Chapter 3 - Protein, Carbohydrates and Lipids

Question 1

Monomer

Answer 1

A molecule that can be covalently bonded to other identical molecules to form a polymer

Question 2

Isomers

Answer 2

Molecules that have the same chemical formula, the same kinds and numbers of atoms, but with the atoms arranged differently

Question 3

Structural Isomers

Answer 3

Isomers that differ in how their atoms are joined together

Question 4

Cis-trans Isomers (geometric)

Answer 4

Same molecular formula but must contain a C=C (carbon carbon double bond)

Question 5

Optical Isomers (stereoisomers or enantiomers)

Answer 5

Two 3D molecules that are mirror images of each other; not superimposable (placed on top of each other); one isomer typically is biologically active and the other isomer is inactive

Question 6

Chiral Carbon

Answer 6

When a carbon atom has 4 different atoms or groups of atoms attached to it

Question 7

Condensation (Dehydration) Reactions

Answer 7

Result in the formation of covalent bonds between the same type of monomers (ie. 2 amino acids, 2 nucleotides, etc); an H2O is removed

Question 8

Hydrolysis

Answer 8

Result in the breakdown of polymers into their component monomers to release energy

Question 9

Protein

Answer 9

Polymers made up of 20 amino acids in different proportions and sequences; most prevalent macromolecule

Question 10

Zwitterion

Answer 10

A molecule or ion having separate positively and negatively charged groups

Question 11

Amino Acids

Answer 11

Building blocks of protein; contains an amino group, a carboxyl group, a hydrogen and a R group (side chain) all attached to a carbon atom

Question 12

Polypeptide chain

Answer 12

Single, unbranched chain of amino acids

Question 13

Amino acids are in what 2 isomeric forms?

Answer 13

Amino acids are optical isomers with with a right side, D-amino acid, and a left side, L-amino acid; L-amino acids are found in organisms

Question 14

Disulfide bridge

Answer 14

The terminal –SH group of cysteine can react with another cysteine side chain to form a disulfide bridge or disulfide bond (–S–S–); this creates protein folding in the tertiary structure

Question 15

Primary structure of protein

Answer 15

Sequence of amino acids that determines the secondary and tertiary structure–how the protein is folded

Question 16

Secondary structure of protein

Answer 16

Amino sequences creates two types of secondary structures: alpha helix and beta pleated sheet; these structures are due to the interactions of the backbone or polypeptide chain(s)

Question 17

Alpha helix

Answer 17

Right handed coil (clockwise) resulting from hydrogen bonding between N–H groups on one amino acid and C=O groups on another

Question 18

Beta pleated sheet

Answer 18

2 or more polypeptide chains that are aligned; hydrogen bonds form between the chains

Question 19

Functional groups

Answer 19

Groups of atoms with specific chemical properties and consistent behavior; hydroxyl, aldehyde, keto, carboxyl, amino, phosphate, sulfhydryl functional groups

Question 20

Tertiary structure

Answer 20

Bending and folding results in a macromolecule with a specific 3-D shape; determined by interactions between R-groups/side chains

Question 21

Denaturation

Answer 21

Heating a protein will break down the secondary and tertiary structures causing protein denaturation

Question 22

Renaturation

Answer 22

When cooled, a denatured protein can sometimes return to its normal tertiary structure

Question 23

Degradation

Answer 23

The breakage of peptide bonds in the primary structure of the protein; irreversible

Question 24

Proline side chain

Answer 24

Forms a ring, which limits its hydrogen bonding ability and the ability to rotate about the alpha carbon; often found where a protein bends or loops in the secondary structure

Question 25

Quaternary structure

Answer 25

Functional proteins contain 2 more polypeptide chains or subunits and results from the ways the subunits interact--hydrophobic interactions, van der Waals forces, ionic attractions and hydrogen bonds

Question 26

Conditions that alter secondary and tertiary structure

Answer 26

Increased temperature, pH and salt concentrations

Question 27

Chaperone

Answer 27

A protein that surrounds a denatured protein and allows it to refold or surrounds a newly formed unfolded protein and allows it fold properly

Question 28

When do proteins change shape?

