Microscopes and cells Flashcards
What does an enlarged Image of a specimen allow us to do?
See tiny structures otherwise too small to view
What is the maximum magnification on a light microscope?
X1500
What does an electron microscope use instead of a beam of light?
A beam of electrons, in a vacuum, which is focused with magnets
What has a greater resolution an electron microscope or a light microscope?
An electron microscope
What is resolution?
The ability to distinguish two points as separate from each other
What is the maximum magnification of an electron microscope?
X2,000 000
Why do we use iodine when viewing onion epidermis (skin)?
To make the cell wall, nucleus and starch grains show up
How to view a slide:
- Place slide on stage clips, specimen must be over a hole
- Turn lense to smallest magnification objective lens (eg x4) click in place
- Turn light on and look down the eyepiece lens
- Turn focusing knobs (course first then fine) to make the image clear
- Rotate lenses to next objective lens (eg x10)
- Use fine focus knob if image is not clear
How do work out the total magnification?
Total magnification=objective lens magnification X eyepiece lens magnification
How do you work out the image size?
Image size=actual size X magnification
A scale bar is sometimes next to the drawing. How do you work out the magnification?
Magnification=actual length of scale bar on the page ➗ length the scale bar represents
What might you have to do to the units first?
Convert them because the units must agree
What is an electron Microscope and a light microscopes resolving power
O.5 nm and 200nm
What characteristics does a white blood cell have?
Can change shape, large nucleus, fight pathogens (illness)
What characteristics does a red blood cell have?
Haemoglobin (red pigment - carries O2) , no nucleus
What characteristics does a surface skin cell have?
Quite flat, packed together
What characteristics does a bone cell have?
They have brunches (used to make a hard substance - has calcium)
What characteristics does a columnar epithelial and goblet cell have?
(From the windpipe) mucus traps pathogens (illness) cilia ,I’ve the mus us away from the lungs
What characteristics does a cardiac muscle cell have?
Heart - keeps you alive, muscle fibres
What characteristics does a skeletal muscle cell have?
Stripes - myo-fibres
What characteristics does a neuron have?
Dendrites, nucleus, cell membrane, axon, monitor end plate, cell body mitochondria plus ribosomes, has many cytoplasm
What characteristics does a smooth muscle cell?
Wall of organs expand, gut, stomach, bladder, can’t control them
What characteristics does a sperm cell have?
Nucleus, haploid- 23 chromosomes - 1 set, acrosome ( enzymes that help the sperm penetrate the egg, tail (flagellum), mitochondria (releases a lot of energy to help the sperm swim
What characteristics does an egg cell (ovum) have?
Cell membrane, mitochondria, nucleus and nuclear membrane, 23 chromosomes
What characteristics does a ciliates epithelial cell have?
Cilia, basement membrane, goblet cell, mucus
What do ribosomes do?
Make proteins