CELL STRUCTUREWhat is the role of the cell nucleus?

What are the functions of vacuoles, lysosomes, and the cytoskeleton?

What organelles help make and transport proteins?

What are the functions of chloroplasts and mitochondria?

What is the function of the cell membrane?

Cell Organization-Eukaryotes• Complex busy place, divide it into two parts. The Nucleus

and the Cytoplasm• Cytoplasm is the part of the cell outside the Nucleus• Organelles are specialized parts of the cell, “little organs”• The cell is kind of like a factory or a city, everything has a

job that is important to the cell

Nucleus• Contains the DNA, with

instructions for making proteins and other important molecules (prokaryotes have DNA which does the same but without the nucleus)

• Nucleus is surrounded by the nuclear envelope

• Nuclear envelope contains nuclear pores that allow material to move in and out of the nucleus

• Chromosomes are found in the nucleus as well this is the genetic info

ORGANELLES THAT STORE, CLEAN UP AND SUPPORTVacuoles/Vesicles “Storage”

Lysosomes “Clean-up Crew”

Cytoskeleton “Support System”

Vacuoles• A sac-like membrane

enclosed structure• Store material (water,

salt, protein, carbs)• Plant cells have large

‘central vacuole’ • Helps to increase rigidity• Helps to hold leaves and

flowers• What happens to a vacuole

that may cause a plant to wilt?

Vacuoles…• Unicellular organisms

and animals may have cells with vacuoles too. • Paramecium has a

“contractile vacuole”, which pumps out water from the cell

• They help move materials between surfaces, and to and from the cells surface

Lysosomes• Found in both plant and animal cells• Removes ‘Junk’ from the cell

• Some diseases can be attributed to Lysosomes failure

• Break down lipids, carbohydrates, and proteins into smaller molecules.• Remember what these molecules were called?

• Break down organelles that have outlived usefulness

Cytoskeleton• Network of protein filaments • Helps transport materials between different part of the cell• Also involved in movement, cilia and flagella are parts of

the cytoskeleton

Cytoskeleton…Two Types

Microfilaments

• Thread-like• Protein called actin• Form flexible framework

for cell• Helps cell move• Assembly and

disassembly responsible for movement of amoebas or other cells that ‘crawl’

Microtubules

• Hollow structures• Protein called tubulins• Important to cell division,

organization• Not found in plant cells• Help build cilia and

flagella, which helps cells “swim” through liquid

ORGANELLES THAT BUILD PROTEINSRibosomes “Machine”

Endoplasmic Reticulum “Assembly of Lipid”

Golgi Apparatus “Shipping”

Ribosomes• Makes/assembles proteins• Small particles of RNA and protein found in cytoplasm• Follows instructions from its’ “Boss” DNA to make proteins• If a cell is an especially active protein maker it will contain

more ribosomes

Endoplasmic Reticulum

Rough ER

• Ribosomes on surface• May modify proteins

made by the Ribosomes• Proteins made will be

released, secreted, and destined for lysosomes

• Abundant in cells that make a lot of protein for export

Smooth ER

• No ribosomes on surface• Contains enzymes that

perform specialized tasks• Like synthesis of membrane • Detoxification (Liver Cells)

Golgi Apparatus• Modifies, sorts, and packages proteins and other material

for either storage in the cell, or transportation out of it• Finishing touches are put on the proteins before

“shipment” from the cell

ORGANELLES THAT CAPTURE AND RELEASE ENERGYChloroplasts “Solar Power Plant”

Mitochondria “Power Plant”

Chloroplasts• Capture energy from the sun and convert it into energy for

the cell• There are two membranes around a chloroplast, as well

as other membranes within the organelle, which contain the green colored chlorophyll

• Contain it’s own DNA, theory is it may have descended from an independent microorganism

Mitochondria• Found in nearly all eukaryotic cells, and plants• Convert the energy stored in food to compounds which

can be more easily used by the cell• Has outer and inner membrane like the chloroplasts• Inner membrane is folded up inside• Like the Chloroplasts it also contains its’ own DNA

“endosymbiotic theory” we’ll talk about this later in the year

CELLULAR BOUNDARIESCell Walls “Roof”

Cell Membranes

Cell Wall• Some organisms may have cell wall and membrane• Most prokaryotes and eukaryotes have it for protection• Animal cells DO NOT have cell walls• Porous, allows some materials to pass through easily• Provide strength for plants

Cell Membrane• Flexible structure from a lipid bilayer• Regulates what enters and leaves the cell• Protects and supports• Some made from lipid bilayer

• Hydrophilic and Hydrophobic parts to keep water out• Proteins found within it

• Most are selectively permeable or semi permeable