Unit 3 Biology Review Flashcards

Unit 3 Review Sheet (Chapters 6-7 and Labs)

General Instructions

• Make a copy of this document to work privately or with a small group.
• Test 3 will cover Chapters 6-7 and various lab activities including Cell Structure & Function, Microscopy, Osmosis and Diffusion.
• Review material from online lectures, guided notes, and class activities.
• Summarize information and create concept maps for better retention.
• Self-quiz and create test questions to solidify knowledge.

Chapter 6: Introduction to Cells

Key Concepts

• Cells Definition: Basic structural, functional, and biological unit of all living organisms.
• Size Range of Cells: Varies widely from 1 µm (bacteria) to 100 µm (eg. human egg).
• Cell Theory:
  1. All living organisms are composed of cells.
  2. The cell is the basic unit of life.
  3. All cells arise from pre-existing cells.
• Characteristics Common to All Cells:
  1. Plasma membrane
  2. Cytoplasm
  3. DNA (genetic material)
  4. Ribosomes
  5. Metabolic processes.

Chapter 6: Eukaryotic Non-Membranous Structures

Organelles

• Membranous vs Non-Membranous Organelles:
  • Membranous: Surrounded by a membrane (e.g., nucleus, mitochondria).
  • Non-Membranous: Lack a membrane (e.g., ribosomes, cytoskeleton).
• Non-Membranous Organelles:
  • Cell Wall: Provides structure in plant cells; permeable to water and air.
  • Cytoskeleton: Maintains cell shape; consists of microtubules, microfilaments, and intermediate filaments.
  • Centrioles: Involved in cell division.
  • Cilia and Flagella: Important for cell movement.

Chapter 6: Membranous Organelles and Endomembrane System

Organelles & Functions

• Endomembrane System: Network of organelles (nucleus, endoplasmic reticulum, Golgi apparatus, vesicles) involved in protein and lipid synthesis.
• Organelle Structures:
  • Plasma Membrane: Semi-permeable barrier.
  • Nucleus: Control center of the cell; contains nuclear envelope and nucleolus.
  • Ribosomes: Sites of protein synthesis (free and membrane-bound).
  • Endoplasmic Reticulum:
    • Rough ER: Studded with ribosomes; synthesizes proteins.
    • Smooth ER: Synthesizes lipids; detoxifies drugs.
  • Golgi Apparatus: Modifies, sorts, and packages proteins.
  • Lysosomes: Contain digestive enzymes.
  • Mitochondria: Powerhouse of the cell; involved in ATP production.
  • Chloroplasts: Site of photosynthesis in plant cells.

Chapter 6: Cell Growth and Surface Area

Growth Implications

• As a cell increases in size, the surface area increases by the square of the radius while the volume increases by the cube of the radius.
• This impacts the surface-to-volume ratio, which decreases with increased size, affecting nutrient uptake and waste removal.

Chapter 7: Membrane Structure & Function

Membrane Composition

• Cell (Plasma) Membrane Functions: Semipermeable barrier, communication, and support.
• Major Molecules: Phospholipids form the bilayer; proteins embedded for transport and signaling.
• Membrane Properties:
  • Polar heads face outward; non-polar tails face inward.
  • Membranes are fluid due to the arrangement of phospholipids.

Passive Transport

Movement Principles

• Brownian Motion: Continuous motion of atoms/molecules due to kinetic energy.
• Diffusion: Movement of molecules from high to low concentration until equilibrium is reached.
• Types of Transport:
  • Simple Diffusion: Movement across membranes without assistance (e.g., oxygen).
  • Facilitated Diffusion: Requires helper molecules such as transport proteins.

Active Transport

Mechanisms

• Active Transport: Movement of molecules against the gradient, requiring ATP (e.g., sodium-potassium pump).
• Cotransport: Simultaneous movement of two molecules; one is passive, the other is active.

Lab Activities Overview

Microscope and Cell Structure

• Prokaryotes vs Eukaryotes:
  • Prokaryotes: Simple, no internal compartments (e.g., bacteria).
  • Eukaryotes: Complex, with organelles (e.g., plant and animal cells).
• Lab Exercises:
  • Microscopy procedures, calculating sizes of observed specimens, and identifying cell types based on structures viewed.

Review of Osmosis and Diffusion

Definitions and Processes

• Osmosis: Movement of water across a semipermeable membrane; affected by solute concentration.
• Tonicity: Classification of solutions based on concentration differences (hypertonic, hypotonic, isotonic).
• Cell Reactions: Cells experience changes (e.g., plasmolysis, turgidity) when exposed to solutions of varying tonicity.

Example Problem

• Concentration Calculation: To determine concentration, use formula:

  \text{Percent concentration} = \left( \frac{\text{Volume of solute}}{\text{Total volume}} \right) \times 100

  E.g., for a 20 mL solution with 8 mL of sucrose:
  \text{Percent concentration} = \left( \frac{8}{20} \right) \times 100 = 40\%

Conclusion

• Review material systematically, utilize diagrams for understanding structures, and practice problem-solving through example scenarios from lectures and labs.