bio final 🧬🦠 (unit 3)

L15- how to alter enzyme function

1) increase/decrease transcription/translation of enzyme gene/protein 2) location - alter location of enzyme's location 3) activate if needed 4) inhibition

L17/18- what is the purpose of aerobic glucose catabolism

produce ATP to carry out cellular functions

L17/18- why does a cell undergo anaerobic vs. aerobic glucose catabolism if a prokaryote? eukaryote?

prokaryote does not have a mitochondria to perform aerobic glucose catabolism (glycolysis, p.o., krebs, o.p) so the presence of oxygen doesn't make a difference eukaryote lack of oxygen in cell, no final electron acceptor, ETC fails and thus so does the KC and PO...driving the pyruvates into anaerobic route

*look at slide 8 of the key powerpoint* L14- in order to start an exergonic reaction, a certain amount of energy must be absorbed by the reactants. This is called the energy of activation. which of the following is the normal energy of activation?

a

*look at slide 8 of the key powerpoint* L14- graph illustrates how an enzyme catalyzes reactions in biological systems. From an energy standpoint, is this reaction an endergonic or exergonic reaction a. endergonic. b. exergonic. c. there is not enough information in this graph to decide the type of reaction.

b. exergonic

*look at slide 15* L17/18- what are the main stages

glycolysis lactic acid fermentation

L15- name the type of inhibition shown

noncompetitive inhibition

L16- how does the cell get more energy after glycolysis

NADH (created in glycolysis) transfers the electrons to carrier proteins in the electron transport chain (ETC) pyruvate molecule will be further broken down during pyruvate oxidation and the Krebs cycle to make more NADH, FADH2, and ATP

L16- why is NADH worth more ATP than FADH2?

NADH produces 3 ATP during the ETC + chemiosmosis (oxidative phosphorylation) NADH gives its electron to Complex I (at a higher E-level than the other Complexes) FADH2 produces 2 ATP during the ETC + chemiosmosis (oxidative phosphorylation) It gives its electron to Complex II, bypassing Complex I; by bypassing Complex I, less protons have been pumped thus less ATP generated

Q5. CO2 is a gaseous by-product of cellular respiration that you exhale with each breath. briefly explain where the CO2 comes from.

The CO2 comes from the organic molecules (food) that you consume and is a by-product of aerobic glucose catabolism in the stages of pyruvate oxidation and Krebs cycle.

Q9. label each of the following systems as high or low entropy: a. perfume the instant after it is sprayed into the air b. an unmaintained 1950s car compared with a brand new car c. a living cell compared with a dead cell

a. low b. high c. high

L17/18- these cells or cell types were mentioned in our discussion of glucose catabolism: muscle cells bacteria yeast mold plant cells animal cells heterotrophs autotrophs what types of cells undergo glucose catabolism?

all

L15- differences between autotrophs and heterotrophs

autotrophs can create own energy (glucose) from sun heterotrophs can't make own energy (glucose) must rely on other organisms for food

*look at slide 8 of the key powerpoint* L14- which of the following represents the energy of activation that is modified by an enzyme?

b

Q2. a child is brought to the hospital with a fever of 107°F. Doctors immediately order an ice bath to lower the child's temperature. which of the following statements offers the most logical explanation for this action? a. elevated body temperature will increase reaction rates in the child's cells and overload the limited number of enzymes found in the cell. b. elevated body temperatures may denature enzymes. This would interfere with the cell's abilities to catalyze various reactions. c. elevated body temperatures will increase the energy of activation needed to start various chemical reactions in the body. This will interfere with the ability of enzymes to catalyze vital chemical reactions. d. elevated body temperatures cause molecules to vibrate more quickly and prevent enzymes from easily attaching to reactants. This would slow vital body reactions.

b. elevated body temperatures may denature enzymes. This would interfere with the cell's abilities to catalyze various reactions.

Q1. aspirin prevents inflammation by inhibiting an enzyme in the prostaglandin pathway, but by inhibiting this enzyme and this pathway they also inhibit pathways that protect the stomach from damage by stomach acid and that prevent aggregation of blood platelets to form blood clots. what can you conclude from this? a. the enzyme inhibition is nonreversible. b. the enzyme is found in many different types of cells. c. prostaglandins cause blood clotting. d. aspirin should not be given to people who people who need to synthesize enzymes.

b. the enzyme is found in many different types of cells.

