Chapter 7 Cell Structure and Function Lab Biology

Chapter 7 Cell Structure and Function Lab Biology CP

Chapter 7: cell structure & function • • 7. 1 Life is Cellular 7. 2 Cell Structure 7. 3 Cell Transport 7. 4 Homeostasis and Cells

7. 1 life is cellular

The Cell Theory by Rudolf Virchow, Theodor Schwann, and Matthias Schleiden • 1. ) All organisms are made up of one or more cells. • 2. ) The cell is the basic unit of life. • 3. ) All cells come from preexisting cells.

Other Contributors • Robert Hooke: – 1 st to view cells under the microscope (1665) – viewed cork cells (plant cells) • Matthias Schleiden – Used a microscope to study that all plants are made of cells (1830’s)

Microscope History • Anton von Leeuwenhoek – Made the 1 st simple microscope – Looked at pond water – Magnified 270 x

Leeuwenhoek Microscope • A subject was placed on the needle and could be positioned with the adjusting screw.

Types of Microscopes • • • Leeuwenhoek microscope (270 x) Fluorescence microscope (1500 x) Phase contrast microscope (1500 x) Brightfield/Darkfield microscope (2000 x) Transmission electron microscope (100, 000 x) Scanning electron microscope (200, 000 x)

Electron Microscopes • Scanning Electron Microscope – A beam of electrons is scanned over the surface of the specimen – Produces 3 -D images • Transmission Election Microscope – Make it possible to explore cell structures and large protein molecules – Electrons can only pass through thin samples, so cells and tissues must be cut thin

Microscope Parts • • • Ocular Lens/Eyepiece – what you look through Body tube – supports the ocular lens/eyepiece Nose piece – where the objectives are located Arm and Base- what you carry the microscope by Stage- where the slide is placed Adjustments: – Course adjustment- lowers the stage up and down – Fine adjustment - focusing • Light- provides a light source to view your slide • Diaphragm- controls how much light is let in • Stage Clips – holds the slide in place

View through a microscope • Upside down and inverted http: //www. youtube. com/watch? v=Xw 98 KA 8 Uq. U

Cells

Some different types of cells

Common Cell Traits (All cells have these) • 1. ) Cell Membrane: – Outer covering • Plant Cells have a Cell Wall also • 2. ) Cytoplasm: – Gel-like material inside of the cell

Cell Types • Eukaryotes (Eukaryotic): – Have membrane-bound structures in their cells and a nucleus – Nucleus: brain of the cell; genetic info here – Organelles: membrane-bound structures – Animal and Plant Cells • Prokaryotes (Prokaryotic): – Do not have membrane-bound structures in their cells – Bacteria and pond scum

Eukaryotes (have membrane-bound organelles)

Prokaryotes (Do NOT have membrane-bound organelles)

7. 2 cell structure

Outer Coverings of Cells • Cell Membrane – Found in ALL cells – Made of a protein, lipid bi-layer – Semi-permeable – Fluid-Mosaic Model • Cell Wall – Found in plants only – Tough outer covering – Made up of cellulose • Also made up of pectin and lignin

Cell Membrane Structure

Cell Wall Structure

Cell Membrane and Cell Wall Comparison

Organelles (membrane bound organelles in inside of the cell) • Nucleus • Mitochondria • Endoplasmic Reticulum – Smooth and Rough • • • Ribosomes Golgi Bodies Lysosomes Cytoskeleton Chloroplasts (plant cells only)

Nucleus • Center of cell • Brain of the cell • Directs all the cell’s activities • DNA located here

DNA • Deoxyribonucleic Acid • A Nucleic Acid • Organized into chromosomes • DNA segments that carry genetic information are called genes

Chromosomes • long pieces of DNA found in the center (nucleus) of cells • come in pairs • Normally, each cell in the human body has 23 pairs of chromosomes (46 total). – half come from the mother – the other half come from the father

Mitochondria • Powerhouse of the cell • Provides energy for the cell • Where Cellular Respiration takes place

