DNA Key Words

Question 1

Alleles

Answer 1

Different forms of a gene which occupy the same relative positions on a pot of homologous chromosomes

Question 2

Artificial selection

Answer 2

A method used by humans to produce plants and animals with desired qualities

Question 3

Asexual reproduction

Answer 3

The process resulting in the production of genetically identical offspring from one parent, without the fusion of gametes

Question 4

Codominance

Answer 4

A condition where both alleles express themselves in a hybrid, as they are both either dominant or recessive to one another

Question 5

Continuous variation

Answer 5

Traits with phenotypes ranging from one extreme to the other

It is brought about by combined effects of many genes

It is affected by environmental conditions
Intelligence
Height
Skin colour
In humans

Question 6

Diploid

Answer 6

Cells that contain the full number of chromosomes

Question 7

Discontinuous variation

Answer 7

Traits that show limited variation in their phenotypes which are easily distinguishable

Usually controlled by only one or a few genes

Not affected by the environment

Question 8

Dominant

Answer 8

A form of a gene that is expressed and masks the recessive gene

It gives the same phenotype in both homozygous and heterozygous conditions as it expresses itself

Question 9

Gamete

Answer 9

A reproductive cell containing the haploid number of chromosomes

Question 10

Gene

Answer 10

A hereditary factor found on a particular locus in a chromosome

Controls a particular characteristic

Codes for a specific protein

Question 11

Genetic engineering

Answer 11

A technique used to transfer genes from one organism to another

Question 12

Genotype

Answer 12

The combination of genes in an individual

Question 13

Haploid

Answer 13

Cells that contain half the number of chromosomes as the parent cells which produced them

Question 14

Heterozygous

Answer 14

A condition where you have different alleles for a particular trait

Question 15

Homologous pairs

Answer 15

Chromosomes which have the same genes, shape and length

Question 16

Homozygous

Answer 16

Having identical alleles for a particular trait

Question 17

Meiosis

Answer 17

A form of cell division such that the daughter cells contain half the number of chromosomes as the parent cell

Forms gametes (sex cells)

Question 18

Mitosis

Answer 18

Cell division such that the daughter cell produced contains the same number of chromosomes as the parent cell

Will be diploid

Forms body cells

Question 19

Mutation

Answer 19

The sudden or spontaneous change in gene structure or a chromosome or even the chromosome number

May be inheritable

Question 20

Phenotype

Answer 20

The physically expressed trait in an individual

Question 21

Recessive

Answer 21

A form of gene that expresses itself only in the homozygous condition

Question 22

Sexual reproduction

Answer 22

The process involving the fusion of two gametes to form a zygote

Results in the production of genetically dissimilar offspring

There will be variation