DNA and inheritence Flashcards
Describe DNA
DNA is a two-stranded polymer shaped like a double helix. The strands are connected by base pairs which are themselves connected by hydrogen bonds.
What is a gene?
A gene is a section of DNA that codes for a specific protein
Where is DNA located?
Genes are located in thread-like shapes called chromosomes which belong in the nucleus of the cell.
Adenine
Thymine
Thymine
Adenine
Guanine
Cytosine
Cytosine
Guanine
alleles
Alleles are alternative forms of genes which give rise to differences in inherited characteristics.
Dominant allele
an allele whose phenotype is always expressed when it is present
Recessive allele
an allele whose phenotype is only expressed in a homozygous recessive genotype.
Homozygous
a genotype with two same alleles
Heterozygous
a genotype with two different alleles
Phenotype
the inherited characteristics of an organism
Genotype
an organism’s set of alleles
