Download - Cells
Cells
The Cell Theory
• All living things are composed of one or more cells.
• Cells are the basic units of structure and function in living things.
• New cells are produced from existing cells (reproduction).
Unicellular organism undergoing cell division
Prokaryotes vs. EukaryotesProkaryote Eukaryote
No nucleus (DNA not enclosed) DNA in nucleus
No membrane-enclosed structures
Membrane-enclosed structures
0.1-10 micrometers (µm) 10-1000 micrometers (µm)
Evolved 3.5 billion years ago Evolved 1.5 billion years ago
Kingdoms: Bacteria and Archaea
Kingdoms: Protista, Fungi, Plantae, Animalia
Prokaryotes (bacteria) vs. Eukaryotes (cheek cells)
Prokaryotes vs. Eukaryotes
What 3 structures can be found in all cells?
cell membrane, cytoplasm, ribosomes
Prokaryotic Cell (Bacterial Cell)
Eukaryotic Cell – Animal Cell
Eukaryotic Cell – Plant Cell
Eukaryotic Cells – Animal Cell vs. Plant Cell
Which structures are unique to animal cells? Plant cells?
Animal: Centriole Plant: Large Central Vacuole, Cell Wall, Chloroplast
Eukaryotic Cells – Animal Cell vs. Plant Cell
A Cell is a Factory…
• security: __________________
• machines/workers: _________
• shipping: _________________
• manufacturing/packaging: _________________
• waste disposal: ____________
• management: _____________
• power generator: ___________
• product: protein
Cell Membrane
• Double layer of lipids (fat)
• A barrier that controls what enters and leaves the cell
Ribosome
• Appear as tiny, grain-like structures
• Can be free in cytoplasm or stuck to ER
• Protein synthesizers
Nucleus
• Contains DNA and associated proteins (chromosomes)
• DNA controls cell activities by directing synthesis of proteins
• Dark mass called nucleolus synthesizes ribosomes
Mitochondrion
• “Powerhouse” of the cell
• Uses oxygen to convert chemical energy (food) to useable energy (ATP).
• What types of cell in your body would have many mitochondria?
Endoplasmic Reticulum
• Rough ER – ribosomes (makes protein)
Smooth ER – no ribosomes (makes lipids)
• Lipids and proteins synthesized on the ER are packaged in vesicles for transport throughout the cell.
Golgi Apparatus
• “Post office” of the cell
• Wraps proteins in sacs called vesicles and sends them out of the cell
• Cells that do a lot of secreting (like the cells of glands) have many golgi bodies.
Lysosomes• Small vesicles filled
with enzymes used to break down cellular wastes
• Certain white blood cells that consume pathogens and cell debris have many lysosomes – why?
Lysosome Animation
Vacuoles• Vacuoles found in
both plant and animal cells – large central vacuole found in plant cells only
• LCV stores water and food in plant cells
• When full provides pressure to keep plant upright (plants lack skeletons!)
Cell Walls
• Plant cells only (and most fungi and bacteria)
• Plant cell walls made up of cellulose
• Gives plant cells its fixed shape
Chloroplasts
• Plant cells only
• Contains green pigment chlorophyll that traps sunlight used to make food during photosynthesis
• Which part of the plant contains cells with the most chloroplasts?