EXAM 2 BIO 240 REVIEW

Distinguish between oxidation and reduction reactions with respect to loss/gain of hydrogen atoms, electrons, and energy

OIL RIG

Oxidation

loss of H, loss of election, therefore losing energy

Reduction

gaining electrons and gains energy

State which molecules and oxidized and which are reduced in a given reaction in cellular respiration and/or fermentation

Look at number of electrons and Hydrogens before and after. If a molecule loses energy it is oxidized

State the overall reaction of cellular respiration

C6H12O6 + 6 O2 --\> 6 H2O + 6 CO2

Describe the connection between cellular respiration and breathing

Breathing brings in O2 which is needed for respiration. It also pushes CO2, a respiration byproduct, out

Explain why humans cannot survive without oxygen and why we breathe out CO2

Without O2, the electrons have nowhere to go at the end of the ETC, so the whole ETC is stopped up and we cannot produce much energy.

Describe the role of cellular respiration in cells

Cellular resp. provides energy for the cell in the form of ATP

Diagram glucose metabolism, including inputs and outputs of each step

glycolysis - Glucose + 2 ATP --\> 4 ATP + 2 Pyruvate + 2 NADH

Pyruvate oxidation

Pyruvate --> CO2 + NADH + Acetyl CoA

Citric Acid Cycle

Acetyl CoA --> 2 CO2 + 3 NADH + FADH2 + ATP

ETC

NADH and FADH2 bind to sites and lose electrons

Explain the purpose of electron carriers in cellular respiration

Electron carriers capture energy from the oxidation of glucose to use it later in the electron transport chain

Identify specifically when (i.e., what step of glucose metabolism) carbon dioxide (CO2) is generated

Pyruvate oxidation makes 2 per glucose (1 per pyruvate)

Identify specifically when (i.e. what steps of glucose metabolism) oxygen (O2) is used

O2 is used at the end of glucose metabolism as an electron receptor

Identify where each step of glucose metabolism occurs inside a cell

glycolysis - cytoplasm

Pyruvate oxidation - mitochondrial matrix

Citric acid cycle - mitochondrial matrix

ETC - mitochondrial inner membrane

Chemiosmosis - mitochondrial inner membrane

Explain how enzymes allow the reactions of cellular respiration to proceed at a rate that allows for life to occur

enzymes speed up reactions by lowering activation energy

Draw or identify a free-energy diagram of cellular respiration

products have less free energy than reactants

Distinguish between the major function of the electron transport chain and ATP synthase

ETC creates the hydrogen gradient, ATP synthase uses the diffusion of H+ to create ATP

Explain the role of electrons, hydrogen, water, electron carriers (NADH & FADH2) and oxygen in the function of the electron transport chain and ATP synthase

Electrons - provide energy to pull e- across membrane

Hydrogen - different concentrations on sides of membrane so H+ goes through ATP synthase to make ATP

Electron carriers - bring e- to the etc.

O2 - the final receptor of electrons, turn to H2O

Explain why energy is released in a step - wise manner in the electron transport chain

Only 10% of energy can be captured, so it is released step after stop so more can be captured

Differentiate between an uncoupler and an ETC inhibitor on ATP production and oxygen usage

Uncoupler - pokes holes in membrane.

Slows down ATP production but continued O2 use

ETC inhibitor - Blocks O2 from taking e-

In cellular respiration, the purpose is to make \______ by \__________.

energy, oxidizing glucose

Formation of Acetyl CoA

Pyruvate moves to mitochondria and starts a new life!

Each pyruvate is converted to acetyl CoA

Citric Acid Cycle (aka Krebs Cycle)

Acetyl CoA joins up with Citric Acid, there's a Wild Ferris Wheel Ride (2x) - Results in NADH, FADH2, ATP, AND CO2 waste \--- Breathe out!!

ETC & Chemiosmosis

NADH and FADH2 move to inner membrane of mitochondria and ramp up ATP production. Oxygen is the real MVP! So much action in this ep

cellular respiration

Harvesting of energy from glucose has 4 stages shown

For each molecule of glucose, the cell makes \~32 ATP

Cristae

Infoldings of the inner membrane of a mitochondrion that houses the electon transport chain and the enzyme catalyzing the synthesis of ATP.

