Test 2 Chemistry of Life Pt. 2 Final

Question 1

distinguishing carbs from lipids

Answer 1

Lipids
Made of mostly carbon & hydrogen
Can be used to store energy
LONG chains of CH2
Renders molecule nonpolar and thus insoluble in water
Carbs
1:2:1 ratio of CHO

Question 2

things that end in -ose are what?

Answer 2

sugars

Question 3

making proteins process

Answer 3

Info from DNA is “copied to a messenger molecule, mRNA
mRNA takes the info, tells ribosomes how to make proteins
Proteins are assembled at the ribosome by joining together amino acids (ribosomes read RNA)
DNA -> RNA -> Protein

Question 4

nucleic acids

Answer 4

macromolecules containing H, O, N, C, and P (phosphorus). They are polymers assembled from nucleotides

Question 5

DNA vs. RNA

Answer 5

DNA - double helix (2 strands), deoxyribose (5 carbon sugar), ACTG A=T C=G
RNA - single strand, ribose (5 carbon sugar), ACGU (uracil (U) replaces thymine (T) in RNA) A=U C=G

Question 6

Chargoff Rules

Answer 6

A’s = T’s (U’s)
C’s = G’s

Question 7

Nucleotides

Answer 7

Phosphate (PO4), 5 carbon sugar, and nitrogenous base
Monomer - nucleotide
Polymer - nucleic acids

Question 8

bonds between nitrogenous bases

Answer 8

hydrogen bonds

Question 9

organic vs. inorganic

Answer 9

Organic compounds have carbon and hydrogen, inorganic don’t

Question 10

amino acids

Answer 10

Proteins are polymers of amino acids

Each amino acid has a central carbon atom to which are attached a hydrogen atom, an amino group –NH2, a carboxyl group –COOH, and one of 20 different types of –R (remainder)
groups

Question 11

R side chain

Answer 11

The R group can be either:
polar and hydrophilic
nonpolar and hydrophobic
charged (+ or -)

These different side chains give different amino acids
different properties and will cause them to interact
with each other differently!

Question 12

Proteins (AKA polypeptides)

Answer 12

Amino acids joined together end-to-end
COOH of one AA covalently bonds to the NH2 of the
next AA
Special name for this bond - Peptide Bond

Two AAs bonded together – Dipeptide
Three AAs bonded together – Tripeptide
Many AAs bonded together – Polypeptide

Characteristics of a protein determined by
composition and sequence of AA’s
Virtually unlimited number of proteins

Question 13

protein assembly: dehydration synthesis

Answer 13

Occurs at the ribosome
Amino acids are joined together in long chains called polypeptides.
Each amino acid is added one at a time using dehydration synthesis.

A typical protein can be hundreds of
amino acids long.

Question 14

digesting proteins: hydrolysis

Answer 14

Usually facilitated by an enzyme like
protease

A water molecule is split and the -H
& -OH are added to restore the
carboxyl and amino groups,
breaking the peptide bond and
separating the amino acids.

Individual amino acids can be reused
to build new proteins.

Question 15

primary structure protein molecules

Answer 15

Literally the sequence of amino acids
A string of beads (up to 20 different colors)

Question 16

secondary structure protein molecules

Answer 16

The way the amino acid chain coils or folds
Describing the way a knot is tied

Question 17

tertiary structure protein molecules

Answer 17

Overall three-dimensional shape of a polypeptide
Describing what a knot looks like from the outside

Question 18

quarternary structure proteins

Answer 18

When more than one polypeptide comes together to make an
even larger molecule
Like several completed knots glued together

Question 19

how important are enzymes?

Answer 19

All chemical reactions in living organisms require enzymes to work
Building molecules
Synthesis enzymes
Breaking down molecules
Digestive enzymes
Enzymes speed up reactions
Catalysts

Question 20

enzyme info

Answer 20

Enzymes are proteins
Each enzyme is the specific helper to
a specific reaction
each enzyme needs to be the right shape
for the job
enzymes are named for the reaction
they help
sucrase breaks down sucrose
proteases breakdown proteins
lipases breakdown lipids
DNA polymerase builds DNA

Question 21

enzymes aren’t used up

Answer 21

Enzymes are not changed by the reaction
used only temporarily
re-used again for the same reaction with other molecules
very little enzyme needed to help in many reactions

Question 22

lock and key model

Answer 22

specific enzyme for each specific reaction

the enzyme’s active site and the shape of the substrate molecule are complementary to one another. This allows the substrate to fit into the enzyme, like how a key would fit into a lock. If the substrate doesn’t fit, then the enzyme will not act on it

Question 23

peptide bond

Answer 23

A type of covalent bond which is formed by joining the carboxyl group of one amino acid to the amino group of another

Question 24

catalyst

Answer 24

A substance that speeds up the rate of a chemical reaction

Question 25

enzyme

Answer 25

Proteins that act as biological catalysts

Question 26

substrate

Answer 26

The reactants of an enzyme-based reaction

Question 27

active site

Answer 27

A site on an enzyme to which substrates bind

Question 28

what affects enzyme action

Answer 28

Correct protein structure
correct order of amino acids
Temperature
pH (acids & bases)

Question 29

enzymes - temp

Answer 29

Optimum temperature
greatest number of collisions between enzyme & substrate
human enzymes: 35°- 40°C (body temp = 37°C)
Raise temperature (boiling)
denature protein = unfold = lose shape
Lower temperature T°
molecules move slower
fewer collisions between enzyme & substrate

Question 30

enzymes - order of amino acids

Answer 30

Wrong order = wrong shape = can’t do its job!

Question 31

enzymes - pH

Answer 31

Effect on rates of enzyme activity
changes in pH changes protein shape
most human enzymes = pH 6-8
depends on where in body
pepsin (stomach) = pH 3
trypsin (small intestines) = pH 8

Question 32

what determines protein shape?

Answer 32

the sequence of amino acids within the protein