Cell specialisation Flashcards
What is the process by which cells gain new sub-cellular structures to suit their role?
Differentiation
Differentiation allows cells to become specialized for specific functions.
What type of cells can differentiate throughout their entire life?
Stem cells
Stem cells have the ability to differentiate into various cell types.
How do most animal cells differentiate?
Most cells only differentiate once
This is in contrast to many plant cells that can continue to differentiate.
What is the primary function of sperm cells?
To carry the male’s DNA to the egg cell
This is essential for successful reproduction.
What adaptations do sperm cells have to aid in their function?
- Streamlined head and long tail for swimming
- Many mitochondria for energy
- Acrosome containing digestive enzymes
These adaptations help sperm cells reach and penetrate the egg.
What is the primary function of nerve cells?
To transmit electrical signals quickly
This function is crucial for communication within the body.
What structural feature of nerve cells allows them to carry impulses over long distances?
Long axon
The axon acts as a conduit for electrical impulses.
What are dendrites and their role in nerve cells?
Extensions from the cell body that form connections with other nerve cells
Dendrites are crucial for receiving signals from other neurons.
What do nerve endings contain to facilitate the transmission of impulses?
Many mitochondria that supply energy for neurotransmitters
Neurotransmitters are chemicals that transmit signals between nerve cells.
What is the primary function of muscle cells?
To contract quickly for movement
Muscle cells are specialized for contraction, enabling movement of bones or squeezing of organs.
What do muscle cells store that is used in respiration?
Glycogen
Glycogen serves as an energy reserve for muscle cells.
What is the function of root hair cells?
Specialised to take up water by osmosis and mineral ions by active transport from the soil
Found in the tips of roots
How do root hair cells increase water uptake?
They have a large surface area due to root hairs
This allows more water to move in
What role does the large permanent vacuole play in root hair cells?
Affects the speed of movement of water from the soil to the cell
Why do root hair cells contain mitochondria?
To provide energy from respiration for the active transport of mineral ions into the root hair cell
What is the primary function of xylem cells?
Specialised to transport water and mineral ions up the plant from the roots to the shoots
What happens to xylem cells upon formation?
Lignin is deposited, causing the cells to die and become hollow
They join end-to-end to form a continuous tube
How does lignin help xylem cells?
It is deposited in spirals, helping the cells withstand the pressure from the movement of water
What is the function of phloem cells?
Specialised to carry the products of photosynthesis (food) to all parts of the plants
What structures form when the cell walls of phloem cells break down?
Sieve plates
These allow the movement of substances from cell to cell
How do phloem cells obtain the energy they need?
Supplied by the mitochondria of the companion cells
What process do stem cells undergo to become specialised?
Differentiation
Involves some genes being switched on or off to produce different proteins
What happens to most cells in animals after they differentiate?
They lose the ability to differentiate further
How do specialised cells in animals reproduce?
Most can make more of the same cell by undergoing mitosis
Which type of animal cells cannot divide and are replaced by adult stem cells?
Red blood cells
They lose their nucleus
What is the primary reason for cell division in mature animals?
To repair or replace damaged cells
What is a key characteristic of plant cells regarding differentiation?
Many types retain the ability to differentiate throughout life
When do plant cells typically differentiate?
When they reach their final position in the plant
Can plant cells re-differentiate if moved?
Yes, they can re-differentiate when moved to another position
