Lecture 3 Genes and Gene families Flashcards
Define gene
a segment of the DNA that codes for a functional end product.
Define discontinous gene
Gene that is split up into exonic coding regions and intronic non coding regions.
Define gene family
A group of genes that have either the same nucleotide sequence or a very similiar nucleotide sequence, and code for identical proteins, or similiar proteins.
Define simple multigene family
Group of identical genes that have the same nucleotide sequence and encode the same functional end product. This allows the gene to
Explain what is meant by the Molecular clock
This provides a measure of the rate at which the sequence of a gene changes over time. It is used to determine the point at which a pair of genes were formed by a gene duplication event.
What are pseudogenes
These are genes that have lost their function and are now non functional.This happened because their nucleotide sequence changed so much it became non functional.
What is a gene duplication event
Where a gene duplicates, is replicated. there are now 2 copies of that same gene in genome.
What is meant by a functional end product
proteins and RNA
What percentage of total RNA is coding, messenger RNA
just 4 percent
What are the different types of RNA that exist in a cell?
sno RNA si RNA sn RNA m RNA r RNA t RNA
Give the legnth of the shortest genes
Less than 100 bp
Give the legnth of the longest genes
2,400,000 base pairs.
How many base pairs in a kilobase pair
1kb = 1000 base pairs
How many base pairs in a mega base pair
1Mb = 1000 kb = 1 million base pairs.
Define molecular clock
A device based on the inferred mutation rate that enables time to be assigned to the branch points in a gene tree.
