Study guide

Chemistry & Macromolecules Study Guide

1. Molecules vs. compounds

  • Molecule: Two or more atoms chemically bonded together.

  • Compound: A substance made of two or more different elements chemically bonded.

  • Example: O₂ is a molecule but not a compound; H₂O is both.

2. Trace elements of the body

Elements needed in very small amounts:

  • Iron (Fe)

  • Copper (Cu)

  • Zinc (Zn)

  • Iodine (I)

  • Fluorine (F)

  • Manganese (Mn)

  • Chromium (Cr)

  • Selenium (Se)

3. Covalent vs. ionic vs. hydrogen bonds

  • Covalent: Atoms share electrons.

  • Ionic: Electrons are transferred, creating charged ions that attract each other.

  • Hydrogen: A weak attraction between a slightly positive hydrogen and another electronegative atom.

4. Solution vs. suspension vs. emulsion vs. colloid

  • Solution: Particles are evenly dissolved; do not settle. Example: salt water.

  • Suspension: Large particles that can settle out. Example: muddy water.

  • Emulsion: Two liquids that normally don’t mix are dispersed together. Example: oil and water.

  • Colloid: Intermediate-sized particles that don’t settle easily. Example: milk.

5. Anabolic vs. catabolic reactions

  • Anabolic: Builds larger molecules from smaller ones; requires energy.

  • Catabolic: Breaks larger molecules into smaller ones; releases energy.

6. Functional groups of amino acids

The basic groups are:

  • Amino group: –NH₂

  • Carboxyl group: –COOH

  • R group: Varies between amino acids and determines their properties.

7. Most abundant elements of the body

The four major elements are:

  • Oxygen (O)

  • Carbon (C)

  • Hydrogen (H)

  • Nitrogen (N)

8. Atomic number and atomic mass

  • Atomic number = number of protons

  • Mass number = protons + neutrons

  • Atomic mass on the periodic table is the weighted average of an element’s isotopes.

9. Atomic structure

  • Protons: Positive (+), in nucleus

  • Neutrons: No charge, in nucleus

  • Electrons: Negative (−), outside nucleus

10. What atomic particle determines chemical properties and bonding?

Electrons, especially valence electrons (electrons in the outermost shell).

11. What happens to salt when put in water?

Salt dissociates into its ions.
For example: NaCl → Na⁺ + Cl⁻

The water molecules surround and separate the ions.

12. Anion vs. cation

  • Cation: Positive ion → lost electrons

  • Anion: Negative ion → gained electrons

CATion = positive is an easy way to remember.

13. Properties of water

Water:

  • Is polar

  • Is an excellent solvent

  • Has high heat capacity

  • Has cohesion and adhesion

  • Helps regulate body temperature

  • Participates in chemical reactions

14. What is # of molecules per volume?

This is concentration.

A common measure is molarity (M):
Moles of solute ÷ liters of solution

15. pH scale

Measures how acidic or basic a solution is.

  • 0–6 = acidic

  • 7 = neutral

  • 8–14 = basic/alkaline

    Lower pH = more H⁺
    Higher pH = less H⁺

16. How does your body maintain constant blood pH?

Mainly through:

  1. Buffer systems — act quickly

  2. Respiratory system — lungs regulate CO₂

  3. Kidneys — regulate H⁺ and bicarbonate

Normal blood pH is about 7.35–7.45.

17. Types of reactions

Four major types:

  • Synthesis: A + B → AB

  • Decomposition: AB → A + B

  • Exchange: AB + CD → AD + CB

  • Reversible: Reaction can go in both directions.

18. Exergonic vs. endergonic

  • Exergonic: Releases energy.

  • Endergonic: Requires/absorbs energy.

19. Factors that increase or decrease reaction rate

Reaction rate can be affected by:

  • Temperature: Higher temperature usually increases rate.

  • Concentration: Higher concentration usually increases collisions.

  • Particle size/surface area: More surface area increases rate.

  • Catalysts/enzymes: Speed up reactions.

  • Chemical nature of reactants: Some substances react more easily than others.

20. Functional groups

Important functional groups include:

  • Hydroxyl: –OH

  • Carbonyl: C=O

  • Carboxyl: –COOH

  • Amino: –NH₂

  • Phosphate: –PO₄

  • Sulfhydryl: –SH

21. What makes a compound organic?

An organic compound generally contains carbon bonded to hydrogen (C–H).

22. Hydrolysis vs. dehydration synthesis

  • Dehydration synthesis: Removes water to build a larger molecule.

  • Hydrolysis: Adds water to break apart a larger molecule.

