4.6.1 reproduction

Question 1

Sexual reproduction involves?

Answer 1

the joining (fusion) of male and female
gametes

Question 2

in animals

Answer 2

sperm and egg cells

Question 3

in plants

Answer 3

pollen and egg cells

Question 4

what is there in sexual reproduction and what does it lead to?

Answer 4

In sexual reproduction there is mixing of genetic information which
leads to variety in the offspring

Question 5

The formation of gametes involves?

Answer 5

gametes

Question 6

Asexual reproduction involves

Answer 6

only one parent and no fusion of
gametes

Question 7

in asexual reproduction, there is no mixing of genetic information. what does this lead to?

Answer 7

This leads to
genetically identical offspring (clones).Only mitosis is involved.

Question 8

meiosis ?

Answer 8

halves the number
of chromosomes in gametes

Question 9

fertilisation?

Answer 9

restores the full
number of chromosomes.

Question 10

Cells in reproductive organs divide by?

Answer 10

meiosis to form gametes.

Question 11

When a cell divides to form gametes:

Answer 11

copies of the genetic information are made
* the cell divides twice to form four gametes, each with a single
set of chromosomes

Question 12

all gametes are?

Answer 12

genetically different from each other

Question 13

Gametes join at fertilisation to?and the new cell divides by?

Answer 13

restore the normal number of
chromosomes.
The new cell divides by mitosis.The number of cells
increases

Question 14

As the embryo develops?

Answer 14

cells differentiate

Question 15

The genetic material in the nucleus of a cell is composed of

Answer 15

a chemical called DNA

Question 16

what is DNA?

Answer 16

DNA is a polymer made up of two strands
forming a double helix

Question 17

. The DNA is contained in structures called?

Answer 17

chromosomes

Question 18

what is a gene?

Answer 18

A gene is a small section of DNA on a chromosome

Question 19

what does a gene do?

Answer 19

Each gene codes for a particular sequence of amino acids, to make a specific
protein.

Question 20

what is the genome of an organism?

Answer 20

The genome of an organism is the entire genetic material of that
organism

Question 21

has the whole genome been studied?

Answer 21

The whole human genome has now been studied and
this will have great importance for medicine in the future.

Question 22

what is he importance of
understanding the human genome?

Answer 22

search for genes linked to different types of disease
* understanding and treatment of inherited disorders
* use in tracing human migration patterns from the past.

Question 23

Some characteristics are controlled by a single gene, such as:

Answer 23

fur
colour in mice; and red-green colour blindness in humans

Question 24

different forms of the same gene is called?

Answer 24

alleles

Question 25

The alleles present, or genotype, operate at?

Answer 25

a molecular level to develop characteristics that can be expressed as a phenotype.

Question 26

dominant allele

Answer 26

A dominant allele is always expressed, even if only one copy is present

Question 27

recessive allele

Answer 27

A recessive allele is only expressed if two copies are present (therefore no dominant allele present)

Question 28

homozygous

Answer 28

If the two alleles present are the same the organism is homozygous for that trait

Question 29

heterozygous

Answer 29

if the alleles are different they are heterozygous

Question 30

In females the sex chromosomes are the same

Answer 30

(XX).

Question 31

In males the chromosomes are different

Answer 31

XY

Question 32

22 pairs control characteristics only, but one of the pairs carries the genes that determine?

Answer 32

sex