Discussion Reading 2 Flashcards
(19 cards)
Number of genes in the human genome
less than 25000
humans make how many different types of protein
90000
Why so few genes when you need to produce many proteins?
Alternative splicing
Alternative splicing increases an organism’s
complexity
Number of human genes subject to alternative splicing
75%
Alternative splicing
introns may be kept during the splicing process, and exons may be discarded.
Prior belief about splicing
Introns always discarded, exons always kept.
Which enzyme carries out RNA editing?
Spliceosome.
RNA editing is controlled by what?
Splicing regulatory (SR) proteins.
Spliceosomes are composed of what?
5 snRNA (Small nuclear RNA) and 150 proteins.
Spliceosomes do what?
Recognize start and ends of introns and cuts introns out and joins exons in the pre-mRNA transcript.
Are humans the only organism with alternative splicing?
No, many other organisms have this, like fruit flies.
Most common type of alternative splicing in mammals
Exon skipping
Alternative splicing dangers
an error in splicing can cause defective proteins, or mutations.
Organism with most introns per gene
humans
On average, each gene generates this many alternatively spliced mRNAs
3
Exotic sequences make up what percent of our genome?
1-2 percent
understanding splicing mechanism advantage
Lead to cures for inherited and acquired disorders
Humans, mice, and other primates are very different from each other, despite having very similar genes because of:
alternative splicing
