inheritance variation and evolution Flashcards
allele definition
a version of a gene
DNA definition
The chemical that all of the genetic material in a cell is made up from.
what the structure of DNA?
double helix
chromosome definition
thin strands of DNA
gene definition
a small section of DNA found on a chromosome
genome definition
the entire genetic material of an organism
nucleotide definition
consists of a sugar, a phosphate group and a base
complementary base paring definition
A always pairs with T
C always pairs with G
hormone definition
a protein that is used to carry messages around the body
structural proteins
are physically strong e.g.,. collagen
mutation
a random change in the genetic code of an organism over time
sexual reproduction definition
where genetic material from two organisms is combined to produce offspring which are genetically different to either parent.
asexual reproduction definition
there is only one parent so the offspring are genetically identical to that parent.
advantages of sexual reproduction
.offspring have a mixture of two sets of chromosomes, which produces variation in the offspring
.variation increases the chance of a specie surviving a change in the environment.
.we can use selective breeding to speed up natural selection
homozygous definition
if an organism has two alleles for a particular gene that are the same
advantages of asexual reproduction
.there only needs to be one parent so uses less energy than sexual reproduction
.asexual reproduction is faster than sexual reproduction
.many identical offspring can be produced in favourable conditions
heterozygous definition
if an organism has two alleles for a particular gene that are different
dominant vs recessive genes
dominant= CC or Cc
recessive= and cc
genotype definition
A genotype is the collection of genes an organism has.
phenotype definition
the physical characteristics of an organism
what is cystic fibrosis caused by?
a recessive allele
what is polydactyly caused by?
a dominant allele
gamete definition
a reproductive cell of an animal or plant
variation definition
the differences that exist between individuals of a species
evolution definition
The theory that all living organisms evolved from earlier less complex forms of life during the history of the earth
selective breeding
when humans artificially select the characteristics of the plants and animals they are going to breed.
advantages and disadvantages of selective breeding
advantages=
.better quality of foods can be produced
.crops will have higher resistance to disease
disadvantages=
.reduces the gene pool, so variation decreases
.can cause health problems because greater chance of organisms inheriting harmful genetic defects when gene pool is limited.
fossils definition
remains of organisms that have decayed many thousands of years ago
speciation definition
the development of new species
classification definition
is organising living organisms into groups based on their characteristics
Classification order 1-7
1.kingdom
2.phylum
3.class
4.order
5.family
6.genus
7.species
Archaea domain definition
they were thought to be primitive bacteria but they are a different type of prokaryotic cell. They were first found in extreme places such as hot springs and salt lakes.
bacteria domain definition
contains true bacterial like coli and staphylococcus
Eukaryota domain definition
includes broad range of organisms including fungi, plants, animals and protists
how are organisms named?
they are named according to the binomial system
