Biology Exam 1

Chapters 2-6

Compounds

Atoms joined by bonds

number of protons

determines atom identity

electron distribution

determines ability to form bonds

matter

takes up space and has mass, made up of elemets

elements

can’t be broken down to other substances

atom

smallest unit of mater, composed of subatomic particles

neutrons,

neutral, form atomic nucleus

protons

positively charged, form atomic nucleus

electrons

negatively charged, forms “cloud” of negative charge around nucleus

Atomic number

number of protons

mass number

sum of protons and neutrons

atomic mass

total mass

isotopes

two atoms of an element that differ in neutrons, same number of protons but different number of neutrons

valence electrons

in the outermost shell

chemical bonds

atoms with incomplete shells share/transfer VE with other atoms and held by attractionsc

covalent bonds

sharing of a pair with VE by two atoms

molecule

two or more atoms held by covalent bonds

single bond

sharing of one pair of VE

double bond

sharing of two pairs of VE

electronegativity

atom’s attractions for electrons in a covalent bond

fluorine

which element is most electronegative

nonpolar

equal electrons

polar

different electronegativity and don’t share electrons equally

partial positive or partial negative charge

unequal electrons

ionic bonds

attraction between cation and anion

cation

positively charge ion

anion

negatively charged ion

ion

a charged atom

ionic compounds

compounds formed by ionic bonds

hydrogen bond

forms when a hydrogen covalently bonded to one electronegative atom is attracted to another electronegative atom

In ice, water molecules are far apart. In liquid, water molecules slip together. Ice is less dense than liquid.

How does ice float in water?

Cohesive behavior, moderation of temperature, expansion upon freezing, water solvent

What are 4 properties of water?

Cohesion

hydrogen bonds hold water molecules together, help against gravity

adhesion

attraction between different substances

heat absorbed

hydrogen bonds break

heat released

hydrogen bonds form

solution

completely homogeneous mixture of substances

solvent

dissolved agent of solution

solute

substance dissolved

aqueous solution

water is solvent

hydrophillic

affinity for water (ionic, polar)

hydrophobic

no affinity for water (nonpolar)

molecular mass

sum of all masses of all atoms in molecule

1 mol

6.02 × 10²³

Molarity

number of moles per liter of solution

hydrogen ion (H+)

hydrogen leaves electron behind and transferred as proton

hydroxide ion (OH-)

lost the proton

hydronium ion (H3O+)

molecule with extra proton, could also be written as H+

acid

increases H+ concentration of solution

base

reduces H+ concentration of solution

pH

negative log of H+ concentration

neutral solution

pH=7

carbon

can form large, complex, and varied molecules. Can form four bonds

organic chemistry

study of compounds containing carbon

electron configuration

determines the number of bonds an atom will form with other atoms

hydrocarbons

organic molecules consisting of only carbon and hydrogen

isomers

compounds with same molecular formula

structual isomes

cis-trans isomers

enantiomers

functional groups

components of organic molecules involved in chemical reactions

hydroxyl group

alcohol

carbonyl group

ketone/aldehyde

carboxyl group

acid

amino group

base

sulfhydryl group

stabilize protein, thiol

phosphate group

contributes negative charge

methyl group

affects expression of genes

methyl groups

which function group is nonpolar?

carbohydrates, lipids, proteins, nucleic acid

What are the four large biological molecules?

polymer

long molecule with similar building blocks (made of monomers)

monomer

building blocks

dehydration synthesis

synthesizing polymer, removes water molecule, forming a new bond

hydrolysis

breaking down a polymer, adding water molecule, breaking a bond

carbohydrates

include sugar and polymers of sugars

monosaccharides

simplest unit of building blocks of carbohydrates

disaccharide

two monosaccharide units

polysaccharides

long chain of monosaccharides

chitin

structural polysaccharide, found in exoskeleton of arthropods and cell walls of fungi

lipids

hydrophobic organic compounds made of carbon and hydrogen atoms, and some oxygen

fats

constructed from glycerol and fatty acids, store energy

glycerol

three carbon alcohol with hydroxyl group, energy source

fatty acids

carboxyl group with hydrocarbon skeleton

saturated fats

solid at room temperature

unsaturated fats

liquid at room temperature

phospholipid

two fatty acids and phosphate group attached to glycerol, lipid bilayers of membranes

hydrophobic

Are fatty acid tails hydrophobic or hydrophilic?

hydrophilic

Are phosphate heads hydrophobic or hydrophilic?

steroids

signal molecules traveling through the body, carbon skeleton with four fused rings

cholesterol

type of steroid, in animal cell membranes and precursor from other steroids are synthesized

protein

biologically functional molecule that consists of one or more polypeptides

polypeptides

unbranched polymers built from amino acids

amino acids

molecules with amino and carboxyl groups

peptide bonds

link amino acids

Amino acids make up polypeptides, and polypeptides make up proteins

How are protein, polypeptides, and amino acids related?

enzymatic protein

moves chemical reactions

storage protein

stores amino acids

defensive protein

protects against disease

transport protein

transport substances

hormonal protein

coordination of organism’s activities