Q11. what happens if an enzyme is not functioning in a chemical reaction in a living organism that needs it? a. the reaction stops. b. the reaction proceeds, but much more slowly. (Enzymes only speed up reactions that would normally occur in the cell.) c. the reaction proceeds faster without the interference. d. there is no change in the reaction rate.

b. the reaction proceeds, but much more slowly. (Enzymes only speed up reactions that would normally occur in the cell.)

L15- enzymes catalyze the many reactions in a cell. There are hundreds of different enzymes in a cell—each with a unique three- dimensional shape. why do cells have so many different enzymes? a. each enzyme molecule can only be used once. b. the shape of an enzyme's active site generally fits a specific substrate. c. the substrate molecules react with enzymes to create new enzymes. d. enzymes are randomly produced. With thousands of different shapes—one is likely to work.

b. the shape of an enzyme's active site generally fits a specific substrate.

L16- describe the major role of NADH in cellular respiration

bring high energy electrons to the ETC to help generate the H+ gradient.

Q7. when most people hear the word respiration, they think about breathing in and out...what's the connection between breathing and cellular respiration (which is part of aerobic glucose catabolism does this relate to)?

bringing in oxygen into the cell so the ETC will work. Meaning the NADH and FADH2 can drop off their electrons to help generated the H+ ion gradient in order to produce ATP during chemiosmosis. Without the H+ ion gradient, not a lot of ATP can be produced. Note: ATP can still be produced in glycolysis.

Q10. which of the following is the best example of the first law of thermodynamics? a) a body getting warmer after exercise b) a piece of fruit spoiling in the fridge c) a power plant burning coal and producing electricity

c) a power plant burning coal and producing electricity

Q8. DNA replication involves unwinding two strands of parent DNA, copying each strand to synthesize complementary strands and releasing the resulting two semi-conserved strands of DNA. Which of the following accurately describes this process? a. this is an anabolic process. b. this is a catabolic process. c. this is both an anabolic and a catabolic process. d. this is a metabolic process, but is neither anabolic nor catabolic.

c. this is both an anabolic and a catabolic process. reason for both: anabolic = making molecule bigger...that is what happens when DNA is being synthesized (nucleotides are put together)...but we have to break the H-bond holding the two strands together so this is also a catabolic reaction.

L15- similarities between autotrophs and heterotrophs

carry out reactions (exer/endergonic) (catabolic/anabolic)

L15- different types of inhibition

competitive competitive inhibitor binds to the active site blocking the substrate. Now substrate cannot bind to active site and enzyme cannot do its job. noncompetitive allosteric inhibitor binds to the allosteric site on the enzyme thereby changing the shape of the active site. Now substrate cannot bind to active site and enzyme cannot do its job.

L15- how to overcome each type of inhibition

competitive- add more enzyme (if possible) add more substrate mild heat treatment to break weak H-bonds if inhibitor bound by covalent bond, nothing can be done noncompetitive- add more enzyme (if possible) mild heat treatment to break weak H-bonds if inhibitor bound by covalent bond, nothing can be done

L16- NAD+ can carry 2 electrons and H+ ions. where does this "cargo" come from

electrons are released when covalent bonds are broken. The H+s are released from the carbon-hydrogen bonds when breaking down the organic molecule.

L14- which reaction is spontaneous & why scientifically

exergonic 2nd law- things break down over time naturally so it doesn't require ATP

L14- contrast endergonic vs. exergonic reactions

exergonic catabolic hydrolysis endergonic anabolic dehydration synthesis

*look at slide 10 of key powerpoint* L14- What type of reaction is shown

exergonic catabolic hydrolysis

L14- cellular respiration is a(n) _________ reaction. why?

exergonic larger molecule is being broken down into smaller molecules --> catabolism --> exergonic.

L14- what is the relationship between exergonic and endergonic reactions

exergonic reactions release energy that is then used to fuel endergonic reactions

Q4. true or false: a substance that makes the inner mitochondrial membrane leaky to H+ ions increases ATP production in mitochondria. if false, make it a correct statement.

false, it would decrease ATP production as ATP synthase efficiency would be reduced.

Q12 why do you get more energy from a fat vs. a carbohydrate? Hint: think about the structure of a carbohydrate vs. that of a fat.

fats have more C-H bonds that can be broken and thus more electrons can be released...thereby reducing NAD+ to NADH. More NADH = more H+ ions to build a gradient = more ATP produced.

