Biology Level 1 NCEA

Question	Answer
Allele	Is the expression of a gene (e.g. either blue or brown allele for the eye colour gene)
Dominant Allele	Is the one that is always expressed (If its present). The recessive allele will only be expressed if there are NO dominant alleles present,
Genotype	Is the genetic code an organism has for a particular trait. (e.g. TT, Tt, tt)
Phenotype	Is the physical appearance of that genotype (e.g. brown eyes, blue eyes etc.)
Homozygous	Is when two alleles are the same (e.g. TT or tt)
Heterozygous	Is when two alleles are different (e.g. Tt)
DNA	Is the genetic code in the nucleus. Made up of bases; A, C, G and T. Is a double helix structed
Chromosome	A strand of coiled DNA.
Gene	A section of DNA that codes for a trait.
Trait	A characteristic or feature.
Mitosis	1. DNA replicates 2. Chromosomes line up 3. Chromatids pulled apart 4. Nuclear membranes form 5. Two cells form. Two identical daughter cells are produced for growth and repair in the body cells.
Semi Conservative	Half the daughter strand is old from the parent strand and half of the strand is new from the new base pairs.
Meiosis	Chromosome cross over. Only occurs in the sex cells and produces four different daughter cells.
Gametes	Are sex cells, they have half the number of chromosomes.
Zygote	Two gametes make a zygote, which has a full number of chromosomes.
Pure Breeding	Is when both parents are homozygous.
Genetic Variation	Allows a species to adapt to its changing environment.Can come from 1. Meiosis 2. Crossing over 3. Mutations
Punnet Square	Shows the potential offspring
Genotype ratio	The ratio of offspring with different alleles
Phenotype ratio	The ratio of offspring with different physical traits.
Pedigree Chart	Shows the phenotype of a family

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Biology Level 1 NCEA

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	Created by Laura Arthur about 9 years ago