Chapter 2&4 Molecular Interactions and Cell Metabolism

Monosaccharides

Simple sugars, used for energy, ex. Glucose

Disaccharides

Glucose bonded to another carbohydrate, broken down into monosaccharides, used for energy

Carbohydrates

Rich in carbon, hydrogen, and oxygen, 5-6 carbons per

Polysaccharide

Large polymers of glucose

Glycogen

The major polysaccharide used in mammalian/human tissues, Used for energy storage in. Muscle and liver after meals, Many glucose molecules bonded together

Lipids

Fats and oils, varied structures

Fatty Acids

long hyrdocarbon chais with -COOH group at the end, Used for energy,

Mono-, Di-, and Triglycerides

1,2, or 3 fatty acides bonded to glycerol, Used for energy storage

Steroids

Lipid-like chemical messengers derived form cholesterol Used for cell communication

Phospholipids

Major component of cell membranes

Has 2 fatty acids, glycerol, phosphate head

Nucleotides

As polymers- form DNA and RNA sequences, it is genetic code

As monomers- form energy capture/transfer molecules and signaling molecules Ex. ATP, ADP, AMP(energy capture/transfer), NAD,FAD(energy capture/transfer), cAMP(cell signaling)

Proteins

Polymers of amino acids, bonded together by peptide bonds

Amino Acids

Contains: Amino group(-NH2), Alpha carbon bound to an “R” group(determines identity of amino acid), 20 different aa’s used in humans(each aa has different R group

Substrate

The molecules that a protein interacts with.

Proteins are selective in what _____ they interact with

Specificity

The ability of a protein to bind/interact with a molecule or group of similar-shaped molecules

Affinity

Degree to which a protein is attracted tp a a specific substrate

Energy

The capacity to do work, usually seen in form of calories or kilojoules

Mechanical work

movement and muscle action

Chemical work

Involves breakdown synthesis of cellular molecules

Transport work

Involving “active transport” of substances across membranes

Potential energy

Stored energy ex. A car parked at top of hill, a molecule in the low end of a concentration gradient, electron position that form chemical bonds

Kinetic energy

When potential energy is released it is transformed into this; "energy of motion“

Ex. Car rolling down a hill, molecule moving down concentration gradient, chemical bond breaking

First law of thermodynamics

The total amount of energy in a closed system is constant; energy cannot be created nor destroyed merely converted from one to the other

Second Law of Thermodynamics

Natural spontaneous processes from one state of order to a state of disorder (entropy)

Ex. Decreasing entropy, maintaining order, requires energy

Reaction Rate

The rate if disappearance of reactant or the rate of appearance of products

Free energy

The potential energy stored in chemical bonds (kcal/mol)

Activation energy (Ea)

The initial input of energy requires to bring reactant position to react

Lower Ea

Lower- required means the reaction is more likely to occur spontaneously (faster rate)

Higher Ea

Required means the reaction is less likely to occur spontaneously (slower rate)

Exergonic reactions

Releases energy so the free energy of the products is lower than the reactants

-to do work

-dissipated as heat

Endergonic reactions

Required a net input of energy and the free energy of the products is heighten than that of the reactants

-energy is stored in bonds during syntheses reactions

ATP + H2O > ADP + Pi + ENERGY

ATPACE

Hydrolysis of water

What effects rate of chemical reactions?

Temp, pH, Conc. Of enzyme, Conc, of substrate

Cofactor/ Coenzyme

These attach to enzymes that require a separate molecule to form the active site and allow binding.

Allosteric activation

When a modulator binds to the protein at a different region than the active site. This activator allows the active site to be more accessible

Allosteric inhibition

When a modulator binds to the protein at a different region than the active site to inactivate the active site.

Competitive Inhibition

When a modulator ‘competes’ w/ a substrate for the same active site. The modulator will not actually affect anything the merely block the active site.

Four classifications of enzymatic reactions

Oxidation-Reduction, Hydrolysis-Dehydration, Addition-Subtraction-Exchange, Ligation

Oxidation-Reduction (redox)

Involve the transfer of protons or electrons, often involve electron carrier nucleotides (NAD/NADH, FAD/FADH2)

OIL RIG (Oxidation loses, Reduction gains)

Dehydration Reaction

Look for smaller molecules turning into larger as well as a formation of a a H2O (dehydration synthesis)

Ex. Formations of sucrose from glucose and fructose

Hydrolysis Reaction

A substrate is split into 2+ products by adding water

Ex. Removal of an amino acid from the end of a peptide or protein

Addition-Subtraction-Exchange Reaction

Involve movement of functional groups to or from 1+ reactants

Ligation Reaction

Two molecules joined using enzymes known as synthetases or ligases. Requires energy (usually ATP)

Ex. Acetyl coenzyme a is formed by mooing in acetyl group w/