BSC 1005 Ch.6

Describe all the different molecules that can be metabolized via aerobic cellular respiration and indicate where each type of molecule enters the pathway.

Amino acids, lipids, and other carbohydrates can be converted to various intermediates of glycolysis and the citric acid cycle, allowing them to slip into the cellular respiration pathway through a multitude of side doors.

Describe the evolutionary basis of the role of glycolysis in both respiration and fermentation. What data support the theory that glycolysis evolved very early in evolutionary history.

Ancient prokaryotes used glycolysis to make ATP way before oxygen even existed. Due to no requirement of oxygen, the first prokaryotes generated ATP only through glycolysis, due to the fact that it can be performed without oxygen.

.Diagram the events that occur during the intermediate step or "link" between glycolysis and the citric acid cycle

Each pyruvate (3 carbons) is then converted to acetyl coA (2 carbons). This process generates: 1 NADH (since glucose gave you 2 pyruvates, this means you get 2 additional NADH here) 1 CO2 (Again, 2 per glucose you started with)

Summarize all reaction pathways of cellular respiration and account for all of the ATP produced. How much ATP is produced by each individual stage of respiration?

Glycolysis: 2 ATP Citric Acid cycle ( kreb Cycle) 2 ATP ETC ( Electron transport chain) 34 ATP Total= 38 ATP

Describe the types of molecules that make up the Electron Transport Chain

NADH and FADH2 to pump hydrogen ions out of the mitochondrion (3 for NADH, 2 for FADH2). For each one, this process consumes one molecule of O2, and produces 2 molecules of water. The hydrogen ions produce a gradient that drives a pump that produces more ATP from the energy of hydrogen flowing back into the mitochondrion.

Are there some organisms that can survive solely from anaerobic respiration? If so, what type of organism are they?

Other bacteria and archaea are obligate anaerobes, meaning they can live and grow only in the absence of oxygen. Oxygen is toxic to these microorganisms and injures or kills them on exposure.

Describe the role of oxygen in cellular respiration.

Oxygen accepts high-energy electrons after they are stripped from glucose. Cellular respiration accomplishes two major processes: (1) it breaks glucose down into smaller molecules, and (2) it harvests the chemical energy released and stores it in ATP molecules.

Explain why oxygen is described as an "electron grabber".

Oxygen attracts electrons very strongly, similar to how gravity pulls objects downhill.

Explain how photosynthesis and cellular respiration are related.

Photosynthesis and cellular respiration are connected through CO2 and H2O as these are the substrate in photosynthesis and end products in cellular respiration. The reactants and products is simply the photosynthesis formula reversed. Photosynthesis: 6H2O+6CO2⇒C6H12O6+6O2 Respiration: C6H12O6+6O2⇒6H2O+6CO2

What are the reactant and products of photosynthesis?

Reactants = carbon dioxide and water Products = glucose and oxygen

Describe the steps in Lactic Acid Fermentation

Step 1 : From glycolysis a pyruvate and NADH enter the cycle. Energy from NADH molecules provides energy for a pyruvate to turn into 2 lactic acids. When NADH is used it is converted back into NAD+ Step 2 : Recycling of 2 NAD+ back to glycolysis allows it to continue

Identify the main purpose for photosynthesis. What is the primary product? What is the waste product or by- product of photosynthesis?

The final products of photosynthesis are glucose (sugar) and oxygen. The oxygen allows animals and other organisms to breathe and produce energy through cellular respiration.The sugar (food) is also used by other organisms to make energy. Both oxygen and glucose are ingredients in the process of cellular respiration, which all organisms undergo, to make energy.

Identify in what part of the cell each of the three stages of cellular respiration take place.

The process begins in the cytoplasm and is completed in a mitochondrion.

How are Lactic Acid and Alcoholic Fermentation similar and how are they different?

The similarity is that they both happen under anaerobic conditions and produce a little amount of ATP. The difference is that alcoholic fermentation gives CO2 while lactic acid does not

Predict approximately how many molecules of ATP are produced for every one molecule of glucose that undergoes aerobic cellular respiration.

Two molecules of ATP are generated for every one molecule of glucose . This is a substrate level phosphorylation. At this point in glycolysis, two molecules of ATP have been used and two have been generated. Thus, there is a net gain of 0 ATP.

Identify which types of organisms perform both photosynthesis and respiration and which types of organisms perform only cellular respiration.

both=plant cells and some bacteria and algae. only During cellular respiration, all that is needed is for oxygen to reach the cell.EX: plants don't breathe but take in oxygen within the plant

Diagram of citric acid cycle ( also known as the kreb cycle)

converts those acetyl coA that were made above. Those acetyl coA molecules (2 carbons each) then enter the cycle, combining with oxaloacetate (4 carbons) to make citrate (6 carbons). remember that oxaloacetate is always regenerated in the end. This process gives you: 3 NADH (6 per starting glucose) 1 FADH2 (2 per glucose) 1 GTP (2 per glucose) 2 CO2 (4 per glucose) COMBINING THE FIRST AND LAST STEP: YOU HAVE: 2 ATP 10 NADH 2 FADH2 2 GTP 6 CO2

Explain how breathing is related to cellular respiration.

lungs take up O2 and takes it to blood stream. The bloodstream carries O2 to muscle cells. Mitochondria in the muscle cells use O2 to generate ATP. Breathing- C02 and 02 are exchanged between lungs and that air. Cellular respiration- cells use O2 to break down fuel, releasing CO2 as a waste product.

Identify which molecules are undergoing oxidation and which molecules are undergoing reduction during the three stages of cellular respiration.

oxidation = a molecule loses electrons reduction = a molecule gains electrons The molecules NAD+ and FADH gain electrons, so these are being reduced . pyruvate is being oxidized In the last phase of cellular respiration, the electron transport chain, FADH2 and NADH are also being oxidized when they give off their gained electrons.

What molecule acts as the final electron acceptor in the ETC?

Oxygen

What is the role of the enzyme ATP Synthase in this process?

to synthesize ATP from ADP and inorganic phosphate (Pi) in the F1 sector.

Describe the steps in Alcoholic Fermentation

two steps: glycolysis and NADH regeneration. During glycolysis, one glucose molecule is converted to two pyruvate molecules, producing two net ATP and two NADH.

Diagram the process of glycolysis

-converts 1 molecule of glucose (6 carbon atoms) into 2 molecules of pyruvate (3 carbons each) that then go to the Krebs cycle( also known as the citric acid cycle) Produces: -2 ATP (immediately usable as energy) 2 NADH (used to make ATP in the electron transport chain)

Identify which form of NADH/NAD+ is the reduced form and which is the oxidized form.

NAD+ =oxidized NADH = Reduced

Identify what class of molecules make up the electron transport chain.

NADH and FADH2

Describe how the cell is able to harness the huge, explosive amount of energy released as hydrogen and oxygen combine to form water.

if energy is released from a fuel all at once it cannot be harnessed efficiently for constructive work therefore cellular respiration does not oxidize glucose in a single explosive step but does it in a series of steps and each step is catalyzed by an enzyme, in each key step electrons are stripped from the glucose; each electron travels with a protein as a hydrogen atom and the hydrogen atoms are not transferred directly to oxygen but passed first to electron carrier

List the reactants and products in aerobic cellular respiration.

respiration used oxygen and glucose to produce energy, and also creates water and carbon dioxide