that happens when a diploid cell divides to produce haploid gametes.

Question 11

What is the first thing that happens in the parent cell when meiosis takes place?

Answer 11

DNA replication.

Question 12

What’s the difference in the steps after DNA replication between mitosis and meiosis?

Answer 12

Mitosis: The parent cell splits into 2 diploid cells with 46 chromosomes per cell.
Meiosis: The parent cell splits into 4 haploid cells with 23 chromosomes each.

Question 13

True or false:

Meiosis produces 4 identical haploid daughter cells.

Answer 13

False, they are non-identical.

Question 14

True or false:

Cloning is an example of asexual reproduction.

Answer 14

True.

Question 15

What are the 6 main steps when cloning animals.

Answer 15

1. Nucleus is removed from egg cell.
2. The diploid nucleus is removed from an adult body cell.
3. The removed diploid nucleus is placed inside the empty egg cell.
4. The cell is then stimulated with an electric pulse to start mitotic division.
5. The cell divides and grows as an embryo.
6. The embryo is placed in a surrogate mothers uterus.

Question 16

What is one advantage of cloning?

Answer 16

If the animal coned has desirable features then all of its offspring will have the same good features.

Question 17

Name 3 disadvantages of cloning.

Answer 17

• It’s more difficult to clone a mammal than a plant. Cloning a mammal will take several attempts.
• Cloned mammals may suffer more health problems than usual which can cause them to die early.
• Any genetic defects will be passed on from parent to offspring.

Question 18

What is a stem cell?

Answer 18

A differentiated cell that can divide to produce many different types of cells.

Question 19

What are the two main kinds of stem cell?

Answer 19

• Embryonic: taken from embryos that only contain a few cells.
• Adult: found in differentiated tissue e.g. bone and skin for repair.

Question 20

What are the pros and cons of using embryonic stem cells?

Answer 20

Pros:

• Easy to extract.
• Can produce any type of cell (except gametes).

Cons:

• Unethical.
• Body will reject without drugs.

Question 21

What are the pros and cons of using adult stem cells?

Answer 21

Pros:

• No ethical issues.
• If taken from the same person they won’t face rejection.

Cons:

• Difficult to find and extract tissue.
• Produce only a few types of cell.

Question 22

Name one advantage and one disadvantage of stem cells in general.

Answer 22

Advantage: They replace a faulty cell with a healthy cell.

Disadvantage: They can produce cancer cells instead.