Section 1: Discovering Cells What are Cells? Cells are the basic units of structure and function in living things

How can we see cells? Cells are two small to be seen with the naked eye so we must use a microscope

What is a Microscope? A microscope is an instrument that makes small objects look larger A compound microscope contains more than one lens

How do Microscopes Work? Some microscopes use lenses to focus light onto an object The lenses in light microscopes are similar to the clear curved pieces of glass used in eyeglasses

Who was Robert Hooke? He was one of the first people to observe cells He observed cork cells using a microscope he had built himself

Who was Anton van Leeuwenhoek? He was a Dutch businessman who observed water from a pond and was the first person to see what are now called bacteria

What is the cell theory? A widely accepted explanation of the relationship between cells and living things

For a light microscope to be useful what two properties must be combined? Magnification Resolution

What is Magnification? The ability to make things look larger than they are

How do light microscopes make things look bigger? The lens or lenses in a light microscope magnify an object by bending the light that passes through them

What is a Convex Lens? A lens with a curved shape These lenses cause the light passing through the sides to bend inward; when this light hits the eye the object seems larger

How does a compound microscope magnify an object even more? It has more than one lens Light passes through a specimen and then through two lenses

How do you calculate total magnification? The total magnification is equal to the magnification of the two lenses multiplied together Example: First lens(10) second lens(40) total = 400

What is resolution? The ability to clearly distinguish the individual parts of an object Another term for sharpness

What other kind of microscopes are there? Electron Microscopes – use a beam of electrons instead of light to examine a specimen

Section 2: What is inside a cell? Organelles – tiny cell structures that carry out specific functions within the cell

What is the structure surrounding the cell? Cell wall - a rigid layer of nonliving material that surrounds the cells of plants and some other organelles

What is the cell wall made of? Cellulose – a tough, yet flexible, material (fiber) Wood contains a lot of cellulose

What is the function of the cell wall? A plant’s cell wall helps to protect and support the cell Cell walls allow trees to stand so tall

If the cell wall is so stiff can materials still pass through the cell wall? Yes, many materials, including water and oxygen, can pass through the cell wall

What is just inside the cell wall? Cell membrane – controls what substances come into and out of a cell All cells have cell membranes

How does the cell membrane allow things to pass through? There are tiny pores in the membrane that allow things to pass through like a window screen

What is the large, oval structure located within the cell? Nucleus – the cell’s control center, directing all of the cell’s activities

What is found within and surrounding the nucleus? Nuclear Membrane Chromatin Nucleolus

What structure surrounds the nucleus? The nuclear membrane – protects the nucleus

How does the nucleus know how to direct the cell? Chromatin – strands that contain genetic material, the instructions that direct the functions of a cell

What is the smaller structure located within the nucleus? Nucleolus – where ribosomes are made (ribosomes are the organelles where proteins are produced)

What is the clear, thick, gel-like fluid outside of the nucleus? Cytoplasm – the region between the cell membrane and the nucleus

Where are most cell organelles found? In the Cytoplasm: Mitochondria Endoplasmic Reticulum Ribosomes Golgi Bodies Chloroplasts Vacuoles Lysosomes

What are the rod-shaped structures located within the cytoplasm? Mitochondria – known as the “powerhouses”of the cell because they produce most of the energy the cell needs to carry out its functions

What forms a maze of passageways? The endoplasmic reticulum – the passageways carry proteins and other materials from one part of the cell to another

What is attached to the outer surface of the endoplasmic reticulum? Ribsomes – Small grainlike bodies Can also be found floating in the cytoplasm Function as factories to produce proteins

What are the structures that look like a flattened collection of sacs and tubes? Golgi Bodies – receive proteins and other new materials, package them, and distribute them to other parts of the cell Known as the cell’s mailroom

What are the large green structures in the cytoplasm? Chloroplasts – capture energy from sunlight and use it to produce food for the cell Animal cells do not have these; plant cells do These give plants their color

What is the large, round, water-filled sac in the cytoplasm? Vacuoles – The storage area of the cell Most plant cells have one large vacuole

What else can be found in the cytoplasm? Lysosome - Small, round structures that contain chemicals that break down large food particles into smaller ones

How are bacterial cells different from plant and animal cells? Smaller No nucleus - genetic material is found in the cytoplasm

Are we made up of all the same cells? No, we are made up of many different cells (skin, bone, etc.) Cells are structured to suit their unique function