11 Inheritence

Question 1

Define inheritance

Answer 1

Transmission of genetic information from generation to generation

Question 2

Define chromosome

Answer 2

thread-like structure of DNA, carrying genetic information in the form of genes

Question 3

Define gene

Answer 3

length of a DNA that codes for a protein

Question 4

Define allele

Answer 4

Versions of a gene

Question 5

Define mitosis

Answer 5

nuclear division giving rise to genetically identical cells

Question 6

How many pairs of chromosomes are there in humans

Answer 6

23 pairs

Question 7

Define haploid

Answer 7

Containing a single set of unpaired chromosomes

Question 8

Role of mitosis (4)

Answer 8

Repair of damaged tissues

growth

asexual reproduction

replacement of cells

Question 8

Define diploid

Answer 8

Containing two sets of chromosomes

Question 9

Define meiosis

Answer 9

reduction division in which the chromosome number is halved from diploid to haploid, resulting in genetically different cells

Question 10

How are gametes produced

Answer 10

Meiosis

gametes have single set of chromosomes. When the two gametes fuse, they become diploid cell with normal number of chromosome

Question 11

Define genotype

Answer 11

genetic make-up of an organism in terms of alleles present

Question 12

Define phenotype

Answer 12

observable features of an organism

Question 13

Define homozygous

Answer 13

having two identical alleles for a particular gene

Question 14

Define heterozygous

Answer 14

having two different alleles for a particular gene

Question 15

Define dominant allele

Answer 15

allele that is expressed if present

Question 16

Define recessive allele

Answer 16

allele that is only expressed when no dominant allele is present

Question 17

Two types of phenotypic variation (2)

Answer 17

Discontinuous variation

continuous variation

Question 18

What is discontinuous variation

Answer 18

characteristic can only have a limited number of specific phenotypes

Question 19

Examples of discontinuous variation

Answer 19

sex, blood group, tongue rolling

Question 20

What is continuous variation

Answer 20

where characteristic can have any value in a range

Question 21

Examples of continuous variation

Answer 21

body weight, length of hair

Question 22

Define variation

Answer 22

differences between indivudals of the same species

Question 23

Causes of phenotypic variation

Answer 23

Environmental causes -

genetic causes -

Question 24

What is discontinuous variation caused by

Answer 24

genetic variation

Question 25

What is continuous variation caused by

Answer 25

genes
and
environment

Question 26

Define gene mutation

Answer 26

change in gene or chromosome

Question 27

Causes of mutation (2)

Answer 27

exposure of ionising radiation - EG: gamma rays, x-rays

chemical mutagens

Question 28

Define natural selection

Answer 28

best adapted organisms having a better chance of passing on their genes to the next generation

Question 29

Describe the process of natural selection (5)

Answer 29

In any population there is variation between individuals

organisms reproduce —> produce many offspring —> struggle for survival

offsprings have different combinations of variations from parents

Offsprings with adaptive features help them compete better for resources

Offsprings reproduce and pass on their alleles to the next generation

Question 30

Define adaptation

Answer 30

process resulting from natural selection by wich populations become more suited to their environment over many generations

Question 31

Describe evolution

Answer 31

chance in adaptive features of a population over time as a result of natural selection

Question 32

Describe the development of strains of antibiotic resistance in bacteria

Question 33

Describe selection breeding (2)

Answer 33

When a breeder chooses which parent organisms to breed together

selection of offspring showing the desirable features

Question 34

Differences between natural selection and artificial selection (2)

Answer 34

humans decide on characteristics they want vs unpredictable as those most adapted to environment selected

Artificial selection are useful to humans while natural selection are better adapted to the environment