(L6,7) Genomes

?
What was the first complete sequenced genome (eukaryote)?
Yeast- Saccharomyces cerevisiae (12.1 million base pairs)
1 of 29
Describe the genome for yeast
12.1Mbp in 16 chromosomes, 5995 likely protein coding genes, aprox. 140 genes for ribosomal DNA, 275 for tRNA, 40 for small nuclear RNA's
2 of 29
First sequenced plant genome
Arabidopsis thaliana
3 of 29
Describe the genome for Arabidopsis thaliana
125mbp, 25,498 protein coding genes
4 of 29
Describe the genome for black cottonwood
485Mbp, 45,555 predicted gene-coding proteins, 5248 have no identifiable Arabidopsis equivalent (evidence of particular expansion in number of genes associated with lignins and resistance to stress)
5 of 29
Describe the genome for wheat
94% of genome sequenced, approx. 17,000mbp, 107,891 protein-coding genes, wheat is triploid (3 ancestors)
6 of 29
Describe the genome for a nematode
97.1mbp, >19,000 protein-coding genes
7 of 29
Describe the genome for a fruit fly
180mbp, 15,500 protein coding genes
8 of 29
Describe the genome for honey bees
A new family of genes coding for major royal jelly protein, especially queen bee, more genes for taste receptors (odours are important in social communication and flower recognition)
9 of 29
Describe the genome for the human
Estimated 3286mbp, approx. 21,000 genes
10 of 29
Which differs the most? Genome size or number of genes?
Genome sizes, many genomes contain large amounts of 'extra DNA'
11 of 29
Where is the extra DNA?
Within genes (mainly introns), between genes (much of this is repetitive DNA)
12 of 29
RNA processing in eukaryotes
1) Addition of 7-methyl G cap, 2) Removal of introns, 3) 3' end cleavage and addition of poly(A) tail
13 of 29
Why is the cap attached?
It protects the end of the mRNA from accidental degradation of cell
14 of 29
Intron
Sequence within the transcribed region of a gene that is removed during RNA processing
15 of 29
Exon
Sequence that is present in mature mRNA
16 of 29
What is RNA splicing?
The removal of introns
17 of 29
Which part of introns are important?
The beginning and end (they are conserved), especially GU or AG, a region in the middle is also important
18 of 29
What 2 steps are involved in excision of an intron?
1) 5' cut and formation of a loop with a tail: lariat (loop is formed by 5'-2' phosphodiester bond, 2) 3' cut and joining of exons
19 of 29
What is intron excision catalysed by?
Spliceosome
20 of 29
What is a spliceosome?
Contains ribonucleoprotein complexes: snRNPs, and several polypeptides
21 of 29
What do the snRNPs do?
Bind to mRNA precursors by specific base pairing to conserved sequences required for intron removal
22 of 29
Describe how spliceosomes remove introns
snRNPs bind to primary transcript, interactions between snRNPs form spliceosome, this cuts 5' end of intron and forms lariat, it also cuts 3' end of the intron and joins exons
23 of 29
What percentage of human genes code for more than one protein?
Approx. 60%
24 of 29
What are the differences due to?
Alternative splicing
25 of 29
What is alternative splicing?
A regulated process during gene expression resulting in different exons being used in different kind of cells (coding for more than one protein)
26 of 29
What are the similarities between the gene products of the same gene?
Different products of a gene have related but not identical functions, they can be specific to a particular tissue or developmental stage
27 of 29
a-tropomyosin
Different type of muscle and non-muscle cells have different forms of tropomyosin (form the same gene), there are at least 8 different mRNA's for tropomyosin
28 of 29
Huntingtin gene
In humans and pufferfish,
29 of 29

Other cards in this set

Card 2

Front

Describe the genome for yeast

Back

12.1Mbp in 16 chromosomes, 5995 likely protein coding genes, aprox. 140 genes for ribosomal DNA, 275 for tRNA, 40 for small nuclear RNA's

Card 3

Front

First sequenced plant genome

Back

Preview of the front of card 3

Card 4

Front

Describe the genome for Arabidopsis thaliana

Back

Preview of the front of card 4

Card 5

Front

Describe the genome for black cottonwood

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Molecular Biology and Development resources »