The Microscope or light source

The Microscope Scientist use microscopes to reveal details that otherwise might be difficult or impossible to see –Biologist use them to study organisms and their parts

Simple Microscope The simple microscope is a single lens microscope is used to produce an enlarged image.

Compound Microscope Compound Microscope- shines light through specimen and has at least two lenses to magnify an image.

Compound light microscopes can magnify objects up to 2,000 times. Section 7.1 Summary – pages The Development of Light Microscopes

The Microscope Magnification- the increase of an object’s apparent size Power of magnification is the degree of enlargement (how many times will the object be multiplied?) Power of magnification = ocular (eyepiece) lens X magnification of objective lens

The Microscope Resolution- the ability of the microscope to deliver a clear image **the higher the magnification the lower the resolution

 The electron microscope was invented in the 1940s.  This microscope uses a beam of electrons to magnify structures.. Development of Electron Microscopes

Transmission Electron Microscope (TEM) Transmission Electron Microscope (TEM)- –a beam of electrons must pass through a very thinly sliced specimen. –Has great resolution of internal structures –Can magnify objects up to 500,000 times. The transmission electron microscope (TEM) allows scientists to study the structures contained within a cell.

Scanning Electron Microscopes (SEM) Scanning Electron Microscope- –passes beams of electrons over (scans the surface of) the specimen’s surface and provides a 3D image –Can be magnified up to 100,000 times.

SEM Pictures

Compound Light MicroscopeElectron Microscopes 1. beams of lightbeams of electrons 2. glass lenseselectromagnetic lenses 3. view through ocular lenses view on a florescent screen or photographic plate 4. can view living things can only view dead things X500,000X

Father of Microscopy  Anton Van Leeuwenhoek ( )  Leeuwenhoek is known to have made over 500 "microscopes," of which fewer than ten have survived to the present day. These typically magnified between 20 to 30 times.  He discovered blood cells, and was the first to see living sperm cells of animals. He discovered microscopic animals.

Chapter 4 Cells

What is a cell? A cell is the smallest unit of life that can carry on all the functions of life.A cell is the smallest unit of life that can carry on all the functions of life.

Who first discovered cells? Robert Hooke first discovered cells in 1665 He was an English scientist that looked at a cork oak tree with an early light microscope; they reminded him of the rooms or “cells” where monks lived.

Who first observed living cells? Anton van Leeuwenhoek in 1673 He viewed pond water organisms and called them “Wee beasties”. We now call them protists.

What are the three parts of the cell theory? 1. All living things are made of cells 2. Cells are the basic units of structure & function in all organisms. 3. Cells come only from the reproduction of existing cells.

What shapes do cells come in? Cells come in a variety of shapes and their shapes usually reflect their function.Cells come in a variety of shapes and their shapes usually reflect their function. Examples:Examples: (we will do the chart together)

How big or small are cells? -Cells are measure in micrometers(µm) -Most cells are only 10-50µm in diameter. -The smallest cell is bacteria ostrich egg -The largest cell is ostrich egg nerve cell in a -The longest cell is nerve cell in a giraffe’s leg

How big or small are cells?

How big can cells get? The size of a cell is limited by the relationship of the cell’s outer surface area to it’s volume –(Surface area to volume ratio)

Surface Area A two-dimensional measurement of the size of the surface of an object

Volume The amount of three dimensional space occupied by an object.

SA to Volume Ratio As cells grow, their volume increases much more than their surface area! The limited surface area would not allow materials to enter or leave the cell quickly enough to meet the cell’s needs.

Surface Area to Volume What would happen if you fried the whole potato instead of making French fries?

What are the three main parts? 1. Cell Membrane- semi or selectively permeable. It controls which substances pass in and out of the cell. Made up of a phospholipid bilayer. 2. Nucleus- contains the hereditary information (DNA) and directs most of the cell’s activities. 3. Cytoplasm- the region between the cell’s nucleus and the cell membrane, which contains the organelles and the cytosol (jelly-like substance)

What are the two types of cells? Eukaryote - cells that have a nucleus and membrane-bound organelles. Examples: plant and animal cells Prokaryote cells that do not have a nucleus and membrane-bound organelles. Examples:bacteria

How do plant and animal cells differ? PLANT Cell wall Central vacuole Chloroplast No lysosomes ANIMAL No cell wall No central vacuole No chloroplast Lysosomes

What is the difference between unicellular and multicellular organisms? Unicellular- one cell can carry out all the functions of life. Example: bacteria, paramecium, amoebaUnicellular- one cell can carry out all the functions of life. Example: bacteria, paramecium, amoeba Multicellular – organisms composed of many cells that are specialized to carry out specific jobs (Cell Specialization)Multicellular – organisms composed of many cells that are specialized to carry out specific jobs (Cell Specialization) –Therefore the cells depend upon other cells for survival (Cell Interdependence)

What are the levels of structural organization in multicellular organisms? 1.Atom and molecule 2.Macromolecules 3.Organelles 4. Cell 5. Tissue 6. Organ 7. Organ System 8. Organism

Pictures

More pictures Tissue Organ

Organ Systems

Cells Product All cells must generate protein (monomer: amino acid) Cells make protein through a process called protein synthesis.

Cells Product Transcription: the process of making a copy of DNA into mRNA. This occurs in the nucleus Translation: the process of translating mRNA to tRNA into an amino acid chain.