Genetics Definitions For NCEA Exam Flashcards
Gene
Made of DNA, an instruction for a set protein.
DNA
Genetic material, instruction to build an organism.
Allele
Different form of a gene.
Chromosome
Made from DNA, contains genes, has 46, 23 pairs.
Nucleotide
Base block of DNA, sugar, phosphate, base
Semi Conservative
Half new, half old.
Complimentary Base Pair Rule
A goes to T, C goes to G.
Sexual Reproduction
2 parents, genetic variation.
Asexual Reproduction
1 parent, no genetic variation.
DNA Replication
Doubling up or making copies of DNA.
Genotype
The 2 alleles.
Phenotype
The physical feature/characteristic.
Test Cross
Crossing an individual with an individual who is HOMOZYGOUS RECESSIVE.
Mutation
A sudden permanent change in the DNA sequence.
Mutagen
Causes a mutation, (e.g x-rays, UV rays, chemicals e.t.c)
Meiosis
Cell division which creates gametes, occurs in sex organs, produces 4 genetically different daughter cells, half number of chromosomes.
Mitosis
Cell division which creates 2 genetically identical daughter cells, occurs in body. Purpose is growth & repair. Full number of chromosomes.
Variation
Survival of a species through meiosis. A difference in base sequence.
Environment
The habitat in which you live, e.g temperature, food, water, wind, disease.
Gamete
Sex cell (sperm or egg), contains half number of chromosomes.
Zygote
Cell formed when a sperm cell fuses with an egg cell. (Fertilised egg).
Somatic
Body cell, contains full amount of chromosomes.
Homozygous
2 same alleles.
Heterozygous
2 different alleles.
Recessive
Only show if dominant not present, e.g bb.
Dominant
It will be EXPRESSED if present.
Crossing Over
Occurs during meiosis a homologous pair swaps a section of DNA for the same gene.
Homologous Pair
Pair of chromosomes with the same genes one from each parent.
Independent Assortment
The random alignment of the homologous pair along the equator of the cell during meiosis.
2n
Diploid (means twice something else).
n
Haploid (means one of something).
Pure breeding
A group of identical individuals that always produce offspring of the same phenotype when interbred.
Fertilisation
Fusing of 2 gametes, female & male to form a zygote.
Inherited
What comes from the individuals parents.
Non-Inherited
What doesn’t come from the individuals parents.
