Inorganic Chemistry and Carbohydrates – Page 1 Notes

Water is the most abundant inorganic compound. It is present in all living cells and accounts for about 68% of the volume of living cells. Rough intuition: if a room were a cell, about 80% of it would be water; dehydration could drop toward ~60%. These figures establish water’s foundational role in biology.
Key properties of water discussed:
- High heat capacity: water absorbs a lot of heat without a large rise in temperature.
- High heat of vaporization: a lot of energy is required to evaporate water.
- Polarity: water is polar and interacts well with other polar molecules (e.g., glucose, a polar molecule).
- Reactivity and cushioning: water participates in reactions and provides cushioning/protection for tissues.
Practical takeaway: water is central to cell physiology, structure, and thermodynamics.

Salts dissociate in water into ions. When salts dissolve, they yield ions; these ions are electrolytes.
Example: table salt is sodium chloride. When NaCl dissolves in water, it yields
- Na⁺ (cation) and Cl⁻ (anion)
All salts are electrolytes, and knowing a salt example (e.g., NaCl) is useful for exams.
Basic note used in classroom questions: identifying a salt example (NaCl) and distinguishing cations vs. anions (Na⁺ vs. Cl⁻).

Acids and bases are both electrolytes and dissociate in water.
Acids: proton donors. They release hydronium ions (H₃O⁺) in solution. In simple terms: acids donate H⁺.
Bases: proton acceptors. They accept protons and often produce hydroxide ions (OH⁻) which can combine with H⁺ to form water. A classic strong base example: NaOH → Na⁺ + OH⁻.
Understanding of proton transfer is central to acid–base chemistry in biology (Brønsted–Lowry framework).
A typical exam-style question mentioned: identifying which substance is not a proton donor (i.e., not an acid).

pH is the measure of hydrogen ions in an aqueous solution. In short: it reflects [H⁺] in solution.
The pH scale ranges from 0 to 14, with 7 being neutral.
A standard reference often used in physiology is the blood pH range:
- In this course, blood pH is discussed as approximately 7.35 to 7.4 (a narrow physiological range).
The lecture emphasizes what to know on exams: the general pH concept, 7 as neutral, and how pH is important for physiological processes.

Buffers help maintain pH within narrow limits in the body. They bind or release hydrogen ions as needed to resist pH changes.
Examples of typical pH values in different parts of the body:
- Stomach: around pH ≈ 1 (high acidity)
- Small intestine: about pH 6–7
- Blood: about pH 7.35–7.4
- Saliva: around pH 7
- Tears: around pH ~6
Buffers are essential for survival because fluctuations in pH can disrupt enzyme activity and cellular processes.

Core topics to know for inorganic compounds: water, salts, acids and bases, pH, and buffers.
These concepts underpin physiology and are repeatedly tested in exams.

Dehydration synthesis (condensation): monomer + monomer → polymer +
- a molecule of water is produced in the process.
Hydrolysis: polymer + water → monomer(s)
The course repeatedly references this pair of reactions (synthesis vs hydrolysis) in carbohydrate chemistry.

Carbohydrates can be described as monosaccharides (single sugars), disaccharides (two sugars), and polysaccharides (many sugars).
- The term poly- means many; di- means two; mono- means one.
An example trajectory shown: two monosaccharides join via dehydration synthesis to form a disaccharide, with water released in the process.

The lecture highlights three common monosaccharides:
- Glucose
- Fructose
- Galactose
These are typically the foundational monosaccharides discussed in introductory carbohydrate chemistry.

The instructor notes an error in a slide: the slide labeled a particular disaccharide pairing should list glucose instead of fructose. Correct pairings (as clarified in class) are:
- Glucose + Glucose → Maltose
- Glucose + Fructose → Sucrose
- Glucose + Galactose → Lactose
The takeaway: learn the corrected pairs for disaccharides listed above.

Formed by linking two monosaccharides, typically via dehydration synthesis, with the release of a water molecule.
Examples from the lecture (and standard biochemistry):
- Maltose: glucose + glucose
- Sucrose: glucose + fructose
- Lactose: glucose + galactose

Formed by linking many monosaccharides through repeated dehydration synthesis reactions.
The lecture mentions the formation of polysaccharides and sets up the concept, but specific polysaccharide examples are not detailed in the provided transcript.

Carbohydrates serve as a major energy source (e.g., glucose) and as structural components in some organisms.
The interplay between dehydration synthesis and hydrolysis is foundational for building complex carbohydrates and for metabolism (energy extraction via hydrolysis).

Salt dissociation (example):
ext{NaCl}
ightarrow ext{Na}^+ + ext{Cl}^-
Acid dissociation (conceptual):
ext{HA}
ightarrow ext{H}^+ + ext{A}^- ext{ (in water forming } ext{H}_3 ext{O}^+ ext{)}
Base dissociation (conceptual):
ext{B} + ext{H}^+
ightarrow ext{BH}^+ ext{ (or formation of OH⁻ in some bases) }
Dehydration synthesis (general):
ext{Monomer}1 + ext{Monomer}2
ightarrow ext{Disaccharide} + ext{H}_2 ext{O}
Hydrolysis (general):
ext{Disaccharide} + ext{H}2 ext{O} ightarrow ext{Monomer}1 + ext{Monomer}_2
Monosaccharide examples (three highlighted):
- glucose, fructose, galactose
Disaccharide examples (corrected pairings):
- - maltose:
    ext{glucose} + ext{glucose}
    ightarrow ext{maltose} + ext{H}_2 ext{O}
- sucrose:
  ext{glucose} + ext{fructose}
  ightarrow ext{sucrose} + ext{H}_2 ext{O}
- lactose:
  ext{glucose} + ext{galactose}
  ightarrow ext{lactose} + ext{H}_2 ext{O}

This notes document summarizes the key points from the first portion of the lecture:

Inorganic chemistry basics (water, salts, acids/bases, pH, buffers)
Foundational physiologic ranges (blood pH, buffer roles, pH in stomach/intestine/saliva/tears)
Carbohydrate chemistry basics (dehydration synthesis, hydrolysis, monosaccharides and disaccharide examples, and the polysaccharide concept)
Corrected teaching points and an emphasis on how these concepts connect to biology and physiology.