EOY B1 Flashcards
1m = cm?
100cm
1cm is mm
10mm
1mm is how many micrometers
1000
1 micrometer is nanometres
1000
How do electron microscopes work?
They use a beam of electrons to form an image
What type of electron microscope makes 2D images, with high mag and resolution?
Transmission electron microscope
What type of electron microscopes give dramatic 3D images but with lower mags?
Scanning electron microscopes
What is the equation for total mag?
Objective lens x ocular (eyepiece) lens
How do you use a microscope?
- Place specimen or object on to slide. This is called mounting.
- You may have to cut the object or stain it to make the features stand out or to see through it
- After, cover with a small, thin square of glass called a ‘cover slip’.
- Secure the slide to the stage with 2 clips.
- Turn large wheel (course focus) until stage is as close to objective lens as possible
- Turn turret to lowest mag (usually 4x) until lens is over slide
- Look down eyepiece lens (usually 10x mag)
- Turn course focus slowly until you see cells
- Turn fine focus until you see clearly
- Do again with next objective lens
Advantages of light microscope
Relatively cheap
Mag up to 2000x
Can be used almost everywhere
Disadvantages of light micro
Limited mag
Limited resolution
Advantages of electron micro
High mag up to 2000000x
High resolution
Can give 3D images
Disadvantages of electron micro
Expensive
Must have specific temp, pressure and humidity needed
Equation for mag
Image height / object height
Or
Size of image/ size of real object
What is resolution?
How is it measured?
How detailed an image is, high resolution = more detail image holds.
Is measured by shortest distance between 2 points that can be seen as 2 separate points by observer
Equation for magnification triangle
I (image size)
A (actual object size M (magnification)
I AM
What sub nuclear components are found in the animal cell?
Nucleus
Cytoplasm
Cell Membrane
Mitochondria
Ribosomes
What does the mitochondria do?
Structures in the cytoplasm where aerobic respiration takes place, releasing energy for the cell.
What do ribosomes do?
Where protein synthesis takes place, making all the proteins needed in the cell.
What are algae?
Simple aquatic organisms
Make their own food via photosynthesis and have similar features to plant cells.
They are now classified as part of the Protista kingdom
All plant and algal cells have a cell wall made of —
Cellulose
What are chloroplasts?
Green sub cellular structure
Contain chlorophyll which absorbs light so the plant can make food by photosynthesis.
What is a permanent vacuole?
Is a space in the cytoplasm filled with cell sap
This is important for keeping the cells rigid to support the plant
What is in a Eukaryotic cell?
Animal and plant cells
They all have a cell membrane, cytoplasm, genetic material enclosed in a nucleus.
The genetic material is called DNA and this forms structures called chromosomes that are contained within the nucleus
Give examples of eukaryotes
Humans
Animals
Plants
Fungi
Protista
Give example of prokaryote
Bacteria
What do bacterial cells have?
Cytoplasm
Cell membrane
Cell wall (not cellulose, murin)
Genetic material (not in nucleus)
Bacterial chromosome (single DNA loop in cytoplasm)
May also have extra small rings of DNA called plasmids. These code for specific features such as antibiotic resistance.
Some have a protective slime capsule
Some have a flagellum (long strand of protein that lashes out, so they can move around)
How do cells get specialised?
It gets different sub cellular structures that endangers it to carry out a specific function.
What is the function of a nerve cell?
Carry electrical impulses around the body of an animal