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

ATP synthase

Large protein that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP

An uncoupler results in \______ use of oxygen and \______ production of ATP

continues, a change in the

Uncouplers

compounds that prevent ATP synthesis without effecting the ETC and thus decreasing the efficiency of the ETC/oxidative phosphorylation pathway

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ADP builds up, ATP synthesis decreases,

Describe, in broad terms, how molecules in addition to glucose (e.g. lipids & proteins) are catabolized and feed into cellular respiration

Other molecules enter the process of cellular respiration at different stages after glycolysis

Describe how glycolysis is regulated via feedback inhibition

When there is too much ATP, glycolysis is slowed or stopped because ATP inhibits Phosphofructokinase, an enzyme that catalyzes an early step in glycolysis

Distinguish between oxidative and substrate-level phosphorylation

Substrate level phosphorylation- makes ATP by using the energy from a coupled reaction

Oxidative phosphorylation- chemiosmosis (end of ETC), makes most of our ATP for use

Compare the amount of potential energy in intermediate and final products of glucose metabolism by referring to the degree to which glucose is oxidized

The more oxidized it is, the less energy it has left

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Glucose - not oxidized

Pyruvate - oxidized once

Acetyl CoA - oxidized twice

CO2 - fully oxidized

Describe the difference between cellular respiration and fermentation

cellular respiration involves steps after glycolysis such as pyruvate oxidation, the Citric acid cycle, and the ETC

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Fermentation uses glycolysis the creates other compounds such as ethanol or lactate

Predict when fermentation would occur in aerobic organisms

Fermentation will occur in aerobic organisms when not enough O2 can be ingested to pick up the e- at the end of the ETC. This will happen if something is drowning or working too hard for the body to keep up, such as lifting weights

Distinguish between anaerobic respiration and fermentation, and explain why fermentation is much less efficient (produces less ATP per molecule of glucose processed) than either anaerobic or aerobic cellular respiration

anaerobic respiration doesn't use O2 as its final electron receptor and is as efficient as aerobic respiration.

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Fermentation is less efficient because it doesn't utilize as many steps as respiration does

State which of the following, if any, plays a role in producing ATP when either (1) fermentation or (2) anaerobic respiration occurs: glycolysis, fermentation, pyruvate processing into acetyl CoA, the citric acid cycle, the electron transport chain or chemiosmosis through ATP synthase

glycolysis always makes ATP

fermentation makes other compounds after glycolysis, none of which produce ATP.

pyruvate oxidation does not make ATP

Citric Acid Cycle makes ATP in respiration

ETC does not make ATP

Chemiosmosis makes the majority of ATP is respiration

Describe the role of each of the following in fermentation: pyruvate, NADH, NAD+, CO2, ethanol, lactic acid

Pyruvate is made after glycolysis in fermentation

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NADH is used to convert pyruvate into Lactate or acetaldehyde into ethanol

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NAD+ is converted to NADH by glycolysis

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CO2 used in alcohol fermentation (not lactic acid fermentation) as a byproduct so that pyruvate can become acetaldehyde and then ethanol

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Ethanol is the end product of alcohol fermentation

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Lactic acid is the end product of lactic acid fermentation

Explain how cellular respiration and photosynthesis are opposite reactions

their overall reactions are opposite

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Resp: Glucose + O2 --> CO2 + H2O

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Photo: CO2 + H2O --> glucose + O2

Identify the net inputs and outputs of photosynthesis

Net inputs - 6 CO2 + 6 H2O + light energy

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Net outputs - glucose + 6 O2

State which atoms in the outputs came from which inputs

Glucose ends as CO2

O2 ends as H2O

Identify the electron carriers in cellular respiration & photosynthesis, and state the oxidized and reduced state of each

Resp:

NADH - reduced

NAD+ - oxidized

FADH2 - reduced

FAD - oxidized

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Photo:

NADPH-reduced

NADP+-oxidized

State that mitochondria are present in animal and plant cells, and chloroplasts are present only in plant cells (recall endosymbiotic theory)

they were engulfed by larger cells

Label the basic structures found within a plant leaf, including the locations of mesophyll cells, bundle sheath cells, and stomata

Mesophyll top, bundle sheath in mid, stomata are openings on the bottom of the leaf

For each of the basic leaf structures from the previous LO, explain its role in photosynthesis

Mesophyll cells do the whole process of photosynthesis in C3 and CAM plants (CAM also has malic and for CO2 "storage")

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C4 plants convert CO2 to malic acid in mesophyll cells and then complete calvin cycle in bundle sheath cells

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Stomata allow CO2 into the leaf and O2 to leave the leaf

State examples of organisms (other than plants) that use photosynthesis

algae, certain bacteria, certain protists

What is the Metabolism

the totality of your body's chemical reactions

Metabolic Pathways

begins with a specific molecule which is then altered in a series of defined steps and ends up being a certain product.

