Lesson 4 - Active Transport Flashcards
meaning carrier proteins
proteins that move a substance through the membrane in active transport. They require ATP
meaning cyanide
a metabolic poison that stops mitochondria working
meaning phagocytosis
the active process when a cell engulfs something relatively large such as bacteria and encloses it in a vesicle
meaning pinocytosis
the active process by which cells take small amounts of extracellular fluid into vesicles
meaning active transport
the net movement of molecules and ions through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration
what are the conditions for active transport
the energy needed for active transport is supplied via ATP. The active transport carrier system in the membrane involves ATPase, which catalyses the hydrolysis of ATP, releasing energy
describe how active transport is a one-way system
active transport only allows substances the travel in one direction. So, active transport is faster than diffusion
explain the sodium pump
it actively moves potassium ions into the cell and sodium ions out
why is the sodium pump important
it’s vital for the working of the nervous system, as each nerve impulse depends on an influx of sodium ions through the axon membrane. These ions have to be actively pumped out of the neuron again so that another impulse can pass
describe the steps of glucose molecules through the phospholipid bilayer via active transport
- The protein carriers allow glucose molecules to enter, as they have a matching and specific shape
- The protein carrier changes shape to allow glucose molecules into the cell. This requires energy from the hydrolysis of ATP
- The protein carrier returns passively to its original shape to allow more glucose molecules to enter
state the 4 points that act as evidence for active transport
- active transport only takes place in living, respiring cells
- The rate of active transport depends on temperature o-and oxygen concentration. These affect the rate of respiration, and the production of ATP
- Cells which carry out lots of active transport carry lots of mitochondria, which are the site of aerobic respiration and ATP production
- Poisons that stop respiration such as cyanide, also stops active transport
contrast active transport and diffusion
- diffusion is a passive process, so doesn’t require ATP, whilst active transport does require ATP and is an active process
- the direction of movement of molecules in diffusion is from a high to low concentration, whilst in active transport it’s form low to high
- active transport is faster than diffusion
- Diffusion includes channels and protein carriers, whilst active transport only includes protein carriers
contrast endocytosis and exocytosis
- endocytosis is the movement into a cell, whilst exocytosis is the movement out of a cell
- both endocytosis and exocytosis require ATP
- a type of endocytosis is phagocytosis. Whereas, in exocytosis it’s pniocytosis
contrast phagocytosis and pinocytosis
- phagocytosis takes in large, solid particles, however pinocytosis takes in fluids and dissolved substances
- phagocytosis forms larger vesicles than pinocytosis
- both phagocytosis and pinocytosis require ATP
- phagocytosis only only occurs in specialised cells, whilst pinocytosis occurs in all cells
