Stuff Need To Know For The Exam Flashcards
(32 cards)
Regulation of gene expression at transcriptional level
- lac operon
- trancription factors - short non coding pieces of rna that act within a cells nucleus, activate or supress transcription of the gene - tumour supressor genes and proto-oncogenes
Post transcriptional gene regulation
- introns and exons - introns are non coding parts of DNA some may encode proteins and some may be short non coding lengths of RNA involved in gene regulation
Post translational level of gene expression
- enzymes are activated by being phosphorylated
Describe how post translational activation happens
- hormone binds to receptor on plasma membrane of target cell
- actives g protien
- actives adneyl cyclase
- converts ATP to cAMP
- cAMP activates PKA
- PKA catalyses phosphorylation of proteins hydrolysing ATP in the process, activates enzymes in the cytoplams
- PKA phosphorylates CREB
- enters nucleus and acts as a transcriptional facotr
Homeobox sequence
180 base pair found within gene that are involved in regulating patterns of anatomical development in animal fungi and plants
What is the homeodomain sequence
Homeodomain sequence can fold into a particular shape and bind to DNA regularing transcription of adjacent genes
60 amino acid sequence
Contains two alpha helixes connected by one turn
Binds to TAAT sequence of the enhancer region
How are hox genes regulated
- gap genes and pair rule genes - regulatated by maternally supplied mRNA from egg cytoplasm
Apoptosis
Chromatin condenses, nuclear envelope breaks down
DNA breaks into fragments
Physical mutagenic agents
X rays
Gamma rays
Uv light
Chemical agents
Mustard gas
Nitrous acid
Aromatic amines
Reactive oxygen
Biological agents
Viruses
Transposons - jumping genes and remnants of viral nucleic acid that have become incorporated into genomes
Food contaminants such as mycotoxins from fungi
Deletion
Part of chromosome is lost
Inversion
A section of chromosome mag break off turn 180 degrees and join again
Translocation
- piece of one chromosome breaks off and attaches to another chromosome
Duplication
When chromosome is duplicated
Non disjunction
One pair of chromosomes or chromatids fails to separate leaving one gamete with an extra chromosome
Aneuploidy
Chromosome number is not an exact multiple of the haploid number for that organism
Polyploidy
If a diploid gamete is fertilised by a haploid gamete the resulting zygote is triploid
Codominance
Where both alleles present in the genotype of a heterozygous individual contribute to the indiviudals phenotype
Multiple alleles
Characteristics for which there are three or more alleles in the populstioms gene pool
Epistasis
Interaction of non linked gene loci where one masks expression of the other
Geographical isolation
Allopatric speciation
Reproductive isolation
Sympatric speciation
Describe pyrosequencing
- long length of DNA is cut into fragments of 300-800 base pairs using a nebuliser
- lengths are then degraded into single stranded DNA these are the template DNas and are immobilised
- sequencing primer is added and DNA is incubated with enzymes DNA polymersse, ATP sulfurylase , luciferase , apyrsse and the substrates adenosine 5 phosphosulfate and luciferin
- only one of the 4 possible activated nucleotides ATP, TTP, CTP and GTP are added and any light detected is generated
- one activayed nucleotode incorporated into a complimentary strand of DNA uses the strand to be sequenced as a template as this happens two extra phosphoryls are released as pyrophosphate
- in the presence of APS the the enzyme ATP sulfurylase converts the pyrophosphate to ATP
- in the presenxe of this ATP enzyme luciferase converts luciferin to oxyluciferin
- this creates visible light which can be captured by a camera
The amount of visible light is proportional to the amount of ATP available
