SB1a-b Flashcards
How do you work out the magnification of a microscope?
Multiply the magnifications of the two lenses.
Example:
x5 eyepiece lens + x10 objective lens = x50 magnification
How do you work out an image’s magnification?
Size of image
______________
Real size
What is a microscope’s resolution?
The smallest distance between two points that can still be seen as two points.
What are the advantages of using an electron microscope over a light microscope?
An electron microscope can magnify an image up to x2,000,000 times, while light microscopes can only magnify up to x1,500 times.
What are the disadvantages of using an electron microscope over a light microscope?
An electron microscope cannot be used on living cells, because the beams of electrons kill the cells. The light from a light microscope does not, and can therefore be used on living cells.
List all 4 measurement units after centimetres (cm).
- Millimetres (mm) - ÷1,000
- Micrometres (μm) - ÷1,000,000
- Nanometres (nm) - ÷1,000,000,000
- Picometres (pm) - ÷1,000,000,000,000
Check Biology book page 3.
What is a eukaryotic cell? Examples of eukaryotic cells? (4)
A cell with a nucleus.
Examples:
Main:
1. Animal
2. Plants
Extra:
3. Fungi
4. Protists
What does a human white blood cell consist of? (6)
- Cell membrane
- Cytoplasm
- Mitochondrion
- Nucleus
- Red blood cells
- Ribosomes
What does a plant cell consist of? (6)
- Nucleus
- Cell wall
- Cytoplasm
- Cell membrane
- Chloroplasts
- Vacuole
Explain the role of each part inside human white blood cells and plant cells.
Cell membrane: Very thin bag - controls what enters and leaves, and separates one cell from another.
Cytoplasm: Contains watery jelly - where most of the cell’s activities occur.
Mitochondrion: Jelly-bean shaped structures - where aerobic respiration occurs.
Nucleus: Controls the cell and its activities. Inside it are chromosomes which contain DNA.
Red blood cells: Contains protein called hemoglobin which carries oxygen from the lungs to all parts of the body.
Ribosomes: Make protein.
Cell wall: Made of cellulose - supports and protects the cell.
Chloroplasts: Contain chlorophyll which traps energy transferred from the sun. Energy is used for photosynthesis.
Vacuole: Large and permanent sac - stores cell sap and helps to keep the cell firm and rigid.
Check Biology book page 4 & 5.
What is the field of view? (FOV)
Circular area you see in light microscopes. If we know its diameter, we can estimate sizes.
What are scale bars?
Shown on micrographs and used to estimate sizes. Tells us how big a section of a picture is.
Check Biology book page 5.
