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?