Metabolism

What You Need to Know 9-11 LS1F All of the functions of the cell are based on chemical reactions. Food molecules are broken down to provide the energy and the chemical constituents needed to synthesize other molecules. Breakdown and synthesis are made possible by proteins called enzymes. Some of these enzymes enable the cell to store energy in special chemicals, such as ATP, that are needed to drive the many other chemical reactions in a cell.

Synthesis

Breakdown

Synthesis

Breakdown

Synthesis happens in plants and animals They are needed for the synthesis of glucose from Carbon Dioxide in photo-synthesis

Living Systems Breakdown molecules Starch Glucose

How Glucose is used For immediate energy ATP or Stored in liver as Glycogen This is synthesis in the digestive process

All the chemical activities and changes that take place in a cell or an organism are collectively know as its Metabolism

What’s so special about ATP? Cellular Respiration is a Breakdown reactions that releases energy Synthesis reactions require energy: an example is making muscles from amino acids that were originally in your food. The LINK between the two: ATP from breakdown reactions becomes the source of energy for reactions that synthesize, or build up (growth, repair, all life processes) ATP makes sure that energy from breaking down molecules is not wasted.

Without ATP, Organisms die

Four Biosynthetic Reactions Building proteins Making glucose in photosynthesis Growth Repairing cells and tissues Finish from SWIFT site

Carbohydrates are how we get our energy How do people who eat the Atkins' diet, or other protein based diets get energy if they are eating very little carbohydrates?

Enzymes Help synthesize new molecules Help breakdown other molecules

Organisms need many types of macromolecules What’s a macromolecule? It’s a big molecule made from many small molecules. Proteins, carbohydrates, and lipids are macromolecules

Organisms must synthesize amino acids, lipids and other molecules from the matter that the organism takes in

Other molecules besides glucose can be used in cellular respiration Fats can be broken down to fatty acids and glycerol. These are long chains of carbon and hydrogen. Glycerol can be made into a molecule to be used in Glycolysis to enter cellular respiration Proteins are broken down to amino acids. If the nitrogen is removed from these, they can also go through the Krebs cycle.

We can use Proteins for Energy It’s not very efficient The most efficient way is to use it as a source of amino acids to build new proteins.

If a body is starving In Anorexia nervosa for example, there aren’t enough proteins, fats or carbohydrates in the person’s diet They can’t assemble the macromolecules they need The muscles of the person’s body are consumed for the fuel they need