General Biology: Foundations, Chemistry of Life, and Biological Molecules

Chapter 1: Introduction to Biology

Emergent Properties and Scientific Method

Biology is the scientific study of life, encompassing a wide range of topics from molecular biology to ecosystems. Understanding life requires knowledge of both the properties of living systems and the scientific methods used to study them.

• Emergent Property: A characteristic that arises when smaller components combine to form a more complex system, resulting in properties not present in the individual parts. Example: The heart can pump blood, a property not found in individual heart cells.

• Reductionism: The approach of simplifying complex systems by studying their individual components.

• Experiment: A scientific test involving a control group and variables to determine cause and effect.

• Inductive Reasoning: Drawing general conclusions from specific observations.

• Hypothesis: A testable explanation for an observation or scientific problem.

Atomic Structure and Isotopes

Atoms are the basic units of matter, composed of protons, neutrons, and electrons. Isotopes are variants of elements with different numbers of neutrons.

• Isotope: Atoms of the same element with different numbers of neutrons.

• Hydrocarbon: Molecules consisting entirely of hydrogen and carbon atoms.

• Calorie: The amount of heat required to raise the temperature of 1 gram of water by 1 degree Celsius.

Chapter 2: Properties of Life

Characteristics of Living Things

All living organisms share certain properties that distinguish them from non-living matter.

• 1. The ability to adapt

• 2. The ability to use energy

• 3. The ability to reproduce

• 4. The ability to grow and develop

• 5. The ability to respond to the environment

• 6. The organization of cells and tissues

• 7. The ability to regulate body temperature (homeostasis)

Chapter 2: Chemical Bonds in Biology

Types of Chemical Bonds

Chemical bonds are forces that hold atoms together in molecules. The type of bond affects the properties and functions of biological molecules.

Bond Type	Example	Characteristics
Ionic bond	Salt (NaCl), Magnesium chloride	Formed between a metal and a nonmetal; involves transfer of electrons
Covalent bond	H2O	Strongest bond type; involves sharing of valence electrons
Hydrogen bonds	Water, H2	Weak bond; forms when a hydrogen atom with a partial positive charge is attracted to an electronegative atom
Hydrophobic interactions	Water and oil	Non-bonded; occur when nonpolar molecules aggregate to avoid water
Van der Waals	Lizard's feet	Weakest bond type; due to temporary dipoles

Chapter 3: Water and Life

Importance of Water

Water is essential for life due to its unique chemical and physical properties.

• Universal Solvent: Water dissolves more substances than any other liquid, facilitating chemical reactions in living organisms.

• Temperature Regulation: Water has a high specific heat, helping organisms maintain stable internal temperatures.

Calorie Calculations

Understanding how much energy is required to heat water is important in biological systems.

• Formula: $\text{Calories} = \text{mass (g)} \times \text{temperature change (°C)} \times \text{specific heat}$

• Example: To heat 500g of water by 10°C: $500 \times 10 = 5,000$ calories

Origin of Organic Compounds

The synthesis of organic molecules is a key step in the origin of life. Experiments such as the Miller-Urey experiment demonstrated that organic molecules could form under prebiotic conditions.

• Miller-Urey Experiment: Simulated early Earth conditions and produced amino acids from inorganic precursors.

Chapter 4: Structure and Function of Biological Molecules

Cis-Trans Isomers

Cis-trans isomers are molecules with the same molecular formula but different spatial arrangements due to the inflexibility of double bonds.

• Cis Isomer: Same atoms or groups on the same side of a double bond.

• Trans Isomer: Same atoms or groups on opposite sides of a double bond.

Enantiomers

Enantiomers are pairs of molecules that are mirror images of each other but cannot be superimposed. They often have different biological activities.

• Example: S-ibuprofen is effective as a pain reliever, while R-ibuprofen is not.

• Pharmaceutical Importance: Many drugs are only effective in one enantiomeric form.

ATP as an Energy Molecule

ATP (adenosine triphosphate) is the primary energy carrier in cells. Energy is released when ATP is hydrolyzed to ADP and inorganic phosphate.

• Reaction: $\text{ATP} + \text{H}_2\text{O} \rightarrow \text{ADP} + \text{P}_i + \text{energy}$

• Key Point: Breaking the terminal phosphate bond releases energy used for cellular processes.

Functional Groups in Organic Molecules

Functional groups are specific groups of atoms within molecules that determine the chemical properties of those molecules. There are seven major functional groups in biological molecules:

1. Hydroxyl group (-OH)

2. Carbonyl group (C=O)

3. Carboxyl group (-COOH)

4. Amino group (-NH2)

5. Sulfhydryl group (-SH)

6. Phosphate group (-PO42-)

7. Methyl group (-CH3)

• Example: The carboxyl group gives amino acids their acidic properties.

Chapter 2 & 3: Acids, Bases, and pH

pH and Molarity

The pH scale measures the concentration of hydrogen ions in a solution. The sum of pH and pOH in aqueous solutions at 25°C is always 14.

• Formula: $\text{pH} + \text{pOH} = 14$

• Molarity: The concentration of a solute in a solution, typically expressed in moles per liter (M).

• Calculating pH: $\text{pH} = -\log_{10}[\text{H}^+]$

Additional info: Molarity calculations and pH are fundamental for understanding biochemical reactions and cellular processes.