1.2 - Specialised Cells and Their Functions Flashcards
What is differentiation in cells?
Differentiation is the process by which a cell gains new sub-cellular structures to suit its role.
What are stem cells?
Stem cells are cells that have the ability to differentiate throughout their whole life.
How do differentiation patterns differ between animals and plants?
In animals, most cells only differentiate once, while in plants, many cells retain the ability to differentiate.
What is the function of sperm cells?
Sperm cells are specialised to carry the male’s DNA to the egg cell (ovum) for successful reproduction.
What features aid sperm cells in swimming?
Sperm cells have a streamlined head and a long tail to aid swimming.
Why do sperm cells have many mitochondria?
Sperm cells have many mitochondria to supply the energy needed for movement.
What is the role of the acrosome in sperm cells?
The acrosome contains digestive enzymes that break down the outer layers of the egg cell’s membrane.
What does haploid mean in the context of sperm cells?
Haploid means that sperm cells have 23 chromosomes, rather than the 46 that most other body cells have.
What are egg cells specialised for?
Egg cells are specialised to accept a single sperm cell and develop into an embryo.
What feature of egg cells allows them to accept only one sperm cell?
Egg cells are surrounded by a special cell membrane that can only accept one sperm cell during fertilisation.
What happens to the egg cell membrane after fertilisation?
The egg cell membrane becomes impermeable following fertilisation.
Why do egg cells contain lots of mitochondria?
Egg cells contain lots of mitochondria to provide an energy source for the developing embryo.
What is the significance of the large size and cytoplasm of egg cells?
The large size and cytoplasm of egg cells allow quick, repeated division as the embryo grows.
What are ciliated epithelial cells specialised for?
Ciliated epithelial cells are specialised to waft bacteria trapped by mucus to the stomach.
What are the long, hair-like processes on ciliated epithelial cells called?
The long, hair-like processes are called cilia.
How do cilia help in protecting the body?
Cilia waft bacteria trapped by sticky mucus down to the stomach, where they are killed by stomach acid.
What produces the sticky mucus that traps bacteria?
The sticky mucus is produced by nearby goblet cells.
What is one way our body protects against illness?
One way our body protects against illness is through the action of ciliated epithelial cells.
What are root hair cells specialised for?
Root hair cells are specialised to take up water by osmosis and mineral ions by active transport from the soil as they are found in the tips of roots.
What feature of root hair cells increases water absorption?
Root hair cells have a large surface area due to root hairs, meaning more water can move in.
How does the large permanent vacuole affect root hair cells?
The large permanent vacuole affects the speed of movement of water from the soil to the cell.
What is the role of mitochondria in root hair cells?
Mitochondria provide energy from respiration for the active transport of mineral ions into the root hair cell.
What are xylem cells specialized for?
Xylem cells are specialized to transport water and mineral ions up the plant from the roots to the shoots.
What happens to xylem cells upon formation?
A chemical called lignin is deposited which causes the cells to die.
How do xylem cells facilitate the movement of water and mineral ions?
They become hollow and are joined end-to-end to form a continuous tube.
What is the role of lignin in xylem cells?
Lignin is deposited in spirals which helps the cells withstand the pressure from the movement of water.
What are phloem cells specialized for?
Phloem cells are specialized to carry the products of photosynthesis (food) to all parts of the plants.
What structures do the cell walls of phloem cells form?
The cell walls of each phloem cell form structures called sieve plates when they break down, allowing the movement of substances from cell to cell.
How do phloem cells obtain the energy they need to be alive?
Despite losing many sub-cellular structures, the energy these cells need to be alive is supplied by the mitochondria of the companion cells.
