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
What do cell membranes do?
Controls what goes in and out if the cells
What does the nucleus do?
Controls the cells activity, DNZ
What does the cytoplasm do?
Where all the chemical reactions happen
What does the mitochondria do?
Aerobic respiration happens there, creates energy
What does the cell wall do?
Supports and protects the cell against microorganisms
What does the vacuole do on the plant cell?
Stores the cells sap
What do the chloroplasts do?
Makes the cell green and turns the enrgy from the sun into glucose, photosynthesis
What don’t prokaryotic cells have?
Membrane bound organelles, a nucleus
What is one this a eukaryotic cell has?
membrane bound organelles
What are 3 safety precautions when viewing a slide?
You should wear goggles because the chemicals can go in your eyes
The slides are sharpe so you can cut yourself if your not careful
Wash your hands if the get chemicals on them
Why should you dispose of animals cells in disinfectant?
Because you could have infections it can stop it spreading
Why do you use stain when viewing a slide?
It’s so the cell shows up because part of the cell is transparent
Why does a light microscope use a beam of light and glass lenses?
To produce an enlarged, or magnified image of a specimen
Give an advantage of an electron microscope
Has a greater resolution and magnification
What does resolution mean?
The ability to distinguish between two points
Why can some structures in cells only be seen with an electron microscope?
They are very small
How do we calculate total magnification?
Eyepiece lens ✖️ objective lens
What is the equation for working out actual size?
Image size ➗ magnification
What comes next: milli, micro, ………..
Nano
If 10 to the power of -3 means millimetre, what does X10 to the power of -6 mean?
Micrometer
What are all living things made from?
Cells
What is the job of the cell membrane?
To control what goes in and out of the cell
What process happens in the mitochondria?
Aerobic respiration
Where in a cell would you find chromosomes?
In the nucleus
Name 3 structure present in a plant cell but not in an animal cell.
Chloroplast, vacuole, cell wall
What is the job of a cell wall?
To support the cell
What is the job of the chloroplasts?
To trap sunlight energy and carry out photosynthesis
What is the job of a flagellum in a bacterial cell?
It rotates to propel it along/move
What two types of DNA do bacterial cells have?
Chromosomal DNA and plasmid DNZ (circular)
What does diploid mean?
Having the full set of chromosomes, 46 in a human
Why do human sperm cells only have 23 chromosomes?
As it will fuse with an egg cell with 23 to make 46 chromosomes
What does haploid mean?
Half the full set of chromosomes I.e 23 in humans
Which cells are haploid?
Gametes/sperm and egg cells
Why does an egg cell have a lot of cytoplasm?
To nourish the developing embryo
What is the job of a sperm cell?
To swim to and fertilise and egg cells to join their DNA
What is an acrosome for in a sperm cell?
Contains enzymes to penetrate the egg cell membrane
Why do sperm cells need a lot of mitochondria?
To make energy to swim
Which cells waft mucus along in the airways?
Ciliated epithelial cells
Why are bacterial cells described as prokaryotic?
They don’t have a nucleus
In a cell what do ribosomes do?
Make proteins
Why are animal and plant cells described as eukaryotic?
They have a nucleus
