Reproduction and Inheritance Flashcards
what is a gene?
length of DNA that codes for a specific protein
what is an allele?
a version of gene that code for different forms of a protein e.g. a tall plant or a dwarf plant
what must each offspring inherit from its parents?
one allele from either parent
homozygous means…
both chromosomes have the same allele
a dominant allele only needs…
one allele present to be expressed
a recessive allele needs…
two alleles present to be expressed
heterozygous means…
the chromosomes have one of each allele
genotype is…
combination of alleles - eg. TT or Tt
phenotype is…
what is expressed - eg. tall or dwarf
what are parent carriers?
parents don’t have the disease but carry the allele for the disease
codominance is when…
neither allele is recessive, so you show characteristics from both alleles - eg. AB blood group
monohybrid inheritance is when…
when you inherit a single characteristic
natural selection evolution theory (6 marker)
1) Random rate mutations cause increased variation of species
2) Individuals with mutation increase competition for food with non-mutated individuals
3) Mutated individuals more likely to survive and reproduce
4) pass on this allele to the next generation
5) therefore offspring likely to inherit parent characteristics
6) this repeats for many generations of species
antibiotic resistance (6 marks)
1) originally, none of bacteria were resistant, no antibiotics used
2) doctors began to use antibiotics, killing bacteria
3) chance mutation gives some bacteria resistance to the antibiotic
4) this resistant bacteria adapted to environment where antibiotics used
5) resistant bacteria reproduced rapidly and passed on the resistance allele
6) this repeats for many generations of bacteria
