Science AT3

Genetics, Evolution and Genetic Modification

Adenine

The base that combines with thymine to form a base pair

Allele

A version of a gene, 2 of each gene

Amino acid

A small molecule that joins with others to form proteins

Anaphase

A stage of cell division in which the chromosomes separate

Base

Part of a DNA molecule that comes in four types

Base pair

Two bases joined together, A-T or G-C

Cell cycle

The repeated process of cell growth and division

Cell division

The splitting of a cell to form new cells, 2 types - mitosis and meiosis

Chromosome

DNA molecule that condenses during cell division

Crossing over

The swapping of genes between chromosomes in a homologous pair

Cytosine

The base that combines with guanine to form a base pair

Daughter cell

Any new cell formed by cell division

DNA

a molecule that contains genetic information

Dominant allele

A version of a gene that is expressed even when only one copy is present

Dominant trait

A feature that appears when at least one allele is present

Double helix

A structure consisting of two chains twisted around each other

Fertilization

The joining of an egg and a sperm to form a new organism

Gene

A unit of genetic information, a section of a DNA molecule that provides instructions for building a specific protein

Generation

Members of a family that are born and live at about the same time

Guanine

The base that combines with cytosine to form a base pair

Heterozygous

A genotype in which the 2 alleles are different

Homologous pair

2 chromosomes that contain versions of the same genes

Homozygous

A genotype in which the 2 alleles are the same

Inheritance

The passing down of traits via genes from one generation to the next

Interphase

The stage of the cell cycle in which a cell grows and copies its DNA

Meiosis

A type of cell division that produces sex cells for reproduction

Metaphase

A stage of cell division in which the chromosomes line up in the middle of the cell

Mitosis

A type of cell division that produces cells for growth and repair

Mutation

A permanent change in the sequence of bases that make up a gene

Parent cell

Any cell that divides to form new cells

Pedigree

A family tree that shows how a trait is passed down through generations

Phenotype

The collection of traits observable in an organism, includes genotype and environmental effects

Prophase

A stage of cell division in which the chromosomes condense and the nucleus starts to break down

Protein

A large molecule made up of amino acids, form structures and perform functions in an organism

Recessive allele

A version of a gene that is only expressed when 2 copies are present

Recessive trait

A feature that only appears when two alleles are present

Sex chromosome

A chromosome that helps determine an organism's gender

Simple inheritance

When the appearance of a trait is controlled by a single gene

Telophase

A stage of cell division in which 2 nuclei form, each with its own set of DNA

Thymine

The base that combines with adenine to form a base pair

Trait

A feature of an organism

Acquired trait

A feature that is gained during an individual's lifetime

Adaptation

A genetic trait that helps an organism survive in its environment

Behavioural adaption

A behaviour or action that helps an organism survive

Common ancestor

A species that 2 or more species have evolved from

Evolution

A change in the genetic traits in a population over many generations

Evolutionary tree

A diagram that shows how species are related

Extinction

The dying out or complete disappearance of a species

Genetic diversity

The amount of genetic variation in a population, makes some individuals better adapted to environment than others

Natural selection

The survival of organisms that are better adapted to their environment

Physiological adaption

An internal bodily process that helps an organism survive

Population

A group of organisms of the same species living the same place

Selection pressure

A challenge that affects an organism's ability to survive and reproduce

Speciation

The formation of a new species, occurs when a population splits into 2 isolated ones that evolve under different selection pressures

Species

A group of similar organisms that can breed to produce fertile offspring

Structural adaptation

A physical feature of the body that helps an organism survive

Variation

A difference in traits between individuals of the same species

Watson and Crick

First 2 scientists to propose the double helix structure of DNA in 1953

Genetic modification (GM)

the gene for a desired characteristic is transferred from the DNA of one organism and inserted into the DNA of the organism you want to modify

DNA fingerprinting

a laboratory technique used in forensic investigations and paternity/maternity tests

Transgenics

where one or more DNA sequences from another organism have been introduced by artificial means

Clones

organisms that are genetically identical

VESP

V - Variation in a characteristic exists

E - Environmental pressure

S - Survival of the fittest

P - Passed on through population