Cell Discovery and Theory Section 7.1

Section 7.1 Summary – pages 171-174 The cell theory is made up of three main ideas: All organisms are composed of one or more cells. The cell is the basic unit of organization of organisms. All cells come from preexisting cells. Section 7.1 Summary – pages 171-174

Microscope Technology Compound Light Microscope What we use Has a series of lenses and uses visible light to magnify an image Electron Microscope- 1940’s More detailed views TEM: transmission electron microscope SEM: scanning electron microscope STM: scanning tunneling electron microscope AFM: atomic force microscope

Cell Diversity Cells vary in shape, which relates to their function Skin cells are flat to cover the body Nerve cells are branched to transmit impulses Cell size is limited by the surface area-to-volume ratio If a cell’s volume gets too large, its exchange of substances would take too long and the cell could die

Section 7.1 Summary – pages 171-174 Two Basic Cell Types Prokaryotic cells : cells that do not contain internal membrane-bound structures Examples: Bacteria and some other single celled organisms Blue Green Algae Blue Green Algae Bacteria Section 7.1 Summary – pages 171-174

Prokaryotic cells Basic structure

Section 7.1 Summary – pages 171-174 Two Basic Cell Types Eukaryotic cells: contain membrane-bound structures . Examples: all plant and animal cells – some single celled organisms Section 7.1 Summary – pages 171-174

Eukaryotic cells

Eukaryotic v. Prokaryotic

Section 7.1 Summary – pages 171-174 Basic Parts of a Cell Plasma membrane – Cell’s outer boundary Organelles- membrane-bound structures within eukaryotic cells. Each organelle has a specific function that contributes to cell survival. Cytoplasm-The region within the cell Nucleus-The central membrane-bound organelle that manages cellular functions in eukaryotes. Cilia and Flagella- projections from a cell that aids in movement/feeding. (eukaryotic cells-external, prokaryotic-inside of plasma membrane) Section 7.1 Summary – pages 171-174

The Plasma Membrane Section 7.2

Purpose: To act as a barrier between a cell and its environment To maintain homeostasis in a cell (a balance of conditions suitable for life)

How? The plasma membrane is selectively permeable, so it allows certain substances (like oxygen and nutrients) in, while getting rid of others (like waste.)

Summary Section 2 – pages 175-178 Plasma Membrane Oxygen Amino acids Water Glucose Wastes Wastes Carbon dioxide SELECTIVE PERMEABILITY Summary Section 2 – pages 175-178

It’s composed of a phospholipid bilayer What does it look like? It’s composed of a phospholipid bilayer Polar heads (phosphate) on the outside hydrophilic Nonpolar tails (fatty acids) on the inside hydrophobic Two layers of phospholipids back-to-back

Polar heads: with phosphate group face outward and stay in contact with water inside and outside of cell Nonpolar tails: fatty acid chains point inward toward one another.

The Model The model of the p.m. is called the fluid mosaic model because the phospholipids move within the membrane and proteins in the membrane move among the phospholipids. It’s flexible

What does that mean? “Fluid” means it can move “Mosaic” Animation http://www.susanahalpine.com/anim/Life/memb.htm

What are the other parts of the p.m.? Cholesterol keeps the fatty acid tails from sticking together, keeps the membrane stable. Carbohydrates stick out from the cell surface to help cells identify chemical signals.

Summary Section 2 – pages 175-178 Other components of the plasma membrane: Transport proteins allow things to move through the plasma membrane.(2 types) Channel protein – always open Carrier protein – only open to certain substances Summary Section 2 – pages 175-178

Cell Structures, Functions and Transport 7.3

Prokaryotic cells Eukaryotic Cells cells that do not contain internal membrane-bound structures Bacteria and some other single celled organisms contain membrane-bound structures all plant and animal cells

Cytoplasm The environment inside the plasma membrane Semifluid material Thought to be where organelles float Cytoskeleton The supporting network of protein fibers that provide a framework for the cell (microfibers and microtublues) Organelles are anchored

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Animal Cell Cytoplasm Nucleolus Nucleus Cell Membrane Lysosomes Go to Section:

Eukaryotic Cell Organelles and Function Nucleus Nickname: “The Control Center” Function: holds the DNA Parts: Nucleolus: dark spot in the middle of the nucleus that helps make ribosomes

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Animal Cell Cytoplasm Nucleolus Ribosomes Nucleus Cell Membrane Lysosomes Go to Section:

Eukaryotic Cell Organelles and Function Ribosomes Function: makes proteins Found in all cells, prokaryotic and eukaryotic

Eukaryotic Cell Organelles and Function Endoplasmic Reticulum (ER) Nickname: “Roads” Function: The internal delivery system of the cell

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Animal Cell Cytoplasm Nucleolus Ribosomes Nucleus Cell Membrane Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum Lysosomes Go to Section:

Endoplasmic Reticulum 2 Types: Rough ER: Rough appearance because it has ribosomes Function: helps make proteins, that’s why it has ribosomes Smooth ER: NO ribosomes Function: makes fats or lipids

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Ribosomes Section 7-2 Cytoplasm Ribosomes Nucleolus Nucleus Cell Membrane Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum Golgi Complex Lysosomes Go to Section:

