DNA stuff

Question 1

Allele

Answer 1

An alternate form of a gene.

Question 2

DNA

Answer 2

Stands for deoxyribose acid. A molecule that carries the genetic code.

Question 3

Amino acids

Answer 3

The building blocks of protein

Question 4

Bases

Answer 4

A,T,C,G

Question 5

Chromosome

Answer 5

A long strand of DNA containing a specific set of genetic information.

Question 6

Complementary bases

Answer 6

A with T, C with G. Ensures the genetic code is replicated correctly during DNA replication.

Question 7

Crossing over

Answer 7

Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

Question 8

DNA sequencing

Answer 8

Determining the exact order of the base pairs in a segment of DNA.

Question 9

Dominant

Answer 9

The allele requires only one copy to be present to display its phenotype.(A)

Question 10

Evolution

Answer 10

Gradual change in the genetic code of organisms over a long period of time. May result in formation of new species.

Question 11

Fertilisation

Answer 11

Fusion of DNA from an egg and sperm cell

Question 12

Gametes

Answer 12

Sex cells containing half the chromosomes of the parent

Question 13

Genome

Answer 13

All the DNA in a single cell of an organism

Question 14

Gene

Answer 14

A short segment of DNA that codes for a specific trait/protein

Question 15

Genetic code

Answer 15

The bases of a gene are read in sets of three and each triplet codes for an amino acid, which in turn, are joined to make a protein.

Question 16

Gene marker

Answer 16

A short segment of DNA that can be used to follow inheritance of a trait (especially if it is not visible) or determine relatedness of different organisms.

Question 17

Genetic Variation

Answer 17

The total number of different alleles in a population of organisms.

Question 18

Genotype

Answer 18

The combination of alleles that an individual has for a gene. (AA, Aa, aa)

Question 19

Genotypic ratio

Answer 19

The predicted ratio of inheritance of alleles from mating of two individuals.

Question 20

Heterozygous

Answer 20

When an individual has two different alleles for their genotype.(Aa)

Question 21

Homozygous

Answer 21

When an individual has two similar alleles for their genotype.(AA, aa)

Question 22

Homologous pairs

Answer 22

Pairs of chromosomes that have the same genes on them (but the alleles might be different). One chromosome is inherited from each parent.

Question 23

Independent segregation

Answer 23

During the formation of gametes, each gamete receives just one gene copy, which is selected randomly. Each pair of alleles segregates independently of the other pairs and all possible combinations of alleles can occur in the resulting gametes.

Question 24

Karyotype

Answer 24

A display/picture of the chromosome pairs of a cell arranged by size and shape.

Question 25

Meiosis

Answer 25

a type of cell division which produces egg and sperm cells -gametes- with half the number of chromosomes of the parent cell.

Question 26

Mutation

Answer 26

A permanent change in the DNA base sequence that creates a new allele.

Question 27

Offspring

Answer 27

The resulting individuals of reproduction.

Question 28

Pedigree chart

Answer 28

A chart which shows several generations of related families and how alleles/traits are passed down through the offspring.

Question 29

Phenotype

Answer 29

The form of the trait the individual displays.(brown hair, sickle cell anaemia etc.)

Question 30

Phenotypic ratio

Answer 30

the ratio of phenotypes produced by a cross

Question 31

Phylogenetic tree

Answer 31

A branching diagram that represents a hypothesis about the evolutionary history of a group of organisms.

Question 32

Proteins

Answer 32

Polymers of amino acids that make up our traits.

Question 33

Punnet square

Answer 33

A method of showing the probability of all the potential offspring genotypes and phenotypes that can occur from two mating individuals.

Question 34

Population

Answer 34

A group of individuals in a species that live in a defined area.

Question 35

Recessive

Answer 35

The allele requires two copies to be present to be shown in the phenotype. (aa)

Question 36

Sexual Reproduction

Answer 36

Reproduction involving two parents. Offspring inherit half their DNA from each parent.

Question 37

Species

Answer 37

A group of living organisms consisting of similar individuals that can create fertile offspring.

Question 38

Trait

Answer 38

The observable variation that is being studied. (e.g hair type, skin colour, disease)

Question 39

Triplet code

Answer 39

Bases of genes are read in threes(triplets), each triplet codes for an amino acid to build a protein.