Biology and Biochemistry Year-End Review

Scientific Method

• Hypotheses are formed from observations and are tested experimentally.

Parts of the Cell

• Cell Membrane: Composed of lipids and proteins; structured as a phospholipid bilayer.
• Ribosomes: Built from RNA and proteins; essential for protein synthesis; found on the rough endoplasmic reticulum or free in the cytoplasm.
• Smooth Endoplasmic Reticulum: Synthesizes lipids and lacks ribosomes.
• Nucleus: Houses DNA; messenger RNA is transcribed from DNA and exits through nuclear envelope pores to be translated into proteins.
• Mitochondria: Known as the powerhouse of the cell; produces most ATP; contains its own DNA for independent replication.
• Golgi Apparatus: Packages cellular products into vesicles for transport.
• Peroxisomes: Detoxify hydrogen peroxide (H2O2).

ATP Production

• Cellular Respiration: Comprises three stages—Glycolysis, Krebs Cycle, and Oxidative Phosphorylation.
  • Glycolysis: Occurs in the cytoplasm, converts glucose to 2 pyruvate, produces 2 net ATP, and is anaerobic.
  • Krebs Cycle (Citric Acid Cycle): Takes place in mitochondria, generates 2 ATP, and requires oxygen.
  • Oxidative Phosphorylation: Produces 34 ATP via the electron transport chain (ETC) in the inner mitochondrial membrane; oxygen acts as the final electron acceptor.
• Cyanide is lethal as it disrupts the ETC, preventing ATP production.

Types of Particle Movement

• Simple Diffusion: Movement of fat-soluble substances across the cell membrane without energy.
• Facilitated Diffusion: Water-soluble substances move via protein channels (e.g., Na+ channels) without energy.
• Active Transport: Movement against the concentration gradient from low to high concentration, requiring ATP (e.g., Sodium/Potassium pump).
• Osmosis: Water diffuses towards charged particles; cell behavior varies in hypertonic and hypotonic solutions.

Genetics

• Transcription: DNA is converted to RNA by RNA polymerase; RNA is translated into proteins by ribosomes.
• Base Pair Rules: Guanine pairs with cytosine; adenine pairs with thymine (uracil replaces thymine in RNA).
• Mutation: Point mutation refers to random changes in the DNA sequence.
• Genotype vs. Phenotype: Homozygous is represented as AA or aa; heterozygous as Aa; genotype is the genetic representation, while phenotype is the observable trait.

Mitosis vs. Meiosis

• Mitosis: Results in two identical daughter cells.
• Meiosis: Produces two daughter cells with half the genetic information, occurring in sex cells for reproduction.

Biochemistry Basics

• Subatomic Particles:
  • Protons: Positively charged, found in the nucleus.
  • Neutrons: Neutral, also located in the nucleus.
  • Electrons: Negatively charged, orbit in shells around the nucleus.

Periodic Table Essentials

• Atomic Number: Represents the number of protons in an element.
• Mass Number: Sum of protons and neutrons.
• Atomic Mass: Average mass of all isotopes of an element.
• Isotopes: Atoms of the same element that differ in neutron count.
• Valence Electrons: Outer electrons significant in chemical reactions.

Types of Chemical Bonds

• Covalent Bonds: Involve sharing of electrons to form molecules.
• Ionic Bonds: Result from the transfer of electrons, forming ions.

Macronutrients

• Proteins: Composed of amino acids linked by peptide bonds; glycine is the simplest amino acid.
• Protein Structures:
  • Primary: Sequence of amino acids.
  • Secondary: Folding into alpha helix or beta-pleated sheet.
  • Tertiary: Further folding into a 3D structure.
  • Quaternary: Combination of multiple polypeptide chains.
• Enzymes: Proteins that lower activation energy and accelerate reactions; can denature due to heat or acids.

Lipids

• Triglycerides: Composed of a glycerol backbone and three fatty acid tails.
• Cholesterol: A lipid that serves as the foundation for steroid hormones.

Carbohydrates

• Monosaccharides: Includes glucose, fructose, and galactose.
• Disaccharides: Comprise sucrose (glucose + fructose), maltose (glucose + glucose), and lactose (glucose + galactose).
• Isomers: Molecules with identical atom counts but differing arrangements, e.g., fructose and glucose.

Acid/Base Chemistry

• Acids: Proton donors that release H+ ions in solution.
• Bases: Proton acceptors that bind H+ ions.
• Neutralization Reaction: Combines an acid and base to form salt and water, achieving neutrality.

This quiz covers key concepts from biology and biochemistry, focusing on the scientific method, cell structure, and functions. Test your knowledge on the various components of the cell and their roles. A great way to review before the year-end exams!