The Chemistry of Life

A substance that _____ is considered to be a chemical compound.

contains at least two different elements

An ionic bond is formed when

an anion meets a cation

The ionization of a sodium atom to produce Na+ is an example of

oxidation

The weakest and most temporary of the following chemical bonds are

hydrogen bonds

A substance capable of dissolving freely in water is

hydrophilic

A carboxyl group is symbolized

- COOH

The only polysaccharide synthesized in the human body is

glycogen

The arrangement of a polypeptide into fibrous or globular shape is called its

tertiary structure

Which of the following functions is more characteristic of carbohydrates than of proteins?

energy storage

The feature that most distinguishes a lipid from a carbohydrate is that a lipid has _____

a lower ratio of oxygen to hydrogen

When an atom gives up an electron and acquires a positive charge, it is called a/an _____

cation

Dietary antioxidants are important because they neutralize _____

free radicals

Any substance that increases the rate of a reaction without being consumed by its a/an _____. In the human body, _____ serve this function.

catalyst, enzymes

All the synthesis reactions in the body form a division of metabolism called _____.

anabolism

A chemical reaction that joins two organic molecules into a larger one and produces water as a by-product is called _____.

dehydration synthesis

The suffix _____ denotes a sugar, whereas the suffix _____ denotes an enzyme.

- ose, - ase

The amphipathic lipids of cell membranes are called _____.

phospholipids

A chemical named _____ is derived from ATP and widely employed as a “second messenger” in cellular signaling.

cyclic adenosine monophosphate

When oxygen is too limited to meet a cell’s ATP demand, a cell can employ a metabolic pathway called _____ to produce ATP.

anaerobic fermentation

A substance acted upon and changed by an enzyme is called the enzyme’s _____.

substrate

The monomers of a polysaccharide are called _____

monosaccharides (simple sugars)

Most of our reserve energy is stored in _____

fat

Two molecules with the same atoms arranged in a different order are called _____

isomers

The products of catabolism contain _____ chemical energy than reactants

less

A polysaccharide is a chain of _____ joined by peptide bonds.

amino acids

A saturated fat is defined as a fat to which no more _____ can be added.

hydrogen

_____, like catalysts, are not consumed by the reactions they catalyze.

enzymes

Above a certain temperature, _____ denature and cease working

enzymes

A solution with pH 9 has _____ the hydrogen ion concentration of one with pH 7.

one-tenth

Chemical elements

The simplest form of matter to have unique chemical properties.

The six most important chemical elements:

oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorous

Trace elements

Essential cofactors for enzymes, facilitating oxygen transport, and regulating metabolic processes, hormone function, and immune response.

Structure of an atom

Protons (+) Neutrons (neutral)

• located inside the nucleus

Electrons (-)

• orbit in orbitals around the nucleus

Valence electrons

Electrons in an atoms outermost energy level.

Atoms bond by sharing _____ or transferring _____ valence electrons to achieve full valence.

Covalent bonds, Ionic bonds

Isotopes

Different versions of the same element.

• Same number of protons

• Different number of neutrons

Radioisotopes

An isotope whose nucleus is unstable releases energy through radioactive decay.

Radioactive decay

Emits radiation

What are the three forms of Ionizing radiation?

Alpha particles, Beta particles, and Gamma Rays.

Physical half-life

Time for half of the radioactive atoms to decay.

Biological half-life

Time for radioisotopes to be removed from the body through natural processes.

Atom

Neutral particle (same number of protons and neutrons)

Ions

A charged particle formed when an atom gains or loses electrons - so the number of electrons no longer matches the number of protons.

Cations

• Positive ions

• Formed by losing electrons

• NA+

Anions

• Negative ions

• formed by gaining electrons

• CI-

Electrolytes

Substances that produce ions in solutions and conduct energy.

The function of electrolytes is _____.

Fluid balance, osmosis control, nerve impulses, and muscle contractions, acid - base pH balance, enzyme and hormonal function.

Free radical

A damaged, unstable molecule that can damage other cells in the body while trying to fix itself.

Antioxidants

Molecules that can safely donate an electron with out becoming unstable.

• The body uses this to neutralize free radicals.

Molecule

A group of atoms held together by bonds.

Compound

A molecule made of different kinds of atoms.

