Chapter 2 and Atlas 2: Chemistry of Life

Question 1

What is an element?

Answer 1

Simplest form of matter to have chemical properties. Each identified by atomic number (number of protons in nucleus).

Question 2

What is an atom?

Answer 2

Nucleus composed of protons (single positive charge, P+) and neutrons (no charge, N0).
Around nucleus are electrons (single negative charge, E-) in electron shells (first, second, and third level energy). More energy electron has, farther away from nucleus.

Question 3

What is an isotope?

Answer 3

Same number protons, different number neutrons. Unstable isotopes are called radioisotopes, and process of decay is radioactivity.

Question 4

What is ionizing radiation?

Answer 4

Destroys molecules and produces dangerous free radicals and ions in human tissue.

Question 5

Physical half-life vs Biological half-life

Answer 5

Physical: time required for 50% of atoms to decay to a more stable isotope.
Biological half life: time required for half of it to disappear from body.

Question 6

What is an ion?

Answer 6

charged particle with unequal number of protons and electrons. Consists of single atom with positive or negative charge, group of atoms, or a molecule.

Question 7

What is ionization?

Answer 7

The giving up of electrons to fill valence shell, forming ions.

Question 8

What is an anion vs cation?

Answer 8

Anion: Particle that gains electrons acquires negative charge.
Cation: Particle that loses electrons acquires positive charge because of extra protons.

Question 8

What is an anion vs cation?

Answer 8

Anion: Particle that gains electrons acquires negative charge.
Cation: Particle that loses electrons acquires positive charge because of extra protons.

Question 9

What is an electrolyte?

Answer 9

Acids, bases, or salts that ionize in water and form solutions that conduct electricity.

Question 10

What is a free radical?

Answer 10

Unstable, highly reactive chemical particles with an odd number of electrons.
Added dot at the end of element represents extra electron.

Question 11

What is an antioxidant?

Answer 11

Chemical neutralizes free radicals.

Question 12

What is a molecule?

Answer 12

Chemical particle with two or more atoms united by chemical bond.
Molecules composed of two or more elements are called compounds. (CO2)

Question 13

What is an isomer?

Answer 13

Two molecules with the same molecular formulae but different arrangements of atoms.

Question 14

What is covalent bond?

Answer 14

Formed by the sharing of valence electrons. (H2)
Single covalent bond: sharing of single electron.
Double covalent bond: Sharing of two pairs of electrons. (0=C=0)

Question 15

Polar vs Nonpolar Covalent bonds

Answer 15

Polar: two atoms share electrons unequally.

Non polar: Two atoms share electrons equally.

Question 16

Hydrogen Bonds

Answer 16

Weak attraction between positive hydrogen atom and a negative oxygen/nitrogen atom.

Question 17

Van der Waals Forces

Answer 17

Weak, brief attraction between neutral atoms. Important in protein folding, binding of proteins and lipids.

Question 18

Water and its ability to support life

Answer 18

Most important, universal solvent, 50-75% of body weight, covalent bonds, polar.
Functions: Major component in cells, important solvent, route transport of waste, chemical reactions, lubrication, body temp.
Ability to support life: Solvency, Cohesion, Adhesion, Chemical Reactivity, Thermal Stability.

Question 19

What is solvency?

Answer 19

Ability to dissolve other chemicals. Water is universal solvent.
Hydrophilic: Substances that dissolve in water (eg. sugar)
Hydrophobic: Do not dissolve in water (fats)
To be soluble, molecule must be polarized or charged.
POLARS dissolve POLARS, NONPOLARS dissolve NONPOLARS

Question 20

What is adhesion vs cohesion?

Answer 20

Adhesion: tendency of substances clinging to another.
Cohesion: Molecules of same substance cling to eachother. (eg. surface tension)

Question 21

What is chemical reactivity of water?

Answer 21

Ability to participate in chemical reactions, such has hydrolysis or dehydration synthesis.

Question 22

What is Thermal Stability of water?

Answer 22

Helps stabilize internal temperature of body. Hydrogen bonds inhibit movement so water can absorb heat without changing temperature.

Question 23

What is a Solution?

Answer 23

Consists of particles of matter called solute (gas, solid, liquid) mixed with other substances.
Defined by:
Solute particles under one nm in size
Usually transparent, particles don’t scatter light
Solute particles can pass through most selective permeable membranes
Solute doesn’t separate from solvent.

Question 24

What is a colloid?

Answer 24

``` Mixture of protein and water. Can change from liquid to gel state. Defined by: 1 to 100 nm in size Particles scatter light, cloudy Too large to pass though membrane Small enough to remain mixed in solvent ```

Question 25

What is a suspension?

Answer 25

``` eg. blood cells in plasma Emulsion: suspension of one liquid in another. Defined by: Particles over 100 nm Cloudy and opaque Too large to penetrate membranes Too heavy, so suspensions separate. ```

Question 26

What is an acid?

