Cellular Respiration Sample Test

Here are some useful links for cellular respiration:










November 4, 2010: Glycolysis Introduction Video
By: Joanne Kim

Today, we had our biochemistry quest, and watched 2 short clips about glycosis.
The general points I got from the video are:
- living organisms need a constant supply of energy, either Directly (from the sun), or indirectly
- the body extracts energy from food entering the stomach; carbohydrates are the bulk of this energy
- glucose has its bonds broken through cellular respiration
- glucose + oxygen -> energy + carbon dioxide + dihydrogen oxide (water)
- ATP contains adenine, ribose, and 3 phosphate groups; the phosphate groups provide most of the energy
- Energy comes in glucose, and must be transferred to ATP through cellular respiration
- most life forms have common ancestry, shown through similar way energy is processed
- Before glycolysis takes place, glucose must be available.
- glycogen is the storehouse of glucose in the body
- liver glycogen is broken to glucose, and transported around the body

1st half of glycolysis: requires energy input, provided by ATP, which breaks glucose bonds
1) phsphorylation : phosphoryl group of 1 ATP moved to glucose; ADP + Glucose phosphate
2) it encounters 1 ATP, where fructose phosphate is formed (since fructose phosphate is very unstable, it has a tendency to reverse back to glucose, yet reaction coupling is used to prevent this reversal. This is why coupling reactions are the driving force for glycolysis)
3) Reacts with another ATP, fructose diphosphate formed.
4) They form 2 3-carbon molecules (DHAP and PGAL)
5) DHAP is converted into PGAL, leaving you with 2 PGAL molecules. At this point, there is more energy in PGAL than there first was in glucose.

2nd half: everything happens in duplicates. PGAL synthesizes ATP and NAD. NAD is the intermediate energy carrier; energized NAD is called NADH, which is electron rich.
6) NAD becomes PGAL, as it picks up 2 electrons and an H ion.
the NAD reaction is an reduction, and the reaction containing DPGA is an oxidation.
7) DPGA encounters ADP, phosphate is transferred to form ATP, leaving behind the PGA.
8) The molecules are rearranged
9) water is lost, forming a PEP. The bond holding phosphates is weakened.
10) pyruvate is formed.

Throughout this process, there is a net gain of 2 ATP, which only accounts for 2.2%. Although this seems like a small amount, in smaller organisms such as yeast, the extra 2.2% can help it to thrive.

Sorry if any of the jot notes are confusing; hopefully this will make more sense when we go into further detail.

This is an animation site I found explaining glycolysis; it goes through the steps as well:

This is a diagram of the stages:

by Sarah Drury
Text book reference pages: 90 and beyond

Cellular Respiration

C6H12O6 (aq) + 6 O2 (g) -------> 6 CO2 + 6 H2O (l) + energy (ATP + heat)

Anaerobic *Ends with 2 ATP*
- in cytoplasm in all organisms
- starts with glucose -> makes 2 pyruvate, 2 ATP, 2 NADH and water
Fermentation - occurs to make NAD+ for use in glycolysis
- in cytoplasm
For yeast:
- starts w/ glycolysis, makes: 2 pyruvate -> 2 ethanols, 2 NAD+
- 2 NAD+ ensure glycolysis can continue
For bacteria, humans:
- starts w/ glycolysis, makes: 2 pyruvate -> lactic acid, 2 NAD+

Aerobic *Ends with 34 ATP*
Pyruvate Oxidation
- in mitochondrial matrix (fluid)
- start with 2 pyruvate, makes: 2 acetyl-coA, 2 NADH, CO2 (waste)
Krebs Cycle
- in mitochondrial matrix
- start with 2 acetyl-coA joining w/ 2 oxaloacetates (2 turns of cycle)
- makes (including both cycles): 2 ATP, 2 FADH2 (intermediate energy carrier), 6 NADH, 6 CO2 (waste)
Electron Transport Chain (ETC) - where the vast majority of energy is made available
- in mitochondrial matrix, inner mitochondrial membrane and intermembrane space
- NADH and FADH2 transfer their energy to ATP
- electrons are transported
  • Oxygen is final electron acceptor
- makes: water, 32 ATP


Source: http://access.mmhs.ca/docs/science/MMHS%20Web%20Folder/Kamla/mitochondrion2.gif

