Plasma Membrane
Diffusion/ Osmosis
Transport (proteins)
Energy
Cellular respiration
100
What is the major molecular component of the plasma membrane?
Phospholipids
100
Describe the concept of diffusion. Provide an example, real or not.
Diffusion refers to the passive (non-energy requiring) movement of molecules down their concentration gradients from an area of high concentration, to an area of lower concentration. Diffusion will persist until there is equilibrium.
100
Describe the differences between Active and Passive transport.
Active- this type of transport requires energy
Passive- this does not require energy
100
Describe the differences between potential and kinetic energy.
Kinetic energy is the energy of an object/molecule in motion, where as potential energy is the energy of an object/molecule that has the potential to move
100
What is the difference between terms reduction and oxidation in a Redox reaction?
Redox reactions have both reductions, where a molecule gains electrons (or a hydrogen atom, and is therefore reduced), or a molecule is oxidized, where is electrons (or a hydrogen atom, therefore oxidized) are removed.
200
Draw a phospholipid bilayer. Describe its hydrophobic/hydrophilic components. Label it with "extracellular fluid" and the "cytosol"
Dr. A will draw!
200
Diffusion question: If the extracellular fluid has 37 molecules of O2, and the cytosol has 15 molecules of O2, which has a higher concentration? Will O2 diffuse, if so which way?
The extracellular fluid has a higher concentration of oxygen, therefore, oxygen will flow into the cytosol until equilibrium is met
200
What are the differences between a transmembrane integral protein and a peripheral protein?
Integral proteins completely pass through the plasma membrane, whereas peripheral proteins are only found on the surface of the plasma membrane, cytosolic and extracelullar surfaces.
200
What is an endergonic reaction?
A reaction that requires energy
200
What are the 4 metabolic reactions within Cellular respiration?
Glycolysis
Oxidation of pyruvate
TCA
Oxidative Phosphorylation
300
What type of molecules can freely pass through the plasma membrane and why?
Small non-polar molecules, because they are not repelled by the non-polar hydrophobic fatty acid tails within the phospholipid bi-layer of the plasma membrane.
300
List 3 things that affect the rate of diffusion.
-concentration
-temperature
-solubility
-mass of molecule
-surface area
-distance traveled
300
What type of integral proteins are used for facilitated (passive) transport across the plasma membrane?
Channel and Carrier proteins
300
What is an exergonic reaction?
A reaction that releases energy
300
Where spatially in the cell does glycolysis occur? What about TCA or the Electron transport chain?
cytoplasm
mitochondria
400
List the two key components that help to make the plasma membrane "fluid" and how.
Unsaturated fatty acid tails in the phospholipids and cholesterol. Temperature is also important.
400
What is osmosis? What is osmolarity?
Osmosis is the specific diffusion of water. Osmolarity refers to the solute concentration in water. A solution with high solute concentration has a high osmolarity, meaning that water would move towards this solution across a semi-permeable membrane.
400
Describe the differences between a uniporter, symporter, and an antiporter transmembrane protein.
Why would a cell need to use these forms of active transport?
A uniporter moves one molecule in one direction, a symporter moves two molecules in one direction, an antiporter moves two molecules in opposite directions.
Cells need to use active transport (requires energy) to move molecules AGAINST their concentration gradients.
400
What are the two laws of thermodynamics?
1. energy cannot be created or destroyed, but can be transformed
2. Entropy is always increasing, i.e. the transfer of energy is not always efficient, meaning that energy will sometimes be transformed into an unusable form of energy (often heat)
400
Why is the mitochondria structure, with an inner membrane and outer membrane, important for ATP generation?
The inner membrane is what creates the mitochondrial matrix (inner most solution) and the inner membrane space (space between the membranes). It also creates the cristae (creating large surface area) for the transmembrane proteins (complex I, II, III, IV) to bind and generate the H+ ion concentration gradient to be used for ATP synthase.
500
Why is this depiction of the plasma membrane referred to as the fluid mosaic model?
Fluid- the unsaturated fatty acid tails and the insertion of cholesterol make the membrane flexible. Additionally, components of the membrane are able to float/move around the membrane
Mosaic-the plasma membrane is made up of many different components like a mosaic
500
Osmolarity question: Na+ is a ion, and therefore cannot freely pass through the plasma membrane. There are 42 molecules of Na+ in the cytoplasm and 19 molecules of Na+ in the extracellular matrix. Which side of the cell has the higher osmolarity? Which way will water move? What type of solution is the cell in? hypertonic, isotonic or hypotonic?
FUN QUESTION: What type of ion is Na+??
The cytoplasm has the higher osmolarity, therefore water will flow into the cell. This will swell the cell and make it hypotonic.
Fun question: CATion because it is PAWsitive
500
Describe the differences between bulk transport mechanisms of phagocytosis and pinocytosis. What type of eukaryotes heavily rely on endocytosis ?
Phagocytosis is cell eating, and Pinocytosis is cell drinking. Protists, single celled eukaryotes heavily rely on these forms of endocytosis for survival.
500
Provide an example of potential and an example of kinetic energy within a cell. Think of molecules and movement.
Potential energy
-chemical bonds
-concentration gradients
Kinetic energy
-breaking of chemical bonds-molecules moving down their concentration gradients
500
What is the difference between an aerobic and anaerobic metabolic reactions? What metabolic pathways are used in an anaerobic condition?
aerobic-oxygen is present
anaerobic-oxygen is not present
Cells can complete glycolysis without oxygen, and then must also go through lactic acid fermentation to regenerate (oxidize) the co-enzymes to be used for glycolysis again.