Genes Flashcards
What is a promoter gene?
Sequence of genes at the start of the strand which are triggered to start transcription.
What is an enhancer gene?
Sequence of genes which can be triggered to increase the rate of transcription
What is the terminator gene>
Sequence of genes at the end of the DNA strand which stop transcription
What is retrotranscription?
Conversion of RNA to DNA
Which microbes use retrotranscription?
Viruses insert viral RNA into the host cell which produces Viral DNA via retro transcription
What is nuclear DNA?
16,600bp of linear DNA inherited from both parents contained within the nucleus
What is mitochondrial DNA?
32bp of circular DNA maternally inherited
What is the order of genetic material in the body?
gene< DNA< chromatin< chromosomes
What is the structure of chromatin?
Chromatin is composed of nucleosomes- 146bp of two DNA strands wrapped around a histone protein core separated by linker DNA of 72bp.
What makes up the majority of nuclear mass?
Chromatin
What are the forms of chromatin?
Euchromatin which is less dense
Heterochromatin which is more dense
Which chromatin is used in transcription?
Euchromatin
What are telomeres?
Ends of DNA to prevent damage during replication
What is the long arm of chromosome?
Q arm
What is the short arm of the chromosome?
p arm
What is transcription?
The use of DNA template strand to create an RNA copy, initiated by RNA polymerase
What are distal control elements?
Regulatory genes
What are transcription factors?
Control the rate of transcription
What is the role of the preinitiation complex?
To orientate RNA polymerase to the target DNA site
Which direction does RNA polymerase add nucleotides?
5’ to 3’ end
What does the majority of the genome code for?
Structural proteins, regulatory proteins, junk DNA
How do transcription factors repress transcription?
Causes deacetylation of histone protein which increases binding regions for DNA to associate more strongly
How do transcription factors increase transcription rate?
Causes acetylation of histone protein which weakens DNA associations for RNA polymerase access. Also recruits distal control elements to bind to the enhancer genes
What is a primary transcript?
The mature RNA strand of only exons
What is splicing and where does it occur?
Removal of introns from conserved sequences
What is the process of splicing?
Cleavage of introns by enzymes which moves downstream to form a lariat loop which is excised
What is alternative splicing?
Differences in splicing due to cell type, differentiation
How is mature RNA stabilised?
Polyadenylation of 100-600 bases on 3’ end and cap added to 5’ end via guanyl transferase enzyme to replace triphosphate group
What are the common post translational modifications?
phosphorylation and glycosylation
How is RNA regulated?
microRNA and long non-coding RNA (over 200 bases long)
What is the function of the small and large ribosomal subunits?
small- binding of tRNA and mRNA
long- catalyses the addition of polypeptide
What is the function of TRNA?
Transfer of amino acids to the anticodon
What happens after stop codon is reached?
Releasing factor is excreted which causes disassembling of the ribosome
What is the difference in translation between prokaryotes and eukaryotes?
Prokaryotes use tRNA for protein synthesis instead of ribosomes
Why is the antibiotic tetracyclin prescribed?
antibiotic by preventing association of tRNA with ribosome
Why is the antibiotic chloramphenicol prescribed?
antibiotic which blocks bacterial ribosome from binding
What is secondary structure?
folding of protein in alpha helix and beta pleated sheets due to h bonds
What is the quarternary structure?
3d structure of a protein due to the
What are homologous chromosomes?
identical chromosomes
How long is cell division?
24 hours
Function of G2 Phase?
protein replication, cell grows in size
How does the centromere attach to chromosomes?
via the kinetechore, a complex of centromeric proteins
What is the order of mitosis?
prohase, prometaphase, metaphase, anaphase, telophase
What occurs during prophase?
chromosomes supercondese, centrosomes produce spindle threads that move to opposite cell poles
What are centrosomes?
organelles that produce tubulin which form microtubules in an orientation that forms spindle threads
What occurs during prometaphase?
Where are spindle threads produced in the cell?
Why is fluorouracil prescribed?
Why is fluorouracil prescribed?
Process of thymine synthesis?
Why is methotrexate prescribed?
Process of folate synthesis?
Why is vinblastine prescribed?
Why is paclitaxel prescribed?
Why is cyclophosphoamide prescribed?
Why is cyclosporin prescribed?
Why is tacrolimus prescribed?
Why is sacrolimus prescribed?
What are the cytostatic drugs?
What is karyotype and what is it used for?
What are the types of centromeric abnormalities?
Why are RBCs separated from the rest of the blood sample when obtaining patient karyotype?
How do we prevent progression from metaphase during karyotyping?
How can we idenfity homologous chromosomes?
Give examples of sex abnormality conditions
Give example of autosmal recessive conditions
Give example of autosomal dominant condition
Give examples of X linked inheritance?
WHat is chromosomal disjunction and the conditions associated with it?
What is the function of the CFTR gene?
What are the classes of cystic fibrosis?
What is a nonsense mutation?
What is a missense mutation?
What is repeat expansion mutation?
What is a truncated protein?
What is polymorphism?
What should medical professionals consider for patients with genetic conditions?
What is PCR?
What is a microsatellite?
What is a single nucleotide repeat?
What are examples of genetic polymorphism in the population?
What is the human leukocytic antigen?
What can we use polymorphism for?
How do restriction enzymes identify sickle cell?
What are genetic maps?
What is genetic recombination?
What is the Hardy- Wenburg principle in non-evolving population?
