AIM: How do we describe cells? TOPIC: CELLS AIM: How do we describe cells?

How do we know that cells exist? The discovery of the microscope

Robert Hooke Observed slices of cork with a comp. microscope (1600’s)

Anton van Leeuwenhoek 1600’s Used a simple microscope First to look at living cells

Observed one- celled organisms like bacteria Rain pond water, the mouth, intestines

Matthias Schleidan Observed plant cells All plants are made of cells

Theodor Schwann Observed animal cells All animals are made of cells

Robert Virchow All cells are made from pre-existing cells. (Cells divide  more cells)

Cell Theory 1. Cells are the basic unit of structure in all living things. (Living things are made of cells)

2. Cells are the basic unit of function of all living things (They carry out life processes) 3. All cells come from pre-existing cells.

1. Viruses are NOT cells, and are NOT made of cells. Exceptions to the Cell Theory 1. Viruses are NOT cells, and are NOT made of cells.

Virus do not reproduce by division because they are not cells.

2. Mitochondria & Chloroplasts cell parts that have their own DNA and reproduce on their own. (Don’t need the nucleus to reproduce)

3. The first cell could not have come from a pre-existing cell.

Cells Microscopic Found in living things There are different types Smallest living thing on earth

EXAMPLES OF CELLS Skin cells Bone cells

MORE CELLS Brain cells Blood cells

If there are so many cells how do we classify them? Based on location or function of the cell blood cell muscle cell If there are so many cells how do we classify them? 2.Based on the type of organism it belongs to Plant cell Animal cell

Any living thing Examples: Shark -Tree -Bacteria Human -Bird Organism

Nucleus or No Nucleus?? EUKARYOTES Some cells have a nucleus, they are called EUKARYOTES (Hey, you!! Do you have a nucleus?) Animal and Plant cells are eukaryotes. Some cells don’t have a nucleus, they are called PROKARYOTES Bacteria are prokaryotic cells.

Organelles they contain organelles Cells work (perform life activities) because they contain organelles Structures that are found in the cell that perform all cell activities a.k.a cell parts Organelles

Examples of organelles Nucleus Located in the center of the cell Appears as a circle Sometimes solid in color The function is to be the control center for the cell and contains chromosomes. Contains a Nucleolus – helps in protein production. Chromosomes - contain hereditary genetic information

Cell Membrane Located around the entire cell Appears as a thin line Similar to the walls of the classroom The function is to be a barrier (wall) between the outside of the cell and the inside. AND…… Allows materials to transport in and out of the cell

Cytoplasm Located inside the cell membrane and outside the nucleus Appears as the “liquid” between all the organelles The function is to support all the organelles AND… Transport materials around the cell Similar to the ______in our bodies

Vacuole Location is scattered around the cytoplasm Appears as an empty circle Vacuole The function is to be the storage site for wastes and other cellular materials Similar to the garbage pails in each room

Endoplasmic Reticulum Located around the nucleus Appears as canals A.k.a. – ER The function of the ER is to transport materials within the cell AND…. Sometimes contains ribosomes

Ribosomes Located on the ER and scattered around the cytoplasm Appears as dots The function is protein formation (synthesis) RIBosomes---Baby-back ribs give you protein

What do cells need to do all this work? Mitochondria Located within the cytoplasm Appear as bean shaped structures The function is the production of energy A.k.a – the powerhouse

More Organelles Golgi Bodies Located in the cytoplasm Appear as a structure with many folds The function is to package all the wastes for removal

Lysosome Located in the cytoplasm Appear as small circular structures with particles inside The function is to digest (break down) cellular materials

Centriole Located in the cytoplasm Often near the nucleus Appears in a set of two ONLY IN ANIMAL CELLS Centriole The function is to help the cell with cellular division of the chromosomes

Chloroplasts The function is to perform photosynthesis                                                                                                         Located around the edge of the cell Appear as oval structures with lines ONLY IN PLANT CELLS Contain Chlorophyll Chloroplasts The function is to perform photosynthesis Photosynthesis process in which plants produce their own food

Cell wall Located outside the cell membrane ONLY IN PLANT CELLS The function is to provide support and structure for the cell

Organelle Challenge