Topic 1 - Specialised Cells And Their Functions Flashcards
What is the process by which cells specialise?
Differentiation
Differentiation involves cells gaining new sub-cellular structures to suit their specific roles.
What type of cells have the ability to differentiate throughout their whole life?
Stem cells
Stem cells can differentiate at any point in their life cycle.
In which organisms do most cells only differentiate once?
Animals
Most animal cells undergo differentiation only a single time.
Do many plant cells retain the ability to differentiate?
Yes
Unlike most animal cells, many plant cells can continue to differentiate throughout their life.
Fill in the blank: Cells can either differentiate once early on or have the ability to differentiate their whole life (these are called _______).
stem cells
What are the new structures that cells gain during differentiation called?
Sub-cellular structures
These structures enable the cell to perform its specific functions.
What is the function of sperm cells?
Specialised to carry the male’s DNA to the egg cell (ovum) for successful reproduction
Sperm cells have a streamlined head and long tail to aid swimming.
What adaptations do sperm cells have to aid in movement?
Streamlined head and long tail, many mitochondria
Mitochondria supply the energy for movement.
What is the role of the acrosome in sperm cells?
Contains digestive enzymes that break down the egg cell’s membrane
This allows the sperm to penetrate the egg during fertilization.
What does haploid mean in relation to sperm cells?
Contains 23 chromosomes
Most other body cells have 46 chromosomes.
What is the primary function of egg cells?
Specialised to accept a single sperm cell and develop into an embryo
Egg cells are crucial for reproduction.
How do egg cells prevent multiple sperm from fertilising them?
Surrounded by a special membrane that becomes impermeable after one sperm enters
This ensures only one sperm fertilises the egg.
What is the significance of mitochondria in egg cells?
Provide an energy source for the developing embryo
Energy is essential for early cell division.
What adaptations do ciliated epithelial cells have?
Long, hair-like processes called cilia
Cilia waft bacteria trapped by mucus to the stomach.
What is the function of root hair cells?
Specialised to take up water by osmosis and mineral ions by active transport
Found in the tips of roots.
How do root hair cells maximize water uptake?
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
It helps maintain turgor pressure.
What is the function of xylem cells?
Specialised to transport water and mineral ions up the plant
They move nutrients from roots to shoots.
What happens to xylem cells upon formation?
Lignin is deposited causing the cells to die and become hollow
This creates a continuous tube for transport.
Why is lignin important for xylem cells?
Helps cells withstand the pressure from water movement
Lignin is deposited in spirals.
What are phloem cells specialised for?
To carry the products of photosynthesis (food) to all parts of the plants
What structures do the cell walls of phloem cells form when they break down?
Sieve plates
How do sieve plates function in phloem cells?
Allow the movement of substances from cell to cell
What do phloem cells lose during their development?
Many sub-cellular structures
How do phloem cells obtain the energy they need to be alive?
From the mitochondria of the companion cells
