Unit 2 exam review Flashcards
Explain the fluid mosaic model
It is membranes that consist of a bilayer of phospholipids in which globular proteins are inserted.
What are globular proteins?
They are spherical shaped proteins.
List the 4 components of the cell membrane.
- Phospholipid bilayer 2. Transmembrane proteins 3. Interior protein network 4. Cell surface markers. (They tell the cell what to do)
What organic macromolecule is cholesterol?
It is a lipid.
Are phospholipids solid or fluid? Also explain phospholipids.
They are fluid. Individual phospholipids and unanchored proteins can move freely through the membrane. Saturated fatty acids make membrane more fluid than unsaturated fatty acids. Also warmer temperatures make it more fluid than cooler temps.
Name the 6 membrane protein functions.
- Transporters 2. enzymes 3. cell surface receptors 4. cell surface identity markers 5. cell to cell adhesion proteins 6. attachments to the cytoskeleton
List 2 facts about integral membrane proteins
They span the lipid bilayer or the transmembrane proteins. Also they are nonpolar domains so they are hydrophobic AA and are embedded in the hydrophobic regions of the lipid bilayer.
What do transmembrane domains do?
They span the lipid bilayer and they are a region of protein containing hydrophobic AA. Additionally, 7 is common.
What can Beta sheets form?
They can form a Beta barrel which is a cylinder.
What do Beta barrel do?
They regulate what goes in the cell.
Is passive or active transport diffusion?
It is passive.
What do channel proteins do?
They allow polar molecules to pass through
What do carrier proteins do?
They bind to a specific molecule and change shape so they can move through the pore and release the molecule.
What are the 2 types of channel proteins and what are they?
- ion channels, they allow the passage of ions that are associated with water. 2. Gated channels, they open of close in response to chemical or electrical stimulus(potential energy)
What is aquaporins?
It is water pores where osmosis moves water through towards hypertonic solution.
What are 2 things that active transport require?
It requires ATP or energy and it requires a specific carrier.
What three things do carrier proteins use in active transport?
- Uniporters, moves one molecule at a time 2. Symporters, moves 2 molecules at a times in the same direction. Usually one with active transport and the other with passive transport 3. Antiporters, they move 2 molecules in opposite directions.
Describe the Sodium-potassium (Na+-K+) pump.
It uses ATP, and it uses an antiporter. Sodium out, potassium in
What is coupled transport?
It is an active transport, uses energy released when a molecule moves by diffusion to supply energy for active transport. A symporter is used.
What are the three parts of endocytosis? Name and explain them
- Phagocytosis the cell takes in particular matter2. Pinocytosis the cell takes in fluid i.e. water. 3. Receptor-meditated endocytosis specific molecules are taken in after they bind to a receptor
What are three things to know about exocytosis?
- The vesicles fuse with the membrane and release their contents to the exterior. 2. used in plants to export cell wall material. 3. used in animals.
What is freeze fracturing?
It is a technique that separates the layers and reveals the membrane proteins using a scanning electron microscope (SEM).
What are photons associated with?
Light energy
What are two types of energy, and what do they do?
Kinetic energy, it is the energy in motion. Potential energy, it is the stored energy.
What is heat energy measured in?
Calories
What does one calorie equal?
Heat energy required to raise the temp of one gram of water by 1 degree c.
What is one kilocalorie(kcal) equivalent to?
1000 calories and 1 food calorie
Does oxidation in redox lose or gain an electron?
It loses an election
What does the first law of Thermodynamics state?
Energy can’t be destroyed nor created, only converted from one form to another.
What is an example of the first law of thermodynamics?
Sunlight energy to chemical energy through the process of photosynthesis which is an anabolic reaction.
What does the 2nd law of thermodynamics state?
Without external energy input all systems would get our of order
What is entropy?
It is the disorder of something
What is free energy?
It is energy available to do work, it is represented by G, which stands for Gibb’s free energy.
What is enthalpy?
It is energy contained in a molecule’s chemical bond
What is the equation for free energy?
Free energy=enthalpy-(temp X entropy) or G=H-TS or delta G = delta H- T delta S
What is delta G positive?
When products have more free energy than reactants, an example is light energy
What is delta G negative?
When reactants have more free energy than products, an example is cellular respiration
What is the turnover rate?
It is how many molecules of a substrate converts into product per second.
What are enzymes?
They are biological catalyst and are mostly proteins but can be RNA which would be ribosomes.
Do enzymes reactions have to be unnatural or natural?
They have to be natural
What is an endergonic reaction?
It is an “energy required” reaction that is positive delta G It is an anabolic reaction
What is an exergonic reaction?
It is an “energy yielding” reaction that is negative delta G. It is a catabolic reaction
What is the structure of ATP?
ribose (5 C sugar) adenine ( a nucleotide) and 3 phosphates
What is a substrate?
It is a molecule that will undergo a reaction. It is the reactant.
What is the active site?
It is a region of the enzyme that binds with the substrate
What is the pH in humans?
7.2 to 7.4
What is an inhibitor?
It is molecules that bind to the enzyme and decrease their activity.
What is a competitive inhibitor?
It competes with the substrate for binding to the active site. It has affinity.
What happens as the affinity increases?
It gets more tight and effective.
What is an allosteric inhibitor?
It binds to the site other than the active site. It changes shape therefore the function changes. It is the breaks.
What is an allosteric activator?
It is the gas. It binds to allosteric site to activate the enzyme.
What is anabolism?
It is an endergonic reaction that uses energy to make chemical bonds.
What is catabolism?
It is an exergonic reaction that breaks bonds and energy is released.
What are co-factors?
They are usually metal ions found in active site. Trace metals form the active site.
What are co-enzymes?
They are nonprotein organic molecules often used in a redox reaction as an electron donor or acceptor.