BIO 1330 Functional Biology Exam 4 Fill-In Study Guide: Units 3.2 & 4

A complete set of practice flashcards for BIO 1330 Functional Biology Exam 4 Fill-In Study Guide covering Unit 3 (Energy, Reactions, and Enzymes) and Unit 4 (Metabolism, Aerobic Cellular Respiration, and Photosynthesis).

What is potential energy, and what form of potential energy is stored in molecular structure in cells?

Potential energy is stored energy associated with position, structure, or arrangement; in cells, energy stored in molecular structure is chemical potential energy.

How is Gibbs free energy defined in biological systems?

Gibbs free energy is energy available to do useful work and drive biological processes.

What is the formula used to calculate the change in Gibbs free energy ($\Delta G$)?

$$\Delta G = G_{\text{products}} - G_{\text{reactants}}$$

How do exergonic and endergonic reactions differ in terms of $\Delta G$ and energy?

An exergonic reaction has $\Delta G < 0$ and releases free energy overall, whereas an endergonic reaction has $\Delta G > 0$ and requires energy input or coupling.

How do anabolic and catabolic pathways differ in their substrates and products?

Anabolic pathways build complex products from simpler substrates, whereas catabolic pathways break complex substrates into simpler products.

How are macromolecule synthesis and glucose breakdown classified in terms of metabolism?

Building a macromolecule is generally anabolic, whereas glucose breakdown is catabolic.

What reaction types and water-associated processes correspond to polymer building and polymer breakdown?

Polymer building is commonly associated with endergonic reactions and condensation/dehydration, whereas polymer breakdown is commonly associated with exergonic reactions and hydrolysis.

On a reaction-energy curve, what are the transition state and the activation energy ($E_A$)?

The transition state is the highest point on the reaction-energy curve, and activation energy ($E_A$) is measured from the reactant energy level to the transition state.

How is $\Delta G$ represented on a reaction free-energy graph?

$\Delta G$ is the free-energy difference between the products and the reactants.

How does the relative free energy of products versus reactants determine whether a reaction is exergonic or endergonic?

If products are lower in free energy than reactants, $\Delta G$ is negative and the reaction is exergonic; if products are higher in free energy than reactants, $\Delta G$ is positive and the reaction is endergonic.

How does an enzyme affect activation energy ($E_A$), reaction rate, and overall $\Delta G$?

An enzyme lowers activation energy and therefore increases reaction rate, but it does not change the overall $\Delta G$ of the reaction.

How does an enzyme-catalyzed pathway compare to an uncatalyzed pathway on a free-energy graph?

The enzyme-catalyzed pathway has a lower peak (lower activation energy) but the same reactant and product energy levels.

What is the active site of an enzyme, and what is the role of substrate binding?

The active site is the enzyme region where the substrate binds, and substrate binding helps the reaction reach the transition state.

What is the difference between competitive inhibition and allosteric inhibition?

A competitive inhibitor binds the enzyme's active site, whereas an allosteric inhibitor binds at a site different from the active site and changes enzyme shape/activity.

How does feedback inhibition regulate metabolic pathways?

In feedback inhibition, the end product inhibits an early enzyme in the pathway to prevent unnecessary continued production when product levels are high.

How do changes in active-site shape affect substrate binding and enzyme activity?

If the active-site shape changes so the substrate fits poorly, substrate binding will likely decrease, and a major shape change can reduce enzyme activity.

What happens to pathway intermediates and products when an enzyme in the pathway is nonfunctional?

A nonfunctional pathway enzyme may cause upstream intermediates to accumulate and downstream products to decrease.

What three components make up ATP, and what occurs during ATP hydrolysis?

ATP contains adenine, ribose, and three phosphate groups; hydrolysis removes the terminal phosphate to form ADP + $P_i$, which is an exergonic reaction that can couple to an endergonic reaction.

How are oxidation and reduction defined in terms of electron transfer?

Oxidation is the loss of electrons, reduction is the gain of electrons, and the electron donor is oxidized.

What happens when $NAD^+$ accepts high-energy electrons?

When $NAD^+$ accepts high-energy electrons, it is reduced to NADH.

What is the chemical formula of glucose, and what happens to it during cellular respiration?

Glucose has the molecular formula $C_6H_{12}O_6$, stores chemical potential energy in its covalent bonds, and is progressively oxidized during respiration.

What is the overall balanced equation for aerobic cellular respiration?

$$C_6H_{12}O_6 + 6\,O_2 \rightarrow 6\,CO_2 + 6\,H_2O + \text{released energy captured in ATP}$$

In aerobic cellular respiration, which molecule is oxidized, which is reduced, and what are the two major electron-carrier pairs?

Glucose is oxidized to $CO_2$, while $O_2$ is reduced to $H_2O$; the two major electron-carrier pairs are $NAD^+/NADH$ and $FAD/FADH_2$.

Is overall aerobic cellular respiration endergonic or exergonic?

Overall aerobic respiration is exergonic.

What are the matrix, the intermembrane space, and the cristae of a mitochondrion?

