Cells!!

Yay! We’re so excited!! I always wanted to learn about cells and stuff…really Mr. Mason…I’m not bored….this is awesome…just like

cheese, which is also awesome…but not quite as awesome as cells. Well, except for melted cheese…and that fancy cheese at Costco…

that stuff is pretty awesome. Wait…what was I saying??? Oh yeah…cells! Woohoo!

Cell Theory

• Life consists of cells

• All cells are derived from pre-existing cells

Cell Theory

• Life consists of cells

• All cells are derived from pre-existing cells

– Cells are the smallest units of matter that exhibit all five characteristics of life

Sizes of Cells

• Most bacteria: 1-10 μm• Plant/animal cells: 10-100 μm

• Can see with unaided eye down to 0.2mm (200 μm)

• Largest cell?• Smallest cell?

Sizes of Cells

• Most bacteria: 1-10 μm• Plant/animal cells: 10-100 μm

• Can see with unaided eye down to 0.2mm (200 μm)

• Largest cell? egg• Smallest cell? Sperm

• http://learn.genetics.utah.edu/content/begin/cells/scale/

Eukaryotic Cells

• Defined by the presence of membrane-bound organelles (little organs).

• Prokaryotes (bacteria) have an organelle (ribosome), but they are not membrane-bound

Cell Membrane = phospholipid bilayer

Functions of phospholipid bilayer

• Protection• Transportation• Chem. reactions

• Identification/communication

Organelles that process info:

• Nucleus and Ribosomes

Nucleus

• Storehouse for genetic code (DNA)• Synthesizes RNA and ribosomes

Ribosomes

• The site of protein synthesis• Composed of proteins and rRNA (3 types of RNA in

cells – mRNA, tRNA, and rRNA…but we’ll get to that during 2nd semester)

• Either free (proteins used in cytoplasm) or attached to E.R. (proteins inserted into membrane or used for export)

Organelles that process energy

• Mitochondria and plastids

Mitochondria

• Converts energy from organic compounds (such as glucose) into ATP

• Have their own DNA (only organelle that has DNA other than the nucleus)

Plastids • Chloroplasts – convert

sunlight into glucose

• Chromoplasts – give fruits and flowers their color (why?)

• Leucoplasts – store starch (energy source)

• Only found in plants

The endomembrane system

• Endoplasmic reticulum, golgi apparatus, and lysosomes

Endoplasmic Reticulum• Serves as an intracellular

highway

• Rough ER – covered in ribosomes, produces phospholipids and proteins – especially for export

• Smooth ER – produces lipids (steroids, hormones, etc.)

Golgi Apparatus

• Processing, packaging, and secreting organelle

• Modifies proteins for export

Lysosome

• The dumpster of the cell

• Contains hydrolytic enzymes that digest organic molecules

Plant Cells – How are they unique?• Plants have:

– Plastids– Vacuoles: large storage organelle– Cell wall covering phospholipid bilayer