Genetics Flashcards

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1
Q

Genetics definition

A

The study of the inheritance of characteristics

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2
Q

Heredity def.

A

The passing on of features and characteristics from parents to offspring

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3
Q

Species definition

A

A group of organisms capable of interbreeding and producing fertile offspring

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4
Q

Variation definition

A

Variation means there are differences between members of the same species

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5
Q

Acquired characteristics

A

Characteristics developed/learned during life

Eg. Learning to sing, play rugby etc.

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6
Q

Inherited characteristics

A

Characteristics controlled by gene inherited from parents

Eg. Hair, eyes etc.

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7
Q

Name of bundle of chromosomes

A

Chromatin

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8
Q

Chromosomes

A

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

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9
Q

The two types of cells

A

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

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

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10
Q

Chromosome numbers in cells

A

Somatic: 46 chromosomes- 23 pairs

Sex cells: 23 chromosomes.

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11
Q

Types of chromosomes

A

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

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12
Q

Number of types of chromosomes in different cells

A

Somatic cells: 44 Autosomes, 2 sex

Sex cells: 22 Autosomes, 1 sex

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13
Q

Meiosis in testes to form sperm

A

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.

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14
Q

Sex determination

A

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

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15
Q

Gene definition

A

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

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16
Q

Role of genes

A

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

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17
Q

Characteristic definition

Influenced by

A

The features/ traits that an individual displays

Influenced by genes and environment

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18
Q

Gene expression definition

A

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

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19
Q

Junk DNA

A

DNA that doesn’t code for any protein.

Found in between genes and on the gene

20
Q

DNA
Name
Where
Types

A

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

21
Q

Father of genetics

A

Gregor Mendel

22
Q

Genetic crosses definition

A

Study of how characteristics are inherited.

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

23
Q

Gamete

A

A sex cell capable of fusion

Egg and sperm

24
Q

Allele

A

Alternative form of gene

Eg. C, c, D, d

25
Q

Locus

A

Location of gene on chromosome

26
Q

Genotype

A
Genetic makeup of an organism
Letters
Female genotype: XX
Male genotype: XY
Other: Cc, GG, yy
27
Q

Phenotype

A

Physical makeup of an organism

Eg. Blue eyes, brown hair, female etc.

28
Q

Homozygous

A

Condition in a cell where the alleles present are the same

Eg. BB, bb, XX

29
Q

Heterozygous

A

Condition in cell where the allele present are different

Eg. Bb, XY

30
Q

Recessive allele

A

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

31
Q

Dominant allele

A

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

32
Q

Incomplete dominance

A

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.

33
Q

Progeny/ F1 generation

A

Offspring produced

34
Q

F2 generation

A

Offspring produced as a result of F1 crossing with another F1

35
Q

Linkage

A

Genes that are located on the same chromosome

36
Q

Sex linkage

A

The characteristic is controlled by a gene on the X chromosome

37
Q

Monohybrid crosses

A

Study of inheritance of one characteristic

Eg. Eye colour

38
Q

Dihybrid crosses

A

Study of inheritance of two characteristics

Eg. Hair colour and eye colour

39
Q

Steps of a cross

A
Key
Parents
Gametes
F1 generation
Phenotype
40
Q

Law of segregation

A

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

41
Q

Law of independent assortment

A

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

42
Q

Linkage crosses

A

Linked alleles must go in the same gamete

43
Q

Significance of linkage

A

Less variety in progeny produced

44
Q

Sex linkage crosses

A

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

45
Q

What characteristics are controlled by sex linkage

A
Colour blindness
Haemophilia
Albinism
Male pattern baldness
Muscular dystrophy
Eye colour in fruit flies
46
Q

Difference in male and females in sex linkage

A

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