A) An example of chemical work using ATP is supplying energy for non spontaneous, endergonic reactions, including protein synthesis and DNA replication. b) An example of mechanical work using ATP energy is the beating of cilia or movement of flagella, contraction of muscle fibres, or movement of chromosomes during mitosis/meiosis. c) An example of transport work using ATP energy is pumping substances such as Na+ or K+ ions across membranes against their concentration gradient.

What does the universality of ATP in all living species suggest about the relationship of species to one another?

The universality of ATP as an energy source for every type of cell in every living organism supports an argument that all species have evolved from one original organism.

(a) Describe the structure of an ATP molecule. (b) How does the structure of the ATP molecule relate to the large amounts of free energy it contains?

A) ATP can be described as a phosphorylated sugar. It has a triphosphate group attached to a ribose sugar molecule, which is attached to a molecule of adenosine. b) Structure of ATP molecule permits it to contain large amounts of free energy; the unique feature that permits this is the triphosphate tail where several high energy bonds are located. These bonds can be recycled through cellular machinery.

Describe the process of ATP hydrolysis.

ATP hydrolysis is the process by which ADP and Pi (phosphate) are formed and water is consumed. The process releases free energy.

During the hydrolysis of ATP, energy is released, but most of the molecule, the ADP portion, remains intact. How does this compare to what happens to a molecule of glucose when it is used as an energy source?

During the hydrolysis of ATP the ADP is retained and recycled. This is in contrast to the oxidation of glucose, in which the entire molecule is catabolized. When a cell uses glucose during cellular respiration the entire molecule is oxidized and converted into water and carbon dioxide.

Why is it necessary for cells to “recycle” ADP and Pi rather than just release them as waste products?

There is very little ATP in the diet and it is a relatively large and energy-rich molecule. It would be extremely wasteful and inefficient to use an “entire ATP” and discard it just to obtain the energy released by a single hydrolysis reaction.

Explain, in your own words, why both gasoline and glucose make good fuels.

Both gasoline and glucose make good fuels. Chemically both compounds contain a very high percentage of high-energy C–H bonds. When these molecules react with oxygen, their high-energy valence electrons form strong bonds with the very electronegative oxygen atoms, causing the release of energy. In cars, liquid fuel is advantageous as it is easy to transport. In organisms, a solid power that can be dissolved within the body is beneficial as it allows for easy storage and transport throughout the body and easy absorption from food sources.

(a) Write the chemical equation for the complete combustion of glucose. (b) Which is the oxidizing agent? (c) Which is the reducing agent?

(a) C6 H12 O6 + 6 O2 -> 6 CO2 + 6 H2O (b) Oxygen is the oxidizing agent. (c) Glucose is the reducing agent.

Use diagrams to explain how the relative positions of electrons change during a redox reaction, and how these positions are related to energy changes during the reaction.

Explain the gaining and releasing of energy by electrons, as related to changes in position relative to one or more atomic nuclei.

For any atom, an electron that is farther from the nucleus contains more potential energy than an electron that is more closely held by the nucleus. At the same time, an electron has more potential energy relative to a large nucleus than it would have relative to a small nucleus. As a result, an electron releases energy if it moves closer to a large nucleus and must absorb energy to be pulled away.

List two examples of slow oxidation events and two examples of rapid oxidation events.

Two examples of slow oxidation events are the formation of patina on copper roofs and the rotting of fruits. Two examples of rapid oxidation are the burning of gasoline and the light given off from a road flare.

How is it beneficial for organisms to use controlled oxidation rather than rapid combustion to release energy from their food? Provide at least two benefits.

Controlled oxidation is a benefit to an organism because less energy is lost or wasted as thermal energy during controlled oxidation than would be lost during rapid oxidation. In addition, the cell could suffer damage from the high temperatures required, and created, by rapid combustion.

What happens during cellular respiration?

Nutrients like glucose are oxidized to provide the cell with useful energy.

How many stages are there in cellular respiration?

3 distinct stages

What are the 3 distinct stages of cellular respiration?

-Glycolysis (in cytoplasm and anaerobic) -Citric acid cycle (also known as Kreb's cycle: found in matrix/fluid of mitochondria and is aerobic) -Electron transport chain (ETC) (Found in inner membrane of mitochondria [cristae] and is aerobic)

Stage 1 of Glycolysis

-Start with Glucose (0 ATP, 0 NADH) -ATP phosphorylates glucose to G6P -Phosphate attaches -Becomes G6P

Stage 2 of Glycolysis

-Glucose 6 Phosphate (G6P) (-1 ATP, 0 NADH) -Rearranged into fructose 6 phosphate -G6P rearranged into F6P

Stage 3 of Glycolysis

-Fructose 6 phosphate (F6P) (-1 ATP 0 NADH) -ATP phosphorylates F6P to F1,6-BP -Another phosphate added, activation energy still not met

Stages 4 & 5 of Glycolysis

-Fructose 1, 6-bisphosphate (F1, 6-BP) (-2 ATP, 0 NADH) -Splitting (F1, 6-BP) -F1, 6BP splits into 2 molecules of G3P -New molecules are Glyceraldehyde 3-phosphate (G3P)

