1. Chapter 6
A Tour of the Cell

2. Cell Review Levels of organization
Cell – The smallest basic unit of structure and function that show the characteristics of life
Unicellular – made up of a single cell
Ex Bacteria
Multicellular – made up of multiple cells
Levels of organization
Cell--tissue--organ--organ system-- organism

3. Cell History
Robert Hooke – (mid 1600s) – examined cork and was the first to see “cells”
Anton von Leeuwenhoek – made single-lens microscope and was the first to see living cells

4. Cell Theory Schleiden – studied plants All plants are made up of cells
Schwann – studied animals
All animals are made of cells
Virchow
All cells come from preexisting cells
1. All living organisms are made up of cells
2. All cells carry on life activities
3. New cells arise only from other living cells

5. Two Basic Cell Types Single-celled organisms: bacteria
Prokaryotic – lack any internal membrane-bound structures and nuclei
Single-celled organisms: bacteria
Eukaryotic – have nuclei and membrane-bound structures
Multicellular organisms – plants, animals, fungi, protists

6. Prokaryotic vs Eukaryotic

7. Cell Size Ex: nerve cells – 1 to 2 meters long
Cells are all different shapes and sizes
Vary from 2m to .2 micrometers
Ex: nerve cells – 1 to 2 meters long
Ex: Chicken Egg – single cell

8. Cell Parts 1. Protect inside of cell separating it from outside
Cell membrane – outer covering separates the cell from its surrounding environment
Made up of a phospholipid bilayer, selectively permeable
3 functions
1. Protect inside of cell separating it from outside
2. Support cell and give it shape
3. Control the passage of substances

9. Integral proteins (those embedded within) Transport molecules
Cell Parts
Membrane Proteins
Integral proteins (those embedded within)
Transport molecules
Peripheral proteins (lie on one side)
Aid in chemical rxns
Cytoplasm – aqueous fluid inside the cell that contains organelles

11. Maintain the life of the cell
Organelles
Organelles – membrane-bound structures having one or more specialized functions
Maintain the life of the cell
Ribosomes – where proteins are made
Endoplasmic Reticulum (ER) – intracellular pathway used in transport
Rough ER – ribosomes attached here, site in which proteins are made and transported
Smooth ER – Where lipids are made
Ex: produce steroids in gland cells

13. Organelles Ex: Webbed hands
Golgi Apparatus – processes, packages, and secretes modified proteins for export from cell
Lysosomes – small sacs that contain digestive enzymes
Ex: Webbed hands
Centriole – 2 rod-shaped organelles located near the nucleus of an animal cell involved in cell reproduction

14. Organelles Nucleus – Control center of the cell
Nuclear Membrane – separates the nucleus from the rest of the cell
Nucleolus – place in which ribosomes are made
Chromosomes – structures found inside nucleus that control heredity
Mitochondria – site of cellular respiration, powerhouse of cells
Where we get our energy ATP

17. Plant Cell Parts
Cell Wall – rigid outer covering just outside a plant cell that gives shape and structure
Vacuole – storage site of cell
Chloroplasts – structures that contain the pigment chlorophyll that give plants their green color

18. Animal Cell Diagram
Plant Cell Diagram

19. The Cytoskeleton
Cytoskeleton – long protein strands within the cytoplasm that gives the cell structure
Microfilaments – small protein threads
Actin – protein found in the microfilaments that help muscle contraction
Microtubules – long, hollow tubes made up of the protein tubulin
Cilia – small hair-like projections used in cell movement
Flagella – long whip-like tail used for movement

21. Cell Processes Ex. Perfume Ex: Glucose
Homeostasis – ability to maintain a stable internal environment
Passive Transport – the movement of substances across a cell membrane without the use of energy by the cell
Diffusion – movement of molecules from an area of higher to lower concentration
Ex. Perfume
Facilitated diffusion – type of passive transport in which carriers transport molecules without using energy
Ex: Glucose

23. Turgor pressure – pressure that water exerts against a cell wall
Osmosis
Osmosis – process by which water molecules diffuse across a cell membrane from higher to lower concentration
Hypertonic – solute concentration outside cell is greater than inside cell
Hypotonic – solute concentration outside cell is lower than inside the cell
Isotonic – solute concentration is the same inside and out
Turgor pressure – pressure that water exerts against a cell wall

24. Ex: animal cells (red blood cells)
Cytolysis – swelling of cells due to an intake of water in a hypotonic environment
Ex: animal cells (red blood cells)
Plasmolysis - shrinking of cytoplasm due to loss of water in a hypertonic environment
Ex: Leaves wilting

25. Active Transport Ex. Sodium Potassium Pump
Active Transport – movement of molecules across the concentration gradient from lesser to greater with the use of energy (supplied by ATP)
Ex. Sodium Potassium Pump

26. Movement in Vesicles (large molecules)
Endocytosis – process by which cells ingest external fluid, macromolecules, and large particles by vesicle
Phagocytosis – transport of large particles or whole cells

27. Movement in Vesicles (large molecules)
Exocytosis – process by which a substance is released from the cell through a vesicle that transports the substance out of the cell