Extra Things Flashcards
Examples of prokaryotes
E.coli - causes food poisoning
Streptococcus - causes a sore throat
What are bacteria
The smallest living organisms
How can you observe cells under a microscope
- Move the stage to its lowest position
- Select the objective lens with the lowest magnification
- Place the slide onto the stage
- Turn the coarse focus until the object fits
- Turn the fine focus until it finally comes into clear focus
What way do the knobs on a light microscope go?
Coarse focus
Then
Fine focus
How can you stain cells
- Place the cell on the slide
- Add a drop of stain
- Place a coverslip on top
- Tap it lightly to remove any air bubbles
Common stains
Methylene blue- animal nucleus
Iodine- plant nuclei
Crystal violet - bacterial cell walls
How do electron microscopes work
They use high energy electrons as a “light source”.
What are the 2 types of electron microscope
TEM - Transmission Electron Microscope- produce the most magnified image, because the beam of electrons passes through a very thin slice of the sample, producing an image.
SEM- Scanning Electron Microscope - produces a 3D image of a surface, the beam of electrons is sent across the surface of the specimen and the reflected electrons are collected to form an image.
What is your metabolic rate
The speed at which your cells can transfer energy from its chemical stores in food.
The higher your metabolic rate, the more food you need to eat.
What are carbohydrates
Different types of sugars.
Carbohydrase enzymes break down the carbohydrates
What are proteins
Made up of amino acids.
Protease enzymes break them down
What are lipids
Fats and oils
Lipase breaks them down into 3 fatty acids and 1 glycerol molecule.
What is diffusion
The overall movement of particles from a region of high concentration to an area of lower concentration
What is osmosis
The movement of water molecules from an area of high water potential to an area of lower water potential, across a selectively permeable membrane.
In plant cells, what is a cell called if it is laced in surroundings that have a lower water potential?
Plasmolysed cell
The water moves out through osmosis.
In plants, what is a cell called if it is placed in surroundings that have a higher water potential?
Turgid
Water moves into the cell, increasing its turgor pressure.
In animal cells, what is the cell called if it is placed in a solution of lower water potential
Crenated
The water will move out of the cell by osmosis and it will crinkle up.
In animal cells, what is the cell called if it is placed in a solution of higher water potential
Lysis
The water will move into the cell and it may burst.
How does active transport occur?
Uses carrier proteins, where molecules are transported from an area of high concentration to an area of lower concentration.
Examples of active transport
During digestion- glucose is actively transported into your bloodstream, after it is broken down from carbohydrates
Nerve cells- a carrier protein pumps sodium ions our and potassium ions back in.
Plants- take in minerals from the soil. Mainly nitrate ions.
Where are stem cells found in plants?
Plants are always growing, but it’s only their shoot tips that usually grow. These are called the meristems. Stem cells are found there, and they are much smaller compared to normal plant cells, and have thin walls, small vacuoles and no chloroplasts.
