Topic 1 - Cell biology

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How do light microscopes form an image of an object?
They use a beam of light.
What is the maximum magnification of light microscopes?
2000x
What are the advantages of using a light microscope?
Relatively cheap
Can be used anywhere
Can magnify live specimens
How do electron microscopes form an image of a specimen?
They use a beam of electrons.
What is the maximum magnification of electron microscopes?
200,000 times
What are the disadvantages of using an electron microscope?
Large
Very expensive
Must be kept in special rooms
What is resolution in microscopy?
The ability to distinguish between two separate points.
What is the average size of an animal cell?
10-30 micrometres long.
What is the average size of a plant cell?
10-100 micrometres long.
What are eukaryotes?
Cells that have a nucleus, cell membrane, and cytoplasm, such as plant and animal cells.
What is a prokaryote?
A single-celled organism made up of a prokaryotic cell, smaller and simpler than eukaryotic cells.
What are the adaptations of nerve cells?
Axon that carries nerve impulses
Synapse to pass electrical impulses
What are the adaptations of muscle cells?
Many mitochondria for energy
Glycogen for cellular respiration
What are the adaptations of sperm cells?
Loads of mitochondria for tail movement
Acrosome with digestive enzymes
Large nucleus with genetic information
What are the adaptations of root hair cells?
Large permanent vacuole for water movement
Mitochondria for active transport energy
What are the adaptations of photosynthetic cells?
Positioned in layers for light intake
Large permanent vacuole for rigidity
What are the adaptations of xylem cells?
Spirals and rings of lignin for strength
What are the adaptations of phloem cells?
Cytoplasm removed for sugar movement
Companion cells for support
What is diffusion?
The movement of particles from high to low concentration.
What is osmosis?
The movement of water particles from a dilute to a concentrated solution across a membrane.
What is a dilute solution?
High concentration of water and low concentration of sugar.
What is a concentrated solution?
Low concentration of water and high concentration of sugar.
What is an isotonic solution?
When the concentration of solutes outside is the same as inside.
What is a hypertonic solution?
When the concentration of solutes outside is higher than inside.
What is a hypotonic solution?
When the concentration of solutes outside is lower than inside.
What may happen to a cell in a hypotonic solution?
Water will move in, and the cell may swell and burst.
What may happen to a cell in a hypertonic solution?
Water will move out, and the cell may shrivel and die.
What is active transport?
The movement of particles from low to high concentration using energy.
What are the adaptations for exchanging materials?
Thin membrane for short diffusion path
Efficient blood supply for steep concentration gradient
Ventilation for steep concentration gradient
What are additional adaptations of nerve cells?
Lots of dendrites for connections
What are additional adaptations of muscle cells?
Special proteins that slide to contract
What are additional adaptations of sperm cells?
Long tail for movement
What are additional adaptations of root hair cells?
Large surface area for absorption
What are additional adaptations of photosynthetic cells?
Contain many chloroplasts for sunlight absorption
What are additional adaptations of xylem cells?
Form long hollow tubes for water and mineral flow
How do light microscopes form an image of an object?
They use a beam of light.
What are additional adaptations of phloem cells?
Cell wall has holes like a sieve for sugar movement
What is the maximum magnification of light microscopes?
2000x
What are additional adaptations of phloem cells?
Large surface area for efficient transport
What are the advantages of using a light microscope?
Relatively cheap
Can be used anywhere
Can magnify live specimens