Cells Unit

 Biome  Ecosystem  Community  Population  Organism  Organ System  Organs  Tissue  Cells  Organelle  Molecules Discuss in Ecology We will focus on these areas Properties of Life 1.Cellular Organization 2.Metabolism 3.Homeostasis 4.Growth & Development 5.Reproduction/Heredity 6.Responsiveness/Interaction 7.Evolution

Cells: Organize to form… Tissues: Collect & work together to form… Organs: Work together to form a structure that form… Organism Organ Systems: Work together to perform major bodily Functions. Work with others to create an…

 A group of organs working together for a particular function

 A defined group of tissues that work together for one purpose

 A layer of the same kind of cell

 The basic unit of “living” things.

 = a structure that carries out specific activities in the cell.

 Groups of atoms; the smallest unit of most chemical compounds

 Question: What is a cell?  Answer: the most basic unit of life that can perform all life processes.

 Cells are very small.  Cells make up all living things (from bacteria to elephants).  They are the building blocks of all things living.

 Cells can vary greatly in their size and shape.  But they are all still very small.  Just how big are cells?  Cell size is limited for a reason.

Fig. 4-2a, p. 54 This is the business end of a needle. This one’s infested with E. coli. 200µm = 0.2mm Bacteria Finger width = 16mm

Fig. 4-2b, p µm = 0.04mm

Fig. 4-2c, p. 54 1µm = 0.001mm

 Hooke  Leeuwenhoek  Virchow  Schleiden

 Robert Hooke in  Looked at oak cork through a magnifying glass.  Thought the compartments looked like the rooms monks lived in…cells.

Fig. 4-3b, p. 55 oil lampwater flask specimen focusing knob

 Anton van Leeuwenhoek (1660’s)  Looked at all kinds of stuff through the first “microscope”.  Called what he saw “animalicules”, which would later be discovered to be bacteria.

 Schleiden (1838)… Discovered cells in plants.  Virchow (1858)… Was the first to discover cellular division.

 Microscope observations of organisms led to the discovery of the basic characteristics common to all living things.  Scientists first discovered cells in the 1600s using crude microscopes.  There has been many versions, the most recent being very sophisticated electron scanning microscopes.

CELL THEORY:  1. All living things are made up of one or more cells.  This is universal. All living things are made of cells.  2. Cells are the basic units of structure and function in organisms.  Just like amino acids are the basic unit of proteins, cells are the basic unit of life.  3. All cells arise from other cells.

 If cells are so small, how do we see them?  We use microscopes.

 Cells come in a variety of shapes and sizes.  Some are very, very tiny like bacteria  Some are relatively large like the amoeba

 All cells share 4 common features: Copy off the board. 1. The cell membrane is the outer layer that covers a cell’s surface and acts as a barrier between the outside environment and the inside of the cell. 2. The cytoplasm is the region of the cell within the cell membrane. The cytoplasm includes the fluid inside the cell called the cytosol. 3. A ribosome is a cellular organ that makes proteins. 4. The DNA of a cell provides instructions for making proteins, regulates cellular activities, and enables cells to reproduce.

Prokaryotes Eukaryotes

Prokaryotes Eukaryotes  No nucleus  Nucleus

 A large membrane-enclosed structure that contains the cell’s genetic information (DNA)  Controls many of the cell’s activities

 Quick definition: Genetic material (DNA) is NOT contained in a nucleus  More info: Generally smaller and less complicated  Examples include bacteria  Are prokaryotes still living if they are less complicated and microscopic? How do you know this?

 Gram positive organisms have a cell wall that allows them to be stained to see.

 Some bacteria don’t have a cell wall but they can be stained with a different stain.

 When you get sick a lab can run a test to see if you have an infection and what kind of infection you have.

A B C D E F Click to animate the image.

 Quick definition: cells that store DNA in a nucleus  More info: inside these cells, parts are separated from the rest of the cell by membranes  Examples: plants, animals, fungi, amoeba

 Look for a nucleus!

Bacterial cell Animal Cell Very basic Complex

100x bigger! 2 billion years older! More complex

Read each example and decide if it is a prokaryote or a eukaryote. 1. You scrape the inside of your cheek and make a slide of the cells that come off. 2. In an amoeba cell, there are many complex cell parts and a membrane wrapped around the DNA. 3. A bacteria cell has a clump of DNA that looks like a pile of spaghetti.

 1. Eukaryote  2. Eukaryote  3. Prokaryote

 What did you learn today?

Objective  Label common parts of an animal cell and describe their functions Warm-Up  What is the major difference between a eukaryotic cell and a prokaryotic cell?  Part II: Cell Organelle.

Cell wall

Cell membrane

DNA

cytoplasm

ribosome

flagella

 Controls what moves in and out of a cell REGULATOR!

 Protects the cell and gives it shape

 A jellylike material that fills the cell

 Instructions to run the cell. The “brain”.

 Helps the cell move (one direction only)

 Follows instructions to make proteins