Biology Exam 3: Class 1

intro to cell biology

learn about the two types of electron microscopes and understand the differences between all of these instruments.

Transmission Electron Microscope: Passes electrons through a specimen; high resolution for internal structures.

Scanning Electron Microscope: Scans surface with electrons to produce 3D images; good for surface details.

Understand the cell theory and its three main generalizations.

All living organisms are made of cells.

The cell is the basic unit of structure and function in living things.

All cells come from pre-existing cells.

 Understand the basic architecture and components common to all cells.

Plasma membrane, cytoplasm, DNA, ribosomes.

 Describe the structural differences between prokaryotic and eukaryotic cells and relate these structural differences to cell functions.

• Prokaryotes: No nucleus, simple structure, no membrane-bound organelles.

• Eukaryotes: Nucleus present, complex organelles, compartmentalization allows for specialization.

 Understand the structural differences between animal and plant cells, and describe how these structural differences affect cell functions.

• Plants: Have cell wall, chloroplasts, central vacuole — for support and photosynthesis.

• Animals: Lack those but have centrioles and more flexible movement.

Understand the endosymbiotic theory for the origins of some cellular organelles and describe the evidence that supports this hypothesis.

• Theory: Mitochondria and chloroplasts originated as free-living prokaryotes.

• Evidence: They have their own DNA, double membranes, and reproduce like bacteria.

plant cells

Cell wall, chloroplasts, large central vacuole.

animal cells

no cell wall, no chloroplasts, small vacuole

fungal cells

Chitin cell walls, no chloroplasts.

Protists

Diverse; some have chloroplasts, some do not.

bacterial cells

Prokaryotic, lack nucleus and membrane-bound organelles.

Nucleus

Contains DNA.

Mitochondria

Energy (ATP) production

ER

Protein (rough) and lipid (smooth) synthesis

Golgi apparatus

Modification and packaging

Lysosomes

Digestion

Chloroplasts

Photosynthesis

Light microscope

Uses visible light to view cells

Transmission Electron Microscope

Passes electrons through a specimen; high resolution for internal structures.

Scanning Electron Microscope

Scans surfaces with electrons to produce 3D images; good for surface details.