Level 1 Genetics NCEA Genetics

Question Answer
DNA The molecule which genes are made out of
Chromosome A thread-like structure made of thousands of genes
Gene A section of chromosome/DNA that codes for a particular trait
Bases The building blocks of DNA: Adenine
Double Helix The twisted ladder shape of DNA
Nucleus The structure in a cell which contains chromosomes
Cytosine The base that pairs with Guanine
Thymine The base which pairs with Adenine
Guanine The base that pairs with Cytosine
Adenine The base that pairs with Thymine
Gamete The sex cells e.g. sperm or eggs
Testes Where the sperm are made
Ovaries Where eggs are produced
Mitosis Cell division that occurs in the body for growth and repair
Meiosis Cell division to produce gametes (sex cells)
Phosphate A chemical that alternates with a sugar to form the sides of DNA
Sugar A chemical that alternates with phosphate to form the sides of DNA
Allele Different Version of a gene
Asexual reproduction Reproduction involving only one parent. All offspring are genetically identical
Complemantary base pairing Used to describe how the bases A always pairs with T and G always pairs with C
Continuous Variation Variation that shows a range of values For example skin colour
Diploid Cell with a full compliment of chromosomes
Discontinuous variation Variation that is either / or eg blood group
Dominent Allele This allele will be expressed in the phenotype if only one of the alleles is in the genotype
Genotype This is what genes you carry e.g. BB
haploid cell with half the number of chromosomes eg in the sex cells
Heterozygous Two diffeerent alleles
Homozygous The same alleles eg BB or bb
Karotype A photograph of the chromosomes of a cell arranged in an orderly fashion
monohybrid cross A straight forward cross involving only one pair of alleles
Mutation A change in a gene or chromosome
Natural selection Organisms with characterisitics best suited for their environment become more successful and pass these traits to their offspring.
Nucleotide A unit of DNA made up of one phosphate
Phenotype The expression of the genotype. This is what you look like if it is a visable trait eg brown eyes.
Punnett square Grid of squares showing the range of combinations of genes.
Pure breeding A group of individuals that always produce offspring of the same phenotype when interbreed. They are homozygous
recessive This allele can only be expressed if the two alleles are present. eg bb
Sexual reproduction Reproduction involving two parents
Trait Another word for characteristic.
Triplet code genetic code made up by a sequence of three bases. Each triplet codes for an amino acid.
Variation Differenaces amongst individuals. Vital for the survival of species.
Zygote Fertilised egg cell

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