23. Elements found in each macromolecule

Macromolecule

Main elements

Carbohydrates

C, H, O

Lipids

C, H, O

Proteins

C, H, O, N, sometimes S

Nucleic acids

C, H, O, N, P

24. Examples of macromolecules

  • Carbohydrates: Glucose, starch, glycogen

  • Lipids: Fats, oils, phospholipids

  • Proteins: Enzymes, antibodies, muscle proteins

  • Nucleic acids: DNA, RNA

25. Structure of macromolecules

  • Carbohydrates: Sugars/monosaccharides linked together

  • Lipids: Glycerol + fatty acids

  • Proteins: Amino acids linked together

  • Nucleic acids: Nucleotides linked together

26. Hydrophobic vs. hydrophilic

  • Hydrophobic: “Water-fearing”; does not mix well with water.

  • Hydrophilic: “Water-loving”; interacts well with water.

27. Functions of macromolecules

  • Carbohydrates: Quick energy

  • Lipids: Long-term energy, insulation, cell membranes

  • Proteins: Structure, enzymes, transport, movement, defense

  • Nucleic acids: Store and transmit genetic information

28. Denaturation

Denaturation is when a protein loses its normal shape because of things like heat, pH changes, or chemicals.
This can cause it to lose its function.

29. Levels of protein structure

  1. Primary: Amino acid sequence

  2. Secondary: Coils and folds

  3. Tertiary: Overall 3-D shape of one polypeptide

  4. Quaternary: Two or more polypeptide chains together

30. DNA and RNA

  • DNA: Stores genetic information; usually double-stranded.

  • RNA: Helps use genetic information to make proteins; usually single-stranded.

Bases:

  • DNA: A, T, C, G

  • RNA: A, U, C, G

31. Reactants vs. products

  • Reactants: Starting substances in a reaction.

  • Products: Substances made by the reaction.

Example:
Reactants → Products


Buffers & Acid-Base Balance

32. Why is carbon so versatile?

Carbon can form four covalent bonds and can bond with many different atoms and with other carbon atoms. This allows it to form many different shapes and molecules.

33. Function of minerals in the body

Minerals help with:

  • Bone and tooth structure

  • Nerve function

  • Muscle contraction

  • Fluid balance

  • Enzyme activity

  • Blood and oxygen-related functions

34. Function of a buffer system

A buffer resists sudden changes in pH by binding or releasing H⁺ when needed.

35. Examples of buffer systems

  • Bicarbonate buffer system

  • Phosphate buffer system

  • Protein buffer system

36. Bicarbonate buffer system reaction

The basic reaction is:

CO₂ + H₂O ⇌ H₂CO₃ ⇌ H⁺ + HCO₃⁻

  • More H⁺ → bicarbonate can help remove excess H⁺.

  • More CO₂ → produces more H⁺.

  • Lungs control CO₂.

  • Kidneys control H⁺ and HCO₃⁻.

37. Main buffer in blood

The bicarbonate buffer system is the major buffer system in blood.

38. How do the kidneys help regulate pH?

The kidneys:

  • Excrete H⁺ into urine.

  • Reabsorb bicarbonate (HCO₃⁻).

  • Can produce new bicarbonate.

This helps keep blood pH within its normal range.

39. Acid-base conditions

Metabolic acidosis

  • Blood becomes too acidic.

  • Usually caused by too much acid or too little bicarbonate.

  • Example: severe diarrhea or certain metabolic problems.

Metabolic alkalosis

  • Blood becomes too basic/alkaline.

  • Usually caused by too much bicarbonate or loss of acid.

  • Example: prolonged vomiting.

Respiratory acidosis

  • Too much CO₂ remains in the blood because ventilation isn’t removing enough.

  • CO₂ increases → H⁺ increases → pH decreases.

Respiratory alkalosis (you may mean this by “urinary alkalosis”)

  • Too much CO₂ is removed through breathing.

  • CO₂ decreases → H⁺ decreases → pH increases.

Urinary/renal acid-base changes

  • Urine can become more acidic when the kidneys excrete more H⁺.

  • Urine can become more alkaline when the kidneys excrete more bicarbonate.

  • These are kidney responses, rather than the main names used to classify blood acid-base disorders.

Diabetic ketoacidosis (DKA)

  • Can occur when the body doesn’t have enough insulin and starts producing too many ketones.

  • Ketones are acidic, which can cause metabolic acidosis.

⭐ Things I’d memorize first

If you’re short on time, focus especially on:

Cation = positive
Anion = negative
Atomic number = protons
Valence electrons = bonding/chemical properties
Anabolic = build
Catabolic = break down
Hydrolysis = add water/break
Dehydration synthesis = remove water/build
Hydrophobic = doesn’t like water
Hydrophilic = likes water
pH < 7 = acid
pH 7 = neutral
pH > 7 = base
Bicarbonate = major blood buffer
Lungs = CO₂ regulation
Kidneys = H⁺ and HCO₃⁻ regulation