Week 1

Question 1

element

Answer 1

substance that cannot easily be broken down or converted to other substances

fundamental building block of living cell

~100 naturally occurring elements on earth

Question 2

the big four elements (living organisms)

Answer 2

oxygen
carbon
hydrogen
nitrogen

Question 3

hydrogen

Answer 3

5x10^6 atoms = 1mm

one atom has a nucleus with a 1 proton orbited by 1 electron

Question 4

carbon

Answer 4

6 protons, 6 electrons (atomic number = 6)

most versatile of big 4, readily forms 4 covalent bonds

• long linear chains with itself
• branched tree structures

Question 5

nitrogen

Answer 5

atomic number 7

Question 6

oxygen

Answer 6

atomic number 8

Question 7

molecule

Answer 7

group of elements that has been bonded together

Question 8

orbital shell 1

Answer 8

ring around nucleus

can hold 2 electrons

Question 9

orbital shell 2

Answer 9

can hold 8 electrons

electrons in partially full orbital shells are highly reactive

Question 10

Lewis dot structure

Answer 10

write symbol of element, use dots to represent the electrons in outermost orbital shell

Question 11

valence electrons

Answer 11

electrons in outermost orbital shell

Question 12

covalent bond

Answer 12

when atoms share valence electrons to achieve full outer shells

Question 13

methane

Answer 13

CH4

Question 14

ammonia

Answer 14

NH3

Question 15

double covalent bond

Answer 15

when atoms share more than one electron

Question 16

electronegative

Answer 16

elements that hold onto electrons more tightly than others

H=C < N=O

Question 17

non-polar covalent bond

Answer 17

bond between two elements with similar electronegativity

Question 18

polar covalent bond

Answer 18

bond between two elements with different electronegativity

Question 19

most abundant molecule in cell

Answer 19

water (~70%)

-two hydrogen atoms have partial + charge, oxygen partial - charge

Question 20

hydrogen bond

Answer 20

much weaker than covalent bond

interaction between + H atom on one water molecule with - O atom on another

give water important properties (boiling temp, surface tension)

also between water and any molecule with negatively charged O or N

don’t even need to involve water

Question 21

ion

Answer 21

molecule with an unequal number of protons and electrons

HO- hydroxide ion
H3O+ hydronium ion

Question 22

pH

Answer 22

measure of H3O+ in a solution

pH = -log(H3O+)

pH of water is 7

Question 23

mole

Answer 23

measurement: 1x10^23

Question 24

acid

Answer 24

molecule that tends to increase the hydronium ion concentration when placed in a solution

Question 25

weak acid

Answer 25

Don’t completely ionize in solution low pH conditions will favor the neutral form of a weak acid high pH conditions will favor ionized form of a weak acid

Question 26

pKa

Answer 26

pH level above which that acid will be mostly ionized for each acid there is a pH above which that acid will be ionized (low pH conditions, high pH conditions)

Question 27

proteins

Answer 27

2nd most abundant molecule in living cell responsible for most of the action side cells generate energy for cells, mediate cell division, movement, communication, immune response, muscle contraction,... made from amino acid building blocks

Question 28

amino acids

Answer 28

molecules that contain an amino group also carboxyl group, linked to each other through central carbon atom (alpha carbon) 20 different common amino acids in human proteins, differ by side chains/R groups

Question 29

R group/side chain

Answer 29

what makes each amino acid unique each side chain has its own special properties some have only non-polar covalent bonds - hydrophobic some have polar covalent bonds (hydrophilic)

Question 30

glycine

Answer 30

amino acid with side chain H (least bulky) conformational flexibility

Question 31

proline

Answer 31

amino acid with side chain that reaches back and forms covalent bond with amino group N can’t rotate, rigidity

Question 32

cysteine

Answer 32

amino acid with side chain containing a sulfur atom two cysteines -> disulfide bind, form specific 3D shapes disulfide bonds can also form across 2 different proteins

Question 33

aspartame, glutamate

Answer 33

amino acids with weak acid side chains knowing pH of solution tells us if neutral or ionized form of weak acid predominates

Question 34

peptide bond

Answer 34

a covalent bond that forms between amino acids

Question 35

carboxyl group

Answer 35

contained in amino acid weak acid

Question 36

amino group

Answer 36

part of amino acid weak base

Question 37

condensation reaction

Answer 37

water producing process that connects carboxyl group of one amino acid to amino group of another links ribose of one nucleotide to phosphate group of another nucleotide

Question 38

polypeptides

Answer 38

chains of amino acids with many peptide bonds proteins

Question 39

amino or N terminus

Answer 39

end of a protein with a free amino group

Question 40

carboxyl or C terminus

Answer 40

end of a protein with free carboxyl group

Question 41

primary structure of protein

Answer 41

the linear sequence of amino acids in the protein

Question 42

secondary structure of protein

Answer 42

3D shape that local segments of the protein take basic structures: alpha helix or beta sheet

Question 43

tertiary structure of protein

Answer 43

overall global shape that a protein folds into most proteins contains a mix of alpha helixes and beta sheets hydrophilic side chains tend to be on outside hydrophobic side chains tend to be on inside

Question 44

nucleic acid

Answer 44

polymer made up from subunit molecules called nucleotides

Question 45

nucleotides

Answer 45

molecules that contain a 5 carbon ring-like structure called ribose phosphate group linked to C5 carbon atom base linked to C1 carbon atom

Question 46

purine bases

Answer 46

adenine and guanine have double ring structure can be linked to sugar molecule in nucleotide

Question 47

pyrimidine bases

Answer 47

thymine and cytosine single ring structure can be linked to sugar molecule in nucleotide

Question 48

RNA

Answer 48

ribonucleic acid differs from DNA by hydroxy (-OH) group at C2 carbon atom and uses uracil as base instead of thymine

Question 49

DNA

Answer 49

deoxyribonucleic acid only has H (not OH) on C2 atom DNA molecule can be built by repeated bonds between nucleotides sugar phosphate backbone, directionality 5’ end: exposed phosphate group 3’ end: exposed hydroxyl group two long molecules can interact through base regions of nucleotides to form double stranded structure (thymine bases interact with adenine, cytosine with guanine)-hydrogen bonds 2 H bonds between A and T, 3 between G and C