MGD5+6 Flashcards
What are the methods of long-term regulation?
change rate of protein synthesis (transcription or translation)
change rate of protein degradations
What is an isoenzyme?
A different form of the same enzyme that has different kinetic properties.
Define product inhibition and state an enzyme affected by it
The accumulation of the product of a reaction that inhibits the forward reaction.
Hexokinase
If the curve shifts to the left is this an increase or decrease in affinity?
Increase
What are the activators of phosphofructokinase?
AMP
fructose-2,6-bisphosphate
What are the inhibitors of phosphofructokinase?
ATP, H+ and citrate
How do kinases work?
They transfer the terminal phosphate from ATP to the -OH group of the Ser, Thr or Tyr.
Which enzymes remove phosphate groups?
Phosphatases
What is ubiquitin?
A molecule that targets proteins for breakdown.
What are methods of short term regulation?
change in substrate or product concentration
allosteric regulation
covalent modification
proteolytic cleavage
How is heterochromatin packaged?
into solenoids
How is euchromatin packaged?
‘beads on a string’
What is the smallest unit of DNA packaging?
Nucleosome
What is a nucleosome?
A histone core with the DNA wound twice around it
How many subunits make up a histone?
8
Which chromosome is affected in HbS?
Chromosome 11
What kind of mutation causes HbS?
Single base substitution
resulting in a single amino acid substitution
Which chromosome is affected in cystic fibrosis?
Chromosome 7
What is the most common mutation causing cystic fibrosis?
A 3 base pair deletion (CTT)
resulting in a single amino acid deletion (Phe)
What is a genome?
The entire DNA sequence of an organism
What is a nucleoside?
The base and sugar
What is a nucleotide?
The base, sugar and phosphate group.
What is the difference between the sugar in DNA nucleotides and RNA nucleotides?
DNA sugar = deoxyribose
There is no -OH group on carbon 2
What charge do phosphate groups have?
negative
What charge do histones have?
Positive
What type of bond is formed between carbon 5 and the phosphate group?
Phosphodiester bond
How many rings does a purine have?
2 rings
How many rings does a pyrimidine have?
1 ring
What is an RNA stem loop?
When the RNA folds over itself to form H bonds with the complementary bases on the antiparallel part of the strand.
