MC

COOKKED

1. Main differences between prokaryotes and eukaryotes

  • Nucleus: Prokaryotes lack a nucleus; eukaryotes have a nucleus.

  • Organelles: Prokaryotes don’t have membrane-bound organelles; eukaryotes do (mitochondria, ER, Golgi, etc.).

  • Size: Prokaryotes are smaller (1–10 μm); eukaryotes are larger (10–100 μm).

  • DNA: Prokaryotes have circular DNA in the cytoplasm; eukaryotes have linear DNA inside the nucleus.

  • Cell type: Prokaryotes are unicellular; eukaryotes can be unicellular or multicellular.

2. Prokaryotic cell drawing (label):

  • Cell wall

  • Plasma membrane

  • Cytoplasm

  • Nucleoid (DNA)

  • Ribosomes

  • Capsule (optional, in bacteria)

  • Pili

  • Flagellum

3. Animal cell drawing (label):

  • Nucleus (nuclear envelope, nucleolus, chromatin)

  • Mitochondria

  • Endoplasmic reticulum (rough and smooth)

  • Golgi apparatus

  • Lysosome

  • Ribosomes

  • Cytoplasm

  • Plasma membrane

  • Centrioles

  • Cytoskeleton

4. Plant cell drawing (label):

  • Nucleus (with nucleolus)

  • Mitochondria

  • Endoplasmic reticulum (rough and smooth)

  • Golgi apparatus

  • Ribosomes

  • Cytoplasm

  • Plasma membrane

  • Cell wall

  • Large central vacuole

  • Chloroplasts

  • Plasmodesmata

5 & 6. Cell membrane drawing and parts:

  • Phospholipid bilayer

  • Hydrophilic heads (face outward)

  • Hydrophobic tails (face inward)

  • Proteins: integral (span membrane) and peripheral (surface)

  • Cholesterol (between phospholipids)

  • Glycolipids and glycoproteins (for recognition and communication)

7. Structures of a phospholipid and relationship to water:

  • Hydrophilic head (polar phosphate group) = attracted to water.

  • Hydrophobic tails (nonpolar fatty acid chains) = repel water.

  • Arrangement in bilayer: heads face water inside/outside cell; tails face inward.

8. Fluid mosaic model:
The cell membrane is a flexible (fluid) bilayer where proteins, lipids, and carbohydrates float and move around (mosaic).

9. Functions of carbohydrate-related structures:

  • Oligosaccharides: Short sugar chains that attach to proteins/lipids for recognition.

  • Glycolipids: Lipids with attached sugars; cell signaling & recognition.

  • Glycoproteins: Proteins with attached sugars; important for communication, receptors, and immune recognition.

10. Peripheral vs. integral membrane proteins:

  • Integral: Embedded in bilayer; often span entire membrane.

  • Peripheral: Loosely attached to membrane surface (inside or outside).

11. Steps of mitosis (drawing + definition):

  1. Prophase – chromosomes condense, spindle forms.

  2. Metaphase – chromosomes align at equator.

  3. Anaphase – sister chromatids separate.

  4. Telophase – nuclear envelope reforms, chromosomes decondense.
    (Cytokinesis = cytoplasm division after mitosis).

12. Role of MPF & cyclin-dependent kinase (CDK):

  • MPF (Maturation-Promoting Factor) = cyclin + CDK complex.

  • Drives cell from G2 → M phase.

  • CDKs are enzymes that activate/inactivate proteins by phosphorylation; require cyclins to function.

13. Benign vs. malignant tumors:

  • Benign: Non-cancerous, doesn’t spread, localized.

  • Malignant: Cancerous, can invade other tissues (metastasize).

14. Why WBCs don’t kill cancer cells:
Cancer cells can evade the immune system by:

  • Producing proteins that suppress immune response.

  • Hiding surface markers (so they look like normal cells).

  • Rapid mutation that makes them hard to detect.

15. Cholesterol and membrane fluidity:

  • Low temp: Cholesterol prevents phospholipids from packing too tightly → increases fluidity.

  • High temp: Cholesterol stabilizes membrane → decreases fluidity.

  • Phospholipids: Saturated = less fluid; unsaturated (with double bonds) = more fluid.

16. Water potential calculations:
Water potential (Ψ) = solute potential (Ψs) + pressure potential (Ψp).

  • Ψs = -iCRT (i = ionization constant, C = molar concentration, R = pressure constant, T = temp K).

17. Hypertonic / Isotonic / Hypotonic:

  • Hypertonic: Solution has more solute → water leaves cell → cell shrinks.

  • Isotonic: Equal solute → no net water movement.

  • Hypotonic: Solution has less solute → water enters cell → cell swells.

18. Saturated vs. unsaturated fats:

  • Saturated: No double bonds, straight chains, solid at room temp.

  • Unsaturated: One or more double bonds, bent chains, liquid at room temp.

19. Potato core lab data analysis:

  • Measure mass change of potato in different sucrose concentrations.

  • Plot % change in mass vs. sucrose concentration.

  • Where the line crosses 0 = isotonic point = water potential of potato cells.

20. Role of checkpoints in cell cycle:

  • G1 checkpoint: Checks DNA damage before replication.

  • G2 checkpoint: Checks DNA after replication.

  • M checkpoint: Ensures spindle attached to chromosomes.
    Prevents uncontrolled division (cancer).

21. Example of cell-to-cell communication:

  • Immune system: Helper T-cells release cytokines to signal other immune cells.

  • Plant plasmodesmata or gap junctions in animals.

22. Passive vs. active transport:

  • Passive: No energy, moves down concentration gradient (diffusion, osmosis, facilitated diffusion).

  • Active: Requires ATP, moves against gradient (pumps, endocytosis, exocytosis).

23. Diffusion, osmosis, facilitated diffusion:

  • Diffusion: Movement of molecules from high → low concentration.

  • Osmosis: Diffusion of water across a membrane.

  • Facilitated diffusion: Passive transport with help of proteins.

24. Endocytosis vs. exocytosis:

  • Endocytosis: Cell takes in materials by engulfing them in vesicles (phagocytosis, pinocytosis).

  • Exocytosis: Cell expels materials by vesicle fusing with membrane.