Microscopy and Lab Safety Notes (Bio12A)

Grading Rubrics (Page 1)

  • Purpose: Guide for answering essay questions in lab activities; used to assess performance.
  • Criteria and point values: Excellent (3 points), Satisfactory (2 points), Needs Improvement (1 point).
  • Categories:
    • Content:
    • Excellent: Accurate and comprehensive description of key concepts, demonstrating understanding.
    • Satisfactory: Adequate description of key concepts, with minor gaps in understanding.
    • Needs Improvement: Basic description of key concepts, with significant gaps in understanding.
    • Organization:
    • Excellent: Clearly and coherently presented with a logical flow of ideas.
    • Satisfactory: Mostly clear presentation, with some minor disruptions in flow.
    • Needs Improvement: Adequately organized but may lack a smooth flow of ideas.
    • Clarity and Language:
    • Excellent: Clearly written with no grammatical or spelling errors, easy to read and understand.
    • Satisfactory: Mostly clear, with a few minor grammatical or spelling errors.
    • Needs Improvement: Readable and understandable; some clarity issues and occasional grammatical or spelling errors that may affect readability.
    • Depth of Understanding:
    • Excellent: Demonstrates a thoughtful and insightful understanding of the concepts.
    • Satisfactory: Shows a basic understanding of the concepts but lacks depth and insight.
    • Needs Improvement: Superficial understanding with limited insights into the concepts.
    • Readability of Penmanship and Clarity of Drawings and Labels:
    • Excellent: Neat and easily readable handwriting; drawings have labels on the right side and no lines intersecting; magnification of each specimen written below the drawing; uses a Mongol #2 pencil.
    • Satisfactory: Mostly neat and readable, with occasional lapses in handwriting quality; some labels may be lacking or not clear.
    • Needs Improvement: Handwriting legible but may be messy or difficult to read in parts; only a few structures labeled; lines intersect; magnification not shown.
  • Notes on drawings: Specific requirements include labeling, placement of labels on the right side, no line intersections, and indication of magnification below each drawing.

General Guidelines for Using this Workbook (Page 2)

  • Purpose: The workbook is designed to complement learning; activities reinforce concepts from lessons; lessons, instructional materials, and additional resources are available on Moodle.
  • Accessing Lessons:
    • Regularly access and review Moodle lessons for theoretical background and detailed explanations.
  • Workbook Structure:
    • Each lab activity corresponds to a Moodle lesson; check lesson titles and numbers to ensure correct alignment.
    • Start each activity by reviewing the corresponding Moodle lesson to understand key concepts and examples before attempting lab tasks.
  • Completing Activities:
    • Follow instructions carefully; if an activity references a Moodle lesson, review that material first.
    • Take time to thoroughly work through each question; goal is to reinforce understanding.
  • Using the Workbook with Moodle:
    • Keep the workbook handy while studying Moodle lessons; use it to take notes, solve problems, and apply concepts.
    • Regularly cross-reference between the workbook and Moodle to stay up to date on theory and practice.
  • Seeking Help:
    • If difficulties arise, refer to the corresponding Moodle lesson for clarification.
    • Use Moodle discussion forums and communication tools to ask instructors or peers for help.
  • Review and Practice:
    • Periodically review completed workbook activities and revisit Moodle lessons to reinforce understanding.
    • Practice consistently to build and retain knowledge.
  • Integration: Following these guidelines and using the workbook with Moodle helps maximize learning and deepen understanding.

General Guidelines in the Laboratory (Page 3)

  • Safety first: Follow all safety procedures to protect from injury and prevent equipment damage.
  • General safety tips:
    • Read and follow all safety instructions, including chemical and equipment safety information and laboratory procedures.
    • Wear appropriate PPE: safety goggles, gloves, lab coat, face mask, closed-toe shoes.
    • Do not eat, drink, or apply cosmetics in the laboratory.
    • Keep work area clean and organized to prevent accidents.
    • Do not work alone; always have a partner or teacher present.
    • Be aware of surroundings; watch for people and objects.
    • Report spills or accidents immediately.
    • Dispose of chemicals and other materials properly.
    • Wash hands thoroughly after working in the laboratory.
  • Senior High School Biology specific tips:
    • Be aware of hazards of chemicals and equipment; never mix chemicals unless instructed.
    • Never taste or smell chemicals.
    • If chemical touches skin, wash with soap and water immediately.
    • If chemical contacts eyes, flush with water for at least 15 minutes.
    • Report any accident to the teacher immediately.

