17.1 - Studying inheritance Flashcards
What is genotype?
Genetic constiution (make-up) of an organism
It describes all the alleles an organism has
What does the genotype determine?
The limits within the characteristics of an indvidual
Example of genotype
May determine that a human baby could grow to be 1.8 m tall but actual height could be affected by other factors like diet
A lack of element calcium (for growht of bone) at a particular stage of development could mean the individual never reaches his/her potential max height
What is phenotype?
Observale or biochemical characteristic of an organism
What is phenotype result of?
It is the result of interaction between the expression of genotype and the enivnroment
envirnoment can alter phenityoe
What is a gene?
Length of DNA that is sequence of nucleotide bases that normally code for a particular polypeptide
gene does this by coding for a particular polypeptide
What could be polypeptide be?
An enzyme for a biochemical pathway that leads to a production of the characteristic
e.g gene could code for brown pigments in iris of an eye
What are alleles?
One of different froms of an gene
What is locus?
Position of gene of a particular DNA molecule
What is an example of a gene?
In pea plants gene for colour for see pod
gene has two different forms or alleles for green pod and allele for yellow pod
What are homoglous chromosomes?
Two loci carry one allele of a gene
If allele fot each chromosome is same then homozygous
What does codomainance mean?
Both alleles occur together
Phenotype is either a blend of both features (e.g shorthorn cattle with roan coat colour resulting from red and white allele)
What means organisms has multiple alleles?
Sometimes a gene has two allele forms
However as they are only two chromosomes in homoglous pairs it follows that two out of three or more alleles in existence can be present in single organisms
Multiple alleles can occur in humans ABO blood system
What is dominant allele?
Expresses itself even when present with recessive allele of same gene
What is recessive allele?
Expresses itself only in the presence of another identical allele