The matrix is the compartment inside the inner mitochondrial membrane, the intermembrane space is the region between the outer and inner membranes, and cristae are folds of the inner membrane.

What is the correct sequence of the four stages of aerobic cellular respiration?

Glycolysis $\rightarrow$ pyruvate oxidation $\rightarrow$ Krebs cycle $\rightarrow$ ETC/oxidative phosphorylation.

Where in the cell do the four stages of cellular respiration take place?

Glycolysis occurs in the cytoplasm; pyruvate oxidation and the Krebs cycle occur in the mitochondrial matrix; the ETC is in the inner mitochondrial membrane.

What are the net products of glycolysis per molecule of glucose?

1 glucose yields 2 pyruvate + net 2 ATP + 2 NADH.

What are the products of pyruvate oxidation per molecule of glucose?

Pyruvate oxidation produces 2 acetyl-CoA, 2 $CO_2$, and 2 NADH per glucose.

What are the products of the Krebs cycle per molecule of glucose?

The Krebs cycle produces 4 $CO_2$, 6 NADH, 2 $FADH_2$, and 2 ATP per glucose.

How do electrons donated to the electron transport chain drive ATP synthesis?

NADH and $FADH_2$ donate high-energy electrons to the ETC, where electron energy drives $H^+$ pumping into the intermembrane space; $H^+$ then flows through ATP synthase to make ATP.

What is the final electron acceptor in the electron transport chain, and what molecule does it form?

The final electron acceptor is $O_2$, which forms $H_2O$.

How do carbon, energy, and oxygen trace through aerobic cellular respiration?

Carbon from glucose leaves mainly as $CO_2$; energy moves from glucose $\rightarrow$ NADH/$FADH_2$ $\rightarrow$ proton gradient $\rightarrow$ ATP; oxygen from $O_2$ becomes part of $H_2O$ at the end of the ETC.

At what point does fermentation diverge from aerobic respiration, and what is its primary role?

Fermentation diverges after glycolysis at pyruvate, and its key role is to regenerate $NAD^+$ so glycolysis can continue.

What are the end products of animal muscle fermentation versus yeast fermentation, and what is the net ATP yield?

Animal muscle fermentation produces lactate, whereas yeast fermentation produces ethanol + $CO_2$; fermentation yields only 2 net ATP per glucose from glycolysis.

What is the overall equation for photosynthesis, and is the process endergonic or exergonic?

$6\,CO_2 + 6\,H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6\,O_2$; photosynthesis requires energy overall and is therefore endergonic.

Which substances are oxidized and reduced during photosynthesis?

Water ($H_2O$) is oxidized to $O_2$, while carbon dioxide ($CO_2$) is reduced into carbohydrate.

What electron carrier receives electrons in photosynthesis to transport them to the Calvin cycle?

$NADP^+$ accepts electrons to become NADPH, which carries them to the Calvin cycle.

What are the stroma, thylakoids, and grana of a chloroplast, and where is chlorophyll located?

The stroma is the fluid region, thylakoids are membrane sacs organized in stacks called grana, and chlorophyll is located in the thylakoid membrane.

Which regions of light does chlorophyll absorb strongly, and why do plant leaves appear green?

Chlorophyll absorbs strongly in the blue/violet and red regions; plants appear green because much green light is reflected.

How would blocking red and blue light affect the photosynthetic rate of a plant?

Blocking red and blue light would generally decrease the photosynthetic rate.

How do energy and carbon flow through the reactions of photosynthesis?

Energy flows from sunlight $\rightarrow$ ATP/NADPH $\rightarrow$ glucose/sugars; carbon flows from $CO_2$ $\rightarrow$ Calvin cycle $\rightarrow$ G3P $\rightarrow$ carbohydrates.

What is the direct source of the $O_2$ released during photosynthesis?

The $O_2$ released comes from splitting water ($H_2O$).

What two products of the light reactions are required by the Calvin cycle, and where do electrons originate at PSII?

The two light-reaction products used by the Calvin cycle are ATP and NADPH; electrons originate from water ($H_2O$) at PSII.

What reaction does Rubisco catalyze in the Calvin cycle, and what supplies the reducing power and energy to produce G3P?

Rubisco combines $CO_2$ with RuBP during carbon fixation; ATP and NADPH provide energy and reducing power to form G3P.

Why must RuBP be regenerated during the Calvin cycle?

The $CO_2$ acceptor RuBP must be regenerated so that the Calvin cycle can continue fixing carbon.

What two plant polysaccharides are identified in the notes, and how does the animal storage polysaccharide compare structurally?

The two plant polysaccharides are starch and cellulose; the animal storage polymer glycogen is generally more highly branched than starch.

How do the metabolic capacities of green leaf cells compare to those of animal muscle cells?

A green leaf cell containing chloroplasts and mitochondria can perform both photosynthesis and cellular respiration; an animal muscle cell containing mitochondria but lacking chloroplasts can perform cellular respiration but not photosynthesis.

What specific requirements distinguish the ability to perform photosynthesis from aerobic respiration?

Photosynthesis requires light-capturing/photosynthetic machinery, while aerobic respiration requires fuel and $O_2$ as the final electron acceptor.