keywords

Question 1

allele

Answer 1

an alternative form of a gene

Question 2

asexual reproduction

Answer 2

the production of offspring from a single parent by mitosis. The offspring are clones of the parent

Question 3

chromosome

Answer 3

structures that contain the DNA of an organism and are found in the nucleus

Question 4

cystic fibrosis

Answer 4

a disorder of cell membranes that is caused be a recessive allele

Question 5

DNA

Answer 5

a polymer that is made up of two strands that form a double helix

Question 6

dominant

Answer 6

an allele that is always expressed, even if only one copy is present

Question 7

fertilisation

Answer 7

the fusion of male and female gametes

Question 8

gamete

Answer 8

sperm cells and egg cell in animals; pollen and egg cell in plants

Question 9

gene

Answer 9

a small section of DNA that codes for a specific protein

Question 10

genome

Answer 10

the entire genetic material of an organism

Question 11

genotype

Answer 11

the combination of alleles

Question 12

heterozygous

Answer 12

a genotype that has two different alleles, one dominant and one rescessive

Question 13

homozygous

Answer 13

a genotype that has two of the same alleles. Either two dominant alleles or two recessive alleles.

Question 14

meiosis

Answer 14

the two-stage process of cell division that reduces the chromosome number of the daughter cells. It makes gametes for sexual reproduction.

Question 15

mutation

Answer 15

a change in DNA

Question 16

phenotype

Answer 16

the characteristic expressed because of the combination of alleles

Question 17

polydactyly

Answer 17

having extra fingers or toes, It is caused by a dominant allele

Question 18

recessive

Answer 18

an allele that is only expressed if two copies of it are present

Question 19

sexual reproduction

Answer 19

the production of offspring by combing genetic information from the gametes of two parents. Leads to variation in the offspring

Question 20

embryo screening

Answer 20

genetic tests carried out on an embryo to see whether it carries a faulty allele

Question 21

evolution

Answer 21

a change in the inherited characteristics of a population over time through a process of natural selection

Question 22

evolutionary tree

Answer 22

a method used to show how scientists believe organisms are related to

Question 23

extinction

Answer 23

the permanent loss of all members of a species

Question 24

fossils

Answer 24

the remains of organisms from millions of years ago which are found in rocks

Question 25

genetic engineering

Answer 25

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

Question 26

natural selection

Answer 26

the process by which organisms that are better suited to an environment are more likely to survive and reproduce

Question 27

selective breeding

Answer 27

humans selecting animals or plants, that have a required characteristic, for breeding

Question 28

speciation

Answer 28

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

Question 29

variation

Answer 29

differences in characteristics of individuals in a population

Question 30

biodiversity

Answer 30

the variety of living organisms