PREPARATION FOR FINAL EXAM for molec cell Flashcards
(51 cards)
describe secondary structure of amino acids
It is composed of alpha helics and a spiral conformation in which every backbone N-h group donates a hydrogen bond to the backbone C=O group
Why do nonpolar amino acid chains tend to be on the interior
Nonpolar amino acids are typically found on the interior because they have hydrophobic properties and tend to repel water
Describe detergents
They are ampiathetic and disruptive agents
, the hydrophobic ends of detergent molecules interact with the membrane-spanning hydro-
phobic regions of the transmembrane proteins, as well as with the hydrophobic tails of the phospholipid molecules, thereby disrupting
the lipid bilayer and separating the proteins from most of the phospho
lipids
THEY DO NOT ASSOCIATE THE HEAD FROM THE TAIL AND DO NOT SEPERATE THE LIPS
do proteins bind to their ligand as tight as possible
nope this is because a tight configuration will not provide strong enough binding if it is not acessible
When are GTP binding proteins in their active conformation
They are active when it is bound to GTP and inactive or off when bound to GDP
Why are alpha helics more common than beta barrels
Alpha helices are good to anchor proteins into the membrane, or forming small holes that is suitable for compounds like ions, while with beta barrels larger compounds such as sugars, or various drugs can be transported
Which of these do we know that flipase opccurs
Flippases are responsible for transporting phosolipids from the extracelluar sideor noncytosolic to the cytosolic side of the membrane
Describe the cell cortex and it functions
The cell cortex can restrict movement, maintain shape, orgsnizing the cell’s internal components
describe a protein domain
any segment of a polypeptide chain that folds independantly into a compact and stable structure
explain Disulfide bonds
the covalent bond formed between the sulfur atoms of twp cysteines in a protein
covalent cross linkages
reinforce structure of a protein
DO NOT CHANGE THE STRUCTURE
describe hydrolase
he covalent bond formed between the sulfur atoms of twp cysteines in a protein
covalent cross linkages
reinforce structure of a protein
DO NOT CHANGE THE STRUCTURE
what is a nuclease
A nuclease is an enzyme thatr cuts DNA or RNA by breaking phospphodiester bonds between nucleotides
what is a protease
A protease is an enzyme that breaks down proteins by breaking peptide bonds between amino acids
what does a ligase do
A ligase is an emzyme that connects two frag,emts of DNA to make a single fragment
what does synthase do
Synthase is an enzyme that combines two molecules to create a new molecule without ATP hydrolsis
what does an isomerase do
An isomerase is an enzyme that rearranges bonds within a molecule
what do polymerases do
An enzyme that catalyzes polymerization reactions such as the synthesis of DNA and RNA
what does phosphatase do
Is an enzyme that removes a phosphate group from a molecule
what does oxidoreductase do
An enzyme that catalyzes redox reaction when one molecule is oxidized while the other one is reduced
what does ATPase do
An atpase is an enzyme that hydrolyzes ATP to ADP
What is an alloesteric enzyme
An enzyme that both an active site for substrate binding site and alloesteric site for binding of regulatory molecules
what are the functions of the cell membrane
Cell growth and Motility
Cell communication
Import and export of molecules
What are the properties of a lipid
The properties of a lipid is a hydrophillic head and a hydrophobic tail
What is the most common phospholipid in the cell membrane
The most common phospholipid in cell membrane is phosphatidylcholine
