Biology Study Guide: Organelles, Macromolecules, Photosynthesis & Cellular Respiration

Organelles and Their Functions

• Nucleus
  • What it does: Controls all cell activities.
  • Purpose: Stores DNA (genetic material).
  • Think of it like: The brain of the cell.
• Nucleolus
  • What it does: Makes ribosomes.
  • Located in: The nucleus.
  • Think of it like: A ribosome factory inside the brain.
• Cell Membrane
  • What it does: Controls what enters and leaves the cell.
  • Purpose: Protects the cell and helps maintain balance.
  • Think of it like: A bouncer at a club.
• Cell Wall (plants only)
  • What it does: Provides shape, structure, and support.
  • Material: Made of cellulose.
  • Think of it like: A brick wall protecting a garden.
• Vacuole
  • What it does: Stores water, food, and waste.
  • Size: Big in plants, small in animals.
  • Think of it like: A storage container.
• Lysosome
  • What it does: Breaks down waste and damaged parts.
  • Contains: Digestive enzymes.
  • Think of it like: A garbage/recycling center.
• Mitochondria
  • What it does: Makes energy (ATP) through cellular respiration.
  • Purpose: Powers the cell.
  • Think of it like: A power plant.
• Chloroplast (plants only)
  • What it does: Converts sunlight into glucose (food).
  • Contains: Chlorophyll (makes plants green).
  • Think of it like: A solar panel.
• Ribosomes
  • What they do: Build proteins.
  • Location: Float in cytoplasm or on rough ER.
  • Think of it like: Protein factories.
• Rough ER
  • What it does: Transports and makes proteins.
  • Has: Ribosomes on it.
  • Think of it like: A protein-making assembly line.
• Smooth ER
  • What it does: Makes lipids and detoxifies drugs.
  • Think of it like: A cleaning and fat-producing station.
• Golgi Apparatus
  • What it does: Modifies and ships proteins.
  • Think of it like: A post office for proteins.

Labelling Plant and Animal Cells

• Plant Cells: Contain a cell wall, chloroplasts, and a large vacuole.
• Animal Cells: Do not have a cell wall or chloroplasts, possess a small vacuole, and contain centrioles.
• Common Structures to Know and Label:
  • Nucleus
  • Cell membrane
  • Cytoplasm
  • Mitochondria
  • Ribosomes
  • Vacuole
  • ER (rough and smooth)
  • Golgi body
  • Lysosome
  • Chloroplast (plant only)
  • Cell wall (plant only)

Macromolecules Overview

• Macromolecules: Big molecules your body needs to live.
• Monomer: Small repeating unit (building block).
• Polymer: Chain of monomers.
• 3 major types in the body:
  • Carbohydrates
  • Lipids
  • Proteins

Carbohydrates

• Function: Quick energy.
• Monomer: Monosaccharide (single sugar, e.g., glucose).
• Found in: Bread, pasta, fruit, rice.
• Examples:
  • Monosaccharide: Glucose
  • Disaccharide: Sucrose (table sugar)
  • Polysaccharide: Starch (plants), Glycogen (animals)
• Think of it like: Fuel your body burns fast.

Lipids (Fats and Oils)

• Monomer: Glycerol + 3 Fatty Acids (makes triglyceride).
• Function: Stores energy long-term, protects organs, and insulates.
• Found in: Butter, oil, avocado, fatty meats.
• Types:
  • Saturated: Solid at room temperature (butter).
  • Unsaturated: Liquid at room temperature (olive oil).
  • Trans fat: Unhealthy, processed.
• Extra: Cell membranes are made of lipids (phospholipid bilayer).
• Think of it like: Your body's battery pack.

Proteins

• Monomer: Amino acids (20 total).
• Function: Build body parts, fight infection, and speed up reactions (enzymes).
• Found in: Meat, eggs, beans, tofu.
• Structure: Amino group + Carboxyl group + R-group (unique part).
• Types: Enzymes, antibodies, hormones, transport proteins.
• Denaturation: Protein loses shape from heat or pH (e.g., frying an egg).
• Think of it like: The body's workers and repair team.

Photosynthesis vs. Cellular Respiration

• Photosynthesis
  • What it is: Plants use sunlight to make food (glucose).
  • Happens in: Chloroplasts.
  • Purpose: Make glucose for energy and release oxygen.
  • Word Equation: Water + Carbon dioxide \rightarrow Glucose + Oxygen
  • Balanced Equation: 6H2O + 6CO2 \rightarrow C6H{12}O6 + 6O2
  • Energy: Sunlight \rightarrow Chemical energy
• Cellular Respiration
  • What it is: All cells break down glucose to make ATP (energy).
  • Happens in: Mitochondria.
  • Purpose: Release stored energy from food.
  • Word Equation: Glucose + Oxygen \rightarrow Carbon dioxide + Water + ATP
  • Balanced Equation: C6H{12}O6 + 6O2 \rightarrow 6CO2 + 6H2O + ATP
  • Energy: Chemical energy \rightarrow Usable energy (ATP)
• Why They Work Together
  • Photosynthesis makes glucose and oxygen used in respiration.
  • Cellular respiration makes carbon dioxide and water used in photosynthesis.
  • This cycle keeps energy and gases balanced in nature.