chapter 3.1 macromolecules

Question 1

chemical composition of the cell

Answer 1

• dry weight of e.coli: 2.8 x 10^-13 grams
• total weight (70% water): 9.5 x 10^-13 grams

Question 2

chemical composition protein

Answer 2

50% dry weight
(there are 2000 different types of proteins)

Question 3

FUNCTIONAL GROUPS

Answer 3

MEMORIZE

Question 4

covalent bonds

Answer 4

bonds in which electrons are shared between atoms (these don’t break even when H bonds are broken by boiling conditions

Question 5

hydrogen bonds (weak)

Answer 5

hydrogen bonds form between H and other electronegative elements (O or N)

Question 6

other weak bonds

Answer 6

van der waals and hydrophobic interactions

Question 7

GCAT

Answer 7

• takes more energy to separate CG than AT
• AT is 2 bonds
• CG is 3 bonds

Question 8

four classes of macromolecules

Answer 8

• polysaccharides
• lipids (fats)
• nucleic acids
• proteins

Question 9

carbohydrates

Answer 9

CH2O (1:2:1 ratio)
- most relevant carbs contains 4,5,6,7, carbon atoms
- most relevant carbs are D-form sugars
- optically active (chirality)
- OH group of next to last carbon determines chirality of molecule

Question 10

D sugars

Answer 10

• right rotating
• most natural sugars are D
• our enzymes only work with D, not L
• D glucose will have more OH groups on the right, L on left

Question 11

polysaccharides

Answer 11

• high molecular weight carbs containing monomeric units
• can be linked to proteins or lipid molecules to form glycoproteins and glycoproteins

Question 12

polysaccharides
α-glycosidic bond

Answer 12

• right side up H
• carbon and energy reserves in bacteria, plants, and animals

Question 13

polysaccharides
β-glycosidic bond

Answer 13

• right side down H
  often used as structural components of cells (cellulose)

Question 14

lipids

Answer 14

• fatty acids bound to glycerol
• contain hydrophobic and hydrophilic components
• principle component of membranes

Question 15

lipids - bonds

Answer 15

• every C attached to a H is saturated (single bonds outside of func group)
• if H is removed, double bond will form (unsaturated)
• more than one double bond is polyunsaturated

Question 16

lipid structure

Answer 16

bacteria is same as eukarya, but different for archaea

Question 17

phospholipid membrane

Answer 17

• one molecule
• proteins mobile in hydrophobic region of phospholipid membrane, BUT do not leave that area

Question 18

nucleic acid polymers

Answer 18

• DNA is a polymer of deoxyribonucleic acid
• RNA is polymer of ribonucleic acid

Question 19

nucleic acid structure

Answer 19

• ribose or deoxyribose sugar
• nitrogenous base
• phosphate group

Question 20

bases of nucleic acids

Answer 20

• purine or pyrimidine
• purines have two rings (A and G)
• pyrimidines have one ring (C, T, U)

Question 21

nucleic acid configuration

Answer 21

3’ to 5’ configuration via phosphodiester linkage, results in primary structure of nucleic acid

Question 22

nucleic acid base bonds

Answer 22

H bond to one another in a specific manner
- A to T, or U
- G to C

Question 23

secondary structure in RNA

Answer 23

when H bonds form between bases within the chain

Question 24

ribose vs deoxyribose (OH/H)

Answer 24

• ribose has OH on 2’
• deoxyribose has no OH, just H on 2’

Question 25

3 rules of biochemistry

Answer 25

1. biochemistry is backwards 2. biochemistry does not happen in the absence of water 3. biochemistry is STUPID

Question 26

amino acids

Answer 26

- monomeric units of protein and polypeptides - joined to each other in a peptide linkage - 21 commonly occurring amino acids - optically active - L-form commonly used

Question 27

proteins (primary and secondary structure)

Answer 27

- juxtaposition of α-carbon R groups dictates the primary structure of a protein (the amino acid sequence) - twists and folds in the linear sequence caused by H bonding determine the Secondary Structure of the protein

Question 28

secondary structure of protein

Answer 28

α- helix β- pleated sheet

Question 29

we sequence the DNA that codes the protein

Answer 29

not the actual protein itself

Question 30

primary struc

Answer 30

coded in the DNA

Question 31

secondary struc

Answer 31

interaction within a change between amino acids

Question 32

all proteins are peptide, not all peptides are proteins

Answer 32

- may need more than one peptide - 1 gene (amino acid chain) = 1 peptide (single stranded) - protein is the finished product (1 protein = 1 OR more peptides)

Question 33

tertiary structure of a protein

Answer 33

results from further folding of secondary structure and is "cemented" by the covalent bridging of different sections of the chain by disulfide linkages

Question 34

quaternary structure

Answer 34

results when one or more peptide chains interact via strong or weak molecular bonds

Question 35

denaturation of proteins

Answer 35

occur when bonds conferring secondary, tertiary, or quaternary structure are broken either chemically or by heat or radiation