Biology: 3.14 glycolysis and fermentation

The process of cellular respiration begins with glycolysis

A series of chemical reactions take place during cellular respiration to transfer the energy stored in the chemical bonds of glucose to the energy stored in the chemical bonds of ATP.

Types of fermentation

Alcoholic fermentation and lactic acid fermentation

Many food products are made with alcoholic fermentation, which produces ethanol.

Alcoholic fermentation= a type of anaerobic respiration that is responsible for the rising of the dough in pizza and bread. Carbon dioxide is one of the products of alcoholic fermentation. It's the gas that causes the dough to rise. One of the products is ethanol, a kind of simple alcohol molecule. Alcoholic fermentation is the basis for the production of alcoholic beverages such as beer and wine.

Cellular respiration takes place in 3 main stages

Cellular respiration is one process by which cells transfer the energy in glucose to the energy in ATP. Cellular respiration is also called aerobic respiration because it takes place in the presence of oxygen.

NAD and FADH are

Electron carriers

After glycolysis, the 2 molecules of pyruvic acid can take one of several energy-producing pathways

If the cell is part of a multi cell organism and oxygen is present, the pyruvic acid may move into the mitochondria of the cell where the Krebs cycle and the electron transport chain produce a lot of ATP. it's important to know that glycolysis has a net gain of 2 ATP molecules. (Meaning glycolysis generates a small amount of energy) Some organisms and their energy needs are so small that they don't need the large amounts of energy produced in aerobic respiration. For many simple organisms, the energy stored in those two molecules of ATP can fuel all of their needs to survive. (In that case rather than continuing on to the Krebs cycle, the pyruvic acid molecules may enter a different pathway called anaerobic respiration of fermentation.

Electron carriers play a role in cellular respiration

In cellular respiration NADH and NAD+ donate and accept electrons, but you'll see that these molecules play an important role in transferring energy during chemical reactions

Aerobic

Using oxygen; when applied to organisms or cells or tissues, it means they use oxygen to get and use the energy from organic molecules

Glycolysis breaks down glucose into pyruvic acid with a net gain of 2 ATP molecules. Pyruvic acid then may enter into either cellular aerobic respiration or anaerobic respiration.

Cellular respiration is one process by which cells transfer energy in glucose to the energy in ATP. In its first stage, glycolysis, the chemical energy in glucose is transferred to pyruvic acid molecules. This process generates a small amount of ATP. FOLLOWING glycolysis pyruvic acid molecules enter into either aerobic respiration or anaerobic respiration, depending on whether oxygen is present or can be used.

ATP is the end product of cellular respiration, but ATP also powers certain processes during cellular respiration

Every part of your body needs the energy carried in ATP to work properly. (Blinking, scratching your head are things that require ATP) ATP Also provides energy for cells to conduct internal functions such as growth, repair and maintenance and reproduction. Cells don't share ATP, and ATP doesn't leave a cell once it's produced. So each cell has to produce its own ATP. ATP carries energy and releases energy when it becomes ADP

Glycolysis begins and ends with specific molecules.

For glycolysis to take place 1 glucose molecule, 2 ATP molecule and 2 NAD+ molecules must be present. Glycolysis produces 2 pyruvic acid molecules, 4 ATP molecules (2net) and 2 NADH molecules.

What is glycolysis?

Lysis means something is being split or broken into smaller pieces. Glycolysis is the splitting of glucose molecules, and it takes place in the cytosol of cells.

Electron carrier

Molecules such as FADH2 and NADH that carry electrons from one part of a chemical process to another

Anaerobic

Not using oxygen; when applied to organisms cells and tissues, it means they don't use oxygen as part of the process of obtaining energy from glucose

Glycolysis.

The 1st stage of cellular respiration in which glucose molecules are broken down to produce pyruvic acid.

Fermentation

The breakdown of pyruvic acid in the absence of oxygen

Glucose is the ?

The critical molecule in the generation of energy that cells can use.

Glycolysis takes place in several stages

The main end product of glycolysis is 2 molecules or pyruvic acid. At the end 2 ATP molecules and 2 NADH molecules are made, meaning that during glycolysis, some energy is used and some electrons are gained.

Role of fermentation

The role is to supply NAD+ molecules to the cell o keep the process of glycolysis going. It's a feedback loop. Fermentation uses the 2 pyruvic acid molecules and 2 NADH molecules to regenerate NAD+. The NAD+ then feeds back into another round of glycolysis

Lactic acid fermentation sometimes takes place in muscle cells and produces lactic acid

When muscle cells run out of oxygen, they resort to lactic acid fermentation for a supply of energy. When lactic acid accumulates in muscles, it can cause soreness. Eventually the blood carries the lactic acid away, which is why the soreness doesn't last. In lactic acid fermentation, pyruvic acid is converted into lactic acid. NADH donates electrons and becomes NAD+ which is supplied back for another round of glycolysis

Anaerobic respiration generates NAD+ for glycolysis to continue

When oxygen is not present or isn't needed, the pyruvic acid molecules produced during glycolysis enter an anaerobic respiration pathway. This pathway is also called fermentation