Cells – The building blocks of life

Cell theory – the history behind it The cell was discovered by Robert Hooke in 1665 He looked at a piece of cork under a microscope and noted that it looked like honeycomb In 1674 Anthony van Leeuwenhoek saw the first living cells using a compound microscope

Cell Theory All living things or organisms are made of cells New cells are created by old cells dividing into two Cells are the basic building blocks of life

Modern cell theory 1. The cell is the fundamental unit of structure and function in living organisms. 2. All cells arise from pre-existing cells by division. 3. Energy flow (metabolism and biochemistry) occurs within cells. 4. Cells contain hereditary information (DNA) which is passed from cell to cell during cell division. 5.

Modern cell theory continued 5. All cells are basically the same in chemical composition in organisms of similar species. 6. All known living things are made up of one or more cells. 7. Some organisms are made up of only one cell and are known as unicellular organisms. 8. Others are multicellular, composed of a number of cells. 9. The activity of an organism depends on the total activity of independent cells.

Viewing cells – microscopy

Compound Microscopes

Fluorescent Microscopes

Certain proteins will fluoresce

Electron Microscopes

Types of cells Prokaryotic – simple cells, DNA is not contained, no organelles Ex: bacteria Eukaryotic – more complex cells, DNA is contained, organelles Ex: animal cells and plant cells

Eukaryotic Cells - organelles

Cell Membrane A phospholipid layer that allows transport into and out of a cell

Nucleus The control center for the cell Contains DNA Surrounded by a double membrane

Endoplasmic reticulum Allows for transport within the cell Rough E.R – has ribosomes, makes protein Smooth E.R- has no ribosomes, makes lipids (fats) Ribosome: Site of protein sysnthesis

Golgi Apparatus Packages, stores and delivers proteins

Lysosomes Clean the cell and destroy worn out cell parts

Mitochondria Powerhouse of the animal cell – where cellular respiration occurs

Chloroplast Found in plant cells only Site of photosynthesis Clorophyll gives the plant a green color

Cell wall Thick outer layer protecting plant and bacterial cells

vacuoles Storage of water, nutrients (food), waste Plants generally have one large vacuole while animal cells have several smaller vacuoles

Movement across the cell membrane

Structure of the membrane Made of Phosopholipids – provide a barrier from things entering and leaving the cell Fatty acids – maintains shape Proteins – serve as a gate way to allows things in and out of the cell http://www.phschool.com/science/biology_place/biocoach/biomembrane1/regions.html

Membrane animation

Diffusion/osmosis Movement of molecules across the membrane from high concentrations to less concentrations

Terms Isotonic – two solutions with the same concentration Hypertonic – a solution with a higher concentration than another Hypotonic – a solution with a lower concentration than another

Facilitated diffusion Movement of molecules from areas of more concentration to less concentration using proteins Used with larger molecules

Active transport Movement of molecules from areas of lower concentration to higher concentration using proteins Requires energy!

terms Endocytosis - Transport into the cell using a vesicle Phagocytosis – transport into the cell using a vesicle that is destroyed by lysosomes Exocytosis – Tr Video: https://www.youtube.com/watch?v=DuDmvlbpjHQansport out of the cell using a vesicle Animation: http://life9e.sinauer.com/life9e/pages/06/062003.html

Cell division: mitosis vs meiosis

Cancer – when cells go wild!