Catabolic reaction

breaks down larger molecules to creates energy. i.e. cellular respiration

Anabolic reaction

uses energy to build up larger molecules. i.e. photosynthesis

Describe what "free energy" means, and qualitatively account for where all of the energy goes during a reaction or process (keeping in mind that energy neither created nor destroyed)

free energy is the portion of a system's energy that can perform work when everything is uniform.

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Energy is either released as heat (or light or sound) or stored in bonds

first law of thermodynamics

Energy cannot be created or destroyed

second law of thermodynamics

Every energy transfer or transformation increases the entropy of the universe.

Explain the four terms (ΔG, ΔH, ΔS, and T) in the Gibbs free-energy change equation

G - free energy

H - enthalpy (heat)

S - entropy (disorder)

T - temperature

Given a description of a process, predict the sign for each term in the Gibbs free-energy change equation for the process

exothermic has negative enthalpy

endothermic has positive enthalpy

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(Anabolic, endergonic) building up is negative entropy

(Catabolic, exegornic) breaking down is positive entropy

exergonic (spontaneous)

Reactions that release free energy are

G is negative (-)

Endergonic (non-spontaneous)

A chemical reaction that requires the input of energy in order to proceed.

G is positive (+)

Given a set of reactions/phenomena, identify which can be low temperatures

happen at low temps if:

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a) negative ΔH, positive ΔS

b) negative ΔH, negative ΔS

Describe energetic coupling and why it is necessary for cells

energetic coupling - using an exergonic process to release energy and drive and endergonic one.

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This is necessary and it is how we make ATP to power our cells

energonic coupling

Coupling that occurs when the energy released by an exergonic reaction is linked to an endergonic reaction

Describe the roles of enzymes in cells

Enzymes speed up reactions that would otherwise take a very long time

Identify characteristics of the cell's environment that can affect its enzymes

temperature, pH, presence of coenzymes or enzymes inhibitors

competitive inhibitors

bonds to the same site substrate would normally

non-competitive (allosteric) inhibitors

bonds to a different site that forces a change in enzyme shape that makes the active site not work anymore

feedback inhibition

metabolic pathway is halted by the inhibitory binding of the end product back to an enzyme that is used earlier in the process, this slowing down the process

Draw and label the structure of ATP and state which phosphate is removed in ADP

phosphate group on the end is dropped

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adenine, triphosphate group /, ribose sugar

Explain how ATP is used and regenerated and what happens to a cell that doesn't regenerate its ATP

ATP is used to do all the necessary endergonic reactions that a cell must do.

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without ATP a cell would die because it wouldn't be able to do the reactions

Change in Enthalpy (ΔH)

the change in heat of the reaction system

Change in Entropy

ΔS, the change in the "randomness" or "disorder" of the reaction system

Identify the major components of cell membranes

Phospholipid bilayer with a combination of long tailed fatty acids and short ones, some saturated some unsaturated.

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Cholesterol

Proteins

Glycolipids

Glycoproteins

transport proteins

A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane.

cell-cell recognition

The function of membrane proteins in which some glycoproteins serve as ID tags that are recognized by membrane proteins of other cells.

phospholipid bilayer

a two-layered arrangement of phosphate and lipid molecules that form a cell membrane, the hydrophobic lipid ends facing inward and the hydrophilic phosphate ends facing outward.

choleserol

a steroid found in animal plasma membrane and from which other types of steriods are derived

Proteins in cell membrane

Are the passage ways for material to enter or leave the cell

Glycolipids in the cell membrane

sugar-fats that maintain the cell's stability of the membrane and to facilitate cell-cell interactions

Glycoproteins in cell membrane

Act as tags for the cell (communication) allows for cell recognition

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Also help cells attach to and bind to other cells (cell adhesion)

Identify the hydrophobic and hydrophilic regions of a phospholipid molecule and a cholesterol, and predict how phospholipids and cholesterol would organize themselves in water.