Answer 28

Interaction with other molecules; covalent modification--addition of a chemical group to an amino acid

Question 29

Carbohydrate

Answer 29

A macromolecule that is a source of stored energy and used to transport stored energy; can be a straight chain or ring (ring is stronger)

Question 30

Monosaccharide

Answer 30

Carbohydrate monomer that has a 1-ring structure; simple sugars; ie. glucose

Question 31

Disaccharide

Answer 31

2 simple sugars linked by covalent bonds

Question 32

Oligosaccharides

Answer 32

Carbohydrates made up of 3-20 monosaccharides linked by covalent bonds; often covalently bonded to proteins and lipids on cell surfaces

Question 33

Polysaccharide

Answer 33

Carbohydrates made up of hundreds to thousands of monosaccharides; ie. starch, glycogen, cellulose

Question 34

Glucose

Answer 34

Monosaccharide that all cells use an energy source; ring chain form is more common and stable; alpha-glucose contains an attached --H above Carbon-1; beta-glucose contains an attached --OH above Carbon-1

Question 35

Glycosidic linkages

Answer 35

Monosaccharides bind together in condensation reactions; glycosidic bonds can be alpha--both monosaccharides connected downward, or beta--both monosaccharides connected cross diagonally

Question 36

Starch

Answer 36

Polysaccharide in a helix shape that is the storage of glucose in plants; alpha linkages hold monomers together

Question 37

Glycogen

Answer 37

Polysaccharide in a branch shape that is the storage of glucose in animals; alpha linkages hold monomers together

Question 38

Cellulose

Answer 38

Polysaccharide in a linear shape that very stable and good for structural components; beta linkages hold monomers together

Question 39

Chemically modified carbohydrate

Answer 39

Carbohydrate modified by oxidation-reduction reactions by the additional attachment of functional groups--phosphate, groups, amino groups, N-acetal groups (chitin)

Question 40

Lipids

Answer 40

Nonpolar hydrocarbons that are insoluble in H2O; not covalently bonded

Question 41

Triglyceride

Answer 41

Fats and oils that contain 3 fatty acid chains (hydrophobic) and 1 glycerol molecule (hydrophilic)

Question 42

Ester linkage

Answer 42

A condensation/dehydration reaction that covalent bond between the carboxyl group of fatty acids and a hydroxyl group of glycerol

Question 43

Saturated fatty acid

Answer 43

The bonds between C and the hydrocarbon chain are single bonds--the fatty acids are saturated with H atoms; molecules are packed tightly; Animals fats--butter are packed tightly and solid at room temperature

Question 44

Unsaturated fatty acids

Answer 44

The fatty acid hydrocarbon chain contains 1 or more double bond--creates kinks; Plant oils are liquid at room temperature and have unsaturated tails which prevents them being packed tightly

Question 45

Amphipathic

Answer 45

Fatty acids have opposing chemical properties; The hydrophobic tail (nonpolar hydrocarbon chain) and hydrophilic head (carboxyl group) have opposing reactions to water

Question 46

Phospholipid

Answer 46

A glycerol bound to1 phosphate group (hydrophic head) and 2 fatty acids (hydrophobic tails); amphipathic

Question 47

Phospholipid bilayer

Answer 47

2 layers of phospholipids that line up the hydrophobic tails together facing inward and the phosphate heads facing outward; ie. biological membranes

Question 48

Steroids

Answer 48

A type of lipid that is structured with multiple rings that share carbons; three 6-membered rings attached to one 5-member ring; \*\*\*memorize the structure; functions as hormones

Question 49

Cholesterol

Answer 49

Type of lipid/steroid that is an important constituent of cell membranes