Inheritance,Variation,Evolution Flashcards
(73 cards)
How often do mutations occur and does it alter protein
Mutations occur continuously. Most do not alter the protein, or only alter it slightly so that its appearance or function is not changed.
What effects can mutation of dna have
Some can have a serious effect and can change the shape
● The substrate will not fit into the active site so it cannot act as a protein.
● A structural protein may lose its shape
What do coding and non-coding dna do
The coding DNA that determines the proteins and their activity
The non-coding DNA that determines which genes are expressed
What does gamete mean
An organism’s reproductive cell (egg in female and sperm in males), which has half the number of chromosomes (23)
What does chromosome mean
A structure found in the nucleus which is made up of a long strand of DNA.
What does gene mean
Gene-A short section of DNA that codes for a protein, and therefore contribute to a characteristic. Some characteristics are controlled by a single gene, such as fur colour in mice and red-green colour blindness in humans. However, most characteristics are the result of many different genes interacting.
What does allele mean
The different forms of the gene - humans have two alleles for each gene as they inherit one from each parent.
What does dominant allele mean
Only one (out of the two alleles) is needed for it to be expressed and for the corresponding phenotype to be observed.
What dos recessive allele mean
Two copies are needed for it to be expressed and for the corresponding the phenotype to be observed
What does homozygous mean
When both inherited alleles are the same (i.e. two dominant alleles or two recessive alleles).
What does hetrozygous mean
When one of the inherited alleles is dominant and the other is recessive.
what does genotpe mean
The combination of alleles an individual has, e.g. Aa
What is embryonic screening
Embryonic screening allows scientists to observe whether the child will have a genetic condition or not. ● If the embryo is developed in the lab, cells can be taken from it and analysed ● DNA from embryos in the womb can also be extracted
What does phenotype mean
The physical characteristics that are observed in the individual, e.g. eye colour
What is Cystic fibrosis
disorder of the cell membranes, resulting in thick mucus in the airways and pancreas
● Caused by a recessive allele
● Both parents need to either be carriers (have one of the recessive alleles) or one must have CF themselves and the other is a carrier
What does a single gene cross look at
A single gene cross looks at the probability of the offspring of two parents having certain genotypes and phenotypes.This is done using the alleles the two parents have for a gene and a Punnett square diagram.You should be able to draw and use a Punnett square diagram
What is polydactyly
having extra fingers or toes
● Caused by a dominant allele
What are genetic disorders caused by
by inheriting certain alleles
Some disorders are inherited. These disorders are caused by the
inheritance of certain alleles.