CELLSCELLS

Remember-All living things are made of one or more cells.

All the stuff living things do to keep them living is done in the cell!

Cell Types-Cell Types-

There are two general types of cells-

Eukaryotes (“true”)

And Prokaryotes (“first”)

Let’s start with Let’s start with prokaryotes-prokaryotes-

Scientists believe the first cells were prokaryotes, or prokaryotic.

These cells are simpler than eukaryotes: They don’t have many of the cell parts that we’ll identify.

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Prokaryotic cells-Prokaryotic cells-

Have no “membrane-bound” nucleus

They DO have genetic information in a long string of DNA found in the cell

Bacteria are prokaryotic cells

Eukaryotic cellsEukaryotic cells

Have an organized nucleus and membrane-bound organelles

Organelles are small specialized parts of eukaryotic cells that have specialized functions

Eukaryotic CellsEukaryotic Cells

Have different structure for different functions

               

               

               

Eukaryotic organellesEukaryotic organelles

Nucleus controls cell’s activities and cell reproduction; contains cell’s nucleic DNA

Nucleolus inside nucleus produces RNA for ribosomes, is used in cell reproduction

……..more organelles-..more organelles-

Endoplasmic reticulum (ER) is

used for transport within the cell

(like a canal system), sometimes

contains ribosomes (“rough ER”)Ribosomes are tiny organelles where

proteins are assembled (put together from amino acids)

……more organellesmore organelles

The “mighty” mitochondrion is where aerobic respiration releases the energy

from glucose to produce the

ATP molecules that keep our

cells doing their jobs All cells need energy to do their jobs. Respiration is the

chemical reaction that produces energy. Aerobic respiration uses oxygen.

……and more…..and more…..

Golgi complex (aka “body”, “apparatus”) packages secretions produced by the cell

Vacuoles are membrane-bound sacs for storage. Plant cells have a large centralvacuole full of “cell sap”, the products of

photosynthesis.

……and some more….and some more….

The plasma (cell) membrane surrounds all cells and regulates what goes into and out of the cell.

Cytoplasm is the rest of the cell, a jelly-like substance made mostly of water.

Many chemical reactions occur here…and many of those reactions need water.

And then, there are some only And then, there are some only found in found in animal cellsanimal cells--

Centrioles are found near the nucleus and used for cell reproduction

And some only in And some only in plant plant cellscells--

Cell Wall surrounds the cell membrane. It is non-living, made of cellulose, and provides structure (That’s why trees don’t need a skeleton!)

Cell wallsCell walls

May be found in organisms other than plants-such as bacteria and fungus, but the composition of the cell wall may be different

And And greengreen plant cells- plant cells-

Are green because they have chlorophyll in chloroplasts;

Within chloroplasts, plants use carbon dioxide and water to produce (synthesize) glucose, so they don’t have to hunt (or shop!) for their food.

Other autotrophs-Other autotrophs-

Have chlorophyll also, such as this euglena

Prokaryotic autotrophs do not have their chlorophyll contained in membrane-bound chloroplasts

         

And one more organelle-And one more organelle-

A Lysosome is a sac that contains digestive enzymes; used to break apart food particles in amebas, for example; or used by white blood cells to destroy invaders

               

Variety of CellsVariety of Cells

Not all cells look alike: their structure(what they look like) will depend on their function (what they do)

And not all cells have all the organelles For example, a muscle cell will have many

mitochondria because they require a lot of energy Fat cells will have many vacuoles for storage