I say I say I say boy,

What the Cell?An introduction to

cells and their organelles!

Cells! Who wants some?!

Not that type, but this kind…

Cells have a lot of variety and some exists as living, mobile entities

More observations…• Finally in the 1800’s, after the scientific community observed

and recorded cell activities, they concluded this-The Cell Theory:

1) Living things are composed of cells.

2) Cells are the basic units of structure and function of living things.

3) Cells come from other cells

The Tree of Life

At the base, one cell gave rise to species now and once upon a time. It was probably a self-replicating, bacterial cell. It’s also called the Last Universal Common Ancestor or LUCA.

These guys are old!This guy is too, but the oldest, known bacteria dates back to about 3.5 Billion Years Ago. Our current clock’s at 6 Billion years.

Their DNA is also our DNA. At least genes that control metabolism, energy, and replicating DNA.

There was a split though!

From LUCA, there came two camps:Prokaryotes. Prokaryotes have genetic material, but it’s not contained in a membrane (nucleus). An example’s your basic bacterial cell. Think: simpler.

Eukaryotes. Eukaryotes have genetic material bound in a membrane. An example is us. Think: complex.

PRO -- NO

EU -- TRUE

NONO Nucleus

EUEU it’s truetrue they DODO have a nucleus

Prokaryotes

These fellahs, despite their simplicity, carryout activities like any other living creature; in fact, they grow reproduce, respond to their environment and can move. They are older and smaller than Eukaryotes.

The Prokaryotes• Generally smaller and simpler than eukaryotes• Key: have genetic material that is not contained

in the nucleus• Less “complicated” than eukaryotes but still

carry out all aspects of “life”• Bacteria are prokaryotes

Some Prokaryotic Examples

EukaryotesThese fellahs contain internal structures wrapped in a membrane. Think: tiny organs, or, organelles.

Some eukaryotes live as single-celled organisms; others form large, multicellular organisms like plants, animals, fungi, and protists.

My Friends the Eukaryotes• You are made of Eukaryotic cells!!!• Usually contain dozens of structures and

internal membranes• Key: Contain a nucleus in which genetic

material is separated from the rest of the cell

• Can be highly specialized• Much larger and more complex than

prokaryotes• Can be single celled or multicellular:

humans, hamsters, venus fly traps, etc.

Some of our Eukaryotic friends

Cell Types

What is an organelle?

• Membrane bound structure that has a job to do in eukaryotic cells

• They’re not in Prokaryotes! (bacteria)

• Plant cells have an organelle that animals don’t

• Animals have one organelle plants don’t.

Plant vs Animal

VS

Plant Cell

Animal Cell

Nucleus

• Control Center• Contains nearly all DNA – instructions for making

proteins and other important molecules• Surrounded by nuclear envelope– Dotted with nuclear pores = stuff in and out

• Nucleolus – small dense region whereassembly of ribosomes begins

Chromosome

• (The Data) … all the directions

• (DNA)

Nucleolus

• A structure that is within the nucleus that produces ribosomes

Endoplasmic Reticulum• Transportation• Rough Endoplasmic

Reticulum (RER)– Covered in ribosomes (rough)– Makes and transports proteins,

especially membrane proteins• Smooth Endoplasmic

Reticulum (SER)– Synthesis of membrane lipids– Contain enzymes that can

detoxification of drugs – Liver has lots of SER’s

Notice how the E.R. is attached to the nucleus …. Like the ‘hallways’

Ribosomes!

• Protein Factory• Proteins are assembled on these organelles by

following coded instructions from the nucleus

Smooth and Rough ER

review!

Nucleus

Nuclear Pores

Nuclear Envelope

ER

Ribosomes

Golgi Apparatus• Packaging Center• Modify, sort, and package proteins and other

materials from the endoplasmic reticulum for storage or secretion.

Mitochondria

• Power House• Convert chemical energy stored in food to a

form a cell can use (ATP)• In humans you get all of you mitochondria from

your mom• Contain own

‘Mitochondrial DNA’• Has double membrane

Chloroplast• Food Factory • Only in plants• Captures energy from the sun and converts it

into chemical energy by a process called photosynthesis

• Has double membrane

Mitochondria/Chloroplasts• These two utilize energy from food and the sun

respectively and convert it into energy the cell can use.

Cytoskeleton• Cell Framework• A network of protein filaments

that helps the cell to maintain its shape

Vacuoles• Storage Facility• More prevalent in plants• Store materials like water, salts, proteins, and

carbohydrates• In plants, there is a large vacuole which helps with

maintaining pressure. – Allows plant to support heavy

loads like leaves and branches

Lysosome

• Waste Management• In animal cells ONLY• Have enzymes used to break down lipids,

carbohydrates, and proteins • breaking down old organelles

Cell boundaries aka cell membrane• Cell membrane regulates what enters/leaves the cell.

Here’s the protein channel embedded in the cell membrane-doors

Cell Wall• Castle Wall• Only in Plant Cells• Provides support an protection for cell• Mostly made of cellulose– Cellulose is the key component of wood and paper

Come on baby let’s do the locomotion……

• Cilia • Flagella

Plant Cell

Animal Cell

The End . . . Or The Beginning