Extra Things

Question 1

Examples of prokaryotes

Answer 1

E.coli - causes food poisoning

Streptococcus - causes a sore throat

Question 2

What are bacteria

Answer 2

The smallest living organisms

Question 3

How can you observe cells under a microscope

Answer 3

1. Move the stage to its lowest position
2. Select the objective lens with the lowest magnification
3. Place the slide onto the stage
4. Turn the coarse focus until the object fits
5. Turn the fine focus until it finally comes into clear focus

Question 4

What way do the knobs on a light microscope go?

Answer 4

Coarse focus
Then
Fine focus

Question 5

How can you stain cells

Answer 5

1. Place the cell on the slide
2. Add a drop of stain
3. Place a coverslip on top
4. Tap it lightly to remove any air bubbles

Question 6

Common stains

Answer 6

Methylene blue- animal nucleus
Iodine- plant nuclei
Crystal violet - bacterial cell walls

Question 7

How do electron microscopes work

Answer 7

They use high energy electrons as a “light source”.

Question 8

What are the 2 types of electron microscope

Answer 8

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.

Question 9

What is your metabolic rate

Answer 9

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.

Question 10

What are carbohydrates

Answer 10

Different types of sugars.

Carbohydrase enzymes break down the carbohydrates

Question 11

What are proteins

Answer 11

Made up of amino acids.

Protease enzymes break them down

Question 12

What are lipids

Answer 12

Fats and oils

Lipase breaks them down into 3 fatty acids and 1 glycerol molecule.

Question 13

What is diffusion

Answer 13

The overall movement of particles from a region of high concentration to an area of lower concentration

Question 14

What is osmosis

Answer 14

The movement of water molecules from an area of high water potential to an area of lower water potential, across a selectively permeable membrane.

Question 15

In plant cells, what is a cell called if it is laced in surroundings that have a lower water potential?

Answer 15

Plasmolysed cell

The water moves out through osmosis.

Question 16

In plants, what is a cell called if it is placed in surroundings that have a higher water potential?

Answer 16

Turgid

Water moves into the cell, increasing its turgor pressure.

Question 17

In animal cells, what is the cell called if it is placed in a solution of lower water potential

Answer 17

Crenated

The water will move out of the cell by osmosis and it will crinkle up.

Question 18

In animal cells, what is the cell called if it is placed in a solution of higher water potential

Answer 18

Lysis

The water will move into the cell and it may burst.

Question 19

How does active transport occur?

Answer 19

Uses carrier proteins, where molecules are transported from an area of high concentration to an area of lower concentration.

Question 20

Examples of active transport

Answer 20

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.

Question 21

Where are stem cells found in plants?

Answer 21

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.