Bio12A General Biology 1 Lesson 1: Microscopy (Page 4)

Learning Outcomes

  • Identify the parts of a light microscope and their functions.
  • Focus the specimens correctly under the microscope.

Introduction

  • Microscopy introduces the microscope as a powerful tool for exploring the microscopic world.
  • The compound light microscope is the most commonly used in biology labs.
  • Basic principle: light passes through a transparent specimen and an enlarged image is projected into the eye using magnification.

Parts of a Light Microscope (Page 5)

  • Mechanical Parts:
    • Base: sturdy bottom that provides stability and support.
    • Inclination Joint: allows tilting of the microscope head or objective lens.
    • Arm: vertical part connecting base to head; handle for carrying.
    • Stage: flat platform where the slide sits for observation.
    • Stage Clips: secure the slide on the stage.
    • Focusing Knobs: coarse and fine adjustment knobs move the stage to focus.
    • Nosepiece: rotating structure holding objective lenses for magnification changes.
    • Dust Shield: protects objectives from dust particles.

Optical and Magnifying Parts of the Microscope (Page 6)

  • Body Tube: cylindrical tube connecting the eyepiece to the objective lenses, ensuring alignment.
  • Optical Parts:
    • Light Source: reflective surface beneath the stage redirects external light upward through the specimen; can use ambient light or a bulb.
    • Mirror: adjustable angle to control light intensity and direction; planoconvex (planar on one side, concave on the other).
    • Concave side used for natural light; flat side used for artificial light.
    • Condenser: lens system beneath the stage that focuses and directs light onto the specimen.
    • Iris Diaphragm: adjustable device beneath the stage that controls the amount of light.
  • Magnifying Parts:
    • Objective Lenses: lenses of varying magnifications (low, medium, high) on the nosepiece; used to magnify the specimen.
    • Ocular (Eyepiece): lens through which the viewer observes the magnified image; further magnifies the image produced by the objective lens.
  • Note: These parts work together—mechanical, illuminating, and magnifying—to enable observation of the microscopic world.
  • Modern microscopes: often replaced the mirror with a built-in bulb for illumination.

Lab Activity No. 1: How to Use a Microscope (Page 7)

Materials

  • Light microscope
  • Cut letter e (smallest size from newspapers)
  • Glass slides
  • Coverslips
  • Dropper (medicine dropper)
  • Water
  • Scissors
  • Strand of hair

Instructions

  1. Borrow prepared slides from the Biology Department stockroom.
  2. Place slide on a table in front of you; keep slide slightly away from the table edge for stability and comfortable viewing distance.
  3. Use optical lens paper to gently clean all optical surfaces.
  4. Prepare a glass slide with the letter e in its normal position at the middle of the slide; put a drop of water in the middle; cover with a coverslip.
  5. Place the specimen on the stage and secure with stage clips.
  6. Position the low-power objective (LPO) in line with the stage aperture and look through the eyepiece. Adjust the mirror so light is directed toward the specimen. LPO magnification is 4x4x. Bring the specimen up against the objective by turning the coarse adjustment knob. Begin with the LPO.
    • Caution: the high-power objective (HPO) is longer than the LPO; using it incorrectly can crack the slide.
  7. Look at the glass slide from either side and move the LPO downward using the coarse adjustment knob. Look again through the eyepiece.
  8. Use the coarse adjustment knob to focus the specimen roughly while keeping both eyes open.
  9. Use the iris diaphragm to modify the light; too little or too much light makes finer details hard to see.
  10. When the letter e is in focus, move the slide slightly and note the direction; describe what happens when moving left, right, up, or down.
  11. Prepare a hair strand: cut about 1 cm from the root; mount on slide with a drop of water; cover with coverslip.
  12. Examine the hair under the microscope and note the position and size of the hair root as you switch from LPO to HPO; proper focus and correct light intensity are necessary for maximum resolution.

Notes for Safety and Care

  • Handle slides and coverslips carefully to avoid breakage.
  • Ensure light intensity is appropriately adjusted with the iris diaphragm for optimal viewing.

Lab Activity No. 1: Questions (Page 8)

  1. Describe the position of the letter e.
  2. Describe what happens when you move the letter e to the left; also what happens when you move it to the right.
  3. What happens to the size of the letter e when shifting from LPO to HPO?
  4. Describe the position of the root hair under the microscope.
  5. What happens to the size of the human hair root when shifting from LPO to HPO?
  6. How do you avoid breaking the glass slide?