Energy in a Cell

Cells need energy to do work. Cells use chemical energy, which is stored in the chemical bonds of food (glucose, C6H12O6) Energy is released when these bonds are broken

Problem Food molecules can’t supply energy directly to cells. It must first be transferred to molecules that can release it when needed ATP molecules!

What is ATP? ATP = Adenosine Triphosphate ATP is made of 3 parts: 1.A base named adenine 2.A sugar named ribose 3.3 phosphate groups Adenosine

A – P ~ P ~ P ~ represents a high energy bond; it is easy broken; when borken, energy is released ATP – P  ADP or adenosine diphosphate ADP – P  AMP or adenosine monophosphate

ATP-ADP cycle When ATP becomes ADP by removing a P, energy is released to do cell work. When ADP becomes ATP by adding a P, Energy is stored. Energy is stored in ATP molecules during cellular respiration.

Cellular Respiration

Cellular Respiration is the process of breaking chemical bonds of food molecules to release energy. Food = glucose (sugar) C6H12O6

Cellular Respiration It’s a 3 part process: 1.glycolysis, 2.krebs cycle 3.electron transport chain **Steps 2 and 3 only happen if there is oxygen present

Cellular Respiration Cellular Respiration takes food energy and converts it into ATP (an energy storage molecule) so our bodies can do work.

Cellular Respiration Cellular Respiration occurs in the cell’s mitochondria

Cellular Respiration 1.glycolysis= glucose  pyruvate (pyruvate is broken down into acetyl co-a 2.acetyl co-A  Krebs cycle where energy- rich molecules are released 3.NADH and FADH enter into the ETC where a ATP is formed from ADP.

Total of 36 ATP created from one molecule of glucose!

PTS and CR foldable Get a sheet of paper!

On the Outside… PHOTOSYNTHESIS CELLULAR RESPIRATION

On the inside:

FERMENTATION: Anaerobic Respiration

If no oxygen is available, cells can obtain energy through the process of anaerobic respiration. A common anaerobic process is fermentation. Fermentation is not an efficient process and results in the formation of far fewer ATP molecules than aerobic respiration. There are two primary fermentation processes: 1.Lactic Acid Fermentation 2.Alcoholic Fermentation

Lactic acid fermentation occurs when oxygen is not available. For example, in muscle tissues during rapid and vigorous exercise, muscle cells may be depleted of oxygen. They then switch from respiration to fermentation.

The pyruvic acid formed during glycolysis is broken down to lactic acid and energy is released (which is used to form ATP). Glucose → Pyruvic acid → Lactic acid + energy

The process of lactic acid fermentation replaces the process of aerobic respiration so that the cell can have a continual source of energy, even in the absence of oxygen. However this shift is only temporary and cells need oxygen for sustained activity.

Lactic acid that builds up in the muscle tissue causes a burning, painful sensation.

Alcohol fermentation occurs in yeasts and some bacteria. Pyruvic acid formed during glycolysis is broken down to produce alcohol and carbon dioxide and is released (which is used to form ATP).

Glucose → Pyruvic acid → alcohol + carbon dioxide + energy

Fermentation is used in food production. –Yogurt- Soy Sauce –Cheese- Vinegar –Bread- Olives/Pickles –Beer/ Meade- Wine/ Ale –Sauerkraut- Malt

Catabolism of Organic Compounds