Theory, Structure, Function Cells Theory, Structure, Function

What is a Cell? The smallest unit that can carry on all the processes of life

Robert Hooke 1665 Cork Cells “A lot of little boxes” Dead Cells

Students write observations (20 sec), describe what they are looking at, any organelles? 4

Students write observations (20 sec), describe what they are looking at, any organelles? 5

Students write observations (20 sec), describe what they are looking at, any organelles? 6

Cell Theory 1. All living things are made of one or more cells. 2. The basic unit of structure and function within an organism is the cell. 3. All cells arise from existing cells.

Cell Characteristics All cells have the following : Plasma membrane – protective/selective barrier Cytosol – semifluid to suspend components Ribosomes DNA – genetic material

Types of Cells Organisms are composed of one of two types of cells: 1. Prokaryotic – cell that lack a nucleus and other membrane-bound organelles 2. Eukaryotic – cell that has a true nucleus and membrane-bound organelles

What is a Prokaryotic Cell? A cell that lacks a nucleus Lacks other membrane bound organelles also Typically small An organism made of this type of cell is called a prokaryote Ex - Bacteria

Unknown Bacteria of Death (400x)

Prokaryote History First cells to evolve (2.5 billion years ago) Existing in a variety of environments (an extremely wide variety)

Types (Domains) of Prokaryotes Archae – found in extreme environments Bacteria – common bacteria (everyday bacteria) ** - Eukarya and Archae are more closely related to each other than either is to Bacteria (based on rRNA sequences)

Archae Extreme environments! – salt beds, hydrothermal vents, swamps, sewage, cow guts

Bacteria Common everyday germs  Three shapes: Bacilli – rod Cocci – sphere Spirilla - helical

Prokaryotic Structure

What is a Eukaryotic Cell? A cell that has a well defined nucleus Contains membrane-bound organelles Eukaryotic cells can specialize because they have organelles Typically larger cells Organisms composed of one/more eukaryotic cells is called a eukaryote Ex. Plants, Fungi, Animals, Humans

Corn Stem (400x)

Eukaryotic Cells Can Specialize Structure of a cell determines its function

Create a T-Chart With your shoulder partner create a T- chart that state the Differences between Prokaryotes and Eukaryotes. Prokaryotes Eukaryotes 1. 1. 2. 2. 3. 3.

Types of Eukaryotes Plant Cells: Animal Cells: Fungal Cells: Cell Wall (Cellulose) One Large vacuole (animals many small vacuoles) Chloroplasts Animal Cells: Lysosomes Centrosome (Organizes cytoskeleton/etc.) Fungal Cells: Cell Wall (Chitin) Algae Cells (A type of Protist):

Numbers of Cells in Organisms Unicellular – a complete living organism that consists of only one cell (prokaryote or eukaryote) Examples – bacteria Multicellular – a living organism consisting of more then one cell (only eukaryotes) Examples – animals, plants

What is an organelle? A cell component that performs specific functions Example – nucleus, cell membrane

Cell Wall Only in plant/bacteria/fungi cells Relatively inflexible (it’s rigid) Protects and supports the cell Castle Wall Discuss gram +/- bacteria, the stain and how it affects pathogens (peptidoglycan in bacteria, cellulose in plants) 24

Cell Membrane “Filters” molecules semi-permeable Gives shape and flexibility to the cell Bouncer Do plasma membrane wksht 25

Nucleus The cell control center Contains chromosomes (DNA) Involved in protein synthesis Nucleolus makes ribosomes Boss/Manager

Nuclear Membrane Double membrane surrounding nucleus (protects and filters) Has nuclear pores

Ribosomes The site of protein synthesis Can be attached to the ER or float in the cytosol Line workers/ Factory

Endoplasmic Reticulum System of membrane tubes and sacs Transport system of the cell Modifies proteins for golgi (prepares them) Also makes lipids/carbs Rough = w/ribosomes Smooth = no ribosomes Roads

Golgi Apparatus Processes, packages, and secretes cell products (such as proteins) Uses vesicles for transport Post Office

Vesicle Membrane-enclosed sac that transports and stores substances Envelope (the package itself)

Mitochondria Breaks down food molecules and releases energy in the form of ATP Has DNA/ribosomes Battery/Generator

Plastids Ex. Chloroplast Absorb light to create sugar Photosynthesis Give plants color (green pigment) Have DNA/ribosomes Solar Panel

Cytoplasm Space inside of the cell Nutrient rich Semi-fluid material inside a cell - cytosol Nutrient rich

Lysosome Contains digestive enzymes Breaks down and rids the cell of waste Prevents bacteria and viruses from invading Janitor/Custodian

Vacuole Sack of fluid (water in plants) surrounded by a membrane Stores food, enzymes or waste. Storage closet

Cytoskeleton Maintains cell shape and size Participates in movement (of cell itself and of material inside of the cell) Scaffolding of building

Movement Organelles Cilia and Flagella Hair-like organelles that extend beyond the surface of the cell Assist in movement Mobile business

Closing Quiz Cells Which organelles propels a cell through an environment? Which organelles are involved in the processing of a protein? Which three organelles are present in plant cells but not animal cells? What is the difference between a prokaryote and a eukaryote? Mitochondria and chloroplasts have their own DNA, what does this imply about them?