DNA, genes and chromosomes Flashcards
How many pairs of chromosomes are in humans?
23
Compare DNA in eukaryotes and prokaryotes
Eukaryotes = linear DNA, associated with histones and longer
Prokaryotes = circular DNA, not associated with histones and shorter
How is a single chromosome formed?
Eukaryotes = DNA double helix is wound around histone proteins which is coiled repeatedly into a single chromosome.
Prokaryotes = condenses to fit in cell by supercoiling
What is a gene?
A sequence of DNA bases that codes for either a polypeptide or functional RNA
What does the order of bases in a gene determine?
The order of amino acids in a particular polypeptide
What is a sequence of three bases called?
A triplet or codon
What do genes that don’t code for a polypeptide code for?
Functional RNA
What is a genome?
Complete set of genes in a cell
What is a proteome?
The full range of proteins a cell is able to produce
What are introns?
Section of a gene that doesn’t code for an amino acid
What are extrons?
Section of gene that codes for an amino acid
When are introns removed?
During protein synthesis
What is an allele?
Another form of gene. The order of bases in each allele is slightly different and will code for a slightly different version of the same polypeptide
