Test 3 Flashcards
describe primary polypeptide structure
linear structure is dictated by order of amino acids
What are the two structures of secondary shapes?
Alpha helix (Pasta)
Beta sheets (waves)
What dictates secondary structure
The reaction between hydrogen bonds
What dictates tertiary structure?
Can polypeptides be biologically active?
Interaction between amino acids
Yes they can be called proteins if they are at the final shape
What dictates Quaternary structure?
Interactions between two or more polypeptides
What are four types of proteins
1.receptor proteins
2.hormones
3. antibodies
4.enzymes
What is the function of receptor proteins?
The function is that they are embedded within the cell membrane and are complementary binding sites for messenger molecules like hormones
What is the function of hormones?
Bind to receptor proteins are regulate processes e.g. puberty
What is the function of antibodies
Involved in the immune response binds to and deactivates antigens
What is the function of enzymes
They are biological catalyst
Why is the 3D shape important for function?
Shape dictates function
commonly proteins are complementary in shape to substrate molecules
discuss benefits and harms of chemicals that humans use
Caffeine is a positive- it gives you more energy
Panadol as a positive it reduces pain by binding to pain receptors.
Arsenic- stop oxygen
Describe the relationship between the enzymes active site and its substrate.
The enzyme active site is complementary to the shape of the substrate.
Describe the induced fit model
The active site changes shape until the substrate is completely bound to it. This change in shape weakens the bonds of, and correctly orientates the substrate, thus reducing the activation energy and speeding up the reaction.
How are enzymes affected by temperature
They work best at the optimal temperature
too cold =inactive, meaning don’t work until temp increases
too hot= denatured->Dead/cannot catalyse reactions
How are enzymes affected by pH
They work best at optimal pH
too high= denatured
too low=denatured
What does the presence of inhibitors do to the reaction rate
decreases reaction rate
Describe competitive inhibitors
Same shape as a substrate meaning they are complementary to the active site. can reversible (leaves the active site) or be irreversible (does not leave).
Describe noncompetitive inhibitors
Bind to the binding site, which is not an active site. Distort the shape of the active site so nothing can bind to it-meaning the enzyme is useless it reversibly binds.
Describe reasons for regulating metabolic pathways
Lose small amounts of heat at each stage instead of all at the end. Also, collect intermediate products (Doritos). that have specific enzymes for specific substrates at each stage.
What is gene expression?
Gene expression is the amount of protein being made of a specific gene.
What is methylation
Way of controlling gene expression.
Increase methylation = decrease gene expression.
Decreased methylation= increased gene expression.
What is CANCER?
Rapid uncontrolled cell division
What is the function of a proto-oncogenes
They increase cell division
