Enzyme Cell and Membrane Test Flashcards
What is a catalyst?
Substance that speeds reaction
Enzyme shape determines which reaction it catalyzes (same both sides)
Enzyme shape determines which reaction it catalyzes
Why are enzymes considered to be biological catalysts?
speed reaction, works under living organism conditions
Describe the model of induced fit
Enzyme changes shape/confirmation so enzyme can bind to substrate
Enzymes substrate complex and what happens at an active site
Enzyme binds to one or more substrate,
converts to one or more product, Catalyze reaction repeats and binds
How does an active site differ from an allosteric site
Active site: location for catalyse reaction, hydrophobic
Allosteric site: changes shape in enzyme
Cofactor
-non protein group
-binds to enzyme
-metals
-production of energy function requires cofactor
Coenzyme
-Shuttle molecules from one enzyme to another
-NAD is electron carrier of pathways
-Organic molecule acts as cofactor for enzyme
methods of enzyme inhibition
-Lowers catalyzes rate
-Decrease activity
-Fits in active site
-Block access to normal substrate thats why activity is slow
Competitive inhibition
-Concentration is high enough it stops completely
-They compete for a spot in the active site
Non competitive
-don’t compete for a spot
-bind to a location other than the active site
-Can’t bind easily because they change shape
Allosteric sites
-behave like non competitive reversible inhibitors.
-Bind to site thats not active site, changes shape
Allosteric regulation
-protein affected by a molecule binding to another site that’s not the active site
Role of feedback inhibition
-Product of allosteric regulation
-Prevents resources being wasted
Feedback inhibition examples
-thermostat connected to heater
-a cell does not need to break down glucose if there’s enough energy
Animal cells vs plant cells
-Animal cells have a centrosome and lysosomes
-Plant cells have a cell wall, chloroplasts, plastids, vacuole
Eukaryotes vs prokaryots
-Eukaryotes internal components organelles. cytoskeleton. Mitosis cell division
-Prokaryotes have no membrane. Nucleoid dna. Sexual and asexual
4 ROLES OF MEMBRANE PROTEINS *
Transport,
enzyme,
triggering signals,
Attachment and recognition
DEFINITION OF
Transport
Enzyme activity
Triggering signals
Attachment and recognition
Transport ions across membrane
Enzyme activity membrane proteins act as enzymes
Triggering signals binding chemicals trigger changes
Attachment and recognition internal and external membrane attachment point for cytoskeleton
main role of protien membrane 1/4
Transport
Transport ions across membrane
main role of protien membrane 2/4
Enzyme activity
Enzyme activity membrane proteins act as enzymes
main role of protien membrane 3/4
Triggering signals
Triggering signals binding chemicals trigger changes
main role of protien membrane 4/4
Attachment and recognition
Attachment and recognition internal and external membrane attachment point for cytoskeleton
Integral membrane
Integral membrane protein embedded in lipid bilayer
Peripheral membrane
Peripheral membrane protein on surface
Passive transport
-moves substances across membrane without energy
-diffusion drives passive transport
Active transport
Active transport uses energy to move molecules from low to high concentration, uses pumps
concentration gradient
Influence movement of solute, moves down gradient, energy required, atp
Diffusion
Diffusion is movement from high concentration to low
Osmosis
Osmosis diffusion of water across membrane
Hypotonic
Hypotonic lower solute concentration, can burst
Hypertonic
Hypertonic higher solute concentration, can shrink
Isotonic
Isotonic same concentration as others
Channel proteins
Channel proteins hydrophilic pathway, water molecules pass through
Carrier proteins
Protein carries and transport across bilayer
Primary active
Primary active directly utilizes energy, lower to high concentration, Na k pump,
Secondary Active
Secondary Active relies on primary energy, symport same direction, antiport opposite direction
** Na K
Na K pump sodium ions out, potassium ions in, ATP changes shape of protien, resembles nerve
Role of ATP in transport
-Atp used to move substances against their gradients,
-immediate energy source
-Used with exocytosis and endocytosis
Endocytosis (enter)
Endocytosis goes into the cell, carries proteins and large molecules into cell (enter)
Exocytosis (exit)
Exocytosis protein and waste out of cell (exit)
Phagocytosis
Phagocytosis cell eating
Pinocytosis
Pinocytosis cell drinking, water taken in
Receptor-mediated endocytosis
-Molecules taken in bound by receptors
- forms vesicle fuses with lysosome
Role and process of exocytosis
Vesicle formation (waste is trapped), vesicle transport (waste moving towards membrane), membrane fusion, release
Lock and key model
Must have same shape for bonding
Enzymes function by
-lowering activation
- TWISTING AND BENDING
Inducer and inhibitor
Inducer: increase activity
Inhibit: slow things down
Enzyme activator
promotes enzyme function in turned off enzymes
** Selectivity Permeable
-allows certain molecules to pass through,
large molecules cant pass without surgars
Protiens can be amphipathic
polar and non polar
Things that effect diffusion
high to low
concentration and pressure
Tonicity
size of cell will change
turgor
Result of osmosis
hypertonic
Phospholipid tails are..
Phospholipid heads are..
hydrophobic tail
hydrophilic heads
Simple disfusion
small nonpolar substances move across membrane
