Unit 1

Question 1

Why is water polar?

Answer 1

Oxygen pulls electrons more strongly than hydrogen, creating partial charges.

Question 2

What bond holds water molecules together?

Answer 2

Hydrogen bonds.

Question 3

What property of water allows surface tension?

Answer 3

Cohesion (water sticking to water).

Question 4

What property of water explains capillary action?

Answer 4

Cohesion + adhesion.

Question 5

Why does ice float?

Answer 5

Solid water is less dense than liquid water (expansion upon freezing).

Question 6

Which property of water stabilizes body/ocean temps?

Answer 6

High specific heat.

Question 7

Why is water an excellent solvent? Able to dissolve other substances

Answer 7

It dissolves polar and ionic substances.

Question 8

Why is carbon so versatile? Adapting

Answer 8

It can form 4 covalent bonds → chains, rings, and branched molecules.

Question 9

Name two important functional groups in biology.

Answer 9

Carboxyl (–COOH), amino (–NH₂), phosphate (–PO₄³⁻), hydroxyl (–OH).

Question 10

What is the monomer of carbohydrates?

Answer 10

Monosaccharides (e.g., glucose, fructose).

Question 11

What type of bond connects monosaccharides?

Answer 11

Glycosidic bond.

Question 12

Name two storage polysaccharides.

Answer 12

Starch (plants) and glycogen (animals).

Question 13

Name two structural polysaccharides.

Answer 13

Cellulose (plants) and chitin (insects/fungi).

Question 14

Are lipids true polymers?

Answer 14

No.

Question 15

What are fats (triglycerides) made of?

Answer 15

Glycerol + 3 fatty acids.

Question 16

What are phospholipids made of?

Answer 16

Glycerol + 2 fatty acids + phosphate group.

Question 17

Why do phospholipids form bilayers in water?

Answer 17

Hydrophilic heads interact with water, hydrophobic tails avoid water.

Question 18

Difference between saturated and unsaturated fatty acids?

Answer 18

Saturated = straight, solid at room temp; unsaturated = bent (double bonds), liquid at room temp.

Question 19

What is the monomer of proteins?

Answer 19

Amino acids.

Question 20

What bond connects amino acids?

Answer 20

Peptide bond.

Question 21

What determines the properties of an amino acid?

Answer 21

The R-group (side chain).

Question 22

What are the four levels of protein structure?

Answer 22

Primary (sequence), secondary (α-helices, β-sheets), tertiary (3D folding), quaternary (multiple polypeptides).

Question 23

What happens when a protein denatures?

Answer 23

It loses structure → loses function (due to heat, pH, salt).

Question 24

What is the monomer of nucleic acids?

Answer 24

Nucleotides (sugar + phosphate + nitrogenous base).

Question 25

What bond connects nucleotides in the backbone?

Answer 25

Phosphodiester bonds.

Question 26

What bond connects nitrogenous bases in DNA?

Answer 26

Hydrogen bonds.

Question 27

Difference between DNA and RNA?

Answer 27

DNA = deoxyribose, thymine, double-stranded. ## Footnote RNA = ribose, uracil, single-stranded.

Question 28

What do enzymes do?

Answer 28

Speed up reactions by lowering activation energy.

Question 29

Where does the substrate bind on an enzyme?

Answer 29

Active site.

Question 30

What is the current model of enzyme activity?

Answer 30

Induced fit model.

Question 31

What factors affect enzyme activity?

Answer 31

Temperature, pH, substrate concentration.

Question 32

What happens when an enzyme is exposed to extreme heat or pH?

Answer 32

It denatures (loses shape and function).

Question 33

Why are hydrogen bonds important in biology?

Answer 33

They give water its properties and stabilize DNA.

Question 34

Why does a single amino acid change affect protein function?

Answer 34

It can alter folding and 3D structure → changes function.

Question 35

Why does DNA use hydrogen bonds instead of covalent bonds between bases?

Answer 35

So strands can separate easily during replication.

Question 36

What do enzymes do?

Answer 36

Lower activation energy → speed up reactions.

Question 37

Where does a substrate bind?

Answer 37

Active site.

Question 38

What is the enzyme activity model called?

Answer 38

Induced fit model.

Question 39

What factors affect enzyme function?

Answer 39

Temperature, pH, substrate concentration.

Question 40

What happens if an enzyme denatures?

Answer 40

It loses shape → cannot function.

Question 41

Why are hydrogen bonds important in DNA?

Answer 41

They allow strands to separate easily for replication.

Question 42

Why does a single amino acid change matter?

Answer 42

It can alter protein folding and function.

Question 43

How does structure of macromolecules determine function?

Answer 43

Shape and chemical properties dictate interactions and roles in cells.