Eukaryotic Cell Organelles and Function Golgi Complex Nickname: The shippers Function: packages, modifies, and transports materials to different location inside/outside of the cell Appearance: stack of pancakes

Animal Cell Figure 7-5 Plant and Animal Cells Lysosomes Cytoplasm Section 7-2 Cytoplasm Nucleolus Ribosomes Nucleus Cell Membrane Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum Golgi Bodies Lysosomes Go to Section:

Eukaryotic Cell Organelles and Function Lysosomes: circular, but bigger than ribosomes) Nickname: “Clean-up Crews” Function: to break down food into particles the rest of the cell can use and to destroy old cells

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Cytoplasm Nucleolus Ribosomes Nucleus Cell Membrane Mitochondria Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum Golgi Bodies Lysosomes

Eukaryotic Cell Organelles and Function Mitochondria Nickname: “The Powerhouse” Function: Energy formation Breaks down food to make ATP ATP: is the major fuel for all cell activities that require energy

Animal Cell Cytoplasm Nucleolus Ribosomes Nucleus Cell Membrane Mitochondria Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum Golgi Bodies Lysosomes

Now let’s talk about structures only found in PLANT Cells!!

Plant Cell Figure 7-5 Plant and Animal Cells Vacuole Cell Membrane Section 7-2 Vacuole Cell Membrane Go to Section:

Eukaryotic Cell Organelles and Function Vacuoles (animals may have a much smaller vacuole) Function: stores water This is what makes lettuce crisp When there is no water, the plant wilts

Plant Cell Figure 7-5 Plant and Animal Cells Vacuole Chloroplasts Section 7-2 Plant Cell Vacuole Chloroplasts Cell Membrane Go to Section:

Eukaryotic Cell Organelles and Function Chloroplasts Function: traps energy from the sun to produce food for the plant cell Green in color because of chlorophyll, which is a green pigment

Chloroplasts

Plant Cell Figure 7-5 Plant and Animal Cells Vacuole Chloroplasts Section 7-2 Vacuole Chloroplasts Cell Membrane Cell Wall Go to Section:

Eukaryotic Cell Organelles and Function Cell Wall Function: provides support and protection to the cell membrane Found outside the cell membrane in plant cells

Plant Cell Cytoplasm Vacuole Smooth ER Ribosomes Chloroplasts Cell Membrane Cell Wall Nucleolus Golgi Bodies Nucleus Mitochondria Rough ER

Comparing Plant and Animal Cells

Comparing Plant, Animal and Prokaryotic Cells Prokaryotes

Plant Cell Animal Cell Prokaryotic Cell Cell Wall Chloroplasts Cytoskeleton and cytoplasm Nucleus Endoplasmic Reticulum Golgi Apparatus Vacuole Mitochondria Genetic Material Plasma Membrane Ribosomes 1) Lysosomes 2) Centrioles 3) Cytoskeleton and cytoplasm 4) Nucleus 5) Endoplasmic Reticulum 6) Golgi Apparatus 7) Vacuole 8) Mitochondria 9) Genetic Material 10) Plasma Membrane 11) Ribosomes Prokaryotic Cell Cytoskeleton and cytoplasm 6) Capsule Ribosomes 7) Flagella Plasma Membrane 8) Cillia Cell Wall DNA

Cellular Transport Section 7.4

Cellular Transport Passive Transport Movement of particles across the cell membrane without using energy Three Modes of Passive Transport Diffusion Facilitated Diffusion Osmosis

Passive Transport Diffusion Movement of particles from an area of high concentration to an area of lower concentration

Passive Transport Diffusion is controlled by Temperature Pressure Concentration Dynamic Equilibrium Reached when diffusion of material into the cell equals diffusion of material out of the cell Molecules continue to move, but the overall concentration remains the same.

Passive Transport Diffusion in a Cell

Passive Transport Facilitated Diffusion Movement of materials across the plasma membrane using proteins

Passive Transport- Facilitated Diffusion Channel Proteins always open to allow certain substances to pass down their concentration gradient Carrier Proteins change shape as diffusion continues to help move the particle through the membrane

Passive Transport -Video Clip Diffusion: Channel and Carrier Proteins

Passive Transport Osmosis Diffusion of water across a selectively permeable membrane Three Types of Solutions Isotonic Hypotonic Hypertonic Isotonic, Hypotonic, Hypertonic Solutions -Video Clip

Passive Transport Isotonic Solution Water and dissolved substances diffuse into and out of the cell at the same rate. Plant Cell

Passive Transport Hypotonic Solution Solute concentration is higher inside the cell. Water diffuses into the cell. Plant Cell

Passive Transport Hypertonic Solution Solute concentration is higher outside the cell. Water diffuses out of the cell. Plant Cell

Cellular Transport Active Transport

Active Transport Using Carrier Proteins Cellular Transport Active Transport Movement of particles across the cell membrane using energy; going from low to high concentration Active Transport Using Carrier Proteins Against the concentration gradient

Active Transport Types of Active Transport Pumps Na+/K+ ATPase pump Moves three Na+ ions out of the cell and two K+ ions into the cell Sodium-Potassium Pump-Video Clip

Active Transport Endocytosis Process by which the cell surrounds and takes particles into the cell Exocytosis Secretion of material out of the plasma membrane VIDEO

http://www.glencoe.com/sites/common_assets/science/virtual_labs/LS03/LS03.html