Biochemistry Flashcards
What are nucleotides?
Compound = nitrogen containing base + sugar + phosphate
Which end of DNA are new nucleotides added to?
3”
What are ZDV & AZT?
Retrovirals (used to treat HIV)
What are Okazaki fragments?
Short DNA formed on a lagging strand in DNA replication
What does helicase do?
Unwind DNA strand (stop it rewinding)
In which direction is the leading strand formed in?
3” - 5”
In which direction is the lagging strand formed in?
5” - 3”
What do enzymes do?
Catalyse a reaction so it reaches equilibrium faster
Do enzymes alter the position of equilibrium?
No
What are the 2 types of co factors?
Metal ions
Coenzymes
What is an apoenzyme?
Enzyme without cofactor
What is holoenzyme?
Enzyme with cofactor
Where do substrates bind to enzymes?
Active site
What factors affect enzyme activity?
Temperature
pH
Concentration (enzyme or substrate)
What are isozymes?
Isoforms of enzymes
Catalyse same reaction but have different shape & properties
What does increased CK show?
Muscle damage (skeletal)
What are Zymogens?
Inactive precursors of enzymes
What does the Michaelis-Menten equation show?
Kinetics of an enzyme reaction
What is Vmax?
Maximal rate of reaction (with unlimited substrate)
What is Km?
Michaelis constant
Conc of S when 1/2 Vmax
Mechanisms of enzyme control
Allosteric Regulation of transcription Reversible covalent modification Irreversible covalent modification Degradation
What is Allosteric control?
Altered enzyme activity by means of conformation induced by different molecules
Do Allosteric enzymes follow Michaelis-Menten kinetics?
NO
What shape is the curve of an allosteric enzyme?
Sigmoid