Block 2 Lecture 7 & 8: Protein folding + Chemical Energy Flashcards
To change from primary to secondary structure, which bonds must be formed between amino acid side chains?
Hydrogen bonds
what are the two kinds of secondary strucutre
alpha helix and beta pleated sheet
Tertiary structure involves the collapse of ______ components and the facing outwards of ______ components
the collapse of hydrophobic components and the facing outwards of hydrophilic components
what are the bonds present in tertiary structure between non-polar amino acid side chains, and how strong are they relatively
Van der Waals, weak
what bonds are present between polar side chains in a tertiary structure
hydrogen bonds
what bonds are there between charged amino acid side chains on a tertiary structure, and how strong are they relatively?
ionic bonds, weak
What structure of protein do disulphide bridges form and between what two molecules do they form?
form in a tertiary structure between two cysteine molecules. Is a strong bond
what does a quaternary structure consist of?
two or more polypeptide chains each with their own tertiary structure
homodimer and heterodimer complexes are part of which classification of protein structure?
quaternary
where are membrane anchored and secretory proteins initially translated?
on cytoplasmic ribosomes
What is the name of the particle that recognises the signal peptide when it emerges from the ribosome after being translated?
the SRP, signal recognition particle
what is the function of the SRP, the signal recognition particle?
targets specific receptors in the ER membrane
is the signal sequence found at the C terminus or the N terminus of the polypeptide chain?
the N terminus
what is the process for the translocation of a secretory protein (e.g a hormone) across the ER membrane?
chain is completely translocated and the signal sequence is cleaved off by a signal peptidase.
Do secretory proteins remain insoluble in the ER lumen once they have been translocated?
No, they are effectively solubilised in the lumen once they have been translocated.
What is the process for the transaction of a membrane protein across the ER membrane?
one or more of the hydrophobic segments of the polypeptide chain anchors it in the bilayer
Which of membrane and secretory proteins are moved via transport vesicles from the ER to the Golgi?
Both membrane and transport proteins are moves via transport vesicles from the lumen of the ER to the Golgi
What are the different types of vesicles that operate from the Golgi?
Transport vesicles which move proteins to lysosomes, Membrane vesicles which merge proteins to the membrane of the cell, secretory vesicles which export proteins out of the cell via exocytosis.
Which face of the Golgi are vesicles packaged at?
The trans face of the Golgi
______ reactions transfer energy from complex molecules to ATP
catabolic
______ reactions transfer energy from ATP to complex molecules
anabolic
do catabolic or anabolic reactions result in the storage of energy
catabolic
what facilitate the transfer of glucose from the bloodstream into a cell?
insulin
what facilities the conversion of stored glucose, as glycogen, to glucose in the bloodstream?
glucagon
Is glycolysis anaerobic or aerobic and where does it occur?
anaerobic, occurs in the cytoplasm
what is the reactant and what is the product of glyoclysis
Glucose turns into two molecules of pyruvic acid and four ATP
How many ATP are used in the process of glycolysis
2 ATP
How many NAD molecules are reduced by glycolysis
2
what must happen in between glycolysis and the Krebs cycle?
the formation of Acetyl CoA
How is Pyruvic acid converted to Acetyl CoA
aerobic process in the mitochondrial matrix
is the formation of Acetyl CoA anaerobic or aerobic
aerobic, requires O2
What does the Krebs Cycle produce from 1 molecule of Acetyl CoA
1 x ATP,
2 x CO2,
1 x FADH2 and 3 x NADH
Where does the Krebs Cycle occur and is it an aerobic or anaerobic process?
in the mitochondrial matrix, is aerobic
During the electron transport chain, what does the enzyme ATP synthase do as protons move back across the mitochondrial membrane?
Phosphorylate ADP to ATP
what is the final electron acceptor in the electron transfer chain
O2, forms water
ETC uses energy from _____ reactions to fuel pumping of protons up a concentration gradient from matrix to inner membrane space
redox
what is proton motive force derived from
the energy rich electrochemical gradient
how many protein complexes form the ETC?
4
what two kinds of phosphorylation are present during cellular respiration?
substrate level phosphorylation (Krebs and Glycolysis) and oxidative phosphorylation (ETC)
Does NAD+ or FAD promote the production of more ATP
NAD
where is insulin produced
by beta cells of Islets of Langerhans in pancreas
what is the function of insulin
promote glucose uptake into cells (for ATP production or storage in liver). insulin produced when blood sugar levels are high
where is glucagon produced
Produced by alpha cells of Islets of Langerhans in pancreas
what is the function of glucagon
Stimulates the breakdown of glycogen to increase blood sugar levels
Diabetes Mellitus : a disease in which the body’s ability to produce or respond to the hormone____ is impaired, resulting in abnormal metabolism of carbohydrates and _____ levels of glucose in the blood.
insulin, results in elevated/increased levels of glucose in blood
what is the difference between type 1 and type 2 diabetes
type 1: beta cells of pancreas are destroyed so insulin is not produced.
type 2: body produces insulin but receptors are non-functional
what is the most common form of diabetes
type 2
what are some side effects of diabetes
excessive thirst, frequent urination, weight loss, fatigue
