Cell Biology Lecture Notes Review

Introduction to Class Announcements

• Emphasis on building resumes and purposeful travel through summer projects.

• Speaker session scheduled for Thursday at the quadrangle at 11 AM, 12 PM, 1 PM, 2 PM, and 3 PM.

• Sign-up sheet available for email reminders.

Early Feedback Task

• Release Date: Monday at 9 AM.

• Content: 10 multiple-choice questions (MCQs) from a question bank.

• Timing: 20-minute limit for completion.

• Purpose: Helps measure understanding of course material and preparation for future exams.

• Attempts: Can take the quiz multiple times but the first attempt counts as the grade. Quiz is worth only 5% of the overall grade.

• Format: Accessible through Canvas; intended to guide study habits and assess knowledge.

Practical Classes

• Classes begin on Thursday, with two time slots available (10 AM and 1 PM).

• Structure: Three subgroups of 40-minute rotations.

  • Tutorial component led by Imka to discuss topics and activities due later in the semester.

  • Microscopy stations to observe cell characteristics.

• Attendance: Registration via QR codes; prompt attendance necessary due to tight schedule.

• Safety: Closed-toed shoes and lab coats required for wet labs.

• Locations: Level 4 and Level 6 of the Gum Building, with staff available for guidance.

Lab Session Expectations

• Importance of punctuality during lab sessions due to the rotation structure.

• Pre-lab work assigned by Inka and expectations for timely completion discussed.

• Detailed discussion on specific lab activities tailored for palms-on experience with anatomical structures.

Review of Membranes and Membrane Proteins

Membranes

• Cell membranes are selectively permeable barriers.

• Structure includes phospholipid bilayers with embedded proteins.

  • Fluidity: Membranes can change shape and stretch, aiding in functionality.

Membrane Proteins

• Types of Membrane Proteins:

  • Transporters: Facilitate movement in and out of the cell.

  • Anchors: Connect cytoskeleton to the extracellular matrix (ECM).

  • Receptors: Participate in signal transduction, often binding to specific substances.

• Examples of Protein Structures:

  • Alpha Helices: Corkscrew shape allowing protein functionality within membranes.

  • Beta Sheets: Sheet-like configuration contributing to membrane integrity.

Glycocalyx

• Glycocalyx is a carbohydrate-rich layer on the cell membrane, aiding in cellular interaction and protection.

• Functions include:

  • Cell recognition.

  • Lubrication, allowing movement through tissues.

  • Protection against external enzymatic degradation.

Cytoskeleton Overview

• Components: Microfilaments, intermediate filaments, and microtubules provide structural integrity.

• Functions:

  • Maintains cell shape.

  • Facilitates cellular movement and division.

• Dynamic Nature: Some components change frequently (microtubules), while others maintain structural integrity.

Lysosomes and Enzymatic Breakdown

• Lysosomes: Function as the cell's waste disposal system, breaking down macromolecules with specific enzymes (e.g., proteases, lipases).

• Changes in pH, acidic environment aids enzyme functionality and protein degradation.

• Disease Connection: Malfunctioning lysosomes lead to accumulation diseases (e.g., lipofusion in neurons).

Mitochondria

• Structure: Double membrane; outer membrane permeable; inner membrane has high surface area for electron transport and ATP generation.

• Function: Main site of ATP production; involved in cellular respiration.

• Relationship with cellular health and energy needs; quantity correlates with cell activity and energy demands.

  • E.g., liver cells have more mitochondria due to higher energy requirements.

Endocytosis and Exocytosis

• Endocytosis: Process of uptake of materials into the cell through vesicles.

• Exocytosis: Release of materials from the cell through vesicle fusion with the plasma membrane.

• Examples provided including immune cells engulfing pathogens.

Cell Inclusion Types

Glycogen

• Storage form of glucose found in liver and muscle cells, acting as an energy reservoir.

• Can be observed via staining techniques in histological slides.

Lipids

• Energy-dense molecules stored primarily in adipocytes; can be observed as empty spaces in histological preparations due to them being dissolved during processing.

Melanin

• Pigment produced and stored in melanocytes affecting color in skin and hair.

• Protective function against UV light, preventing DNA damage.

Other Inclusions

• Hemoglobin degradation products: e.g., hemosiderin can indicate previous hemorrhage or iron metabolism issues.

• Lipofuscin: Residual waste from lysosomal degradation associated with aging or damage.

• Carotenoids: Pigments associated with color in diets influencing fat color in animals.

Review of Lesson Structure

• Overview of the progression in learning about cell structures and their functions.

• Emphasis on the importance of preparing for assessments and understanding cellular dynamics thoroughly as part of the course.

• Future topics will include the cytoskeleton and further exploration into cellular organelles.