Variation and inheritance (1) Flashcards
Identify the source of an individuals unique genetic code
The gametes from there parents.
Identify the chemical that chromosomes are made of
Chromosomes are made of a chemical molecule called DNA
Explain the purpose of the instructions carried in the DNA code
The DNA code carries the instructions for the production of proteins
Identify the term used to describe the section of a chromosome that carries the genetic code for one protein
Gene. Each gene carries the instructions for the production of one particular protein molecule.
Explain the link between an individuals genetic code and the features of an organism
The features of an organism are determined by their genetic code. Therefore the features of an organism are controlled by their genetic code.
Explain what is meant by discrete variation
Discrete variation is the difference between organisms that fall into distinct groups. These characteristics are features that are controlled by a single gene
Explain what is meant by continuous variation
These characteristics are features that are controlled by more than one gene knowen as polygenic inheritance
What is an allele
Allele- different forms of the same gene
Describe a dominant allele
A dominant allele is represented by a capital letter in the genotype (A) and will always be expressed in the phenotype if the organism
What is a recessive allele
A recessive allele is only expressed in the phenotype of the organism if both alleles in the genotype are recessive.
How do you identify dominant and recessive alleles?
Examine the pattern of inheritance. A recessive characteristic can be passed to the offspring even although if not expressed in the parents so a recessive characteristic often skips a generation and is normal the least common allele
What is a genotype?
A genotype is how the two alleles of a particular gene carried by an organism are represented using letters
What is a phenotype?
This is the expression of an organisms genotype (how it appears or behaves)
What is homozygus
Homozygus is a genotype where both of the alleles are the same ( AA, aa)
What is hetrozygus?
This is a genotype where the two alleles are diffrent (Aa)
