Exam 1 BIOL 1107

element

a pure substance that can not be further broken down

atom

basic unit of matter

true or false:

elements consist of more than 1 type of atom

false, they contain only 1 type of atom

nucleus of an atom

dense center of atom

proton

positively charged particles in nucleus

neutron

neutrally charged particles in nucleus

electron

negatively charged particle that move around the nucleus

what does the atomic number represent

number of protons

what does the atomic mass represent

the number of protons and neutrons

orbital

region in space where electrons are present most os the time

what is the maximum number of electrons in an orbital

2

as electrons get closer to the nucleus energy _____ (increases or deacrease) compared to ones farther away

decreases, they have less energy

shell

1 or more orbital zones within an atom where electrons occur

what is the difference between an orbital and a shell

isotopes

atoms of the same element with a different number of neutrons

ions

electrically charged atoms

molecules

substance made of two or more atoms attached to each other as a unit

chemical bonds

form of attraction between atoms holding them together

valence electron

electrons in outer shell of an atom which participates in the formation of chemical bonds

what is the highest energy level of the atom

the valence electron

covalent bond

a chemical bond formed by a shared pair of electrons holding two different atoms together

when are covalent bonds most stable

when two atoms form a bond to share enough electrons to fill the outermost shell (octet rule)

electronegativity

when bonds dont share electrons equally making a slightly positive and slightly negative charge

polar covalent bond

do not share electrons equally, hydrophilic

non polar covalent bond

have the same/nearly the same electronegativity (H2, O2, C-C, C-H), hydrophobic

ionic bond

two ions with opposite charges associated with each other due to differences in electronegativity, cation/anion (one atom is much more EN than another)

hydrogen bond

attraction between partial positive charge on H atom and a partially negative charge on another atom (O or N)

are hydrogen bonds strong or weak

they are collectively strong but individually easy to break

Van der Waals forces

brief stickiness between regions of a molecule or two different molecules caused by electrical attraction

are van der waals forces strong

no, they are weak, collectively they stabilize structures

cohesion

attraction between molecules, results in surface tension

in terms of heating why are hydrogen bonds useful in water

they make water more resistant to temperature changes, give it a high specific heat which is why humans can have water in cells

what does pH measure

proton concentration of H

what is the equation for pH

-log[H+]

what is a neutral pH

7, protons and hydroxide ions are equal

what is an acidic pH

1-7, protons are higher than hydroxide

are acids hydrogen donors or acceptors

they are hydrogen donors

do acids increase or decrease hydrogen concentration

increases hydrogen concentration

what is a basic pH

7-14, proton concentration is lower than hydroxide concentration

are bases hydrogen donors or acceptors

they are hydrogen acceptors

do bases increase or decrease hydrogen concentration

decrease hydrogen concentrations

are acids hydrophobic or hydrophilic

they are hydrophilic

a proton donor ______ (decreases/increases) the pH and ______ (increases/decreases) the concentration of hydrogen in a solution

decreases, increases

organic molecules

molecules containing carbon

polymer

complex molecule made up of repeated simpler units connected by covalent bonds

monomer

subunit of polymer

functional groups

groups of one or more atoms attached to carbon atoms with their own chemical properties

are many functional groups polar or nonpolar

polar which makes the molecule polar

what are the 7 functional groups

amino, carboxyl, phosphate, carbonyl, methyl, hydroxyl, sulfhydras

amino

-NH2

is amino a base or acid

base

is amino polar or nonpolar

polar

carboxyl

-COOH

is carboxyl acid base of acid

acid

phosphate

-OPO3H2

is carboxyl polar or nonpolar

polar

is phosphate a base or acid

acid

is phosphate polar or nonpolar

polar

carbonyl

>C=O

is carbonyl polar or nonpolar

polar

methyl

-CH3

is methyl polar or nonpolar

nonpolar

hydroxyl

-OH

is hydroxyl acid base or acid

acid

is hydroxyl polar or nonpolar

polar

sulfhydryl

-SH

is sulfhydryl polar or nonpolar

polar

what do amino acids consist of

central carbon, amino group, carboxyl group, hydrogen atom, R group

what determines the structure/composition of the amino acid

R group

what molecular shape are amino acids

tetrahedron

how do amino acids form a chain

carbon atoms on the carboxyl group of one amino acid joins the N atom in the next amino group

what bond forms between amino acids

peptide bond

peptide bond

a covalent bond that links amino acids

what type of synthesis occurs for a peptide bond to form

dehydration synthesis

what is the difference between RNA and DNA

ribonucleic acid the sugar is ribose which has a hydroxyl on the second carbon but deoxyribonucleic acid has only a H atom on the second carbon

what three things a nucleotides composed of

5 carbon sugar, base, phosphate group

how is the phosphate group linked to the nucleotide

linked on the 5’ carbon of the sugar

what gives DNA its mild acidity

the negative charges on the O in the phosphate group

what forms the backbone of DNA/RNA

phosphate group

nucleoside

sugar and base

nucleotide

nucleoside and the phosphate

nucleoside monophosphate

nucleotide and 1 phosphate

nucleoside diphosphate

nucleotide and 2 phosphate

nucleoside triphosphate

nucleotide and 3 phosphate

pyrimidine

single rings

purines

double rings

what bases are pyrimidines

cytosine, thymine/uracil

what bases are purines

guanine, adenine

why is it important that 1 purine and 1 pyrimidine pair

it preserves the distance between the backbone

major groove

larger of two uneven grooves on the outside of DNA

minor groove

smaller of two uneven grooves

how many hydrogen bonds form between A and T

2 bonds

how many hydrogen bonds form between G and C

3 bonds

what bond are nucleotides connected by

phosphodiester bonds

what type of synthesis occurs when phosphodiester bonds form

dehydration synthesis

how are nucleotides connected

the 3’ carbon of one nucleotide is connected to the 5’ carbon of the next nucleotide and are connected through the phosphate group

does the 5’ end have the phosphate group or the hydroxyl

phosphate group

what type of molecule are carbohydrates

fuel molecules

what ratio do carbohydrates come in

1:2:1 C:H:O

what are the simplest carb

saccharides