Topic 3 - Transport in cells Flashcards
What is diffusion?
Diffusion is the movement of particles from an area of high concentration to an area of low concentration. It occurs naturally and does not require energy.
What is osmosis?
Osmosis is a type of diffusion that involves the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.
What is active transport?
Active transport is the movement of molecules or ions across a membrane against a concentration gradient, requiring the input of energy from respiration. This process is crucial for transporting essential molecules, such as mineral ions, across the plasma membrane.
What type of transport happens in plant cells? Why can this not happen in animal cells?
In plant cells, water moves into the cell via osmosis, causing the cell to become turgid and firm. In animal cells, excessive water uptake may cause the cell to burst (lysis) or shrink (crenation) due to osmotic pressure imbalances.
What does active transport allow plants to do? And what happens spontaneously without the need for additional cellular processes?
Active transport allows plants to absorb mineral ions from dilute solutions in the soil, enabling healthy growth. In contrast, diffusion and osmosis do not require energy and occur spontaneously without the need for additional cellular processes.
What is urea?
Urea is a waste product formed in the liver from the breakdown of excess amino acids and is transported from cells into the blood plasma for excretion by the kidneys.
Explain the differences between diffusion, osmosis and active transport
Diffusion is the spontaneous movement of particles from an area of high concentration to an area of low concentration. It does not require energy and occurs naturally.
Osmosis is a type of diffusion that involves the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration. It also does not require energy.
Active transport, on the other hand, is the movement of molecules or ions across a membrane against a concentration gradient, from an area of low concentration to an area of high concentration. It requires the input of energy, typically from the hydrolysis of ATP, to move molecules against their concentration gradient.
In summary, diffusion and osmosis are passive processes that occur naturally, while active transport is an energy-dependent process that moves molecules against their concentration gradient.
