Cell Division And Inheritance

Question 1

How do body cells devide?

Answer 1

By mitosis

Question 2

What do chromosomes contain?

Answer 2

The genetic information

Question 3

What occurs when a body cell divides by mitosis?

Answer 3

Copies of the genetic material are made

Then the cell divides once to form two genetically identical body cells

Question 4

When does mitosis occur?

Answer 4

During growth or to produce replacement cells

Question 5

How many set do gametes have?

Answer 5

One

Question 6

What are gametes?

Answer 6

Sex cells

Question 7

How are gametes formed?

Answer 7

Cells in reproductive organs
Testes and ovaries in humans
Divided to form gametes, when a cell divides to form gametes:
Copies of the genetic information are made
Then the cell divides twice to form four gametes, each which a single set of chromosomes

Question 8

What is meiosis?

Answer 8

It is the type of cell division in which a cell divides to form gametes

Question 9

What happen in meiosis?

Answer 9

Copies of the genetic information are made

Then the cell divides twice to form four gametes, each which a single set of chromosomes

Question 10

What happens when gametes join at fertilisation?

Answer 10

A single body cell with new pairs of chromosomes is formed. A new individual then develops by this cell repeatedly dividing by mitosis

Question 11

Differentiation in plants and animals.

Answer 11

Most this of animals cells differentiate at an early stage whereas many plant cells retain the ability to differentiate throughout life. In mature animals, cell division is mainly restricted to repair and replacement

Question 12

What are stem cells?

Answer 12

They are cells in human embryos and adult bone marrow

Question 13

What can stem cells be used for?

Answer 13

Can be used made to differentiate into many differ et types of cells
e.g. nerve cells

Question 14

What are human stem cells able to do?

Answer 14

To develop into any kind of human cell

Question 15

What may treatment with stem cells be able to help with?

Answer 15

Conditions such as paralysis

Question 16

What are the cells of the offspring produced by and what do they contain?

Answer 16

They are produced by asexual reproduction are produced by mitosis from the parental cells. They contain the same alleles as the parents

Question 17

What does sexual reproduction give and why?

Answer 17

It gives variation because when gametes fuse, one of each pair of alleles comes from each parent

Question 18

How many pairs of chromosomes a in the human body and how many contain the genes that determine sex?

Answer 18

23 pairs

One of which carries the gene that determine sex

Question 19

What do female sex cells look like?

Answer 19

XX

Question 20

What do male sex cells look like?

Answer 20

XY

Question 21

What can some characteristic be determined by?

Answer 21

By a single gene

Question 22

What are alleles?

Answer 22

Different form of the same gene

e.g. eyes have different colours

Question 23

What is a dominate allele?

Answer 23

An allele that controls the development of a characteristics when it is presented on only one of the chromosomes

Question 24

What is a recessive allele?

Answer 24

An allele that control the development do characterises only of the dominate allele is not present

Question 25

What are chromosomes made up of?

Answer 25

Large molecule of DNA (A stands for acid) whichever has double helix structure

Question 26

What is a gene?

Answer 26

A small section of DNA

Question 27

What are special about genes?

Answer 27

Each gene codes for particular combination of amino acids which make a specific protein

Question 28

What does each person have (except identical twins)?

Answer 28

They have a unique DNA. This can be used to identify individuals in a process know as DNA

Question 29

How do you get some disorders?

Answer 29

They are inherited

Question 30

What is polydactyly and what is it cause by?

Answer 30

Having extra fingers or toes

It is causes by a dominant allele of a gene and can therefore be passed on by only one parent who has the disorder

Question 31

What is cystic fibrosis and how do you inherited it?

Answer 31

It is a disorder of cell membranes
It must by inherited by both parents. The parents may be carries of the disorder without actually having the disorder themselves. It is caused by a recessive allele of a gene and can therefore be passed on by parents, neither of whom had the disorder

Question 32

What is embryo screening?

Answer 32

It is when an embryo is screened for the alleles that cause genetic diorders

Question 33

In body cells how are chromosomes normally found?

Answer 33

In pairs