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Bio Exam #3
Terms in this set (37)
A selective (semi-permeable) barrier does what? Give an example of one.
What is osmosis?
Allows water molecules to pass, but not most molecules dissolved in water.
Ex) Plasma Membrane
Diffusion of water molecules across a selective barrier (High to Low)
What is a solute?
What is the concentration of water determined by?
What is solute potential? What is its symbol?
How much solute is in pure water?
Water molecules are most concentrated @?
What happens when you add solutes?
Molecule dissolved in water.
By the concentration of the solutes in the water.
Solute Potential, Ψs, is a measure of the concentration of solutes dissolved in the water. (The lower the amount of solute, the higher the solute potential)
Pure water: Ψs=0 (highest value).
Most concentrated @ Ψs=0.
Adding solutes LOWERS solute potential, Ψs. (negative values).
Water moves from *blank* Ψs to
oves from *blank* Ψs to *blank* Ψs.
The water will continue to move until...
Water moves from higher Ψs to lower Ψs.
Continues to move until the solute potential, ψ, is EQUAL on both sides
Osmosis is critical to...?
The plasma membrane is what type of membrane/barrier?
What do cells depend upon to stay alive, regarding permeable-membranes?
The survival of cells.
The regulated movement of water molecules across the permeable-membrane
If the solute potential inside and outside the cell are equal, water will...
If the solute potential is greater outside, the water will...
If the solute potential is greater inside, the water will...
Enter and leave the cell in equal amounts.
Rush INTO the cell, the cell will swell, and the cell could burst/lyse.
Rush OUT of the cell, the cell will shrink, and the cell could dehydrate and die.
Why do we care about water osmosis and solute potential?
What are brain capillaries?
What do capillary wall cells do?
What are intercellular junctions?
Molecules must exit a brain capillary by...
What is the strict control called?
What is the clinical significance of this strict control?
Fine blood vessels that feed brain tissue.
Form a tube.
Physical connections b/w capillary wall cells.
By moving through the plasma membrane of capillary wall cells.
NOT by passing b/w the cells through the inter-cellular junctions.
Blood-Brain-Barrier. It makes it difficult for doctors when they need to introduce medicines into the brain.
How do you breach the Blood-Brain-Barrier?
(By decreasing size or using a non-polar drug)
Lower the solute potential of blood by injecting a solute; thus water moves into the blood, OUT from the capillary wall cells, shrinking the wall cells slightly, creating an opening b/w cells.
What is energy, E?
What is Kinetic E? (3 forms.)
What is Potential E? (2 forms.)
The capacity to do work.
The energy of motion, a variety of forms. (Heat, light, mechanical).
Stored energy. (Concentration gradient and chemical bonds).
What is thermodynamics?
What does Law 1 state?
What does Law 2 state?
Branch of chemistry that deals w/energy transformations (transfers).
1: Conservation Law: Energy cannot be created nor destroyed and can only change form of one energy to another.: "The universe is a closed system where the total amount of energy remains constant".
2: No energy transfer is 100% efficient; some is always lost (usually as heat) and becomes unusable energy (entropy).
What is entropy? It is continuously what?
What is Usable energy AKA?What is it? It is continuously what? What is its symbol?
Unusable energy; increasing.
Free energy; energy available to do work; decreasing; G
What is the equation for free energy, G, and what does each character stand for?
G = H - TS
G= Free energy.
H= Enthalpy, energy in a molecule's chemical bonds.
TS= The amount of disorder in a molecule.
T= Absolute temp.
In chemical rxns, it is reactants to products.
Both reactants and products have a certain amount of...
Know: The products will either have more or less of this than the reactants, so it will either go up or down.
G, free energy
What determines the type of rxn?
What is exergonic? What are its 2 characteristics?
What is endergonic? What are its 2 characteristics?
Change in free energy, ΔG.
-ΔG; G of products< G of reactants.
1. Energy released can be used to do work.
2. Spontaneous, the rxn has the potential to occur on its own, w/o extra input energy.
+ΔG; G of products> G of reactants.
1. Energy is absorbed
2. NEVER spontaneous; An input of energy is required, hence the energy absorbed.
Why are endergonic and exergonic rxns coupled?
What does ATP stand for and what is it? What does is contain a lot of?
What is ATP hydrolysis and what does it do?
B/c the energy to drive endergonic rxns come from exergonic rxns.
Adenosine TriPhosphate= the "energy currency" of a cell.
ATP contains a lot of free energy.
