Cell Structure & Function Lecture 7 & 8 Flashcards
Primary structure of protein?
Polypeptide chain containing polymers of the 20 amino acids, held together by polypeptide bonds
Secondary structure of protein?
Alpha helix (primary structure coiled and held together by H bonds) and beta sheets (primary structure zig-zags to form pleated sheets which join together by H bonds)
Requirements of secondary structure to function?
C=O the O H bonds to the H in N-H
Tertiary structure of protein?
Alpha helices and beta sheets fold up to form globular molecule held together by intramolecular bonds
Requirements of tertiary structure to function?
Hydrophobic collapse – hydrophilic external faces
van der Waal’s interactions between non-polar amino acid side chains (weak)
Hydrogen bonds between polar amino acid side chains
Ionic bonds between charged amino acid side chains (weak)
Disulphide bridges between cysteine molecules (strong)
Quaternary structure of protein?
Homodimer or heterodimer complex
Alteration in the amino acid sequence at binding groove does?
Alters the target enzyme binding there
Alters how efficiently it can degrade
Different types of proteins in post translational modification?
Cytosolic proteins, organelle-specific proteins, secreted proteins and membrane bound proteins
Cytosolic proteins?
Made by free ribosomes, PTM added by cytosolic proteins
OS proteins, secreted proteins and membrane bound proteins?
Made by attached ribosomes, PTM added by endomembrane proteins (golgi apparatus)
After translation, folding and PTM what else may need to happen so protein works?
Phosphorylation (addition of a phosphate group), phosphorylation cascade happens after
Cellular respiration?
Not spontaneous and requires an input of energy (ATP), coupled reactions, hydrolysis of ATP gives energy to a reaction that needs energy to start
Fuels from food we eat goes where?
Proteins, broken down to amino acids
Fats, broken down to simple fats
Carbohydrates, broken down to simple sugars then absorbed
Three major interlinked biochemical pathways?
Glycolysis, Krebs cycle (citric acid cycle), ETC and chemiosmosis
What is integral to control the production of ATP?
Negative feedback control
What happens if your insulin doesn’t function the way its supposed to?
No glucose in cells leads to no cellular respiration from glucose, no ATP and no glycogen stores
What is insulin?
Produced by beta cells in the pancreas, it promotes glucose uptake in cells (for ATP production and storage in the liver)
What is glucagon?
Produced by alpha cells in the pancreas, stimulates the break down of glycogen stores to increase the glucose level in blood (sugar levels)
What controls blood sugar levels?
Both insulin and glucagon control blood glucose homeostasis
What is diabetes mellitus?
Impairs the body’s ability to respond to the hormone insulin, causing in abnormal metabolism of carbs leading to high glucose levels in the blood
What is type 1 diabetes?
People who are insulin dependent don’t produce insulin as the beta cells in the pancreas are destroyed (not there), affects 5-10% of diabetics and has a genetic onset
What is type 2 diabetes?
People who are not insulin dependent but their receptors don’t function and don’t respond to the bodies production of insulin, affects 90-95% of diabetics
