Lecture 3 - Chemical Reactions and Water in the Body

Enzymes: proteins that function as biological catalysts by...

- Lowering the activation energy necessary for a chemical reaction to start - Allowing the reaction to proceed multiple times as they are not used up by the reaction

Colloid Particle size: Appearance: Will particles settle out?: Will particles pass through selectively permeable membrane?: Examples:

1-100 nm Often cloudy No No Proteins in blood, Intracellular fluid, Milk protein, Gelatin

Water is what percentage of our body weight

50-75%

pH of a neutral solution

7.0 (equal amounts of H+ and OH-)

pH of blood range

7.35 to 7.45

Solution Particle size: Appearance: Will particles settle out?: Will particles pass through selectively permeable membrane?: Examples:

<1 nm Clear No Yes Glucose in blood, O2 in water, Saline solutions, sugar in coffee

Suspension Particle size: Appearance: Will particles settle out?: Will particles pass through selectively permeable membrane?: Examples:

>100 nm Cloudy-opaque Yes No Blood cells, Cornstarch in water, Fats in blood, Kaopectate

When two molecules exchange atoms or groups of atoms

AB+CD --> ABCD --> AC + BD

A proton donor (releases H+ ions) in water

Acid

Tendency of one substance to cling to another

Adhesion

What is an example of a synthesis reaction

Amino acids into a protein molecule

Energy storing synthesis reaction

Anabolism

A proton acceptor (accepts H+ ions)

Base

What temperature is optimum for human enzymes?

Body temperature

How does our body resist changes in pH

Buffers

Energy releasing decomposition reactions

Catabolism

Substances that temporarily bond to reactants, hold them in favorable position to react with each other, and may change the shapes of reactants in ways that make them more likely to react

Catalysts

Potential energy is stored in

Chemical bonds

Symbolizes the course of a chemical reaction

Chemical equation

A process in which a covalent or ionic bond is formed or broken

Chemical reaction

Most mixtures in our bodies consist of...

Chemicals dissolved or suspended in water

Tendency of like molecules to cling to each other

Cohesion

Reaction rates increase when the reactants are more

Concentrated

AB --> A + B is an example of

Decomposition reactions

Large molecule breaks down into two or more smaller ones

Decomposition reactions

Capacity to do work

Energy

What is required to form or break a bond

Energy

Proteins that function as biological catalysts

Enzymes

The pH scale measures the _______ in a solution

H+

Kinetic energy of molecular motion

Heat

Polar water molecules overpower the ionic bond in Na+ and Cl-forming _____________________ around each ion

Hydration spheres

What kind of bonds keep water molecules together

Hydrogen

Substances that dissolve in water

Hydrophilic

Substances that do not dissolve in water

Hydrophobic

Energy of motion; energy that is actively doing work

Kinetic energy

The sum of all chemical reactions of the body

Metabolism

Consist of substances physically blended but not chemically

Mixtures

Hydrophobic substances must be

Non-polarized, neutral, fat

What kind of bonds and v-shaped molecules give water a set of properties that account for its ability to support life

Polar bonds and V shaped molecules

Energy contained in an object because of its position or internal state

Potential energy

When a bond is broken energy is

Released

Reaction rates increase when temperature

Rises

Consists of particles of matter called the solute mixed with a more abundant substance (usually water) called the solvent

Solution

Ability to dissolve other chemicals

Solvency

What is an example of a decomposition reaction

Starch molecules into glucose molecules

A + B --> AB is an example of

Synthesis reaction

Two or more smaller molecules combine to form a larger one

Synthesis reactions

What are reaction rates affected by

Temperature and concentration

What is pH

The concentration of H+ ions in solution

Metabolic reactions depend on

The solvency of water

When hydrogen bonds inhibit temperature increases by inhibiting molecular motion

Thermal stability

What is considered the universal solvent

Water

Example of Adhesion

Watery serous fluid lining pleural and pericardial cavities

The more H+ ions the more

acidic

Name the characteristics of water

adhesion, cohesion, chemical reactivity, thermal stability, and solvency

The less H+ ions, the more

basic

What can pH disturbances cause

disrupt physiological functions and alter drug actions

Changes in pH and temperature alter or destroy the ability of the enzyme to bind to substrate

enzyme-substrate specificity

pH of a basic solution

greater than 7.0

What does molecular motion create

heat

What causes water to be cohesive

hydrogen bonds

pH of an acidic solution

less than 7.0

Basis for chemical reactions is

molecular motion and collisions

Where are the reactants located in a chemical reaction

on the left

Where are the products located in a chemical reaction

on the right

Enzymes vary in...

optimum pH

Factors that change enzyme shape

pH and temperature

A hydrophilic substance must be

polarized

A hydrogen ion is a

proton

What can deviations in normal pH range cause

tremors, paralysis, or death

What causes a reaction to occur

when molecules collide with enough force and the correct orientation