BIOLOGICAL MOLECULES L3

Question 1

carbon backbone

Answer 1

can vary in 4 ways:

• length
• double bond position
• branching
• presence of rings
• geometry affects function

Question 2

hydrocarbons

Answer 2

• organic molecules of only C and H
• nonpolar
• uncharged
• hydrophobic
• nonionic
• ex. methane
• can contain function groups: replace one or more H

Question 3

functional groups

Answer 3

• key to molecular function
• replace H with something else
• ex. estradiol v. testosterone
• 7 key groups

Question 4

hydroxyl group

Answer 4

• OH
• oxygen bound to hydrogen
• alcohols, end in -ol
• polar
  hydrophilic
• ex. ethanol

Question 5

carbonyl group

Answer 5

= O

• carbon with double covalent bond to O
• polar
• hydrophilic
• ex. acetone

Question 6

carboxyl group

Answer 6

• COOH
• carbon with double bond to O and single bond to OH
• can release proton (H+)
• acidic
• polar
• hydrophilic
• important part of amino acids

Question 7

amino group

Answer 7

• NH2
• N bound to 2 H’s
• proton acceptor
• basic
• important component of amino acids
• hydrophilic
• ex. glycine

Question 8

sulfhydryl group

Answer 8

• SH
• sulfur bound to hydrogen
• often important in protein structure
• weakly polar
• ex. cysteine

Question 9

phosphate group

Answer 9

• PO4H2
• oxygen bonded to P, 1 O, 2OH’s
• 1 double bond present
• can release 1 or both H+’s
• exists ionized and nonionized
• acidic
• hydrophilic
• ex. glycerol phosphate
• found in phospholipids and nucleic acids

Question 10

methyl group

Answer 10

• CH3
• C bonded to 3H’s
• all single bonds
• nonpolar
  hydrophobic
• in DNA, effects gene expression
• ex. methyl cytosine

Question 11

macromolecules

Answer 11

• large molecules: thousands of atoms
• polymers: produced by linking monomers
• monomers: identical or similar building blocks

Question 12

dehydration reaction

Answer 12

• synthesizing a polymer

Question 13

hydrolysis

Answer 13

• breaking down a polymer
• adds water molecule, breaks a bond
• enzyme: hydrolase

Question 14

4 classes of biological molecules

Answer 14

• carbohydrates
• lipids: not polymers
• proteins
• nucleic acids

Question 15

carbohydrates

Answer 15

• made of C,H,O
• 1:2:1 ratio
• monomers are sugars
• 3 - 7Cs long
• hydroxyl groups
• carbonyl groups
• very hydrophilic
• end with -ose
• fuel and structure

Question 16

monosaccharides

Answer 16

• single sugars
• classified by number of carbons and location of carbonyl group
• glucose = most common

Question 17

glucose

Answer 17

• C6H12O6
• linear and ring forms
• can form isomers: alpha and beta glucose due to different ways the ring can close

Question 18

disaccharides

Answer 18

• formed via linkage of 2 monosaccharides
• dehydration reaction
• glycosidic linkage (covalent bond)

Question 19

polysaccharides

Answer 19

• polymer of hundreds to thousands on monosaccharides
• two main functions in cells: structure and storage
• function determined by: type of monomer, position of glycosidic linkage

Question 20

plant storage polysaccharide: starch

Answer 20

• alpha glucose subunits

Question 21

animal storage polysaccharide: glycogen

Answer 21

• alpha glucose subunits
• stored in muscles and liver
• larger, more branches than starch

Question 22

structural polysaccharide: cellulose

Answer 22

• most abundant organic compound on earth
• beta glucose subunits
• requires different enzymes
• very few organisms can digest: some microbes, fungi, and snails

Question 23

structural polysaccaride: chitin

Answer 23

• beta glucose with an N-containing group
• monomer = N-acetyl glucoseamine
• arthropod exoskeleton
• fungi cell walls

Question 24

lipids

Answer 24

• diverse
• hydrophobic
• not polymers
• do not dissolve in water
• dissolve in non polar solvents (ex. choloroform)
  3 types:
• fats
• phospholipids
• steroids

Question 25

fats

Answer 25

• most abundant
• energy storage
• structure: glycerol: 3 carbon alcohol, 3 OH groups
• fatty acid: unbranched hydrocarbon
• connection via ester linkage

Question 26

saturated fatty acids

Answer 26

• each C bonded to highest possible number of H
• saturated with H
• tend to be solid at room temperature
• straight chains
• most animal fats are saturated

Question 27

unsaturated fatty acids

Answer 27

• double bonds in hydrocarbon chain
• fewer H than maximum capacity
• monounsaturated = 1 double bond
• polyunsaturated = 2+ double bonds
• double bonds = kinks in molecules
• less dense packing
• tend to be liquid at room temperature
• plant, fish fat

Question 28

trans fatty acids

Answer 28

• double bonds like unsaturated
• but, opposite orientation
• linear fatty acid
• fewer H
• packed tighter than saturated

Question 29

phospholipids

Answer 29

• glycerol + 2 fatty acids + phosphate group
• hydrophilic head (phosphate)
• hydrophobic tail (fatty acid)
• amphipathic

Question 30

steroids

Answer 30

• 3 6C rings + 1 5C ring
• differ in functional groups
• ex. cholesterol, sex hormones

Question 31

proteins

Answer 31

- monomers = amino acids
all have the same basic structure:
- central (alpha) carbon
- H atom
- amino group (basic)
- carboxyl group (acidic)
- R group - side chain - variable

Question 32

peptide bonds

Answer 32

• AAs joined by peptide bonds between carboxyl and amino groups
• form via dehydration reactions

Question 33

polypeptides

Answer 33

• many (100+) AAs joined in linear sequence by peptide bonds

- not a protein yet, requires correct shape

Question 34

protein unfolding

Answer 34

• denaturation: loss of proteins native structure
• lose structure = lose function
• cased by pH, salt concentration, high temp

Question 35

protein functions

Answer 35

• structure
• signaling
• enzymes
• defense
• transport

Question 36

nucleic acids

Answer 36

• polymers of nucleotides
• DNA
• RNA
• store and transmit genetic information