L17/18- overview of cellular respiration

glycolysis location: cytosol/cytoplasm key events: glucose oxidized into 2 pyruvates, 2 NADH, 2 ATP (net) by substrate-level phosphorylation pyruvate oxidation location: mitochondria key events: 2 pyruvates are oxidized to 2 NADH and 2 acetyl CoA krebs cycle/citric acid cycle location: mitochondria key events: 2 acetyl CoA are utilized to make 6 NADH, 2 FADH2, 2 ATP by substrate-level phosphorylation electron transport chain (part of oxidative phosphorylation) location: mitochondrial matrix key events: NADH and FADH2 deliver electrons to various proteins and eventually pass to O2, forming H2O; H+ ions are pumped into intermembrane space chemiosmosis (part of oxidative phosphorylation) location: mitochondrial matrix/inner membrane space key events: H+ gradient is utilized by ATP synthase to produce ~32 ATPs by oxidative phosphorylation total ATP yield = ~34-38 from 1 glucose molecule

L17/18- what are the stages of aerobic glucose catabolism

glycolysis pyruvate oxidation krebs cycle/citric acid cycle oxidative phosphorylation (composed of 2 stages) - electron transport chain -chemiosmosis

*look at slide 15* L17/18- what is the purpose of each stage

glycolysis- produce ATP quickly lactic acid fermentation- recycle NADH back to NAD+

L14- why is a hill diagram better to use when discussing reactions compared to bar graphs

hill diagrams show the progress of a reaction (from reactants to products) and how much energy is being utilized or released throughout. A bar graph simply just shows the amount of energy in the reactants vs. the products.

L15- enzymes are catalysis that speed up reactions by

lowering the activation energy

L17/18- is pyruvate a reactant in the Krebs Cycle? explain why or why not.

neither. acetyl is a reactant. However, pyruvate is used to make acetyl...so it does play a role in creating the molecules in the Krebs cycle.

Q6. sucrase is the enzyme that breaks down sucrose into glucose and fructose. will sucrose also catalyze the breakdown of the disaccharide maltose? briefly explain your answer.

no, because maltose will have a different structure than sucrose and so it will not fit into the active site of sucrose

Q3. if you opened a wine vat, would the yeast inside continue to perform alcoholic fermentation? briefly explain your answer with some details about what would happen.

no, because they would be exposed to atmospheric oxygen and they would preferentially perform aerobic respiration.

L15- differences between noncompetitive and competitive inhibition

noncompetitive bind to a location on the enzyme other than the active site and cause a change in the enzyme's active site. This keeps the enzyme from binding to the proper substrate. competitive bind directly to the active site of an enzyme and inhibit the binding of the proper substrate.

L16- FAD+ picks up high energy electrons to become FADH2. It then transfers those electrons into the electron transport chain to help generate ATP for the cell. is FAD+ the oxidized or reduced state?

oxidized

L17/18- in oxidative phosphorylation, what reactant molecule must have come from outside the cell? how do you know?

oxygen

L16- is NADH in an oxidized or reduced state? explain how you know

reduced has hydrogen associated with it H+ ions follow the negatively charged electrons

L14- how does the first and second law of thermodynamics compare and contrast

the first law of thermodynamics deals only about quantity of energy that is involved in a system and its process. This law states that energy cannot be created nor destroyed. In other words, the total amount of energy coming in the system must be equal to the total energy coming out of the system. The energy might be transferred and transformed but it must remain constant. The second law deals about the quality of the energy being transferred. 2nd law states that in the natural flow of things, the system always favors chaos rather than order. In other words, the entropy (amount of disorder) in a given closed system irreversibly increases and the total amount of entropy is the sum of entropies between the system and its surroundings.

L17/18- what drives the cell to undergo aerobic glucose catabolism vs. anaerobic glucose catabolism

the presence of oxygen

L15- similarities between noncompetitive and competitive inhibition

they both work to inhibit the activity of enzymes

L17/18- what goes in and what comes out glycolysis --> pyruvate

what goes in glycolysis --> glucose pyruvate --> 2 pyruvates what comes out (NET) glycolysis --> 2 pyruvate, 2 ATP, 2 NADH pyruvate --> 2 acetyl CoA, 2 CO2, 2 NADH