B1.1 Flashcards
Eukaryotic cells
Cells that contain genetic material in a nucleus
Prokaryotic cells
Cells that do not contain a nucleus.
Their genetic material floats in the cytoplasm.
Smaller than eukaryotic
Name all the organelles eukaryotic cells contain
- Nucleus
- Cytoplasm
- Mitochondria
4.Cell membrane
Name the 3 extra subcellular structures that plant cells have but not animal cells
- Chloroplast
- Cell wall
- Vacuole
Function of the nucleus
Contains genetic material
Controls activities of cell
Determines cell appearance
Function of cytoplasm
Jelly like substance where chemical reactions take place
Function of mitochondria
Power house of cell. Where respiration takes place
Function of cell membrane
Controls what goes in and out of the cell
Functions of chloroplast
Where photosynthesis takes place
Function of cell wall
Provides support for the cell
Function of vacuole
Contains cell sap and helps keep cell firm
Mrs Nerg?
M - movement
R - reproduction
S - sensitivity
N- nutrition
E - excretion
R - respiration
G - growth
What subcellular structures to prokaryotic cells contain
- Cytoplasm
- Genetic material
- Cell membrane
- Cell wall
Name extra subcellular structures if prokaryotic cells
- Flagella
- Pilli
- Slime capsule
- Plasmid
Function of flagella
Tail like structures that allow the cell to move through liquids
Function of pilli
Tiny hair like structures that allow the cell to attach to structures
Function of slime capsule
Protect bacterium from drying out from poisonous substances
Function of Plasmid
Circular piece of DNA that is used to store extra genes .
Function of ribosome (animal cell)
This is where proteins are made and is found in the cytoplasm
3 examples of commonly found bacteria
- Escherichia coli (or E. coli), which cause food poisoning (Figure 2).
- Streptococcus bacteria, which cause sore throats (Figure 3).
- Streptomyces bacteria, which are found in the soil. The antibiotic streptomycin comes from these bacteria. It kills many disease-causing bacteria.
Name the parts of a light microscope
- Stage
- Fine focus
- Eyepiece lens
- Objective lens
- Slide
- Light
- Course focus
How does a light microscope work
It passes light through an object places on the slide on the stage then through the 2 glass lenses which magnifies it.
Formula for total magnification
Total magnification = eyepiece lens x objective lens
How to use the light microscope
- Move the stage to its lowest position.
- Select the objective lens with the lowest magnification.
- Place the slide, which has cells on it, on the stage.
- Raise the stage to its highest position, taking care that the slide does not touch the lens.
- Lower the stage slowly using the coarse focus knob until you see your
object (it will normally be blurred). - Turn the fine focus knob slowly until your object comes into clear focus.
Name 3 stains
- Iodine
- Methylene blue
- Crystal violet
What do the stains stain.
Methylene blue - animal cells nucleus
Iodine - plant cell nuclei
Crystal violet - bacteria cell walls
What is resolution
A measure of the smallest object which can be seen using an instrument
Name the 2 tropes of electron microscopes
- Transmission electron microscopes (TEM)
- Scanning electron microscopes (SEM)
What are TEM microscopes.
TEM produce the most magnified images. They work in a similar way to a light microscope.
A beam of electrons passes through a very thin slice of the sample.
The beam is focused to produce an image
what are SEM microscope
produce a three-dimensional image of a surface. They send a beam of electrons across the surface of a specimen. The reflected electrons are collected to produce an image.
What are electron microscopes
Electron microscopes use electrons instead of light to produce an image.
Compare light and electron microscopes
Light microscope
• Cheap to buy and operate
• Small and portable
• Simple to prepare a sample
• Natural colour of sample is seen unless staining is used
• Specimens can be living or dead
• Resolution up to 0.2 um (2 × 10-7 m)
Electron microscope:
• Expensive to buy and operate
• Large and difficult to move
• Sample preparation is complex
• Black and white images produced; false colour can be added to image
• Specimens are dead
• Resolution up to 0.1 nm (1 x 10-10 m)