Answer 26

An acid is any proton donor, a molecule that releases a proton in water.

Question 27

What is a base?

Answer 27

A base is a proton accepter, a molecule that accepts protons.

Question 28

pH Scale and Buffers

Answer 28

1-14. Below 7: acidic. 7: neutral. Above 7: Basic. A change of one whole number represents a 10 fold change (x10) Ex. Blood has pH of 7.35/7.45. Buffers are chemicals that resist changes in pH. Measured by concentration of hydrogen ions

Question 29

Energy

Answer 29

Energy is the potential to do work. Potential Energy: stored energy. Kinetic Energy: energy of motion, Chemical Energy: potential energy stored in bonds of molecules. Heat: Kinetic energy of molecular motion. Electromagnetic Energy: Kinetic energy of packets of radiation. Electrical Energy: potential and kinetic forms. Free Energy: Potential energy in system to do useful work.

Question 30

What is a chemical reaction and types?

Answer 30

The process of a covalent or ionic bond being broken. Decomposition: Large molecule breaks down into two smaller molecules (AB=A+B) Synthesis: Two molecules combine to make one (A+B=AB) Exchange Reactions: two molecules exchange atoms (AB+CD=AC+BC) Equilibrium: ratio of products and reactants are stable.

Question 31

What increases reaction rates?

Answer 31

a. concentration b. temperature c. catalyst (temporarily bind to reactants)

Question 32

What is Catabolism?

Answer 32

A division of metabolism. Consists of energy releasing decomposition reactions. Breaks down covalent bonds, produces smaller molecules from larger ones, and release energy.

Question 33

What is Anabolism?

Answer 33

Anabolism consists of energy-storing synthesis reactions. A division of metabolism.

Question 34

What is oxidization?

Answer 34

Any chemical reaction in which a molecule gives up electrons and releases energy.

Question 35

What is Reduction?

Answer 35

A chemical reaction in which a molecule gains electrons and energy.

Question 36

Polymer vs. Monomers

Answer 36

Monomer can be bonded to identical monomers to form a polymer (polymerization) Polymers are molecules made of repetitive monomers.

Question 37

Carbohydrates:

Answer 37

Hydrophilic organic molecule with general formula (CH2O)n. n= number carbon atoms. Monosaccharides: simple sugars. (glucose, galactose, fructose, isomers of eachother) Disaccharides: sugars composed of two mono. (sucrose, lactose, maltose) Oligosaccharides: 3 or more mono. Polysaccharides: thousands of mono. (glycogen, starch, celluose)

Question 38

Lipids

Answer 38

hydrophobic organic molecule, composed of 1 carbon, hydrogen, and oxygen. Fatty acid: chain of 4 to 24 carbons with a carboxyl and methyl group. Saturated FA: has as much hydrogen as it can carry. Unsaturated FA: some carbon atoms joined by double covalent bonds.

Question 39

Lipids pt 2:

Answer 39

Triglyceride: (aka neutral fats) molecule with 3 carbon alcohol called glycerol liked to 3 fatty acids. Phospholipids: same set up as neutral fats except the phosphate group replaces 1 fatty acid group. (eg Lecithin) One head hydrophilic, other head hydrophobic (amphipathic). Eicosanoids: 20 C compound from arachidonic acid. Hormone like signal between cells. Steroid: Lipid with 17 C in 4 rings. Cholesterol is parent steroid.

Question 40

Proteins:

Answer 40

Protein is polymer of amino acids. Amino acid: has central carbon with amino (-NH2) and carboxyl (-COOH) group. Peptide: composed of two or more amino acids joined by peptide bonds (formed by dehydration synthesis.

Question 41

Protein Structure:

Answer 41

Primary Structure: Proteins sequence of amino acids. Secondary Structure: Coiled or folded shape held together by hydrogen bonds. Tertiary Structure: Globular or fibrous shapes. Quaternary Structure: two or more polypeptide chains by noncovalent forces.

Question 42

Protein Functions:

Answer 42

``` Structure: (keratin in nails, hair, skin. Collagen in teeth and bones) Communication: Membrane Transport Recognition and Protection Movement Cell Adhesion ```

Question 43

What is an enzyme?

Answer 43

Proteins that function as biological catalysts. Activation energy needed to cause reaction. 3 Steps of enzyme action: 1. substrate molecule approaches an active site. 2. substrate binds to active site, forming enzyme substrate complex. 3. Substrate form is changed by hydrolysis, released by enzyme. Factors that change enzymes: temperature and pH

Question 44

Nucleotides:

Answer 44

An organic compund with 3 components: single or double carbon-nitrogen ring (nitrogenous base), monosaccharide, or 1 or more phosphate groups.

Question 45

ATP: Adenosine Triphosphate

Answer 45

Most important energy transfer molecule.

Question 46

Nucleic Acids:

Answer 46

Polymers of nucleotides. (DNA, RNA)