ATP+H2O→ADP; (-ΔG); It releases energy that is used to power many ENDERgonic rxns.
ATP diagram (which adenosine phosphate type is in the diagram?)
Structure of ATP include:
Core=? (2 things)
1: ? (blue)
2: ? (red)
3: ? (3 types) (yellow)
For the 3rd part: What type of the 3 different types has the LEAST amount of free energy? (Note: 3 is where the free energy of ATP is). Note:
bonds have a lot of free energy.
Diagram: adenosine triphosphate.
Core= Nitrogenous base (Adenine) + 5-carbon sugar (Ribose).
1. Adenine (blue)
2. Ribose (red)
3. Phosphate (yellow): (Adenosine monophosphate, diphosphate, and triphosphate)
Adenosine MONOphosphate has the least G.
Note: 2 bonds have a lot of G
ATP hydrolysis is what type of rxn? What is the energy from this rxn used for?
What is the equation?
What does the rxn look like on a graph?
ATP synthesis is what type of rxn? Where does the energy required for the rxn come from?
Exergonic; to drive endergonic rxns.
Endergonic; from mitochondria.
What does the hydrolysis of ATP look like? What type of rxn is it? What is the ΔG?
What does the synthesis of Glutamine look like? What type of rxn is it? What is the ΔG?
What does it look like if you were to COUPLE the rxns? What type of rxn is it then? What is the ΔG?
ATP+H₂O→ADP+Pi: Exergonic: -7.3kcal/mol.
Glutamate+NH₄→Glutamine: Endergonic: +3.4kcal/mol.
Glutamate+NH₄+ATP+H₂O→Glutamine+ADP+Pi: Exergonic: -3.9kcal/mol.
What are Kinetics?
What does thermodynamics determine?
What does it NOT determine?
The rate of a rxn is dependent upon what?
The higher the activation energy, the
the rate of rxn. AND VICE VERSA! (So what type of relationship it is?)
What has a higher activation energy? Ender or exergonic rxns?
Which goes faster? endergonic or exergonic?
The RATE at which a rxn occurs.
Whether energy is released or absorbed by the rxn.
It does NOT determine kinetics/speed/rate.
Lower (inverse relationship).
TRICK QUESTION: Thermodynamics does NOT determine kinetics/speed/rate
What are the 2 components of activation energy?
What 2 things do catalysts do?
What are enzymes and what 2 things do they do?
Collision energy of reactants and orientation of reactants during collisions.
Lower activation energy and increase the rate of the rxn.
Biological catalysts. They hold ractants in favorable orientations and stress the chemical bonds of reactants.
Which goes faster? endergonic or exergonic?
Thermodynamics does NOT determine kinetics/speed/rate.
Activation energy is what determines kinetics!!!!
What determines kinetics/speed/rate?
What are the 4 categories of organisms based on carbon and energy sources? (CS and ES) (Which 2 are the most important?)
What ecosystems can each organism be found?
Photoautotrophs (plants and some bacteria): ES=light; CS=CO₂.
Photoheterotrophs (some bacteria): ES=light; CS=organic molecules.
Chemoautotrophs (some bacteria): ES=chemicals; CS=CO₂.
Chemoheterotrophs (animals): ES=chemicals; CS=organic molecules.
All of the organisms can be found within every ecosystem.
What are the 2 components that all ecosystems have?
What does abiotic mean? (examples)
What does biotic mean? What are the 3 types?
What does the energy flow through an ecosystem look like? (diagram)
Abiotic and biotic.
Abiotic=not alive (light, temp., water, pressure, etc.)
3 Types of biotic: Producers=autotrophs; Consumers=eat producers; Decomposers.
Is earth a closed system in regards to E?
How much E does the sun radiate per second?
30% of what reaches the earth is...
20% of what reaches the earth is...
Less than 1% of what reaches the earth is...
30%=reflected by clouds.
20%=reflected by dust in atmosphere.
Less than 1%=absorbed by plants.
What greek word does "trophic" come from and what does it refer to?
What is a trophic level?
What occupy the 1st trophic level?
What does the energy flow through a food chain look like? (diagram).
Is Energy transfer efficient?
Trophe; refers to food or nourishments.
Where an organism is in the food chain or food web.
Sunlight→producers→herbivores (primary consumers)→carnivores (secondary)→ Top carnivores (tertiary)→all going to detrivores (bacteria/fungi).
No! It is very INefficient!
The efficiency of energy transfer between trophic levels is about what %?
Some E is lost in what 3 ways?
