Biological Macromolecules and Protein structures

Question 1

4 classes of macromolecules

Answer 1

carbs, proteins, nucleic acids, lipids

Question 2

common feature of carbs, proteins, nucleic acids

Answer 2

all use monomers to create polymers

Question 3

What is the most important building block of macromolecules?

Answer 3

CARBON because of its 4 valence electrons

Question 4

why is silicon not used instead of carbon?

Answer 4

because it would create unstable molecules because its valence electrons are further from its nucleus

Question 5

what is cholesterol an example of?

Answer 5

a molecule which contains an example of the ways carbon can be bonded–cyclic, branched, long chains

Question 6

Building blocks of macromolecules:

lipids

Answer 6

fatty acids

Question 7

carbs

Answer 7

monosaccharides

Question 8

proteins

Answer 8

amino acids

Question 9

nucleic acids

Answer 9

nucleotides

Question 10

Carbohydrates

Answer 10

monosaccharides, disaccharides, oligosaccharides, polysaccharides

Question 11

disaccharides

Answer 11

two monosaccharides connected by a glycosidic bond which is either alpha or beta
humans are unable to digest beta bonds (diagonal)
eg: sucrose

Question 12

oligosaccharides

Answer 12

small chain covalently attached to lipids and proteins

eg: galactose

Question 13

polysaccharides

Answer 13

long repeat chains of mono or disaccharides

eg: cellulose, starch, glycogen

Question 14

Lipids

Answer 14

fats, steroids, phospholipids

DO NOT dissolve in H2O but do dissolve in organic solvents

Question 15

Fats AKA triglycerides

Answer 15

3 fatty acids and a linker molecule–glycerol

storage of energy

Question 16

Adipocytes

Answer 16

specialized cells which just store fat

Question 17

monomer of fat = ?

Answer 17

fatty acid

Question 18

Fatty acid

Answer 18

free fatty acids are amphipathic–part hydrophobic, part hydrophilic because of carboxyl group at end

Question 19

Unsaturated fat

Answer 19

Has double bonds! will be liquid at room temperature

if it has more than one double bond it is called a polyunsaturated fat

Question 20

Cis fatty acid vs. trans fatty acid

Answer 20

cis at room temp will be liquid. trans will be solid
diets rich in trans fatty acids are considered bad because they contain more high density glycoproteins (bad cholesterol)

Question 21

What determines the properties of fats?

Answer 21

fatty acids! determines the length, whether cis or trans

Question 22

Steroids

Answer 22

amphipathic because of exposed hydroxyl group and the rest is hydrophobic

Question 23

Cholesterol

Answer 23

= steroid. Precursor for other steroid hormones eg: testosterone and estrogen

Question 24

Phospholipids

Answer 24

major constituent of membranes
2 fatty acid chains and a phosphate group
phosphate group can change but is always polar
amphipathic–allows them to order themselves and automatically form lipid bilayer

Question 25

Proteins

Answer 25

Do the work in cells. 20 different amino acids so can vary a lot in shape and size

Question 26

Amino acids

Answer 26

make up proteins! R group determines the chirality

in proteins only L stereoisomer exists

Question 27

Peptide bonds

Answer 27

covalent, produced by a condensation rxn at the ribosome

Question 28

difference between peptide and polypeptide

Answer 28

peptide= 20-30 AA max

polypeptide=up to 400 AA

Question 29

difference between polypeptide and protein

Answer 29

proteins can include more than one polypeptide

Question 30

Primary Structure of proteins

Answer 30

Just the sequence of amino acids, linear never branched

Question 31

Secondary structure

Answer 31

two possible: alpha helix, beta sheets

Question 32

alpha helix secondary structure

Answer 32

R groups face outward
soluble proteins free floating in water in cytoplasm
found in transmembrane domains
R groups that cross membrane point out toward fatty acids
(?)

Question 33

beta sheet secondary structure

Answer 33

R groups point up or down from plane of the sheet

gives protein tensile strength (spider silk)

Question 34

Tertiary Structure

Answer 34

many secondary structures and linkers that may not be in a secondary conformation

Question 35

How do you determine tertiary structure?

Answer 35

xray crystallography–gives average of a whole bunch of proteins
NEW–graphere sheet allows for first ever pictures of single proteins

Question 36

What can tertiary structure be divided into?

Answer 36

Protein domains

Question 37

What are protein domains?

Answer 37

areas of a protein that have a certain function and can act independently made up of 100-200 amino acids
highly conserved DNA sequences and occur in many proteins (if found functional over evolution)

Question 38

Quaternary structure

Answer 38

Multimeric proteins only. Contain more than one subunit

Question 39

homomeric protein

Answer 39

all the same subunits

Question 40

heteromeric protein

Answer 40

not all the same subunits

Question 41

Anfinsen Experiment (1956)

Answer 41

Demonstrated that a proteins S-S bonds do no dictate folding, but folding is dictated by the primary structure (amino acid sequence).
Used Ribonuclease and denatured it using urea and meracaptoethanol then rinsed of urea and then mera and left the ribonuclease alone and came back to find it had folded up again (became functional)

Question 42

Molecular Chaperones

Answer 42

Some proteins needs help to fold up properly because the cell is so crowded. MC prevent improper interactions

Question 43

HSP

Answer 43

heat shock proteins–type of MC that bind to the hydrophobic parts of a protein as it is being made

Question 44

Chaperonin

Answer 44

When HSP is not enough to make the protein fold up properly a chaperonin is necessary
forms a barrel like structure that the hsp guides the protein into so that it can have a place to fold up in (TRiC)