Lecture 12/02.10.25 Flashcards
(28 cards)
What are covalent modification?
Modifications that are often reversible and are done by enzymes which are themsleves subjected to regulation. This form of modification is common
What are protein kinases?
ATP dependent enzymes that add a phosphoryl group to the OH group Tyr, Ser, Thr
What are forms of covalent modification?
phosphorilation/dephosphorylation, adenylylation, ADP-ribosylation, acetylation
What do phosphotases do?
Hydrolyze the resulting side chain phosphate esters releasing Pi.
What are zymogens?
Proenzymes or inactive forms of enzymes
How are zymogens activated?
They are activated into enzymes by proteolytic cleavage(protease activation).
How are zymogens synthesized?
In the pancreas and secreted into the duodenum in small intestine
What is trypsin?
It is a common activator of many zymogens for enzymes involved in protein degradation and digestive functions
What other examples involve zymogens?
Blood clotting, caspases in cell apoptosis, protein hormones, and collagen
What is the function of carbohydrates?
cellular protection, storing/generating biological energy, molecular recognition, cell signaling, etc.
What do carbohydrates yield?
One H2O for every C atom
What is the simplest carbohydrate?
Monosaccharides that are used for fuel for cellular processes and the building blocks for synthesis of complex biomolecules
What are monosaccharides classified into?
ketose or aldose
What is true about the name of monosaccharides?
They are related with the number of carbon atoms they are made of. Such as C4=tetrose, C5=pentose C6=hexose
How are aldose organized?
It is a chiral because the carbon carries 4 different substituents. Due to this, it has 2 stereoisomers that are called enantiomers (nonsuperimposable mirror images)
What are monosaccharides with more than 3 carbons called?
diasteromers
What are diasteromers?
Stereoisomers that are not mirror images of each other and have more than 3 carbons and have more than 1 chiral carbon
Why is it importnat to reduce properties of sugars?
- for forming polysaccharides chains
- for non specific reaction with other molecules
How can carbohydrate be linked together?
glycosidic bonds
What is glucose?
An important source of energy for life stored as a polysaccharide such as glycogen or amylose/amylopectin
What is glycogen and amylopectin?
It is a polymer of glucose. It is good for storage in small area, good to maintain inside cell, and good to reduced osmotic pressure
What is cellulose?
Another polysaccharide made of glucose chains. Also, a polymer. This cannot be digested by humans due to defiecient B-1,4 linkages
How are proteins modified with carbohydrates?
Glycoproteins are modified by carbohydrate at specific aa residues. Takes place in the ER and golgi.
How are blood types determined?
By specific sets of carbohydrated attached to membrane proteins and lipid on red blood cells
