Genetics Flashcards
Pure breeding
Same homozygous so can get only outcomes of the breed they want
DNA
Long molecule that contains the genetic code/info in the sequence of their base
Gene
A particular protein which determine a characteristic
Allele
An alternative form of gene. Different base sequence
Mitosis
Produces 2 identical daughter cells used for growth and repair
What is the chromosome of a female?
XX
What is the chromosome for a male?
XY
What is a punnet square?
Gives probabilities of the outcomes
How many chromosomes do humans have
46 chromosomes and 23 pairs
Inheritance of sex
Each fertilisation has equal chance of producing boy or girl. Male are XY chromosomes and female are XX. Previous offspring to not affect chance
Gametes have how many chromosomes
Half the number than normal called haploid.
Gamer gas half no. Of chromosomes because?
As when a speed fuses with an egg the resulting zygote has the correct number of chromosomes
Ferrilisation
Is random which male gamete fertilises the female gamete- resulting in new combinations of alleles
Sexual reproduction
Produces variation between individuals due to random assortment of chromosomes in meiosis and random fertilisation.
Advantage of variation to a specie
Some individuals may survive if some change to environment/ threatening events could occur. If a new disease arrives, not all individuals will be wiped out. Individuals best suited to an environment will survive to reproduce and pass on their genes to future generations
Mutation
A change in base sequence of a gene/ change in genetic code and therefore a new protein characteristic/ trait being made. Mutations result in new alleles being created within a population( crossing over and independent assortment in meiosis cause a mixing of existing alleles
Mutation in gamete
A mutation occurring in a gamete won’t affect the individual but can be passed on/ inherited. The offspring have this mutation in every cell and it can be passed on in their gametes. Mutations in a somatic cells e.g. Skin cell can not be inherited
Sexual vs asexual reproduction
Sexual reproduction uses meiosis offspring genetically different- takes longer tine - needs 2parents- but offspring have better disease survival. Asexual uses mitosis all offspring are the same produce identical offspring in large numbers much more quickly but offspring have lack of disease survival
