Chapter 6 - Macromolecules I

Question 1

What is a monomer?

Answer 1

A small organic molecule that can bond to similar molecules; building block of polymers.

Question 2

What functional groups allow bonding in monomers?

Answer 2

–OH, –NH₂, –COOH, –PO₄

Question 3

What is a polymer?

Answer 3

A macromolecule made of repeating monomers linked in chains or branches.

Question 4

Analogy for monomers and polymers?

Answer 4

Beads (monomers) strung together into a necklace (polymer).

Question 5

What reaction forms polymers?

Answer 5

Dehydration (condensation) – monomers join, release H₂O, form covalent bond.

Question 6

Examples of bonds in polymers?

Answer 6

Carbohydrates = glycosidic bond, Proteins = peptide bond, Nucleic acids = phosphodiester bond.

peptide: between aminoacids
glycosidic: monosaccharides
phosphodiester : nucleotides

Question 7

What reaction breaks down polymers?

Answer 7

Hydrolysis – water is added to break bonds.

Question 8

Which enzymes break down polymers?

Answer 8

Amylase (starch → sugars), Protease (proteins → amino acids), Nuclease (nucleic acids → nucleotides).

Question 9

Why store monomers as polymers?

Answer 9

Reduces osmotic pressure in cells.

If a cell has too many free monomers floating inside, water will rush in, causing the cell to swell or even burst.
Storing monomers as polymers lowers the number of “particles”

Question 10

How do polymers increase versatility?

Answer 10

Different arrangements of the same monomers create different polymers (e.g., starch vs cellulose).

Question 11

Composition of carbohydrates?

Answer 11

Carbon, Hydrogen, Oxygen (C:H:O ~ 1:2:1).

Question 12

Formula for glucose, fructose, galactose?

Answer 12

C₆H₁₂O₆.

Question 13

Functions of carbohydrates?

Answer 13

Immediate energy (glucose → ATP), storage (starch, glycogen), structural (cellulose, chitin, peptidoglycan).

Question 14

Examples of monosaccharides?

Answer 14

Glucose (energy), Fructose (fruit sugar), Galactose (in lactose), Ribose (RNA), Deoxyribose (DNA).

Question 15

Examples of disaccharides?

Answer 15

Sucrose (glucose+fructose, table sugar), Lactose (glucose+galactose, milk sugar), Maltose (glucose+glucose, starch digestion).

Question 16

Storage polysaccharides?

Answer 16

Starch (plants), Glycogen (animals).

Question 17

Structural polysaccharides?

Answer 17

Cellulose (plants), Chitin (fungi/insects), Peptidoglycan (bacteria)

Question 18

Why can’t humans digest cellulose?

Answer 18

It has β-1,4 bonds (humans can only digest α-linkages).

Question 19

Energy yield of carbohydrates?

Answer 19

4 kcal per gram

Question 20

Composition of lipids?

Answer 20

Mostly C & H, small O; sometimes P, N, S.

Question 21

Are lipids polar or nonpolar?

Answer 21

Mostly nonpolar, hydrophobic.

Question 22

Energy yield of lipids?

Answer 22

9 kcal per gram (more than carbs/proteins).

Question 23

Main functions of lipids?

Answer 23

Long-term energy storage, insulation/protection, membrane structure, hormones/signaling.

Question 24

What are triglycerides made of?

Answer 24

Glycerol + 3 fatty acids, joined by ester bonds.

Question 25

Saturated vs unsaturated fats?

Answer 25

Saturated = no double bonds, solid; Unsaturated = double bonds, liquid.

Question 26

What is a phospholipid made of?

Answer 26

Glycerol + 2 fatty acids + phosphate head

Question 27

Why are phospholipids amphipathic? (water loving and water hating)

Answer 27

Hydrophilic head + hydrophobic tails.

Question 28

What is the function of steroids?

Answer 28

Hormones (testosterone, estrogen), membrane stabilizer (cholesterol), precursor of vitamin D & bile acids.

Question 29

What are waxes made of?

Answer 29

Long-chain fatty acids + long-chain alcohol.

Question 30

Q: What reaction forms triglycerides?

Answer 30

A: Dehydration synthesis (ester bonds).

Question 31

Q: What enzyme breaks down lipids in hydrolysis?

Answer 31

A: Lipase.

Question 32

Q: What is hydrogenation?

Answer 32

A: Adding hydrogen to unsaturated fats → makes oils solid, can create unhealthy trans fats.