A Cellular Respiration Tutorial
ETC Animation
ATP Synthase Gradients Animation
One of the Cellular Respiration Animations we watched in class
Many Interactive Biology Tutorials

November 9: ATP Production and the Electron Transport Chain

By Sangitha Mensingh

The Two Ways ATP is Made
1. Substrate level phosphorylation
- ATP is made directly in an enzyme catalyzed reaction
- A molecule containing phosphate transfers the phosphate to ADP in order to produce ATP

2. Oxidative Phosphorylation (Electron Transport Chain)
-ATP is made indirectly
-Oxygen is the final electron acceptor in the ETC
-NADH becomes NAD+ and thus allowing two electrons to move through the chain
-FADH2 becomes FAD and similarly allows two electrons to move through the chain
-Through the process of ETC the energy is transferred from NADH and FADH2 to ATP

Electron Transport Chain
-The components are arranged in order of increasing electro-negativity and oxygen is the most electronegative.
-The ETC components are embedded in the inner mitochondrial membrane and it is an aerobic process.

Steps: (using NADH)
1. NADH gives up 2 electrons to the first complex of ETC and also loses a H
2. As the 2 electrons move through the ETC they provide the energy to pump 3H+ from the matrix to the intermembrane space
3. The O2 from the matrix picks up the 2 electrons along with 2H+ from the matrix to form H2O
4. The H+ concentration increases in the intermembrane space, creating an H+ gradient and an electrostatic gradient
- These gradients provide the energy to make ATP
- H+ ions move from the intermembrane space to the matrix activating enzymes that catalyze the reaction ADP + Pi (Pi means that the phosphate is inorganic) -> ATP

ATP is created by NADH from pyruvate oxidation and the kreb's cycle, by FADH2 fromt he Kreb's cycle and from NADH from glycolysis
NADH from pyruvate oxidation and from the kreb's cycle (in the mitochondria)
- allow 3H+ to be pumped across the membrane and create 3 additional ATP molecules

FADH2 from the Kreb's cycle
1. The electrons enter in later at the Q complex causing only 2H+ to be pumped across the membrane
2. This forms 2 ATP

NADH from glycolysis (in the cytoplasm) has a similar process to FADH2
1. 2H+ are pumped across the membrane to form 2 ATP molecules

For an overview of the process watch the video below (note: it only shows the process for NADH):
Cannot be embedded. Click on this link: ETC process
Video retrieved from: http://www.youtube.com/watch?v=xbJ0nbzt5Kw

Or this video:

Retrieved from: http://www.youtube.com/watch?v=1engJR_XWVU&feature=related

November 10: Cellular Respiration Summary

By Mimi Chen

Pyruvate oxidation
Krebs Cycle (occurs 2 times to process 1 glucose)
Electron Transport Chain

  1. ATP formed
Where it occurs
mitochondrial matrix
mitochondrial matrix
mito. matrix
inner mito. membrane
intermembrane space


1 glucose
2 pyruvate(3 carbons)
acetyl-CoA + oxaloacetate(4 carbons long)
2 NADH (pyr. oxn)
6 NADH (from Krebs)
2 FADH2 (from Kreb)
2 NADH (from Glycolysis)
6 (3/NADH)
18 (3/NADH)
4 (2/FADH2)
4 (2/NADH)
2 pyruvate
2 acetyl-CoA (2 carbons)
2 CO2
6 NADH (3/pyruvate)
2 ATP (1/pyruvate)
2 FADH2 (1/pyruvate)
32 ATP
32 ATP
ATP Count
Total = 36

Above is a video on the Pyruvate Oxidation and the Electron Trans

For more information on celluar respiration please check out http://www.essortment.com/all/cellularrespira_rmpr.htm

Chapter 3: Photosynthesis
Tuesday, November 15, 2010

By: Eva Klimova

Hello OSCSS Biology Students!,Sorry, but I had troubles posting the wiki note, so I decided to post it as a file. Hope this is not inconvenient for anybody. I am leaving it in two different formats, first will be a PDF file and the other will be a docx. file.

Don't forget to check out these helpful videos that Margaret left for us from her lesson! They're really helpful, so don't hesitate to take a look!