GCSE Year 10 Microscopes
Unit 2.1 Double Award Year 10 Biology
1.1 Cells and movement across membranes
(b) The use of a light microscope to view animal and plant cells
(d) The levels of organisation within organisms: tissues are groups of similar cells with a similar function and organs may comprise several tissues performing specific functions; organs are organised into organ systems, which work together to form organisms
Objectives
Success Criteria
Key words and definitions
Light microscope: a microscope which uses light to produce an image of a specimen
Magnification: how many times bigger an image is, compared to the original size.
Organ: a group of tissues working together to perform a certain function
Organ system: a group of organs which work together performing certain functions
Organism: an individual which can function on its own
Resolution: seeing two cells as two separate cells, the smallest distance between two objects which can be distinguished
Tissue : a group of similar cells carrying out a similar function
Virus Cells
Plant Cells
White Blood Cells
They are all microscopic. They cannot be seen by the naked eye, and you need a microscope to see them.
What do the things below,
have in common?
a microscope
What is Microscopy?
A Brief History of the Microscope - Part 1
1st century AD, Romans start to use glass to magnify objects
Invented by Roger Bacon in 1250, Earliest magnifying glasses were used to look at insects
13th century, Salvino D'Armate, made the first eye glass
A Brief History of the Microscope - Part 2
17th century, Robert Hooke made and recorded many observations through a microscope
17th century, Galileo Galilei develops a compound microscope with a convex and a concave lens
16th century, Hans and Zacharias Jansen made the first compound microscope
A Brief History of the Microscope - Part 3
His microscope was 200 times the power of any other microscope at that time
17th century, Anton van Leeuwenhoek, produced first real microscope
Size Comparison
Eyepiece Lens | This is the lens closest to your eye. It usually has a magnification of x10. |
Objective Lens | There are three lenses of different strengths, which can be used to magnify the image more clearly. |
Stage | This is the place where you put a microscope slide. Clips hold the slide in place |
Diaphragm | Controls the amount of light that goes onto the microscope slide. |
Light | The light source projects light onto the microscope slide. It can be a mirror or an electric bulb. |
Base | This is, heavy to keep the microscope from falling over. |
Arm | This holds the eyepiece lens above the stage. |
Fine Focus Knob | This is used to focus the image, so it is sharp and clear. |
Coarse Focus Knob | Used to focus the image, so that you can see it clearly. |
The Light Microscope
Part | Function |
Eyepiece Lens | Controls the amount of light that goes onto the microscope slide. |
Objective Lens | This is the lens closest to your eye. It usually has a magnification of x10. |
Stage | This is used to focus the image so it is very sharp and clear. |
Diaphragm | This is used to focus the image so that you can see it clearly. |
Light | This holds the eyepiece lens above the stage. |
Base | Three different strength lenses, that can magnify an image more clearly. |
Arm | This is the place where you put a microscope slide. Clips hold the slide in place |
Fine Focus Knob | The light source that projects light onto the microscope slide. |
Coarse Focus Knob | This is very heavy to keep the microscope from falling over. |
Match the part with its function
How Does a Light Microscope Work?
A beam of light passes through a specimen, which travels through the eyepiece lens, allowing the specimen to be observed.
The eyepiece lens magnifies the image, with usually a fixed magnification of x10.
The objective lens magnifies the image, with magnification that can change, e.g., x4, x10, x40.
The diaphragm adjusts the amount of light going through the specimen and entering the objective lens.
The coarse and fine focus wheels are used to focus the microscope. The coarse wheel focuses the image under low-power objective lens, then the fine focus wheel is used to finely focus the image.
Electron Microscopes
Electron microscopes use a beam of electrons rather than light to make an image.
An electron microscope has a higher magnification than the light microscope, but it can only be used to view dead tissue. They also have a higher resolution.
Electron microscopes are also more expensive and require higher maintenance than light microscopes.
Working Out Magnification
Magnification = Eyepiece Lens x Objective lens
If the eyepiece lens has a magnification of x 10
and the objective lens has a magnification of x 40
then the image will be magnified x 400
Calculate the magnification equations set out below:
2. If the eyepiece has a magnification of x 5
40
1000
200
50
Cell Organisation
Tissues are a group of similar cells working together to carry out a particular function, for example, nervous tissue or muscle tissue.
Tissues
Courtesy of Servier
Organs
Heart:
Pumps blood around our body
Stomach:
Where digestion takes place
Brain:
Controls our body’s functions
Lungs:
Allows us to breathe in and out
Liver:
Removes toxins from our body
Kidneys:
Filters our blood and keeps it clean
These are some of the main organs in our body.
They are made from tissues that work together to form the organ.
A group of organs which work together to perform a particular function, for example, nervous system, circulatory system, respiratory system.
Organ Systems
Digestive System
Nervous System
Circulatory System
Organisms
A living thing that can function individually, for example, an animal or a plant.
Definitions
Cell:
The basic building block of life
Organ:
A group of tissues that work together to perform a function
Tissue:
A group of cells of the same type working together to perform a function
Organism
Tissue
Cell
Organ System
Organ
Organelle
Order the words below from smallest size to the largest size. Smallest at the bottom to the largest at the top.
Organism
Tissue
Cell
Organ System
Organ
Organelle
Largest
Smallest
Tissues are made from only one type of cell…
True
False
Or
True
True
False
Or
True
Lots of organ systems work together to make an organism…
True
False
Or
An organelle is bigger than an organ…
False
True
False
Or
True
The spinal cord and brain are organs in the Nervous System…
True
False
Or
False
The Circulatory System carries electrical messages around the body…
EXAM QUESTIONS
Microscope / Light Microscope
X 100
Use x10 objective lens (1)
(explanation the magnification) = eyepiece x objective / owtte (1)
NOT 10 x 10 unqualified
To bring into focus
Efficient
Tissue
(organs are structures made up of several) tissues performing one or more functions / jobs / roles / tasks
GCSE Year 10 Microscopes