Biology- Genetics

Front 1

Mendel's First Law

Back 1

In a cross of parents that are pure for contrasting traits, only one form of the trait will appear in the next generation. Offspring that are hybrid for a trait will have only the dominant trait in the phenotype.

Front 2

Mendel's Second Law

Back 2

Alternative versions of genes (alleles) result in variations in inherited characteristics. For each character, an organism inherits 2 alleles (one from each parent). The alleles for each character segregate (separate) during gamete production (meiosis). Alleles for a trait are recombined at fertilisation becoming genotype for the traits of the offspring.

Front 3

Mendel's Third Law

Back 3

Alleles for different traits are distributed to sex cells (and offspring) independently of one another.

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Homozygous

Back 4

pair of identical alleles for a character (PP, pp)

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Heterozygous

Back 5

two different alleles for a character (Pp)

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Homologous pair of chromosomes

Back 6

Two chromosomes with the same genes in the same location

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Genotype

Back 7

the genes of an organism (all your genes)

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Phenotype

Back 8

an organism's traits (expression of your genes)

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Genome

Back 9

complete complement of an organisms DNA

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Character

Back 10

heritable feature (eg. Hair colour)

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Trait

Back 11

variant for a character (eg. Brown)

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Hybridisation

Back 12

crossing of 2 different true-breeds

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Dominant trait

Back 13

a trait that will appear in offspring if at least one allele is contributed.

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Recessive trait

Back 14

a trait that will appear in offspring if two alleles are contributed.

Front 15

Which pair of chromosomes determines sex?

Back 15

The 23rd pair

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IPMAT C

Back 16

Interphase, Prophase, Metaphase, Anaphase, Telophase, Cytokinesis

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What happens in cytokinesis?

Back 17

The cells divide

Front 18

Simple Inheritance

Back 18

Simple inheritance is when one allele is taken from each parent for a specific trait.

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Co-dominance

Back 19

Co-dominance is when the genes for a particular characteristic combine to give features of both of the individual genes. There is no recessive allele. eg. Roan cow

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Incomplete dominance

Back 20

Incomplete dominance is when genes for a particular characteristic are neither dominant or recessive. If the organism is heterozygous the phenotype is a blend of both characteristics.

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DNA

Back 21

Deoxyribo nucleic acid

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DNA structure

Back 22

Double helix which allows it to duplicate exactly as it unwinds during interphase of cell division

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Sides of the double helix ladder

Back 23

Phosphate group and deoxyribose sugar

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Rungs of the double helix ladder

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Nitrogenous base- Adenine, Thymine, Cytosine, Guanine

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Nucleotide

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A single unit of deoxiribose sugar, a phosphate group and a nitrogen base is called a nucleotide.

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Adenine only bonds with-

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Thymine

Front 27

Cytosine only bonds with-

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Guanine

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Karyotype

Back 28

A picture of chromosomes placed in order of descending size with the sex chromosomes at the end

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Building blocks of DNA

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nucleic acid

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Sex linkage

Back 30

The gene for a specific trait is located on the X or Y chromosome

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Mutations

Back 31

Mutations are changes to the genetic code which affect the proteins that are made. This occurs by changing the order of nitrogenous bases.

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Alleles

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Alternative genes for a particular character

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Chromosomes

Back 33

A threadlike structure in the nucleus of cells which contains the genetic information of an organism in the form of genes.

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Gene

Back 34

A segment of DNA which controls a particular character. They are located on chromosomes.