Isomers

Molecules that have the same molecular formula (same kind and number of atoms) but different structures, meaning they behave different.

Ionic bonds

A bond formed when one atom gives up one or more electrons to another.

• strong in solid form, weaker in water

• often found in salts and electrolytes

Covalent bonds

A bond where atoms share electrons.

• Very strong

• Common in most biological molecules

Hydrogen bonds

A weak attraction between the slightly positive H of one polar molecule and the slightly negative part of another polar molecule.

• weak alone but strong in numbers

• holds DNA strands together

Van Der Walls Force

A weak attraction between molecules due to its temporary shifts in electron clouds.

• weakest type of interaction

• important in how molecules fit together

Compound

ex. like baking a cake - once baked you can not separate the eggs and flour

Mixture

ex. like fruit salad - you can still pick out the grapes or bananas

Solution

A clear, even mixture of two or more substances.

• The solute is completely dissolved in the solvent

• you cannot see the particles, they do not settle out

Plasma in blood is an example of _____.

A solution

Collid

A mixture where the particles are larger than in solutions but still small enough to stay mixed.

• looks cloudy or milky but particles do not settle out overtime

cytosol (fluid inside cells), plasma proteins in blood, or milk are examples of _____.

A collid

Suspension

Has large particles that are visible and will settle out if left standing.

• need to shake or mix to keep together

Blood is an example of what ____.

Suspension

pH

The number that tells us how acidic or basic a solution is.

Base

Removes H+ or gives OH- ions (8-14 range)

Acid

A substance that gives off H+ (0-6 range)

Buffers

• Prevents PH swings, maintain stable pH, and protect cells.

• Soaks up and releases H+ ions, keep body fluids at normal pH levels, ensure enzymes and cells function properly.

Energy

Is the ability to do work or cause change. It is what allows things to move, grow, heat up, and do all kinds of activities.

Kinetic energy

Energy of motion (anything moving)

Blood flowing through vessels and muscle contractions are both examples of _____.

Kinetic energy

Potential energy

Stored energy (energy that can be used later).

Energy stored in chemical bonds of food are an example of what _____.

Potential energy

Combination Reactions

Two or more simple substances combine to form a more complex structure.

What is this an example of:

Hydrogen, Oxygen, Water → H2 + O + H2O

Combination Reaction

Synthesis Reaction

This is a type of composition reaction where small molecules or atoms join together to make a bigger molecule.

• used in building complex molecules in the body like proteins or DNA

• A + B → AB

Exchange Reaction

Parts of the molecules swap places or exchange to form new molecules.

• AB + CD → AD + CB

What determines the rate of a chemical reaction?

1. Concentration of reactants

2. Temperature

3. Presence of a catalyst

4. Surface area

Metabolism

All the chemical reactions that happen in your body to keep you alive.

• how your body builds up things it needs and breaks down thins to get energy

Anabolism

This is where your body makes bigger more complex molecules from smaller ones

• uses energy

• building up

Catabolism

This is when your body breaks down big molecules into smaller ones.

• releases energy

• breaking down

Oxidation

This is when a molecule loses electrons.

• gives away energy

Reduction

This is when a molecule gains electrons.

• gains energy

How is a compound considered organic?

If it contains carbon atoms bonded to hydrogen atoms.

Carbon backbone

This is the main chain or ring of carbon atoms in an organic molecule

• forms skeletons or structure of a molecule

Functional groups

This is specific groups of atoms attached to the carbon backbone.

• gives molecules unique properties and behavior

Hydroxyl

(-OH)

• polar, water loving

• found in alcohol’s and sugars

Methyl

(-CH3)

• non-polar, water fearing

• found in lipids and organic molecules

Carboxyl

(-COOH)

• Acidic, and releases H+

• Found in amino acids and fatty acids

Amino

(-NH2)

• Basic, accepts H+

• found in proteins, and amino acids

Phosphate

(-PO4)

• negative charge, energy trasfer

• found in DNA and ATP

Monomer

single building block molecule

Polymer

many monomers joined together

Dehydration synthesis

builds polymers

• water is released

hydrolysis

breaks polymers into monomers

• water is added

carbohydrates

are organic molecules made up of carbon, hydrogen, and oxygen

• main role is to provide and store energy

What are examples of carbohydrates?

Glucose, starch, glycogen, and cellulose