Lecture 5 - Biomolecules II

Question 1

proteins account for what percent of the dry mass of cells

Answer 1

50%

Question 2

name the monomers of proteins

Answer 2

amino acids

Question 3

name the polymers of proteins

Answer 3

polypeptides

Question 4

name the bonds of proteins

Answer 4

peptide bonds

Question 5

what is the most diverse group of biomelecules

Answer 5

proteins

Question 6

what is the difference between a polypeptide and a protein?

Answer 6

Polypeptide: string of animo acids

Protein: biologically functional molecule that consists of one or more polypeptides

Question 7

describe the structure of an amino acid

Answer 7

amino group + alpha c + carboxyl group.

a side chain/ R group attached to the alpha carbon

Question 8

how many amino acids are there? what differentiates them?

Answer 8

20 amino acids.

the R groups differentiate

Question 9

how are amino acids attached?

Answer 9

opposite ends of a pair of amino acids can undergo a dehydration reaction to form a covalent bond.

the covalent bond between two amino acids is called a peptide bond

Question 10

describe a functional protein

Answer 10

a functional protein consists of one or more polypeptides twisted. folded, and coiled into a unique shape (conformation)

Question 11

what determines a proteins function?

Answer 11

its conformation

Question 12

what determines a protein’s three dimensional conformation?

Answer 12

the sequence of amino acids

Question 13

how many levels of protein structure are there?

Answer 13

4

Question 14

describe primary protein structure

Answer 14

polypeptides unique sequence of amino aicds

Question 15

describe the secondary structure of proteins

Answer 15

coils and folds within the polypeptide chain determined by interactions among various backbone components

Question 16

describe tertiary structure of proteins

Answer 16

determined by interactions among various side chains (R groups)

Question 17

describe quaternary structure of proteins

Answer 17

when protein consists of multiple polypeptide chains

Question 18

primary prtoein structure is determined by what

Answer 18

the sequence of amino acids

determined by inherited genetic information

Question 19

what does primary protein structure determine

Answer 19

ultimate structure (R group interaction) which determines function

Question 20

describe structure of secondary protein structure

Answer 20

coils and folds of secondary structure results from hydrogen bonds between backbone constituents.

typically, secondary structures are a coil called alpha-helix and a folded structure called a pleated beta sheet

Question 21

describe the structure of tertiary protein structure

Answer 21

overall shaoe of a polypeptide is determined by interactions between R groups, not by interactions between bacbone constituent
interactions between R groups include H bonds, hydrophobic interactions, and van der Waals interactions

Question 22

describe the structure of quaternary protein structure

Answer 22

individual polypeptide chains = subunits

alpha chain subunits = alpha helices

beta chain subunits = beta sheets

Question 23

when is tertiary structure final?

Answer 23

if protein is made from one polypeptide

Question 24

when is quaternary structure final

Answer 24

if protein is made of multiple polypeptides

Question 25

Proteorhodopsin, a light driven proton pump, consists of a single polypeptide chain. What is the highest level of structure found in this protein?

Answer 25

tertiary ***

double check notes

Question 26

what is denaturation of proteins?

Answer 26

change in shape or even unfolding of protein because of change in environment (ex. pH, temp, ionic concentrations)

biologically inactive

most enzymes funtional in a narrow range

Question 27

name functions of proteins

Answer 27

• catalyzing chemical reactions
• structural support
• storage
• transport
• cellular communications
• movement
• defense against foreign substances

Question 28

name the polymers of lipids

Answer 28

lipids don’t form polymers

Question 29

what is the unifying feature of lipids

Answer 29

little or no affinity for water

Question 30

why are lipids hydrophobic?

Answer 30

consist mostly of hydrocarbons, which form non polar covalent bonds

Question 31

name the most biologically important lipids

Answer 31

fats, phospholipids, steroids

Question 32

describe fatty acids structure

Answer 32

long hydrocarbon chain (16-22 C long)

Question 33

where are fatty acids found

Answer 33

fats, oils, phospholipids, and as free form fatty acids

Question 34

describe fats functions

Answer 34

energy storage, insulation, protection

Question 35

descirbe fats structure (names)

Answer 35

glycerol and fatty acids

Question 36

describe glycerol

Answer 36

a 3 carbon alcohol with an OH group attached to each carbon

Question 37

describe fatty acid

Answer 37

carboxyl group -COOH attached to a long carbon skeleton