VHS Honors Biology Unit #5 (Cellular Respiration) Review

Define cellular respiration.

Celluar respiration is the process in which cells produce ATP by breaking down organic molecules

What is an autotroph?

An autotroph is an organism that produce its own food (performs photosynthesis).

What is a heterotroph?

A heterotroph consumes (eats) food.

Which organisms perform cellular respiration?

Both autotrophs and heterotrophs (ALL organisms) perform cellular respiration.

What is the equation for cellular respiration?

C₆H₁₂O₆ + 6O₂ ---> 6CO₂ + 6H₂O + ATP

What is the connection between photosynthesis and cellular respiration?

The ending products of photosynthesis (C₆H₁₂O₆ + 6O₂) are the starting products of cellular respiration.

What is the connection between cellular respiration and photosynthesis?

The ending products of cellular respiration (6CO₂ + 6H₂O) are the starting products of photosynthesis.

What are the three parts of cellular respiration?

1. glycolysis

2. aerobic respiration

3. anaerobic respiration

What does aerobic mean?

oxygen is present

What does anaerobic mean?

oxygen is low or absent

What is oxidized during cellular respiration and what does it become?

Glucose is oxidized into carbon dioxide.

What is reduced during cellular respiration and what does it become?

oxygen is reduced into water

Where does glycolysis occur?

Glycolysis occurs in the cytoplasm.

How many (net) ATP are produced during glycolysis?

2 ATP

What is glycolysis?

Glycolysis is the breakdown of glucose into pyruvic acid (or pyruvate).

When glucose is broken down into pyruvic acid, what is picked up? (give details)

Hydrogen ions and electrons are picked up by NAD⁺, reducing it into NADH.

Under what environmental conditions does glycolysis occur?

Glycolysis occurs occurs whether oxygen is present or not.

What is the purpose of fermentation?

The purpose of fermentation is to recycle NAD⁺ from NADH and keep glycolysis operating.

Where does fermentation occur?

Fermentation occurs in the cytoplasm (cytosol).

How many ATP are produced during fermentation

Fermentation produces 0 ATP.

Name the two types of fermentation.

a. lactic acid fermentation

b. ethyl alcohol (ethanol) fermentation

What is produced during lactic acid fermentation?

Pyruvic acid is converted into lactic acid.

Lactic acid fermentation occurs in which organisms?

1. animals (including humans)

2. some bacteria

What gets recycled during lactic acid fermentation?

NADH is oxidized into NAD⁺.

What effect does lactic acid have on your muscles?

It reduce the capacity of the muscle cells to contract.

What food products are produced as a result of lactic acid fermentation?

Bacteria that undergo lactic acid fermentation produce cheeses, buttermilk, yogurt, and sour cream.

Which organisms perform ethyl alcohol fermentation?

Yeast

What is produced during ethyl alcohol fermentation?

ethyl alcohol and carbon dioxide

What occurs during ethyl alcohol fermentation?

Yeast convert pyruvic acid into ethyl alcohol and carbon dioxide.

What gets recycled during ethyl alcohol fermentation?

NADH is oxidized into NAD⁺.

What products are produced as a result of ethyl alcohol fermentation?

a. Alcoholic beverages (beer and wine) are produced as a result of ethyl alcohol fermentation.

b. Bread also rises as a result of ethyl alcohol fermentation.

At the end of anaerobic respiration, how many ATP are produced?

Glycolysis = 2 ATP

Fermentation = 0 ATP

TOTAL = 2 ATP

Under what environmental conditions does fermentation occur?

Fermentation only occurs under anaerobic conditions.

In eukaryotes, aerobic respiration occurs inside:

mitochondria

What is the mitochondrial intermembrane space?

The intermembrane space is the space between the outer and inner membranes.

What are cristae?

Cristae are finger-like extensions (folds) of the inner membrane, which increase the surface area inside the mitochondria, creating more places for cellular respiration to occur.

What is the mitochondrial matrix?

The mitochondrial matrix is the space inside the inner membrane.

Before entering the citric acid cycle, what must occur to the pyrivic acid?

Pyrivic acid must be oxidized.

Name the three events of the oxidation (modification) of pyruvic acid.

1. carbon dioxide is released

2. NAD⁺ is reduced into NADH

3. coenzyme A interacts with pyruvic acid

What occurs during the citric acid cycle?

The acetyl group is completely broken down into carbon dioxide, hydrogen ions, and electrons.

How many ATP are produced during the citric acid cycle?

2 ATP are produced during the citric acid cycle.

Describe the electron carriers of the citric acid cycle.

1. NAD⁺ is reduced into NADH.

2. FAD is reduced into FADH₂.

In eukaryotes, where are the ETC and ATP synthase located?

They are imbedded in the inner membrane of the cristae.

In prokaryotes, where are the ETC and ATP synthase located?

They are imbedded in the inner membrane of the plasma membrane.

What is the final electron acceptor of the ETC?

oxygen

What happens to the oxygen in the ETC?

Oxygen accepts electrons (it is the final electron acceptor) and some hydrogen ions, producing water.

Where does the ETC get electrons?

The electrons come from NADH and FADH₂.

Where does NADH get electrons?

NADH gets electrons from glycolysis, the oxidation of pyruvic acid, and the citric acid cycle.

Where does FADH₂ get electrons?

FADHs gets electrons from the citric acid cycle.

Energy is produced as electrons move through the ETC. What is that energy used for?

The energy produced in the ETC is used to move the hydrogen ions from the mitochondrial matrix to the intermembrane space.

How do hydrogen ions get from the mitochondrial matrix to the intermembrane space?

They pass through the proteins of the ETC.

What is chemiosmosis?

Chemiosmosis is the process in which H⁺ diffuse through ATP synthase, phosphorylating ADP into ATP.

What is the name of the protein that allows hydrogen ions to diffuse from the intermembrane space into the mitochondrial matrix?

ATP synthase

At the end of aerobic respiration, how many ATP are produced?

Glycolysis = 2 ATP

citric acid cycle = 2 ATP

oxidative phosphorylation = 34 ATP

TOTAL = 38 ATP