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cell resperation

Page history last edited by Emilie Held 14 years, 4 months ago

All this info should be on the existing pages. Nothing here needs its own page. Do not edit this page. 11/20   Mr F

 

Cell Resperation

 

Equation:

C6H12O6 + O2 --> CO2 + H2O (+ Energy)

Notice that the cell resperation equation is the exact opposite of the photosynthesis by plants

 

O ----- P ----- P ------ P

ATP Molecule -- triphosphate ---------- making and breaking this bond produces energy

 

Each cell uses 1-2 Billion ATP mol/min

Humans have 100 trillion cells in thier body that are all working at the same time.

 

ATP gets its energy from the bonds of glucose molecules. After breaking the bonds the energy is transfered to the bonds of the ATP molecules which can then be transported anywhere in the body and used.

 

CELL RESPIRATION OCCURS IN 3 PHASES:

As mentioned in the previous page on ATP, the process of respiration is split into 3 distinct areas that occur at different parts of the cell. Respiration involves the oxidation of foodstuff (i.e. glucose

) in order to create ATP.

Respiration can occur with or without oxygen, aerobic and

anaerobic respiration respectively.

 

Glycolysis

Glycolysis occurs in the cytoplasm of a cell where a 6 carbon glucose molecule (the broken down food that you ate earlier) is broken down by enzymes into a 3 carbon

pyruvic acid.

 

The execution of this process requires 2 ATP, and produces a net gain of 2 ATP.

 

The enzymes involved remove hydrogen from the glucose (oxidation) where they take these hydrogen atoms to the cytochrome system, explained soon.

In anaerobic respiration, this is where the process ends, glucose is split into 2 molecules of pyruvic acid. When oxygen is present, pyruvic is broken down into other carbon compounds in the Kreb's Cycle. When it is not present, the pyruvic acid is broken down into lactic acid (or carbon dioxide and ethanol).

 

The Kreb's Cycle

When oxygen is present, respiration can harness more ATP from a single unit of glucose. The pyruvic acid from the glycolysis stage diffuses into a cell organelle called a mitochondrion (pl.

mitochondria). These mitochondria are sausage shaped structures that host a large surface area for the respiration to occur on.

The pyruvic acid is then subject to more enzymes which break it down into a 2 carbon compound, as seen below. The diagram illustrates the

Kreb's cycle, consisting of three main actions

  • The carbon element is in an infinite cycle where the 2 carbon compound derived from pyruvic acid binds with the 4 carbon compound that is always present in the cycle.
  • CO2 is released, where the oxygen that is present in aerobic respiration combines with carbon from the carbon compounds which is released as CO2. Hence the need for animals to breath out and expel this CO2.
  • Enzymes oxidize the carbon compounds and transport the hydrogen atoms to the cytochrome system.

 

Diagram of the Kreb's Cycle, part of the respiration process

 

The Cytochrome System

The cytochrome system, also known as the hydrogen carrier system (or the electron transport system) are where the reduced hydrogen carriers transport hydrogen atoms from the glycolysis and Kreb's cycle stages. The cytochrome system is found in the many

cristae of mitochondria, which are tiny stalked particles found on its outer layer.

 

The system contains many 'hydrogen acceptors' which hydrogen can be added to. By following the path of a hydrogen atom, we can see how the cytochrome system works:

  • Some coenzymes from earlier stages (we shall call these A) are transferred to the next coenzymes (refer to them as B).
  • B is then oxidised, therefore the coenzyme releases the hydrogen and energy is made available.
  • The released hydrogen atom binds with 2 oxygen atoms (oxygen is available in aerobic respiration) which produces water, a by-product of respiration.

 

The diagram illustrates this flow of hydrogen within the cytochrome system and how energy is made available by the flow of these atoms. The green circles illustrate where energy is made available via oxidation.

 

The Cytochrome System - Hydrogen Carriers

 

Overall their is a gain of 38 ATP from one molecule of glucose in aerobic respiration. The food that we eat provides glucose required in respiration. In plants, energy is also acquired via respiration, but the mechanism of delivering glucose to the respiration process is a little different.

Photosynthesis is the process that plants undertake to create organic materials from carbon dioxide and water, with the help of sunlight- all of which is investigated on the next page of the tutorial.

 

Cellular respiration is carried out by every cell in both plants and animals and is essential for daily living. It does not occur at any set time, and, at the same point in time, Neighboring cells may be involved in different stages of cellular respiration. Cellular respiration is an exergonic reaction, which means it produces energy. It is also a catabolic process - it breaks down polymers into smaller, more manageable pieces. The ultimate goal of cellular respiration is to take carbohydrates, disassemble them into glucose molecules, and then use this glucose to produce energy-rich ATP molecules. The general equation for cellular respiration is: one glucose molecule plus six oxygen molecules produces six carbon dioxide molecules, six water molecules, and approximately 36-38 molecules of ATP.

http://207.239.98.140/upperschool/science/Classes/AllBiology/bio/biotext/biowilson/Main%20Info/Ch%208%20Cell%20Energy/resp_summary.jpe

 

 

 

 

 

  Photosynthesis Cell Respiration
Function store energy in the bongs of glucose to break the bonds of glucose and release it in ATP
Location Chloroplasts Mitochondria
Reactants CO2 and H2O glucose and oxygen
Products Glucose and oxygen CO2 and H2O
Equation CO2 + H2O --> C6 H12 O6 + O2

C6 H12 O6  + O2   --> H20 + CO2  

 

 

 

 

Misconceptions = plants are solar powered and do not need to burn fuel to get energy = WRONG!!

 

All eukaryotes including plants and algae use the organic products of photosynthesis to perform celluar respiration.

 

 

Mitochondria Structure:

- double membrane, inner membrane folded to increase suface area, glycolysis -> cytoplasm, kerbs cycle -> matrix, etc. -> membrane

 

 

 

Here's a quick video that explains the process of cellular respiration, including the glycolysis, the kreb's cycle and etc stages. This video provides the "big picture" on cellular respiration.

YouTube plugin error  

 

http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20101/bio%20101%20lectures/Cellular%20Respiration/cellular.htm

This link describes the complete process of cell resperation

 

http://www.youtube.com/watch?v=hxTed-lTe7g

*This is a creative way to explain cellular repiration! It's easy to remember and is the perfect song to help you remember the process of cellular repiration.

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