1. Feces=inefficient absorption of E during digestion.
2. It cannot be extracted, locked up in indigestible structures (cellulose, hair, claws, feathers, etc.).
3. "Staying alive" (moving, metabolizing, breathing).
What does inefficiency lead to in regards to trophic levels?
Giving an example of inefficiency: Cattle:
How much energy is lost due to feces or being locked up in indigestible structure?
How much is lost to "staying alive"?
How much energy is actually available for the next trophic level?
It puts limits on trophic levels.
62% lost to feces and inextractable structures.
34% lost to "staying alive".
Only 4% is available to next trophic level.
What are the building blocks of macromolecules?
Nucleic Acids have...
Unlike energy, matter is...
There is a blank amount of CHONPS on earth.
What is an element's reservoir?
Where the element is when it is not a part of an organism.
Elements cycle b/w blanks and blanks.
What are the 2 common reservoirs? What building blocks are they applied to? In what forms?
What is another reservoir and what building blocks have it?
Reservoirs and organisms.
Water and Atmosphere.
Atmosphere: CO2 (C), N2 (N)
Water: H2O (H and O)
Sediment: P and S
What is phosphorous important for? (3)
What are the 4 steps to phosphorous cycle?
What is sulfur important for?
What are its 4 steps?
Nucleic acids, ATP, and phospholipids (plasma membranes).
1. plants incorporate P from sediment.
2. animals eat plants.
3. plants/animals die and decomposers return P to sediment.
4. step 1 is repeated and cycle restarts.
Certain amino acids (proteins).
Same cycle as P.
What does cycling of CHO connect?
CHO is found in what macromolecules?
Photosynthesis and cellular respiration.
What are the 2 parts of photosynthesis?
Where do light-dependent rxns occur?
What do they require? (2)
What do they produce? (3)
What are dark rxns AKA and where do they occur?
What do they require? (3)
What do they produce? (3)
Light and Dark rxns.
At the thylakoid membrane.
Requires: light as an energy source and water as an electron source.
Produces: ATP as an energy-containing molecule, NADPH as an electron carrier (reduced form), and O2 as a byproduct.
Calvin-Benson Cycle, occurs in stroma.
Requires: CO2 as a carbon source, ATP (from light rxns) as an energy source, and NADPH (from light rxns) as an electron source.
Produces: Glucose as an energy storage molecule, ADP + Pi (from ATP hydrolysis), and NADP+ (from oxidation of NADPH).
What is N needed for?
Is there a shortage?
What is the problem?
What % of air is N2?
N2 is very blank and blank.
How does N enter ecosystems?
What is Nitrogen-Fixing Bacteria? Where do they live? (Diagram).
Proteins and Nucleic acids
Atmospheric N2 is NOT usable by most organisms.
from its reservoir in the atmosphere, through Nitrogen Fixation.
Bacteria that convert unusable inert N2 into reactive, usable ammonia (NH3) and nitrate (NO3).
What are the 4 steps of nitrogen recycling? (diagram).
What % of N needed for living things is provided by Nitrogen-Fixation? Provided by Nitrogen recycling?
What is denitrification and what is it carried out by?
1. Plants incorporate the NH3 and NO3 into macromolecules.
2. N-containing macromolecules are taken up by consumers.
3. Decomposers in the soil convert the N in macromolecules from plants and animals back into NH3 and NO3 (soil).
4. Step 1 repears and the cycle is restarted.
The returning of nitrogen to the air as N2, carried out by bacteria.
Why are reduction and oxidation rxns coupled?
What is the importance of redox rxns?
What is an Electron Transport Chain (ETC)?
What are electron carriers and what happens when they accept electrons and donate electrons?
The 1st electron carrier in an ETC has the blank electron affinity.
Electron carriers are critical for what 2 things?
Something has to be oxidized in order for something to be reduced.
A chain of redox rxns result in a "flow" of electrons called an electron transport chain.
Electron carriers are molecules and enzymes that make-up the ETC. When they accept e, they are reduced and when they donate, they are oxidized.
Photosynthesis and cellular respiration.
What is photosynthesis?
How efficient is its energy transfer?
What % of photon energy ends up stored as chemical energy (glucose)?
Where does photosynthesis occur?
What organelle is involved?
Diagram of chloroplast.
What do thylakoid membranes contain?
What is chlorophyll?
What does stroma contain?
Light energy powering the production of glucose.
Within cells, typically in leaves.
Contain the pigments, CHLOROPHYLL, that capture photon energy.
Contains enzymes for sugar manufacturing.
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