Cell Division (1.2)

Question 1

What does the nucleus of a cell contain?

Answer 1

chromosomes made of DNA molecules

i.e. genetic material

Question 2

What does each chromosome carry?

Answer 2

a large number of genes

Question 3

In body cells, chromosomes are normally found in…

Answer 3

pairs

23 pairs in human body cells

Question 4

What is the cell cycle?

Answer 4

Cells divide in a series of stages

Question 5

What happens during the cell cycle to the genetic material and cells?

Answer 5

the genetic material is doubled and then divided into two identical cells.

Question 6

Before a cell can divide (undergo mitosis), what needs to happen?

Answer 6

it needs to grow and increase the number of sub-cellular structures such as ribosomes and mitochondria.

The DNA replicates to form two copies of each chromosome.

Question 7

What happens during mitosis?

Answer 7

one set of chromosomes is pulled to each end of the cell and the nucleus divides

Question 8

What happens during the last stage of the cell cycle?

Answer 8

the cytoplasm and cell membranes divide to form two identical (daughter) cells

Question 9

Put these in order from smallest to largest: nucleus, DNA, gene, chromosome

Answer 9

gene, DNA, chromosome, nucleus

Question 10

What is cell division by mitosis important for?

Answer 10

the growth and development of multicellular organisms.

Question 11

What is a stem cell?

Answer 11

undifferentiated cells that can produce specialised cells and more stem cells

Question 12

What is the function of human embryonic stem cells?

Answer 12

Stem cells from human embryos can be cloned and made to differentiate into most different types of human cells

Question 13

What is the function of adult bone marrow cells?

Answer 13

Stem cells from adult bone marrow can form many types of cells including blood cells

Question 14

What is the function of stem cells from meristem tissue in plants?

Answer 14

Meristem tissue in plants can differentiate into any type of plant cell, throughout the life of the plant

Question 15

There are more, but you only need to recall two of them?

Which conditions may treatment with stem cells may be able to help with?

Answer 15

diabetes and paralysis

Question 15

What occurs during therapeutic cloning? How is this useful?

Answer 15

an embryo is produced with the same genes as the patient.

stem cells from the embryo are not rejected by the patient’s body so they may be used for medical treatment.

Question 16

What are two problems with the use of stem cells?

Answer 16

• there are potential risks such as transfer of viral infection
• some people have ethical or religious objections

Question 17

3 points

What are the uses of stem cells from meristem in plants?

Answer 17

• they can be used to produce clones of plants quickly and economically
• Rare species can be cloned to protect from extinction.
• Crop plants with special features such as disease resistance can be cloned to produce large numbers of identical plants for farmers.

Question 18

How can bone marrow cells help to treat medical conditions?

Answer 18

can differentiate into many types of cell

so will cure diseases where new cells are needed

Question 19

Why might the levels of bacteria level out in a nutrient broth solution?

Answer 19

shortage of nutrients

so cells die (death rate = rate of cell division)