Cell Division and Inheritance

Question 1

What are chromosomes made from?

Answer 1

Chromosomes are made from DNA. Genes are short sections of DNA.

Question 2

How are genetically identical cells produced?

Answer 2

Genetically identical cells are produced by a type of cell division called mitosis.

Question 3

What is fertilisation?

Answer 3

In sexual reproduction, a male gamete fuses with a female gamete to produce a new cell. This is called fertilisation.

Question 4

How are gametes produced?

Answer 4

Gametes are produced by a type of cell division called meiosis.

Question 5

How many sets of chromosomes do gametes contain?

Answer 5

They contain a single set of chromosomes, whereas body cells contain two sets of chromosomes.

Question 6

What does DNA stand for?

Answer 6

Deoxyribose nucleic acid.

Question 7

What are DNA molecules like?

Answer 7

DNA molecules are large and complex. They carry the genetic code that determines the characteristics of a living thing.

Question 8

Why can people be identified using DNA fingerprinting?

Answer 8

Except for identical twins, each person’s DNA is unique. DNA can be cut up and separated, forming a sort of ‘bar code’ that is different from one person to the next.

Question 9

What is a gene?

Answer 9

A gene is a short section of DNA. Each gene codes for a specific protein by specifying the order in which amino acids must be joined together.

Question 10

Where are chromosomes normally found?

Answer 10

They are normally found in pairs in body cells. Body cells divide by a process called mitosis.

Question 11

What happens when a body cell divides by mitosis?

Answer 11

The genetic material is copied. The cell divides once to form two genetically identical body cells

Question 12

When does mitosis occur?

Answer 12

Mitosis occurs during growth or to produce replacement cells.

Question 13

What are gametes?

Answer 13

Gametes are sex cells.

Question 14

How are gametes formed?

Answer 14

Cells in the reproductive organs (testes and ovaries in humans) divide to form gametes

Question 15

What are male gametes?

Answer 15

Male gametes are sperm (produced in the testes)

Question 16

What are female gametes?

Answer 16

Female gametes are eggs (produced in the ovaries)

Question 17

What is the name of the type of cell division called that produces gametes?

Answer 17

The type of cell division that produces gametes is called meiosis

Question 18

How many sets of genetic information do gametes contain?

Answer 18

Gametes contain one set of genetic information, while body cells contain two sets of genetic information.

Question 19

What happens when fertilisation happens?

Answer 19

When fertilisation happens, a single body cell with new pairs of chromosomes is formed. The new cell then divides over and over again by mitosis.

Question 20

What happens when animal cells differentiate?

Answer 20

Most types of animal cells differentiate at an early stage - they become specialised for a particular function and cannot change into different types of cell.

Question 21

Can plant cells differentiate?

Answer 21

Yes. Many plant cells keep the ability to differentiate.

Question 22

Can stem cells differentiate?

Answer 22

Stem cells can be made to differentiate to form different types of cell, such as nerve cells.

Question 23

Where can human stem cells come from?

Answer 23

Human stem cells can come from human embryos or from adult bone marrow. They are able to develop into any kind of human cell.

Question 24

Can stem cells be used in new treatments for conditions?

Answer 24

Stem cells have the potential to be used in new treatments for conditions such as Parkinson’s disease and paralysis.