Stage 6 of Glycolysis

- 1-3Bisphosphorglycerate (BPG) (-2 ATP, 2 NADH) - Two empty boxes are a NAD+ taking a hydrogen and becoming NADH - Each G3P breaks down into BPG and in that process we build a molecule of NADH (Energy carrier) and there are 2 NADH (since it split earlier)

Stage 7 of Glycolysis

- 3-Phosphohlycerate (3PG) (0 ATP, 2 NADH) -The arrows are meant to be the other way, so ADP comes and explodes into ATP -BPG oxidized and phosphate breaks off and attaches to an ADP (ATP after attachment), 2 ATP made (b/c there are 2 molecules) -Each BPG breaks down into 3PG whilst making ATP molecule

Stage 8 of Glycolysis

- 2-Phosphoglcerate (2PG) (0 ATP, 2 NADH) - 3PG rearranges to form 2PG

Stage 9 of Glycolysis

-Phosphoenolpyruvate (PEP) -Hydrogen and OG cleaved off, forms water and PEP -Each 2PG are converted into a PEP by the removal of water

Stage 10 of Glycolysis

- Pyruvate (2 ATP and 2 NADH) -The arrows are meant to be reversed, another ADP comes and becomes ATP -Each PEP breaks down into a pyruvate while building a molecule of ATP

Where does the citric acid cycle (kreb's cycle) happen?

Happens in the matrix (fluid) of the mitochondria

Is the citric acid cycle aerobic or anaeorbic?

Aerobic

How does the citric acid cycle begin?

Begins when pyruvate is shuttled through the mitochondrial membranes and into the matrix

What must happen to pyruvate before it enters the matrix?

Must be oxidized

Please fill in the boxes and describe what is happening

Pyruvate is converted into acetyl-COA . Pyruvate oxidation ends. Pyruvate started with no ATP, NADH, or FAOH. Acetyl-COA ended up with no ATP, NADH, or FADH but did make a CO2.

Please fill in the boxes and describe what is happening Step 1

Oxaloacetate has 2 ATP, 8 NADH, 2 FADH2, and 6 CO2. It is the first step in the citric acid cycle.

Step 2

Acetyl group (from earlier) joins to oxalocetate to form citrate

Step 3

Citrate is rearranged to form isocitrate

Step 4

Isocitrate is converted to alpha ketoglutarate through oxidization. 0 ATP, 4 NADH, 0 FADH2, 4 CO2.

Step 5

Alpha-ketoglutarate is converted to succinyl-COA.

Step 6

Succinyl-COA loses coenzyme A to become succinate. A free-floating phosphate group is added to a GDP molecule to make GTP. GTP reverts to GDP and transfers the phosphate group to an ADP to produce an ATP molecule.

Step 7

Succinate is converted to fumarate. Correction: Fumarate has 2 FADH2

Step 8

Fumarate is converted to malate

Step 9

Malate is converted to oxaloacetate

Where does electron transport chain (ETC) occur?

Occurs in inner membrane of mitochondria (cristae)

(a) What is the final energy-rich product of the pathways that extracts energy from food? (b) What is this product responsible for in the cell?

(a) The final energy-rich product of the pathways that extract energy from food is ATP. (b) ATP is responsible for providing energy to drive almost all metabolic activities within the cell.

What "series" does electron transport chain involve?

Involves a series of membrane proteins (cytochromes)

Explain the main difference between aerobic respiration and anaerobic respiration.

Aerobic respiration uses oxygen as a final electron acceptor to produce ATP, and anaerobic respiration uses an inorganic oxidizing agent other than oxygen.

Use a Venn diagram to compare and contrast anaerobic respiration with fermentation.

Describe the differences between the following: • obligate aerobes • obligate anaerobes • facultative anaerobes

-obligate aerobes cannot survive without oxygen -obligate anaerobes cannot survive in the presence of oxygen -facultative anaerobes can live with or without oxygen.

(a) What is the overall equation that represents aerobic cellular respiration? (b) Describe this equation using simple words that a non-scientist could understand.

(a) (b)Glucose, or sugar, reacts with oxygen to produce carbon dioxide, water, and energy stored in molecules called ATP.

How many stages are involved in aerobic cellular respiration? Briefly describe each stage.

Aerobic cellular respiration consists of four main stages: -glycolysis, pyruvate oxidation, the citric acid cycle, and electron transport. -In glycolysis, glucose is broken down into pyruvate, producing some ATP and NADH. -Pyruvate oxidation converts pyruvate into carbon dioxide, acetyl molecules, and NADH. -The citric acid cycle fully oxidizes acetyl molecules to CO2, generating more ATP, FADH2, and NADH. -In electron transport, NADH and FADH2 from the previous stages are used to produce ATP through an electron transport system.

Some bacteria cells are quite similar in structure to mitochondria. Both contain their own DNA, and both are able to divide on their own (mitochondria divide within eukaryotic cells). However, bacteria cells are able to survive independently, while mitochondria are not. (a) What part of the aerobic respiration pathway cannot be performed by mitochondria? (b) In terms of energy pathways only, what two chemicals (in addition to ADP and Pi) do mitochondria need to take in to generate ATP?

