1. Organic Molecules
SC Biology Standard- B Summarize how the structures of organic molecules are relative to their caloric value and the function of proteins, carbohydrates and fats in the human body. B2.8- Explain factors that affect the rates of biochemical reactions (pH, temperature and enzymes.

2. Organic Molecules:
All organisms are made of organic molecules- which contain carbon
Most organic molecules are made of smaller units bonded together to form larger molecules
ENERGY is stored in the bonds that link these units together- varies with type of molecule formed
This energy = the caloric value

3. Continued:
Proteins, Carbohydrates and fats/lipids are 3 organic molecules with different structures and different caloric values based upon those structures.

4. Proteins: Composed of chains of amino acids
Amino acids are composed of carbon, hydrogen, oxygen and nitrogen
20 different amino acids that chemically bond to make different proteins.
12 of these are made in the body, the rest must be consumed from foods such as nuts, beans or meat.
Can be used for energy but only if no carbs or lipids are available

5. Carbohydrates: Sugars and Starches
Composed of carbon, hydrogen and oxygen
Basic carbs are simple sugars- monosaccharides such as glucose
Main source of energy for the cell
When carbs are consumed, process of digestion breaks the bonds between larger carbohydrate molecules so simple sugars can be absorbed

6. Carbs continued:
The bloodstream carries simple sugars throughout the body where they cross into the cell across the cell membrane
Used as fuel for cellular respiration which releases energy as ATP
The caloric value of carbs is dependent upon the number of carbon-hydrogen bonds.
If an organism consumes more carbs than needed for energy requirements, then it is converted and stored as fat.

7. Lipids/ Fats:
Composed of carbon, hydrogen and small quantities of oxygen
Made of two main molecules- glycerol and fatty acids so structurally different from carbohydrates
Fats/lipids have more carbon-hydrogen bonds than carbs
Source of energy when carbs are scarce, but accumulates when plenty of carbs

8. Fats/lipids continued:
When fats are consumed- molecules are broken down and absorbed into the bloodstream
Then blood carries fatty acids and glycerol molecules throughout the body where they enter the cell
Stored for later use or as fuel for cellular respiration if no carbs are available
Cellular respiration releases energy held in the chemical bonds of glycerol and fatty acids

9. More:
Due to the structure and number of C-H bonds, fats contain more energy (ATP) per gram which explains why fats have a higher caloric value

10. Functions:
Proteins are involved in almost every function of the human body
More important as Building blocks than energy. Only energy if there is a shortage of carbs or lipids
Used as support for connective tissue and keratin for hair and nails
Transport proteins transport many substances throughout the body

11. Function of Proteins continued:
Hormone proteins coordinate activities such as insulin
Contractile proteins control movements such as muscle movement
Enzymes proteins accelerate the speed of chemical reactions such as digestive enzymes

12. Function of Carbohydrates
Important source of energy
Primary source of energy for cellular respiration
Some carbs are used for structural material in plants= cellulose

13. Function of lipids: Used for energy when carbs are scarce
Provide long term energy storage, cushion vital organs and insulation for the body
Major component of cell membrane and one of the raw materials necessary for production of vitamins and hormones

14. Enzymes & factors that affect the rates of biochemical reactions:
Chemical reactions occur when reactants collide with sufficient energy to react = activation energy
Sometimes CR absorbs energy to start = endothermic reaction
Sometimes CR release energy = exothermic
Changes in temp can affect a CR

15. More:
pH- measures the acidity of a solution. Most organisms have a specific range that they exist in.
A small change in pH can disrupt cell processes.
Buffers within organisms are used to regulate pH so homeostasis can be maintained

16. Still more….
Catalyst is a substance that changes the rate of a CR. They work by lowering the amount of activation energy needed to start a reaction. It is not consumed or used up during a CR. They can be used again and again.
Enzymes act as a catalyst in living organisms.

17. Enzymes:
Enzymes are specific- they only have “one job” and can only do that one job.
Are involved in many of the CR necessary for organisms to live, reproduce, & grow- such as digestion, respiration, reproduction, movement and cell regulation
Can be altered by temp and pH

18. The pH Scale