Biology Test Term 1 Shells Definitions

Alleles

Different versions of same gene

Chromosomes

Found in nucleus of cell - humans have 46

Continuous Variation

Feature that can vary, eg. Height/weight

Discontinuous Variation

Variation where there is limited options, eg. Tongue rolling (either you can or you can't)

DNA (x3)

DeoxyriboNucleic Acid - found in nucleus + contains genetic material

Dominant gene

Gene that shows up as characteristic in organism

Double Helix

DNA shape

Endangered

Species endangered = Only few left in world

Extinct

No more of these organisms left in world

Gametes

Sex cells = sperm & egg

Genes

Made of DNA + control organism's characteristics

Gene Bank

A store of genetic information to help prevent extinction

Genotype

Description of genes of organism

Heredity

Passing of genes from parents to offspring

Natural Selection

Where organisms with characteristics most suited to environment are most likely to survive/pass on their genes

Nucleus

Central part of cell, contains chromosomes & genes

Phenotype

Term used to describe appearance of individual - traits that you can actually see (height/eye colour)

Punnett Square

Diagram used to predict outcome of particular genetic cross

Recessive

Gene that only shows if offspring contains 2 alleles for this characteristic

Sexual Reproduction

Type of reproduction that involves gametes + leads to variation in offspring

Variation

Difference between organisms

My Very Curly Smelly Brown Poo

Mutation, Variation, Competition, Survival of fittest, Breed + Pass on alleles

Mutation

Random + permanent change that occurs in DNA sequence of organism