(a) The part of the aerobic respiration pathway that cannot be performed by mitochondria is glycolysis. (b) Mitochondria need to take in pyruvate and oxygen in order to generate ATP.

Glycolysis, pyruvate oxidation, and the citric acid cycle produce only a small amount of ATP from the energy in a glucose molecule. In what form(s) is (are) the rest of the harvestable energy that is converted to ATP in the electron transport chain and chemiosmosis?

NADH, FADH2, ADP, and Pi

Where does the electron transport chain (ETC) occur?

Occurs in the inner membrane of mitochondria (cristae)

What series does the ETC process involve?

Involves a series of membrane proteins called cytochromes

What do NADH and FADH2 do when they interact with cytochromes? Where is NADH and FADH2 made?

NADH and FADH2 (produced during CAC) give up H+ ions and electrons to cytochromes

What is transported through the chain of cytochromes?

Electrons

Where do H+ ions accumulate in ETC?

H+ ions accumulate in the intermembrane space b/c electrons are claustrophobic and spread out

What happens when there is a high concentration of H+ ions in the intermembrane space?

High concentration of H+ ions in the intermembrane space creates concentration gradient and electrostatic gradient

What do gradients do in the ETC? What is the motor ?

Drive H+ ions through a protein channel; providing energy to synthesize ATP. Think of H+ as air or water and the channels as motors; the H+ ions (in high concentration) want to run through this motor to a less concentrated area; making ATP (energy), the motor is ATP synthase.

How does the Electron transfer chain work? What is the equation used for the production of water?

1. Electrons released by NADH and FADH2 move through the ETC 2. Each cytochrome is alternately reduced and then oxidized 3. All happens until electrons combine with final electron accepter oxygen 4. Once electrons are accepted by the O2, H+ ions are also picked up, resulting in the formation of H20 5. 1/2 O2 + 2H+ -> H20

Theoretically, how much NADH, FADH, and ATP is made in glycolysis, pyruvate oxidation, and kreb's cycle?

Glycolysis -6 ATP (2 NADH * 3) Pyruvate oxidation - 6 ATP (2 NADH * 3) Krebs's cycle -18 ATP (6 NADH * 3) -4 ATP (2 FADH * 2) In total: 38 ATP per glucose

When muscles are overworked, what happens in ATP production? What toxic byproduct is made?

For glycolysis to continue, NAD+ must be replenished in animals, this occurs through lactic acid fermentation. Total production of 2 ATP per glucose molecule. Lactic acid is the toxic byproduct. Glucose -2 NADH and 2 ATP 2 Pyruvate -2 NAD+ end result - 2 Lactic acid

What is the other way to quickly make energy, which only happens in bacteria and yeast?

For glycolysis to continue, NAD + must be replenished. In bacteria and yeast, this occurs through alcohol fermentation, total production is 2 ATP per glucose. Glucose -2 NADH and 2 ATP 2 Pyruvate -2 CO2 2 Acetaldehyde -2 NAD+ End product -2 ethanol

How does the electron transport chain produce ATP? What is the driving force?

1. ETC transfers electrons from NADH and FADH2 to O2 through 4 complexes -Each complex increases in electron affinity 2. 2 Electron shuttles help move electrons between complexes 3. O2 High affinity takes electrons from the cytochrome 4. Causing a sequence where electrons from more electronegative molecules move to less electronegative ones -Drives the ETC

(a) Do the electrons in NADH have the most or the least free energy in the electron transport chain? (b) The electrons in NADH form bonds as they move through the electron transport chain. Do these bond formations use or release energy?

(a) The electrons in NADH have the most free energy in the electron transport chain. (b) These bond formations result in energy being released as the electrons form stronger and stronger bonds as they move through the electron transport chain.

Which stages of aerobic cellular respiration occur in the mitochondria, and which stages do not?

The stage of aerobic cellular respiration that does not occur in the mitochondria is glycolysis. Glycolysis occurs in the cytosol. All of the other stages of aerobic respiration—pyruvate oxidation, the citric acid cycle, the electron transport chain, and chemiosmosis—occur in the mitochondria.

What is the primary function of the proton-motive force?

The primary function of the proton-motive force is the establishment of a chemical and concentration gradient of protons across the membrane. This represents a source of energy that can be harnessed to do work. Cells use the proton-motive force in the process called chemiosmosis, which synthesizes ATP.

Give an example of how uncoupling is used by organisms to increase survival.

An example of uncoupling is brown adipose fat. This fat can use uncoupling to generate thermal energy from the electron transport chain instead of generating ATP. Uncoupling produces energy to maintain body temperature in hibernating animals and in very young offspring, including human infants.

When does anaerobic respiration occur?

Occurs when oxygen is limited or absent Some environments like that are the human gut, underground and oceans

What're 2 anaerobic processes?

Alcohol fermentation and Lactate fermentation

Which organisms carry out alcohol fermentation?

Bacteria and yeasts

What happens in alcohol fermentation?

Pyruvate (product of glycolysis) is decarboxylated to produce acetaldehyde then used to oxidize NADH, regenerating NAD+.