B16-18 Definitions

Question 1

Asexual reproduction

Answer 1

A process resulting in the production of genetically identical offspring from one parent

Question 2

Sexual reproduction

Answer 2

A process involving the fusion of two gametes (sex cells) to form a zygote and the production of offspring that are genetically different from each other

Question 3

Fertilisation

Answer 3

The fusion of gamete nuclei

Question 4

Pollination

Answer 4

The transfer of pollen grains from the anther to the stigma

Question 5

Self-pollination

Answer 5

The transfer of pollen grains from the anther of a flower to the stigma of the same flower or different flower on the same plant

Question 6

Cross-pollination

Answer 6

The transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species

Question 7

Sexually transmitted infection

Answer 7

An infection that is transmitted via body fluids through sexual contact

Question 8

Inheritance

Answer 8

The transmission of genetic information from generation to generation

Question 9

Chromosome

Answer 9

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

Question 10

Gene

Answer 10

A length of DNA that codes for a protein

Question 11

Allele

Answer 11

A version of a gene

Question 12

Haploid nucleus

Answer 12

A nucleus containing a single set of unpaired chromosomes, eg. in gametes

Question 13

Diploid nucleus

Answer 13

A nucleus containing two sets of chromosomes, eg. in body cells

Question 14

Mitosis

Answer 14

Nuclear division giving rise to genetically identical cells

Question 15

Meiosis

Answer 15

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

Question 16

Genotype

Answer 16

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

Question 17

Phenotype

Answer 17

The observable features of an organism

Question 18

Homozygous

Answer 18

Having two identical alleles of a particular gene

Question 19

Heterozygous

Answer 19

Having two different alleles of a particular gene

Question 20

Dominant

Answer 20

An allele that is expressed if it is present

Question 21

Recessive

Answer 21

An allele that is only expressed when there is no dominant allele of the gene present

Question 22

Sex-linked characteristic

Answer 22

A characteristic in which the gene responsible is located on a sex chromosome and that this makes it more common in one sex than in the other

Question 23

Variation

Answer 23

Differences between individuals of the same species

Question 24

Mutation

Answer 24

Genetic change

Question 25

Gene mutation

Answer 25

A change in the base sequence of DNA

Question 26

Adaptive feature

Answer 26

The inherited functional features of an organism that increase its fitness

Question 27

Fitness

Answer 27

The probability of an organism surviving and reproducing in the environment in which it is found

Question 28

Process of adaptation

Answer 28

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