T2 Lesson 9 - Mitosis

Question 1

What is mitosis?

Answer 1

Part of cell division in which the nucleus divides eventually producing 2 daughter cells which are genetically identical to the parent cell.

We say the new cells are clones

Question 2

Give some examples of the use of mitosis?

Answer 2

-cloning
-Asexual reproduction
-making new deploid cells
-growing and healing

Question 3

What is asexual reproduction?

Answer 3

When an organism reproduces (makes more of itself) without exchanging genetic information with another organism through sex.

Question 4

How do humans use mitosis?

Answer 4

• make new diploid cells for growing and healing.

Question 5

The 4 stages of mitosis

Answer 5

-Prophase
-metaphase
-anaphase
-telophase

Question 6

What is a deploid cell?

Answer 6

A cell that contains a complete set of chromosomes in its nucleus.

Each chromosome in a diploid cell has two copies, which are arranged in homologous pairs.

Question 7

Delpoid cells contain……….

Answer 7

a full set of DNA

Question 8

DNA is very long so it coils itself around a protein called……..

Answer 8

**histones **and wrapped into tight shapes called **chromosomes. **

Question 9

How many chromosomes are in a full set of DNA?

Answer 9

46

23 (from father)
23 (from mother)

Question 10

What is meant by **homologus ** pair?

Answer 10

The chromosome of a mother matched to the same chromosome from a father

Question 11

What needs to happen before mitosis occurs?

Answer 11

The DNA inside a nucleus need to replicate (this is called Interphase)

Question 12

How many chromosomes are in a deploid cell after replication?

Answer 12

92 - the amount of DNA doubles from 46

Question 13

PROPHASE

Answer 13

After DNA replication there are now two copies of each chromosome.

• During prophase chromosomes thicken so they become visible under a microscope. Identical copies join together at their
  centre with a structure called a centromere.
• Each chromosome in the pair is now called a chromatid.
• The* nuclear membrane breaks down,* so the chromatids break free.

Question 14

METAPHASE

Answer 14

• Spindle fibres form from the centrioles at either pole (end) of the cell.
• The chromosomes line up at the equator (centre) of the spindle and attach to it by their centromeres.

Question 16

ANAPHASE

Answer 16

• Spindle fibres shorten pulling chromatids to opposite poles.
• This means separate, identical chromosomes get dragged to either end of the cell (called poles just like the ends of Earth) on the spindle structure.

Question 17

TELOPHASE

Answer 17

• The cytoplasm starts to divide to produce two daughter cells.
• Each is an identical copy to the parent.
• Nuclei form around the chromosomes.

Question 18

Looking at the image describe the different stages of mitosis?

Answer 18

Question 19

CENTROMERE

Answer 19

Part of the chromosome where the 2 sister chromatids are held together and which is the attachment site of the spindle fibers during cell division

Question 20

CHROMATID

Answer 20

One of two identical parts or arms of a chromosome

Question 21

Can you name a type of cell that divides by mitosis?

Answer 21

Stem cell

Question 22

When do stem cells stop dividing by mitosis?

Answer 22

When they are asked to turn into specialised cell. This is called differentiation.

Question 23

How many daughter cells are produced during one cycle of mitosis?

Answer 23

2

Question 24

How many stages are there in mitosis?

Answer 24

4

Question 25

Name the missing stage of mitosis.

Answer 25

Anaphase

Question 26

Give the correct label to replace the question mark

Answer 26

centromere

Question 27

Give the correct label to replace the question mark.

Answer 27

Spindle fibre

Question 28

In what phase are new nuclei formed?

Answer 28

telophase

Question 29

In what phase do chromatids line up along the equator?

Answer 29

metaphase

Question 30

Before mitosis, DNA is replicated inside the nucleus. How many chromosomes does the parent cell have as it enters prophase?

Answer 30

92

Question 31

True or False. Daughter cells created by mitosis will be genetically identical to the parent.

Answer 31

True

Question 32

Cancer can result from cells dividing and growing out of control creating a tumour.

Answer 32

Mitosis

Question 33

How many chromosomes are in a diploid cell?

Answer 33

46

Question 34

After DNA replication how many chromosomes will exist in the cell?

Answer 34

92

Question 35

In what stage are these animal (left) and plant (right) cells?

Answer 35

Metaphase as the chromosomes have lined up along the cells equator. Notice the plant cell is more rigid due to its strong cellulose cell wall.

Question 36

At what mitosis stage is the cell in the centre of the image?

Answer 36

Telophase

Question 37

At what stage is this cell in the process of mitosis?

Answer 37

Anaphase

Question 38

You lose millions of skin cells a day. They are replaced by mitosis.

Answer 38

telophase

Question 39

In what stage of mitosis do chromatids thicken and become visible?

Answer 39

prophase

Question 40

The ant only has 1 chromosome in a diploid cell. The Atlas blue butterfly has 448-452 chromosomes in a diploid cell. How many chromosomes do you have in a diploid cell?

Answer 40

46

Question 41

Homologous chromosomes consist of a pair of chromosomes. One from the father and one from the mother.

Answer 41

False