Genes and Genome

Question 1

What is a genome?

Answer 1

A genome is an organism complete set of DNA. Each genome contains all of the information needed to build and maintain that organism.

Question 2

Genome size

Answer 2

vary in different organisms and does not correlate to complexity

Question 3

How are genomes organised ?

Answer 3

chromosomes

no. of chromosomes does not nessecarily correlate to genome site.

Question 4

elements making up a geneome ?

Answer 4

Gene control regions
introns
regions coding for functional rna
centromeres
telomeres
origins of replication
Genes

Question 5

what is a genes

Answer 5

A sequence of nucleotides along dna that provides coded instructions for protein

genes no. dont correlate to genome size

Question 6

What is the c value

Answer 6

total number of base pairs per haploid genome

Question 7

typical structure of human gene

Answer 7

5-10 coding exons
promoter controls when gene is expressed
introns transcribed not translated
atg is start site and stop is stop site

Question 8

UTR?

Answer 8

Variable from protein to protein
show variation in size
contain elements that control the translation,degradation and localisation of mRNA
offucr at both 5’ and 3’ end

Question 9

Introns and Extrons

Answer 9

no. of introns is very variable 0 to several hundered

size is variable
some organisms have no introns
there are specific squences at 5’ to 3’ junctions which allow them to be recognised and removed by splicing

Question 10

splicing

Answer 10

snRNP recognises sequences at 5’ and 3’ end
snRNP then loops out the intron and then 5’ cleavage and free end joined to rna to make lariat
and then 3’ is released
this uses rna ligase

Question 11

alternative splicing

Answer 11

constitutive splicing
exon skipping
mutually exclusive exons
alternative 5’donor sites
alt 3’ donor sites

can generatte different isoforms of gene

Question 12

RNA editing

Answer 12

Discreet changes made after RNA trancription
can be insertion,deletion or deamination

Question 13

rna editing mechanisms

Answer 13

editosome complex anneals to rna strand and is guided to miss matched region and changes it

Question 14

Gene editing

Answer 14

Recombination
also get programmed dna elimination

Question 15

multigene families

Answer 15

protein has two diff genes that code for it

in mamals several copies of genes
family vary in number, how closely related the copys are and genomic locations

> 1 copy of gene means copy can be expressed similarly or diff depending on tissue

Question 16

variation due to mutations

Answer 16

Chromosomal instability (CIN)- gains or losses of whole chromosomes, as well as invertions,deletions etc.

nucleotide level instability- mutations of single or small groups of nucleotides - not visible morphologically

Question 17

SNPs

Answer 17

natural variation- can me measured snp analysis
signpost for disease susceptibility and drug reaction

Question 18

do eukaryotes have operones

Answer 18

vary rare but still have co translation of genes.

Question 19

gene clusters

Answer 19

rDNA
globin gene family
histone genes
Immunoglobulin
tRNA

Question 20

gene expression

Answer 20

Cell identity is determined by this
robust mechanisms needed for control of this and regulation

Question 21

control of gene expression

Answer 21

modification of dna
transcriptional control
posttranscriptional
translational
posttranslational

Question 22

mitochondrial genome

Answer 22

mitochondria have own genome
codes for 35 proteins
is circular
multiple genomes in single mitochondrian
no chromatin structure
3% is non coding
inheritance is maternal
genes are transcribed in poly cistronic manner
many diseases in mtdna alteration

Question 23

choroplast genome

Answer 23

codes for 100 protein
circular
multiple in 1 chloroplast
no chromatin
operons
43%non coding

Question 24

importance of genome medically

Answer 24

diagnosis
- simple disease - 1 loci
- complex disease - multiplw loci
- different mutations in genes

treatment
is drug used appropiate for the cause of that patients probles
- dosage

ge