Genetics

Question 1

Genetics definition

Answer 1

The study of the inheritance of characteristics

Question 2

Heredity def.

Answer 2

The passing on of features and characteristics from parents to offspring

Question 3

Species definition

Answer 3

A group of organisms capable of interbreeding and producing fertile offspring

Question 4

Variation definition

Answer 4

Variation means there are differences between members of the same species

Question 5

Acquired characteristics

Answer 5

Characteristics developed/learned during life

Eg. Learning to sing, play rugby etc.

Question 6

Inherited characteristics

Answer 6

Characteristics controlled by gene inherited from parents

Eg. Hair, eyes etc.

Question 7

Name of bundle of chromosomes

Answer 7

Chromatin

Question 8

Chromosomes

Answer 8

Thread like structure.
Found in nucleus in pairs
Made up of DNA (genetic info) and protein (holds DNA in place)
Genes arranges along the DNA on the chromosomes

Question 9

The two types of cells

Answer 9

Sex cells- reproductive cells capable of fertilisation.
Eg. Sperm and egg

Somatic cells- any call except reproductive cells.
Eg. Cheek cells

Question 10

Chromosome numbers in cells

Answer 10

Somatic: 46 chromosomes- 23 pairs

Sex cells: 23 chromosomes.

Question 11

Types of chromosomes

Answer 11

Autosomes: non sex determining chromosomes, determines characteristics, 22 pairs

Sex chromosome: determines sex of individual. 2 sex chromosomes (X and Y)
Males: XY
Females: XX

Question 12

Number of types of chromosomes in different cells

Answer 12

Somatic cells: 44 Autosomes, 2 sex

Sex cells: 22 Autosomes, 1 sex

Question 13

Meiosis in testes to form sperm

Answer 13

Determines the sex of the individual.
Cells in testes divide by meiosis to produce sperm
X and Y go into different cells
1/2 sperm carry X and half carry Y
All eggs have X
Whichever sperm fuses with egg determines sex.

Question 14

Sex determination

Answer 14

4 weeks after fertilisation, embryo that contains Y chromosome develops testes ( primary male sex organ). Testes secrete testosterone hormone. Testosterone signals to other cells to develop in male pattern

Question 15

Gene definition

Answer 15

A gene is a section of DNA found on the chromosome that codes information for the making of specific protein.

Question 16

Role of genes

Answer 16

Unit of inheritance
Controls the characteristics of an organism
Not everyone has the same version of those genes
More than one type of gene for hair colour

Question 17

Characteristic definition

Influenced by

Answer 17

The features/ traits that an individual displays

Influenced by genes and environment

Question 18

Gene expression definition

Answer 18

The way in which information on a gene is coded to make a protein.

Question 19

Junk DNA

Answer 19

DNA that doesn’t code for any protein.

Found in between genes and on the gene

Question 20

DNA
Name
Where
Types

Answer 20

Name: Deoxyribonucleic acid
Where: nucleus, mitochondria, chloroplast. None in cytoplasm or ribosome
Types: Nuclear DNA- in nucleus, inherited from both parents
Non Nuclear DNA - found in mito and chloroplast, inherited from mother only

Question 21

Father of genetics

Answer 21

Gregor Mendel

Question 22

Genetic crosses definition

Answer 22

Study of how characteristics are inherited.

Each characteristic is controlled by a pair of alleles present in cell

Question 23

Gamete

Answer 23

A sex cell capable of fusion

Egg and sperm

Question 24

Allele

Answer 24

Alternative form of gene

Eg. C, c, D, d

Question 25

Locus

Answer 25

Location of gene on chromosome

Question 26

Genotype

Answer 26

``` Genetic makeup of an organism Letters Female genotype: XX Male genotype: XY Other: Cc, GG, yy ```

Question 27

Phenotype

Answer 27

Physical makeup of an organism | Eg. Blue eyes, brown hair, female etc.

Question 28

Homozygous

Answer 28

Condition in a cell where the alleles present are the same | Eg. BB, bb, XX

Question 29

Heterozygous

Answer 29

Condition in cell where the allele present are different | Eg. Bb, XY

Question 30

Recessive allele

Answer 30

The allele that is not expressed in the phenotype of the individual. Eg. X is recessive in XY genotype.

Question 31

Dominant allele

Answer 31

The allele that is expressed in the phenotype of the heterozygous condition. Eg. Y is dominant in XY pairing

Question 32

Incomplete dominance

Answer 32

Neither allele is expressed in the phenotype of the heterozygous condition, both are expressed together. Eg. Roan in cattle colour where neither red or white display dominance.

Question 33

Progeny/ F1 generation

Answer 33

Offspring produced

Question 34

F2 generation

Answer 34

Offspring produced as a result of F1 crossing with another F1

Question 35

Linkage

Answer 35

Genes that are located on the same chromosome

Question 36

Sex linkage

Answer 36

The characteristic is controlled by a gene on the X chromosome

Question 37

Monohybrid crosses

Answer 37

Study of inheritance of one characteristic | Eg. Eye colour

Question 38

Dihybrid crosses

Answer 38

Study of inheritance of two characteristics | Eg. Hair colour and eye colour

Question 39

Steps of a cross

Answer 39

``` Key Parents Gametes F1 generation Phenotype ```

Question 40

Law of segregation

Answer 40

States that characteristics are controlled by a pair of alleles, which separate at gamete formation, with one allele in each gamete

Question 41

Law of independent assortment

Answer 41

States that at gamete formation, either pair of alleles can combine with either allele of another pair of alleles. Eg. Parent:GgLl Gametes: GL Gl gL gl Either g can combine with either l

Question 42

Linkage crosses

Answer 42

Linked alleles must go in the same gamete

Question 43

Significance of linkage

Answer 43

Less variety in progeny produced

Question 44

Sex linkage crosses

Answer 44

Draw out! Y never has another letter in the gamete. Trait carried by X chromosome Always Y-

Question 45

What characteristics are controlled by sex linkage

Answer 45

``` Colour blindness Haemophilia Albinism Male pattern baldness Muscular dystrophy Eye colour in fruit flies ```

Question 46

Difference in male and females in sex linkage

Answer 46

Males can be either a sufferer or normal. Because no allele present on Y chromosome Females can be sufferers, carriers or normal. Because X chromosome carries allele