Unit 2 Biochemistry 

BASIC REVIEW:

• Three particles that make up an atom are:
  • protons
  • neutrons
  • electrons
• Isotopes are elements with different numbers of neutrons.
• An ion is an atom or molecule with a net electric charge due to the loss or gain of one or more electrons.
• A compound is composed of two or more separate elements; a mixture.
• A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms.
• The two main types of bonds are:
  • Ionic (transferred electrons)
  • Covalent (shared electrons)

WATER:

• Polarity = a property of movement where one side has a net negative charge and the other has a net positive charge.
• Cohesion = polarity that attracts a molecule to itself.
  • Ex: water beads
• Adhesion = polarity that allows for attraction to different substances.
  • Ex: meniscus in a GC
• Adhesion and cohesion both contribute to:
  • Surface tension (elastic like force existing in the surface of a body, especially a liquid, tending to minimize the area of the surface)
  • Capillary action (a force in trees and roots that helps water stick so it can move to the tops of plants)

In summary, the four main properties of water are:

1. Polar
2. Adhesive
3. Cohesive
4. Capillary action and surface tension

MIXTURES: SOLVENTS AND SOLUTIONS:

A mixture is when two or more are mixed together, not chemically bonded.

Ex: salt water

A solution is a mixture of two or more substances where the molecules are dissolved.

Ex: Blood

• Solute = the substance dissolved in the solution
• Solvent = the substance that does the dissolving in the solution
• Water is a universal solvent

Suspension is a mixture of water and non-dissolved material. Water’s movement keeps the particles suspended.

pH SCALE:

• Ranges from 0-14
• pH of acids ranges from 1-6
• pH of bases ranges from 8-14
• Neutral pH is 7

Buffers are bases or weak acids that react with strong acids to prevent sudden changes in pH.

MACROMOLECULES

Interchangeable names are: ORGANIC MOLECULES, and BIOLOGICAL MOLECULES.

Macromolecules are large molecules formed by polymerization.

In macromolecules, small molecules are called monomers. Monomers join together to create larger molecules called polymers.

All macromolecules contain oxygen, hydrogen, and carbon.

There are four different macromolecules:

• Carbohydrates
• Lipids
• Proteins
• Nucleic Acids

CARBOHYDRATES:

Function:

• Main source of immediate energy for cells
• Used for structure in plants (carbs)
• Cellulose makes plants rigid, found in the cell wall

Composed of:

• Carbon (C)
• Hydrogen (H)
• Oxygen (O)

Elements are in a 1:2:1 ratio.

Ring like structure.

Monomers are called monosaccharide. Simple sugars.

Ex: Glucose and fructose.

Polymers are called polysaccharide. Many sugars, complex carbs.

Ex: Glycogen, starch, and cellulose.

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LIPIDS:

Function:

• Energy storage (long term)
• makes membranes (waterproof coverings)
• Insulate organisms
• Non-polar (not soluble in water)

Subunits:

• Glycerol
• Fatty acids

Ex: Fats, oils, and waxes.

Types of Lipids:

• Saturated fatty acid: Solid, bad cholesterol, and straight structure
• Unsaturated fatty acid: Liquid, good cholesterol, and has kinks in structure

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PROTEINS:

Function:

• Structural: Hair, nails, bones
• Transport: Hemoglobin
• Movement: Muscles
• Defense: Antibodies

Cell functions are hormones and enzymes.

Subunits:

• Amino group
• Carboxyl group
• R group

Monomers are called amino acids.

Ex: Valine and serine

Polymers are called protein or polypeptides.

Ex: Collagen, actin/myosin

Held together by peptide bonds.

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NUCLEIC ACIDS:

Function:

• Store and transmit genetic information that is used to make proteins
• Protein synthesis

Composed of:

• Five carbon sugars
• Nitrogenous (nitrogen) base
• Phosphate group

Monomers are called nucleotides.

Ex: Adenine, thymine, guanine, cytosine, and uracil

Polymers are called nucleic acids or polynucleotide.

Ex: DNA, RNA

DECOMPOSITION:

Breaks molecules apart.

• AB → A + B

Hydrolysis is the breaking apart molecules due to the addition of water.

SYNTHESIS:

Combines elements/molecules.

• A + B → AB

Dehydration reactions are the creation of molecules by the removal of water.

Chemical reactions are a process that changes one set of chemicals into another set of chemicals.

Reactants are elements that start (or enter) the reaction.

Products are elements that leave the reaction.

reactants + reactants → products

Activation energy is the energy needed to start a reaction.

A catalyst is a substance that speeds up chemical reaction rates and lowers activation energy.

Enzymes are proteins that act as biological catalysts (speed up reactions)

A substrate is the reactants of the enzyme-catalyst reactions.

An enzyme-substrate complex works like a lock and key.

Enzymes can break down or build molecules.

Enzymes are not changed during chemical reactions.

Enzymes usually end in “ase”

pH, temperature and inhibitors all affect the performance of enzymes.

pH (or temperature) affects an enzyme by denaturing it. It changes the proteins structure (shape) and function.

Inhibitors prevent the substrate from reacting with the enzyme.

Proteins are made of amino acids.

Carbohydrates are made of polysaccharides.

Nucleic acids are made of nucleotides.

Nucleic acids have a nitrogen base.

Butter is an example of lipids.

RNA is an example of nucleic acids.

Glucose is an example of carbohydrates.

Enzymes are an example of proteins.

Proteins help to form hair, bone, and nails.

Lipids are non-polar.

Proteins speed up chemical reaction rates.

Nucleic acids help to code for proteins.

Proteins fight diseases.

Carbohydrates are the main source of energy.

The source of hereditary information comes from nucleic acids.

The main component of cell membranes are proteins.

Lipids store energy for the long term.

VOCAB:

Polarity A property of a molecule where one side has a net negative charge and the other side has a net positive charge.

Ionic bond When atoms are held together due to electrons being transferred.

Ion Positively or negatively charged atoms.

Covalent bond When atoms are held together due to sharing an electron pair.

Cohesion When a molecule bonds to another molecule of the same type.

Adhesion When a molecule bonds to another molecule of a different type.

Solution A mixture of two or more substances that are evenly distributed.

Solute The component of a solution that is dissolved, dissociated, or broken apart.

Solvent The component of a solution that causes another to dissolve, dissociate or break apart.

Suspension A mixture of water and non-dissolved material.

Acid A substance that increases the hydrogen ion concentration in a solution.

Base A substance that reduces the hydrogen ion concentration in a solution.

Buffer Weak acids/bases that react with strong acids/bases to prevent sudden changes in pH.

Monomer The subunit or building block of a polymer.

Polymer A large molecule consisting of many identical or similar monomers linked together.

Carbohydrate A polymer that is the main source of quick energy for organisms.  A sugar.

Monosaccharide Single sugar molecules.

Lipid A family of molecules such as fats, phospholipids, & steroids, that are insoluble in water.

Nucleic Acid Polymers, such as DNA or RNA, that stores hereditary information and act as the blueprint for proteins and cellular activities.

Nucleotide The building blocks of nucleic acids.

Protein A three-dimensional polymer that has many biological functions.

Amino acid The building blocks of proteins.

Chemical Reaction A process that changes one set of molecules into another.

Reactant A starting material in a chemical reaction.

Product An ending material in a chemical reaction.

Activation energy The energy needed to start a chemical reaction.

Catalyst A substance that speeds up a chemical reaction by lowering the activation energy.

Enzyme A specialized protein that acts as a biological catalyst.

Substrate A reactant that binds to an enzyme and undergoes a chemical reaction.

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