2.5 Genetic Variation

Question 1

Gene

Answer 1

section of DNA that codes for a protein that influences a characteristic/ trait

Question 2

Traits

Answer 2

The physical expression of genes as characteristics

Question 3

Sexual reproduction

Answer 3

The creation of new living organisms by combining genetic information from two parent organisms

Question 4

Asexual reproduction

Answer 4

Asexual reproduction occurs when an organism makes more of itself without exchanging genetic information with another organism through sex.

Question 5

Binary fission

Answer 5

A single parent cell divides into two daughter cells

Question 6

Locus

Answer 6

Position of a gene on a chromosome

Question 7

Homologous chromosomes

Answer 7

A pair of chromosomes with one maternal and one paternal. They have genes that control the same trait at the same locus

Question 8

Alleles

Answer 8

Different forms of a gene eg. blue or brown eyes

Question 9

Homozygous dominant

Answer 9

An organism that has two dominant alleles for a gene

Question 10

Heterozygous

Answer 10

An organism that has both versions of an allele and the dominant allele will be expressed

Question 11

Homozygous recessive

Answer 11

An organism that has two recessive alleles for a gene

Question 12

Genome

Answer 12

All of the genetic material within an organism

Question 13

DNA

Answer 13

A molecule composed of many nucleotides with a sugar-phosphate backbone. Two DNA polymers coil around each other to form a double helix carrying genetic instructions for the life processes of all known organisms

Question 14

Nucleotide

Answer 14

A single unit of DNA

Question 15

Name the three parts of a nucleotide

Answer 15

A deoxyribose sugar, a phosphate group, and one of four nitrogenous bases (A, T, C, G)

Question 16

Chromosome

Answer 16

A long DNA molecule with part or all of the genetic material of an organism

Question 17

The genotype of an organism

Answer 17

The two alleles an organism posses for a trait eg. Aa

Question 18

The phenotype of an organism

Answer 18

The observable characteristics of an organism due to their genotype

Question 19

Inheritance

Answer 19

The passing down of genetic information from one generation to the next

Question 20

Meiosis

Answer 20

A type of cell division that produces gametes

Question 21

Gametes

Answer 21

Sex cells

Question 22

Eukaryotes

Answer 22

Organisms whose cells contain a nucleus

Question 23

Diploid cell

Answer 23

Cells that contain an entire set of chromosomes inherited from both parents

Question 24

Haploid cell

Answer 24

Cells that only have a single set of chromosomes

Question 25

Fertilisation

Answer 25

When one gamete (eg. sperm cell) fuses with another gamete (eg. egg) to form a single zygote

Question 26

Zygote

Answer 26

A diploid cell resulting from the fusion of two haploid gametes

Question 27

Punnett squares

Answer 27

Simple diagrams that show the possible allele combinations that can occur when two parental gametes are fertilised

Question 28

Mutations

Answer 28

A permanent change in an organism's genetic material

Question 29

Gametic mutations

Answer 29

Mutations that can be passed down to offspring, as they occur within the cells of testes/ ovaries and therefore present in gametes

Question 30

Centromere

Answer 30

Joins two sister chromatids

Question 31

Sister chromatid

Answer 31

A copy of the original chromosome when it has been replicated

Question 32

Why is meiosis important?

Answer 32

Meiosis produces gametes that can be fertilised to create a new individual. Meiosis maintains the chromosomal number from generation to generation and promotes genetic diversity/ variation in the population

Question 33

Phenotypic variation

Answer 33

The differences in physical features (traits) within a population

Question 34

Genetic variation

Answer 34

The number of different alleles within a population

Question 35

Mutagens

Answer 35

The factors that cause mutations

Question 36

Where does meiosis occur?

Answer 36

Meiosis occurs in specialised germ cells found within sex organs

Question 37

Disjunction

Answer 37

The process during meiosis when chromosomes are pulled apart by spindle fibres

Question 38

Spindle fibres

Answer 38

Structures that form during cell division to separate sister chromatids

Question 39

Point mutations

Answer 39

Mutations that cause one or very few nucleotides in a sequence

Question 40

Chromosomal mutations

Answer 40

Mutations involving a long segment of DNA

Question 41

Random fertilisation

Answer 41

Egg and sperm cells combine randomly with many different possible combinations

Question 42

Non-heritable/ acquired variation

Answer 42

Variation in an individual that can not be passed onto offspring, and usually occur due to environmental factors

Question 43

Why is genetic variation important?

Answer 43

Variation ensures that if conditions change (eg. climate, resources, disease, etc.) some individuals will have adaptations that enable them to continue surviving and reproducing. This ensures the survival of a species.