Nature’s Building Blocks Cells

First discovered in 1665 by Robert Hook Using a microscope, he looked at cork

Why did he call them cells?

All living organisms are composed of cells Single celled organisms Examples are amoebas, paramecia, protozoa, and bacteria Bacteria are important! Help digestion Fix nitrogen Cause fermentation Cause disease

Amoebas

Protozoa

Bacteria

Multicelled organisms Examples: People plants, etc. Cells can come in many different shapes and sizes Largest = ostrich egg Smallest = need high powered microscope to see

Largest cell

Smallest cell

No really  Lives freely in the ocean Bacteria

Cell structure and Function Plant and animals cells = two main Cell wall = plant cells only Made of cellulose in branches and stems Made of pectin in fruits Holds cells together Gives plant structure

Osmosis = Diffusion of WATER Cell membrane Aka plasma membrane Selectively permeable Operates through diffusion Diffusion = transfer of materials from high concentration to low concentration Osmosis = Diffusion of WATER

Homeostasis = balance that cells strive to maintain (steak and dog example) Turgidity = when a cell has the right amount of liquid (turgor & turgor pressure)

More cell parts….

Nucleus Prokaryotic cells = do not have one Eukaryotic cells = have one (sometimes many) Made of nucleic acids, enzymes, and proteins Control center of the cell Contains the genetic code (DNA)

Cytoplasm Thick clear fluid that surrounds the nucleus Suspends other parts of the cell Moves materials around to help keep the cell alive and functioning

Organelles The “mini organs” inside cells They carry out cell functions

Mitochondria Shaped like a peanut Break down nutrients from food and supply cell with energy Cells that need less energy have a lower number of these Known as the “powerhouse” of the cell

Vacuoles Vacuoles are specialized for different functions Made of a membrane that holds H2O and other materials All involve storage Some store wastes from the cell Some store nutrients and enzymes

Microtubules Are like bones Thin, hollow tubes of protein that help give the cell structure Aid in cell division Make cilia and flagella

Microfilaments Fiber like structures Wave back and forth to make a cell move

Ribosomes Where protein molecules are assembled Proteins are a key component of enzymes

Golgi Apparatus Looks like flat sacs bundled together Takes water out of protein and prepares it to leave the cell

Endoplasmic Reticulum Webbed network of double membranes Transports materials within the cell

Lysosomes Digest proteins, carbohydrates, and other molecules Digests foreign invaders like bacteria If other organelles quit working… digests them too!

Plastids Plant cells only 3 types Chloroplasts = convert suns energy to carbohydrates, contain chlorophyll Leucoplasts = store starch, proteins, and lipids, mostly found in seeds Chromoplasts = creates pigments that give fruit its color

Centrioles Centers that organize the microtubules within a cell