B1. Cell Structure and Transport Flashcards
What are the adaptations of nerve cells?
Many dendrites to make connections to other nerve cells
An axon to carry the impulse from one place to another
Synapse which pass impulses to other cells by producing transmitter chemicals
Lots of mitochondria in the synapses to transfer the energy needed to make the transmitter chemicals
What are the adaptations of striated (striped) muscle cells?
Special proteins that slide over each other
Lots of mitochondria to transfer the energy needed for chemical reactions
A store of glycogen that can be broken down and used in respiration to transfer energy
What are the adaptations of sperm cells?
Long flagellum to allow it to swim to reach the egg
Has a streamlined body to make swimming easier
Digestive enzymes in its head to break through the wall
Contains half as much genetic material as a normal so that the sperm and egg together will have the normal amount
What is the main function of root hair cells?
To increase the surface area of the root so that it can absorb water and mineral ions efficiently
What are the adaptations of root hair cells?
To greatly increase the surface area available for water to move into the cell
Has a large permanent vacuole which speeds up the movement of water by osmosis from the soil across the root hair cell
Has lots of mitochondria - To transfer the energy needed for the active transport of mineral ions into the root hair cells
What are the two main functions of the xylem cells?
- Xylem cells transport water and mineral ions from the roots to the stem and leaves
- Xylem tissue supports the plant
What are the adaptations of xylem cells?
Xylem cells are living when they are first formed
Then a chemical called lignin builds up in spirals in the cell walls
The cells die leaving long hollow tubes. Water and mineral ions can move up the tubes
The spirals and rings of lignin make the tubes of xylem very strong
What is the main function of phloem cells?
Transports food made by photosynthesis to the rest of the plant.
What are the adaptations of phloem cells?
The cells walls between phloem cells break down to form sieve plants
Phloem cells lose a lot of their structures but are kept alive by companion cells
The companion cells contain mitochondria that transfer energy to aid the movement of dissolved food in the phloem
What are the adaptations of prokaryotic (bacteria) cells?
Very small and can only be seen with a microscope
Have a cell membrane and a cell wall surrounding the cytoplasm. The cell wall is different to a plant cell wall because it is not made out of cellulose
DON’T have a nucleus. The genetic material is found in the cytoplasm as a long circle of DNA. Some prokaryotic cells also contain extra small circular rings of DNA called plasmids.
Protective slime capsules (some bacteria)
Flagella for movement
Some cause diseases in animals and plants
What is the definition of the term isotonic?
If two solutions have the same concentrations
What is the definition of the term hypertonic?
The solution that is more concentrated (has more solute and relatively less water)
What is the definition of the term hypotonic?
The solution that is more dilute(has relatively more water and less solute)
What is the process plants use to maintain turgor?
Water moves into plant cells by osmosis
The vacuole swells
The cytoplasm is pressed against the cell wall
The cell becomes rigid
The leaves and stem become rigid
How do plant cells be turgid (normal)?
As long as the outside solution is hypotonic, water moves in and keeps the cells rigid to support the plant
