Biology Chapter 9

Food provides living things with chemical building blocks, it serves as a source of raw materials for the body, and as a source of energy.

A calorie is the amount of energy needed to raise the temperature of one gram of water one degree Celcius

A Calorie is equal to 1,000 calories. It is a kilocalorie and is used on food labels.

Glycolysis is a pathway that begins the process of releasing energy from carbohydrates. In glycolysis, 2 molecules of ATP are used to make 4 ATP molecules, one of the reactions removes 4 high-energy electrons and gives it to the electron carrier NAD+, making it NADH, and a glucose molecule (6 carbon atoms) is broken down into 2 pyruvic acid molecules (3 carbon atoms a piece.

The presence of oxygen determines the pathway taken after glycolysis. If glycolysis occurs in the presence of oxygen it leads to two other pathways that realease much energy. If glycolysis occurs without the presence of oxygen then it is followed by a different pathway. The pathways it leads to when in the presence of oxygen is the electron transport chain and the Krebs cycle (cell respiration). The pathway it leads to when not in the presence of oxygen is fermentation, specifically lactic acid fermentation in animals.

Glycolysis takes place in the cytoplasm of a cell, outside of the mitochondrion.

Glycolysis breaks down 1 molecule of glucose into 2 molecules of pyruvic acid.

The products of glycolysis are 4 ATP (net gain of 2 ATP), 2 pyruvic acid, and 2 NADH.

The two main types of fermentation are lactic acid fermentation and alcoholic fermentation. Both types of fermentation use pyruvic acid and NADH, both produce NAD+, and are anaerobic, and they both release energy from food molecules by producing ATP. Lactic acid fermentation occurs in the muscles and in unicellular organisms, produces lactic acid, is used when intensely exercising when not enough oxygen is able to be supplied, causes cramps, and is used in food products such as cheese, yogurt, buttermilk, sour cream, pickles, sauerkraut, and kimchi. Alcoholic fermentation produces ethyl alcohol and carbon dioxide, is used by bakers for raising bread, and is used by the liquor industry for adult beverages.

Bacteria use lactic acid fermentation, which is used to make food products like cheese, yogurt, buttermilk, sour cream, pickles, sauerkraut, and kimchi. Alcoholic fermentation is used to make bread, because it produces carbon dioxide, and in the liquor industry for adult beverages, because it produces alcohol.

The function of NAD+ is similar to that of NADP+ because they both are electron carries that accept high energy electrons and are converted and used in electron transport chains.

...

We produced more CO2 after we exercised because were using more oxygen and cellular respiration occured faster, so it produced more carbon dioxide.

...

An aerobic processes are processes that require the presence of oxygen and anaerobic processes are processes that don't require the presence of oxygen.

Both lactic acid and alcoholic fermentation are anaerobic along with glycolysis. Cellular respiration (including the Krebs cycle and the electron transport chain) requires oxygen.

During the Krebs cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extraction molecules. In the Krebs cycle, pyruvic acid produced by glycolysis enters the mitochondrion, then one carbon atom from pyruvic acid becomes part of a carbon dioxide molecule and the other two carbon atoms join coenzyme A to form acetyl-CoA. A 6-carbon molecule called citric acid is produced from the addition of a 2-carbon acetyl group to a 4-carbon molecule. During the energy extraction phase, energy is extracted when citric acid is broken down into simpler forms (a 4-carbon and a 5-carbon), more molecules of carbon dioxide are produces and electrons join NAD+ and FAD, NADH and FADH2 form and one molecule of ATP is generated.

The Krebs cycle is also known as the citric acid cycle because citric acid is formed and then broken down producing energy.

The Krebs cycle occurs in the mitochondrion.

The electron transport chain uses the high-eneregy electrons from the Krebs cycle to convert ADP into ATP.

The purpose of hydrogen ion movement in the electron transport chain is to spin ATP synthase as it passes through the chain which makes ADP into ATP.

ATP synthase is used to combine electrons with H+ ions and exygen to produse water and to convert ADP into ATP.

Glycolysis produces 4 ATP with a net gain of 2 ATP and cellular respiration uses no ATP and produces about 36 ATP, so cellular respiration produces a net gain of 34 molecules of ATP more than glycolysis.

In the entire breakdown of glucose, about 38 molecules of ATP are produced. About 38% of the total energy of glucose is converted to ATP and about 62% is released as heat.

Runners breath heavily after a race because lactic acid has built up in muscles and extra oxygen is need to rid the body of the lactic acid. The extra oxygen that has been needed builds up a debt that but be repaid.

Fermentation and cellular respiration both breakdown glucose for energy, use pyruvic acid, and produce carbon dioxide, but fermentation does not produce as much ATP, does not require oxygen, and produces lactic acid or ethyl alcohol. Cellular respiration produces a lot of ATP, requires oxygen, and produces water.

Photosynthesis is when producers use the sunlight to produce high-energy sugars and cellular respiration is what consumers used to release the energy stored in the chemical bonds of glucose. Photosynthesis occurs in the chloroplasts of producers, while cellular respiration occurs in the mitochondria of producers and consumers. The reactants of photosynthesis are carbon dioxide and water, but the products of cellular respiration are carbon dioxide, water, and energy. The reactants of cellular respiration are glucose and oxygen, but the products of photosynthesis are glucose and oxygen. Both photosynthesis and cellular respiration occur in more than one step and involve an electron transport chain, electron carriers, ATP, ADP, and ATP synthase. The equation for cellular respiration is basically the same as the equation for photosynthesis reversed.