Inheritance, variation and evolution

Question 1

Alleles

Answer 1

different forms of the same gene sometimes referred to as variants

Question 2

asexual reproduction

Answer 2

involves only one individual and the offspring is identical to the parent. There is no fusion of gametes or mixing of
genetic information

Question 3

bases (DNA)

Answer 3

nitrogenous compounds that make up part of the structure of DNA and RNA. They are represented by the letters A,
T, C, and G

Question 4

carriers

Answer 4

individuals who are heterozygous for a recessive allele linked to a genetic disorder. Carriers have one healthy
allele so are not affected themselves but they can pass on the affected allele to their offspring

Question 5

cystic fibrosis

Answer 5

an inherited disorder that affects the lungs, digestive, and reproductive system and is inherited through a recessive
allel

Question 6

dominant allele

Answer 6

the phenotype will be apparent in the offspring even if only one of the alleles is inherited

Question 7

genetic engineering

Answer 7

the process by which scientists can manipulate and change the genotype of an organism

Question 8

genotype

Answer 8

the genetic makeup of an individual for a particular characteristic, for example hair or eye colour

Question 9

heterozygous

Answer 9

individual with different alleles for a characteristic

Question 10

homozygous

Answer 10

individual with 2 copies of the same allele for a characteristic

Question 11

Meiosis

Answer 11

two stage process of cell division that reduces the chromosome number of daughter cells. It is involved in making
gametes for sexual reproduction

Question 12

mutation

Answer 12

a change in the genetic material of an organism

Question 13

natural selection

Answer 13

the process by which evolution takes place. Organisms produce more offspring than the environment can support.
Only those that are most suited to their environment will survive to breed and pass on their useful characteristics to
their offspring

Question 14

phenotype

Answer 14

the physical appearance / biochemistry of an individual for a particular characteristic

Question 15

Polydactyly

Answer 15

a dominant inherited disorder that results in babies born with extra fingers and/or toes

Question 16

Punnett square

Answer 16

a way of modelling a genetic cross and predicting the outcome using probability

Question 17

Recessive

Answer 17

a phenotype that will only show up in the offspring if both of the alleles coding for that characteristic are inherited

Question 18

Sexism

Answer 18

carry the information that determines the sex of an individual

Question 19

Sex chromosomes

Answer 19

carry the information that determines the sex of an individual

Question 20

Sexual reproduction

Answer 20

involves the joining (fusion) of male and female gametes producing genetic variation in the offspring

Question 21

Selective breeding

Answer 21

speeds up natural selection by selecting animals or plants for breeding that have a required characteristic

Question 22

Tissue cloning

Answer 22

a modern way of cloning plants that allows thousands of new plants to be created from one piece of plant tissue

Question 23

Archaea

Answer 23

one of the three domains, containing primitive forms of bacteria that can live in many of the extreme environments
of the world

Question 24

Classification

Answer 24

the organisation of living organisms into groups according to their similarities

Question 25

Domain

Answer 25

the highest level of classification. There are three domains – Archaea, Bacteria and Eukaryota

Question 26

Evolutionary trees

Answer 26

models used to explain the evolutionary links between groups of organisms

Question 27

Extinction

Answer 27

the permanent loss of all members of a species from an area or from the world

Question 28

Speciation

Answer 28

the process by which two species evolve from a single original species by natural selection

Question 29

Species

Answer 29

the smallest group of clearly identified organisms in Linnaeus’s classification system, often described as a group of
organisms that can breed together and produce fertile offspring