dna and inheritance

Question 1

DNA

Answer 1

the chemical that all genetic material is made up from

Question 2

chromosome

Answer 2

long strands of DNA found in the nucleus of cells

Question 3

gene

Answer 3

short section of DNA that codes for a protein and found on a chromosome

Question 4

allele

Answer 4

different versions of the same gene

Question 5

genome

Answer 5

entire set of genetic material in an organism

Question 6

gamete

Answer 6

sex cells produced by meiosis

Question 7

sexual reproduction

Answer 7

gametes from two parents combine

Question 8

asexual reproduction

Answer 8

production of genetically identical offspring from a single parent

Question 9

fertilisation

Answer 9

fusing of a male sex cell with a female sex cell

Question 10

meiosis

Answer 10

cell division that produces gametes in sexually reproducing organisms

Question 11

Stages in meiosis

Answer 11

1. genetic material is duplicated
2. chromosomes arranged in pairs in the centre of cell
3. first division separates the pairs of chromosomes
4. chromosomes line up in the centre of the cell
5. second division pulls the chromosome arms apart
6. 4 gametes produced each with a single set of chromosomes

Question 12

differences between mitosis and meiosis

Answer 12

• Meiosis produces 4 daughter cells not 2
• meiosis produces genetically different daughter cells
• meiosis produces daughter cells that have half the amount of DNA compared to the parent cell
• meiosis involves 2 divisions/mitosis is 1

Question 13

mitosis is used in =

Answer 13

asexual reproduction - to create identical copies (clones) of the parent cell

Question 14

Mitosis stages

Answer 14

1. chromosomes in nucleus are copied
2. chromosomes and their copies are pulled apart and moved towards poles
3. chromosomes seperate
4. cell divides into two genetically identical daughter cells

Question 15

mitosis is used for -

Answer 15

growth
repair to damaged tissue
replacement of worn out cells

Question 16

Meiosis is used in -

Answer 16

sexual reproduction - which creates gametes the process happens in the male and female reproductive organs.
as a cell divides to form gametes , copies of the genetic information is made, the cell divides to form four gametes. all gametes are different from each other.

Question 17

fertilisation in detail

Answer 17

in humans each gamete has half the number of the total 46 chromosomes that the body requires.when the gametes combine , they merge the two sets of chromosomes to have 46 , this produces a new cell called zygote which will mature into an embryo

Question 18

sex determination

Answer 18

xx females

xy males

Question 19

dominant

Answer 19

allele that determines the phenotype even if there is only 1 copy present

Question 20

recessive

Answer 20

allele that only affects the phenotype if 2 copies are present

Question 21

homozygous

Answer 21

both alleles for a gene are the same

Question 22

heterozygous

Answer 22

the alleles for a gene are different

Question 23

genotype

Answer 23

combination of alleles you have

Question 24

phenotype

Answer 24

characteristicts you will have as a result of your genotype

Question 25

cystic fibrosis

Answer 25

caused by a recessive allele sufferers produce lots of thick , sticky mucus in air passages and the pancreas

Question 26

polydactyly

Answer 26

caused by a dominant allele sufferers have an extra finer or toe

Question 27

embryo screening

Answer 27

a method of determining whether an embryo has genetic disorders

Question 28

reasons for embryo screening

Answer 28

to prevent suffering

treating disorders costs a lot so removing embryos would be cheaper in the long run

Question 29

reasons against embryo screening

Answer 29

screening is expensive

implies that people with genetic problems are undesirable

Question 30

variation

Answer 30

within genes leads to different genotypes and this can bet seen by a different phenotype