Lecture 5: The Molecules Of Life

Question 1

Enzymes

Answer 1

Specialized macromolecules that speed up chemical reactions

Question 2

Dehydration reaction

Answer 2

2 monomers bond together through loss of a water molecule

Question 3

Hydrolysis

Answer 3

Polymers disassembled to monomers through addition of a water molecule

Hydrogen from water attaching to one monomer and hydroxyl group attaching to other

Question 4

Monosaccharides

Answer 4

Simple sugar

Question 5

Disaccharide

Answer 5

Consists of 2 monosaccharides joined by a glycosidic linkage

Covalent bond formed between 2 monosaccharides by a dehydration reaction

Question 6

Polysaccharides

Answer 6

Polymers of many sugars joined by glycosidic linkages via dehydration synthesis

Ex. Starch, glycogen, cellulose

Question 7

Starch

Answer 7

Storage form of glucose in plants

Question 8

Glycogen

Answer 8

Storage form of glucose in animals

Question 9

Cellulose

Answer 9

Contribute fiber

Like starch, cellulose is a polymer of glucose, but glycosidic linkages differ

Question 10

The difference between starch and cellulose is based on

Answer 10

2 ring forms for glucose: alpha(α) and beta (β)

Starch is alpha configured and is largely helical

Cellulose molecules are beta configured and straight and unbranched

Question 11

Enzymes that digest starch by hydrolyzing alpha linkages

Answer 11

Can’t hydrolyze beta linkages in cellulose

Question 12

Cellulose in human food passes through the digestive tract as

Answer 12

“Insoluble fiber”

Question 13

Fats

Answer 13

Constructed from 2 types of smaller molecules: glycerol and fatty acids

Question 14

Glycerol is

Answer 14

3 carbon alcohol with a hydroxyl group attached to each carbon

Question 15

Fatty acid is

Answer 15

One Carboxyl group attached to a long carbon skeleton

Question 16

Fats separate from water because

Answer 16

Water molecules hydrogen-bond to each other exclude fats

Question 17

Nonpolar C-H bonds in hydrocarbon chains of acids are

Answer 17

Hydrophobic

Question 18

Saturated fatty acids

Answer 18

No double bonds between C atoms of chain

Allows fat molecules to pack together tightly (butter- solid at room temperature)

Question 19

Unsaturated fatty acids

Answer 19

1 or more double bonds between C atoms

Kinks of double bonds prevent molecules from packing closely together and can’t solidify (olive oil-liquid at room temperature)

Question 20

Hydrogenation

Answer 20

Process of converting unsaturated fats to saturated fats by adding hydrogen

Allows them to solidify

Question 21

Trans fats may contribute

Answer 21

More than saturated fats to cardiovascular disease

Question 22

Phospholipids structure

Answer 22

Amphipathic:

2 long hydrocarbon tails (fatty acids)- Hydrophobic (nonpolar)

1 glycerol molecule attached to phosphate group- Hydrophilic (polar)

Question 23

In water, phospholipids self-assemble into

Answer 23

A bilateral or micelles

-hydrophilic heads on outside
-hydrophobic tails point towards interior

Question 24

Protiens

Answer 24

Polypeptides are unbranched polymers built from the same set of 20 amino acids (monomers)

Question 25

R group

Answer 25

Variable side chain of 1 or more atoms that identifies a specific amino acid Contributes to overall shape and function of proteins

Question 26

Amino acids join by

Answer 26

Dehydration synthesis

Question 27

Peptide bond formation

Answer 27

Covalent bond between Carboxyl group of 1 amino acid and amino group of another

Question 28

Polypeptide

Answer 28

Polymers of many amino acids linked by peptide bonds

Question 29

Primary protein structure is determined by

Answer 29

1. Number of amino acids in chain 2. Specific sequence of amino acids

Question 30

Secondary protein structure

Answer 30

Consists of coils and folds in polypeptide chain Result from H-bonding between atoms within polypeptide chain

Question 31

Alpha helix

Answer 31

Simple spiral/coil

Question 32

Beta sheet

Answer 32

Flat pleated sheet/parallel

Question 33

Tertiary protein structure

Answer 33

Overall shape of a polypeptide, results from interactions between R groups (side chains), rather than interactions between backbone constituents

Question 34

Tertiary protein structure contributing interactions:

Answer 34

H-bonds, ionic bonds, hydrophobic interactions, van der Waals forces, disulfide bridges

Question 35

H-bonds

Answer 35

Between polar side chains

Question 36

Ionic bonds

Answer 36

Between charged side chains

Question 37

Hydrophobic interactions

Answer 37

Nonpolar side chains end up in clusters at core of protein, out of contact with water

Question 38

Van der Waals forces

Answer 38

Helps hold nonpolar side chains together

Question 39

Disulfide bridges

Answer 39

Covalent disulfide bonds between 2 cysteine monomers which have Sulfhydryl groups as side chains Reinforce protein structure

Question 40

Denaturation

Answer 40

Loss of a protein’s native structure A desaturated protein is biologically inactive Extremely high fevers can be fatal- proteins in blood tend to denature at very high body temperatures

Question 41

Nucleic acids structure

Answer 41

DNA and RNA consist of long chains of nucleotides(monomers), which contain: 1. Pentose (5-C) sugar (DNA or RNA) 2. Phosphate group 3. Nitrogenous Base (A, G, T, C, or U)

Question 42

Nucleoside

Answer 42

Nitrogenous base + sugar

Question 43

Purine bases

Answer 43

Adenine(A) and guanine (G) 6 membered ring fused to a 5 membered ring

Question 44

Pyrimidine bases

Answer 44

Cytosine (C), thymine (T), Uracil (U) Single 6 membered ring

Question 45

Nucleotides are linked together by

Answer 45

A phosphodiester linkage to build a polynucleotide

Question 46

Phosphodiester linkage

Answer 46

Phosphate group that links sugars of nucleotides These links create a backbone of sugar-phosphate units with nitrogenous bases as appendages