The fatty acid tails of phospholipids are hydrophobic.

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Cholesterol has a polar headgroup next to the 4 carbon ring skeleton

Describe which structures in a cell contain membranes

membrane bound organelles have membranes.

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Golgi, nucleus, both ERs, lysosomes, peroxisomes

List and briefly describe different types of membrane proteins and their functions

2 main types-

integral proteins that go into the lipid bilayer.

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peripheral proteins that loosely bind to the surface of membranes, often to the exposed parts of integral proteins.

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Transport proteins- some channel some carrier.

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Enzyme- some enzymes are embedded in membranes (especially in lysosomes or peroxisomes)

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cell-cell recognition- to identify other cells

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intercellular joining- membrane proteins of adjacent cells can hook onto each other to connect cells attachments to cytoskeleton and extracellular

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matrix- attaches to cytoskeleton on inside and ECM on outside for structural support.

Describe and briefly explain the effects of temperature and cholesterol content on the properties of a phospholipid membrane

Hotter temp makes things move faster and stick together less. More cholesterol lessens the effects of extreme temperatures

Predict how a cell can adjust the contents of its plasma membrane to adapt to changes in temperature

longer fatty acids for hotter weather, shorter fatty acids for colder weatherMore unsaturated fats in colder weatherMore cholesterol in more extreme environments, both cold and hot

Identify specific proteins and relate their function to their localization within the cell

be able to say that a protein that binds to DNA and regulates which genes are read would be localized in the nucleus because that is where the DNA is

Predict whether a protein will be processed in the endomembrane system or synthesized by free-floating ribosomes in the cytosol based on the protein's function and localization within the cell

If a protein is supposed to be free floating it can be made in free floating ribosomes. If a protein is going to be in a membrane it must be processed within the endomembrane system (rough ER)

Predict the biological consequences of preventing subcellular localization of a particular protein (for instance, the effects if a cell surface membrane protein doesn't get trafficked to the cell membrane due to via a mutation in the protein's gene or through drugs)

If a cell cant get to where it needs to go it cannot do its job but ask in a pal session

Use the principle of diffusion to predict the net movement of solute molecules between two regions (e.g., across a membrane permeable to the solute) based on the solute concentration in each region

concentration will equal out either through diffusion of solute or solvent or both.

Predict the net direction that water will move across a membrane based on the solute concentration on each side of the membrane

water will go wherever more solute is to make concentration the same.

Distinguish between hypertonic, hypotonic, and isotonic solutions from a description or image, and use tonicity differences to predict which direction water or solute would move across a membrane.

isotonic- same concentration

hypotonic- less concentration of particles in water. More particles in the cell

hypertonic- more concentration of particles outside cell. Thus water molecules move outside cell to balance out, and cell shrivels

Distinguish between simple diffusion, facilitated diffusion and active transport by (a) whether/what kind of membrane proteins are involved; (b) whether the cell uses ATP during transport; (c) whether solutes are moving up or down their concentration/electrochemical gradients

simple diffusion passes through membrane itself and is easiest for small, nonpolar molecules like oxygen

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facilitated diffusion is where a protein facilitates the diffusion passively (channel and carrier)

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active transport is where ATP is used to force something across the membrane.

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Down a gradient- always passive transport never active.

predict whether a solute could be small/large, charged/uncharged, and polar/nonpolar based on whether it passes across a cell membrane (that could contain transport proteins) in the presence and absence of ATP

charged must go through transport proteins if its large.

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small nonpolar can slide through membrane easily.

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with ATP, most things can be actively transported across

compare and contrast channel proteins, carrier proteins, and pumps based on structure and mechanism (hoy they work)

Carrier open and close

Channel are just a channel

Pumps are like carriers except they go against the gradient

Which is more viscous, Saturated or Unsaturated Lipids

Saturated lipids

What do longer lipid tails do to a lipid

make the membrane more viscous and have greater opportunities for interactions between other tails than that of smaller tails

Cholesterol

At warm temperatures, restrains movement of phospholipids to decrease fluidity

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At cool temperatures, it prevents tight packing to decrease viscosity

Cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended

Hypotonic

Having a lower concentration of nonpenetrating solutes than another solution

Hypertonic

when comparing two solutions, the solution with the greater concentration of nonpenetrating solutes