Bio 101 Exam 1: Chapter 7 (Cellular Respiration)

What is substrate level phosphorylation and how many ATP form in glycolysis by this?

Basically, an enzyme transfers a phosphate group (P) from a substrate molecule to ADP, forming ATP in glycolysis. - Process occurs twice, forming 2 ATP in glycolysis.

What do you think you would need to make beer/wine?

Glucose, NAD+, and ADP

stage 2: cellular Respiration

Pyruvate oxidation and the citric acid cycle

citric acid cycle

- As a two-carbon acetyl coA enters the citric acid cycle a series of reactions begin. - Ultimately, the two carbons are released in the form of _Carbon Dioxide__. - Electrons from the intermediate reactions are reduced NAD+ to form how many 3 NADH? - FAD is also reduced to form one FADH2 - Substrate level phosphorylation forms 1 ATP. - ****** Remember that we split glucose into two pyruvates, so everything is doubled

What is the difference (in terms of metabolic activity and organelles) between white fat and brown fat?

- Brown fat --> actively burns energy - White fat (ordinary body fat) --> little metabolic activity

What does the poison cyanide do to cellular respiration?

- Cell runs out of NAD+ - When oxidative phosphorylation is blocked, all these previous stages get backed up too!

explain why food with components other than glucose can be resources for making ATP. For example, how do proteins and fats make ATP?

- Fats are great cellular fuel because they contain a lot of hydrogen atoms and therefore many energy-rich electrons - Proteins are initially digested to amino acids to make its own proteins - Enzymes can covert excess amino acids to intermediates of glycolysis or the citric acid cycle, and their energy is then harvested by cellular respiration

Describe the significance of the gradient of H+? How do the H+ relate to ATP formation? Be sure to use the words chemiosmosis and ATP synthase in your answer!

- Hydrogen ions are transported from the mitochondrial matrix to the inter membrane space through transport proteins - The electron carriers become oxidized (at the same time) which supplies the energy needed to perform the active transport. - The resulting concentration gradients drives hydrogen ions through the enzyme complex ATP synthase through a process called chemiosmosis - The molecular structure structure of ATP synthase enables the synthesis of large amounts of ATP

pyruvate oxidation

- Pyruvate loses a carbon which is released in the form of __Carbon Dioxide___ - Electrons reduce NAD+ to form __NADH___ - A coenzyme called _Coenzyme A__ joins the two carbon compound to form _Acetyl CoA_.

Alcohol fermentation

- Pyruvate releases energy at the same time as CO2 releases and NADH is oxidized into NAD+ - The releasing CO2 cause pyruvate to lose a carbon, resulting in ethanol, a 2 - carbon structure

Besides passing electrons to each other through an electron transport chain, what else do these proteins do?

- These proteins pump hydrogen ions into the inter membrane space - The electron carriers in the chain release energy which enables the active transport of the hydrogen ions

Stage 1 of cellular respiration

1. Glycolysis (splitting of sugar) - Occurs in the cytosol of the cell - Glycolysis begins cellular respiration by breaking glucose down into two molecules of a three-carbon compound called pyruvate

How many pyruvates form in glycolysis?

2

Electrons are passed to NAD+ which is reduced to become NADH. How many NADH form from glycolysis? What will they do?

2 - They will hold/shuttle electrons to the third stage

Each pyruvate has how many carbons?

3

Brown fat, burns fuel and produces heat but does not produce __. (As we would expect during cellular respiration).

ATP

Some poisons block oxidative phosphorylation, yet a small amount of ATP can be made in the presence of these poisons. Explain.

If oxidative phosphorylation is blocked, 4 ATP are still able to be produced for every glucose molecule in the other steps of cellular respiration

An equilibrium of H+ on both sides of the inner membrane would decrease ATP production, because...

Less kinetic energy will be available to power ATP synthase

What is "regenerated" during the process ^ that can then be used again for glycolysis?

NAD+

Anaerobic pathways operate when _____ is absent (or limited). Glycolysis is the first stage to yield 2 __, 2 __, and 2 ______. In the absence of oxygen, the reduced coenzyme used in glycolysis, ___, cannot donate its electrons to the electron transfer chain. Once it is oxidized, we call it _

O2 ATP 2 NADH PYRUVATE NAD+ NADH

Stage 3 of Cellular Respiration How many ATP have been made so far? How much ATP is made at this stage?

Oxidative Phosphorylation 4 28

NADH and FADH2 - What ultimately happens to those electrons?

The electron-carrying molecules become oxidized and the electrons travel to meet o2, the final oxygen receptor, to form water

Where are Electron transport proteins (electron carriers) and ATP synthase are located?

The inner membrane of the mitochondrion

Why do our muscle cells sometimes use lactic acid fermentation?

The need for ATP is great and so it outpaces the delivery of 02 via the bloodstream

Up until recently, we thought only human_______ had brown fat.

infants

lactic acid fermentation

the chemical breakdown of carbohydrates that produces lactic acid as the main end product - Pyruvate releases energy at the same time as NADH is oxidized to NAD+

What is a redox reaction

transfer of one or more electrons from one reactant to another