B10: Variation And Inheritance Flashcards
Allele
A version of a particular gene
Gene
A short section of DNA carrying genetic information.
How many chromosomes in a sex cell?
23
How many chromosomes in a body cell?
46, 23 pairs
List chromosomes, DNA and genes from largest to smallest.
Chromosome
Gene
DNA
2 factors that cause variety.
Genes
Environment
Female Chromosomes
XX
Male Chromosomes
XY
Heterozygous
Having 2 different alleles for the same gene
Genotype
Whether a person is homozygous or heterozygous for a particular characteristic.
Phenotype
Describes the physical appearance of an individual.
DNA meaning
Deoxyribonucleic Acid
Bases
Nitrogenous compounds that make up part of the DNA structure.
How many bases on DNA code for one amino acid?
3
How do bases match up?
A pple T art
C hocolate G ateau
What causes Downs Syndrome?
An extra copy of chromosome 21. (Having 47 chromosomes)
Huntingtons
A disorder that wastes away parts of the brain.
Dominant.
Sickle Cell Anaemia
Causes sickle shaped red blood cells which don’t transport oxygen efficiently.
Recessive.
Cystic Fibrosis
Affects the lungs, digestive and reproductive systems.
Recessive.
Polydactyly
Causes extra fingers and toes.
Dominant.
Amniocentesis
15-16 weeks.
Fluid is taken from around the foetus.
Chorionic Villus Sampling
10-12 weeks.
Small sample is taken off of the tissue of the developing placenta.
Concerns with embryo screening
> Can sometimes give false results.
People would decide to terminate and otherwise healthy pregnancy.
Could lead to designer babies.
Homozygous.
Having 2 identical alleles for the same gene
