Cell Structure and OrganellesUnit 2 - Cells

Cellular BoundariesPAGE 203-204

Cell Membrane• Surrounds all cells in a double layer of lipids!• Is selectively permeable

▫Some things can get in/out, others cant• MAIN FUNCTION

▫Regulates what enters and leaves▫Protection ▫Support

Cell Wall• Found outside of the cell membrane• Found in

▫Plants▫Fungi▫Algae▫Prokaryotes

• MAIN FUNCTION: ▫ Provide support – helps plants stand vs.

gravity▫ shape▫ Protection

Cell Organization on the Inside! PAGE 196-197, 199

Nucleus• All Eukaryotes including plants and animals

have a nucleus• MAIN FUNCTION

▫ Contains DNA (in the form of chromatin) coded instructions for making proteins & other molecules

• Contains the following parts - ▫Nuclear Envelope

membrane for protection and to allow RNA & proteins in and out (through nuclear pores)

▫Nucleolus Makes ribosomes!

Cytoskeleton (Cytoplasm)

• MAIN FUNCTION▫ Made up of protein pieces that helps give the cell

shape. ▫ Involved in many forms of cell movement▫ Houses most of a cells organelles

Organelles That Store, Clean Up, and SupportPAGES 198-199

Vacuoles• MAIN FUNCTION – storage area for water, salts,

proteins, and carbohydrates

• A sac-like structure

• Many plant cells have a single, large vacuole filled with liquid.▫ Helps to support heavy structures such as stems and leaves

• Also found in single-celled organisms and animal cells.

Vacuole in a Plant CellNotice how much room the vacuole

takes up in the cell!!!

Vesicles•Found in all EUKARYOTIC cells

•MAIN FUNCTION▫Store and move materials between

organelles and to the cell surface

Lysosomes

• Filled with enzymes

• MAIN FUNCTION▫Break down lipids, carbohydrates, and proteins

from food into particles that can be used by the cell

▫Break down organelles that are no longer useful

Centrioles• MAIN FUNCTION

▫ used in cell division to separate chromosomes during mitosis

• Usually only found in animal cells in the cytoplasm

Organelles That Build ProteinsPAGE 200-201

Ribosomes• One of the most important jobs in the cell is making

proteins▫ Free ribosomes work in the cytoplasm▫ Bound ribosomes are stuck on the ER (they are what makes it

a “rough” ER!)

• MADE OF – small particles of RNA and proteins

• MADE IN – the nucleolus

• MAIN FUNCTION – make proteins▫ They do this by following coded instructions that come from

DNA in the nucleus

Free and Bound Ribosomes

Endoplasmic Reticulum• Rough Endoplasmic Reticulum

▫ Involved in making protein▫ Has ribosomes on the surface (how it gets its name)▫ MAIN FUNCTION: Modifies proteins

• Smooth Endoplasmic Reticulum▫ No ribosomes on surface▫ MAIN FUNCTION: Make lipids

Interesting ER Facts•((You should write these down!!)•Cells that produce hormones have many

Smoother ER’s▫Example: testes and ovaries have LOTS of

smooth ER

•The liver is the main organ in your body for drug and alcohol detoxification – therefore, the cells of the liver have many smoother ER too!!

The Endoplasmic ReticulumRough ER Smooth ER

Golgi Apparatus (Golgi Body)

• After proteins are made by the RER, they move to the Golgi

• MAIN FUNCTION ▫ packages, sorts, stores proteins and other materials

from the ER.

Organelles That Capture and Release EnergyPage 202

Chloroplasts• Found in plants and SOME other organisms (bacteria and

algae!!!)

• Animals and fungi do NOT contain chloroplasts

• Chloroplasts contain chlorophyll which makes a plant look green!

• MAIN FUNCTION▫ use energy from the sun to make food through photosynthesis

Mitochondria

• MAIN FUNCTION – release energy from stored food molecules to be used to power growth, development, and movement.

• Nearly all eukaryotes have mitochondria

• Important, cells that need more energy have more mitochondria. ▫ Muscles▫ Heart