PL5 Flashcards
What is a gene
The entire nucleic acid sequence that is necessary for the synthesis of a functional product
What can genes be considered as
Transcription units
What do the exons of a gene contain
The coding region or open reading frame
What are control regions, what do they do and where are they found
They are the promoter and cis-regulatory factors and they drive expression of the gene, found upstream of introns and exons
What are introns
They separate the exons and are spliced out during mRNA processing
What do proteins with similar functions often contain
Similar amino acid sequences that encode functional domains
What is the difference in genome size among species due to
Different amount fo non-coding DNS and transposable elements
Is gene density higher or lower in lower eukaryotes than in more complex eukaryotes and why
Greater because our genome is much bigger
What does comparison or related protein sequences from different species illuminate
Evolutionary relationships
What are orthologs
The same protein in different species
What are paralogs
Closely related proteins in the same species
What are the two possible characteristics of protein coding genes
They may be solitary or belong to a gene family
What makes up a gene family
A set of related genes formed by duplication of an original single copy gene
What are examples of a simple-sequence repeat
Micro satellite DNA and mini satellite DNA
Where is microsatellite DNA sometimes found
In transcription units
What happens when microsatellite DNA expands past a certain length
It can cause pathogenic diseases
How can short repeated sequences be generated in microsatellite DNA
By backward slippage during replication caused by DNA polymerase meaning there is a repeated domain
What is larger, mini satellite DNA or microsatellite DNA
Mini
Where is minisatellite DNA often found
In cetromeres and telomeres (structural components of chromosomes)
Where is much simple sequence DNA localized
In particular regions or chromosomes
Why can transposable DNA elements be called mobile
They have the ability to move within genomes by different mechanisms depending on the element
What have mobile DNA elements influenced and what can they cause
Evolution
Mutations leading to disease
What are the two major classes of transposons
DNA transposon (3%) and retrotransposon (40%)
What is the difference between the DNA transposons and retrotransposons
DT: Cut and paste, replication only
T: goes through and RNA intermediate
