Chemistry of Life, Biology

-Cells make macromolecules by bonding smaller molecules  togethes, into chains called polymers

- Four types of macromolecules are carbs, proteins,lipids and nucleic acids. 

Basic properties of each Biological Macromolecule: 

1. Monosaccharide: the smallest type of carb molecule; 2 of the most common are glucose and fructose. These are important energy sources for cells and can help build acids. (can be stored)

- the shape of a molecule determines how it functions and reacts within a cell

-Sugar molecules are made up of carbon, hydrogen, and oxygen. Backbone of a sugar molecule is a hydrocarbon. 

2) Disaccharides: 2 of hydrocarbons. Both are classified as simple carbs. Examples: table sugar, maltose

 3) Polysaccharides: made up of monosaccharides.

Glucose made polysaccharides: 

——Starch: formed by plants to store glucose. Animals

break down starch into individual glucose molecules which

make starch an important food source.

——Cellulose: strong material that is the primary structural component of plants. Cellulose in the food we eat is a dietary fiber that regulates digestion.

——Glycogen: animals and fungi use  it to store glucose from their food. Athletic endurance is related to the amount of glycogen you have stored (glycogens=energy reserve)

——Chitin: has amino groups (NH2) bonded to glucose. Found in exoskeletons of arthropods like crab and spiders. Anything made of chitin can't be digested by animals.

Lipids: macromolecule made of mostly carbon and  hydrogen atoms; ex: fats, steroids, oils. Lipids are not polymers

Types of lipids:

1. Fats: made of C, H, O; Also called tryglycerides as it is made of 1 glycerol and 3 fatty acids. Fats are stored in fat deposits which serve as stored energy. Fats under the skin also give insulation; fats around organs help protect (one gram of fat= 38 kj of energy)

2. Phospholipids: 2 fatty acids and one phosphate group bonded to the glycerol molecule. That is why these molecules have a  hydrophobic and hydrophilic end.

 3. Steroids: macromolecules in this category all share a similar 4 linked carbon atom structure. Cholestrol is the abundant steroid and is the starting material for other steroids like male and female hormones

Proteins: made of amino acids, needed for cells to grow and repair. There are 20 different amino acids that share the same basic structure. The number and arrangement of amino acids in the chain determines the properties and functions of the protein.

- As Amino acids bond together to form a large protein molecule, it naturally twists into its unique shape. One thing that determines the natural shape of a protein is the side chains of an amino acid.

Structure of an Amino Acid:

1. Amino group: made of 2 H atoms, each bonded with a Single covalent bond to a nitrogen atom. Nitrogen atom  is attached to the central Carbon atom by a covalent bond.

 2. Carboxylic Acid Group: made of a Carbon atom, 2 oxygen atoms, and a H atom. It’s bonded to the central Carbon atom.

3. Side chain: only part of the molecular structure that varies between the 20 Amino acids that can make a protein. Attached to the central Carbon atom by a bond.

4. Central Carbon Atom: bonds to each section of the amino acid w/ a single covalent bond

 Functions of Proteins:

1) Antibodies: help defend against invaders

2) Contractile proteins: responsible for the movement of muscles (ex: myosin, actin) 

3) Hormonal Proteins: messenger proteins that help coordinate bodily activities (ex: insulin, oxytocin)

4) Transport proteins: proteins that move molecules (ex:hemoglobin)  

5) Structural proteins: provide protection or support like hair or feathers (ex: collagen and elastin)

6) Enzymes: speed up reactions by decreasing the energy needed for the reaction to occur (ex: lactase/pepsin)

Functions of Enzymes: biological catalysts

—are sensitive to temp. and PH levels, so only work in certain conditions

— Enzyme Inhibitors: substances that bind to an enzyme and change its shape or block its ability to interact w/ the chemical reaction

Functions of Nucleic Acids:

1. carry genetic info needed to build Organisms

2. DNA and RNA