Topic 1 - Key Concepts Of Biolagy - Speciallised Cells And Their Functions Flashcards
What is the process by which cells gain new sub-cellular structures suited to their role?
Differentiation
Differentiation allows cells to perform specific functions.
What are cells called that can differentiate their whole life?
Stem cells
Stem cells retain the ability to differentiate into various cell types.
In which type of organisms do most cells only differentiate once?
Animals
Most animal cells have a fixed role after differentiation.
Which type of organisms often retain the ability to differentiate throughout their life?
Plants
Many plant cells can continue to differentiate as needed.
Fill in the blank: Cells specialise by undergoing _______.
differentiation
True or False: All cells in animals can differentiate multiple times throughout their life.
False
Most animal cells only differentiate once.
What is the main reason for cell differentiation?
To be suited to its role
Differentiation equips cells with the necessary structures for specific functions.
What is the function of sperm cells?
To carry the male’s DNA to the egg cell for successful reproduction
Sperm cells have adaptations such as a streamlined head and long tail for swimming.
What adaptations do sperm cells have to aid movement?
Streamlined head and long tail
These features help the sperm swim effectively towards the egg cell.
What is the role of mitochondria in sperm cells?
To supply energy for movement
Mitochondria are the sites of respiration, providing the energy needed for sperm motility.
What is the acrosome in sperm cells and its function?
Contains digestive enzymes to break down the egg cell’s outer membrane
This allows sperm to penetrate the egg during fertilization.
What does haploid mean in relation to sperm cells?
Contains 23 chromosomes
Haploid means having half the number of chromosomes compared to diploid cells.
What is the primary function of egg cells?
To accept a single sperm cell and develop into an embryo
Egg cells are designed for fertilization and subsequent embryonic development.
What feature of the egg cell membrane prevents multiple sperm from entering?
Becomes impermeable after one sperm cell enters
This ensures only one sperm fertilizes the egg.
Why is the size of egg cells significant?
Allows quick, repeated division as the embryo grows
The large cytoplasm supports early cell divisions.
What is the function of ciliated epithelial cells?
To waft bacteria trapped by mucus to the stomach
This process helps protect the body from illness.
What are cilia and their role in ciliated epithelial cells?
Long, hair-like processes that waft mucus and trapped bacteria
Cilia help move mucus towards the stomach where bacteria are killed.
What is the primary function of root hair cells?
To take up water by osmosis and mineral ions by active transport
These cells are located at the tips of roots for optimal absorption.
How do root hair cells maximize water uptake?
They have a large surface area due to root hairs
This adaptation increases the efficiency of water absorption.
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
The vacuole helps maintain turgor pressure and facilitates osmosis.
What is the function of xylem cells?
To transport water and mineral ions up the plant
Xylem is essential for the plant’s hydration and nutrient distribution.
What happens to xylem cells upon formation?
They die and become hollow, forming a continuous tube
This structure allows efficient water transport throughout the plant.
What is lignin and its importance in xylem cells?
A chemical that strengthens xylem cells and helps withstand pressure
Lignin is deposited in spirals to enhance structural integrity.
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?
They allow the movement of substances from cell to cell
What do phloem cells lose that is typical in other cells?
Many sub-cellular structures
How do phloem cells obtain the energy they need to be alive?
From the mitochondria of the companion cells