Endoplasmic Reticulum (ER) • Transports materials around the cell • 2 Types: – Rough ER: contains ribosomes – Smooth ER: does NOT contain ribosomes

Ribosomes • Make proteins • Located in 2 places – On Endoplasmic Reticulum – Free-floating in the cytoplasm

Golgi Bodies (a. k. a. Golgi Apparatus) • Stacked flattened membranes • Sort and package proteins and other substances into vesicles • Deliver substances to other parts of the cell • “Post Office”

Lysosomes • Digests wastes inside of the cell • Like a “garbage disposal”

Cytoskeleton • • Maintains cell shape Moves cell parts Helps cell move Made up of microfilaments and microtubules

Microfilaments & Microtubules • Microfilaments: threadlike structures made up of protein called actin • responsible for movement • Microtubules: • Hollow structures made up of protein called tubulins • Maintain cell shape • Important in cell division • Formed from Centrioles

Microfilaments & Microtubules

Vacuoles • In Plant Cells • 1 Large Central Vacuole • Largest portion of the cell • Store water, salts and proteins • In Animal Cells • Vacuoles: Controls water content • Vesicles: move materials between cell organelles

What Plants Cells HAVE that Animal Cells Don’t • 1. ) Cell Wall • 2. ) Chloroplasts – Make chlorophyll (green pigment) – Involved in photosynthesis • 3. ) Central Vacuole http: //www. youtube. com/watch? v=Fzj 6 TRn. Xmps&feature=related

Animal Cell (eukaryotic)

Plant Cell (eukaryotic)

What do cells make? • Cells Tissues Organs • Organ systems Organisms

7. 3 cell transport

Passive Transport • How the cell regulates the movement of molecules from one side of the cell membrane to the other WITHOUT ENERGY • 3 Types: – 1. ) Diffusion – 2. ) Facilitated Diffusion – 3. ) Osmosis http: //www. youtube. com/watch? v=AYNwynwa. ALo

Diffusion • When particles move from an area of high concentration to low concentration • Depends on random particle movement

Facilitated Diffusion • Process in which large molecules that can’t directly diffuse across a cell membrane, cross at certain protein channels instead • Some cells have certain proteins that act as channels or carriers and allow for quicker, easier movement of large molecules across a cell membrane

Osmosis • An example of facilitated diffusion • How water passes a selectively permeable cell membrane • Aquaporins: water channel proteins that allow the passing of water across the membrane http: //www. youtube. com/watch? v=sdi. Jt. DRJQEc

How Osmosis Works • Isotonic – When the solution concentration is the same both inside and outside of the cell • Hypertonic – When comparing 2 solutions, the solution with the greater concentration of solutes • Hypotonic – When comparing 2 solutions, the solution with the lesser concentration of solutes

Osmotic Pressure • Pressure that must be applied to prevent osmotic movement across a selectively permeable membrane • Can cause an animal cell in a hypertonic solution to shrink • Cells can also burst

The Effects of Osmosis on Cells

Active Transport • The movement of materials against a concentration difference • Requires ENERGY • Types: – Molecular Transport (small molecules) – Bulk Transport (large molecules) http: //www. youtube. com/watch? v=1 ZFq. Ovx. Xg 9 M&feature=related

Bulk Transport • Endocytosis: – Process of taking materials into a cell by means of infoldings, or pockets, of the cell membrane • Exocytosis: – When the membrane of the vacuole surrounding the materials fuses with the cell membranes, forcing the contents out of the cell http: //www. youtube. com/watch? v=1 w 10 R 9 lv 7 e. Q&feature=related

7. 4 homeostasis and cells

Homeostasis • How organisms grow, respond to the environment, transform energy and reproduce • If homeostasis is not maintained, the organism will die • Multicellular organisms become specialized to maintain homeostasis

Cell Specialization • Each cell has a different role • Example: – Blood cell

Cell Communication • Cells communicate by means of chemical signals that are passed from one cell to another. • Cells must have receptors to accept the signal