B2.1 Flashcards
What is diffusion?
When particles move from an area of high to low concentration and goes against the concentration gradient. It continues till all the particles are the same everywhere. It’s only the movement of particles but energy is not transferred
Where does diffusion occur in the body?
All cells need glucose and oxygen for respiration. blood transports these substances around the body. Glucose and oxygen then diffuse into the cells that need them.
Some of the reactions that happen in cells can make waste products. These can be toxic. For example co2 is poisonous at high levels and it diffuses out of respiring cells.
It is a process where particles enter and leave a cell and they pass thorough the cell membrane from an area of high to low concentration
How does the distance of particles affect the rate of diffusion?
It takes less time for the particles to move a shorter distance so rate of diffusion is quicker
How does the increase in concentration gradient affect diffusion?
The steeper the concentration gradient, the greater the net movement of the particles.
How does Increasing surface area affect diffusion
Allows more space for diffusion so more particles can move in a period of time. Increases the rate of diffusion in molecules
What is osmosis
A type of diffusion of water molecules and it happens in a semi permeable membrane. The movement of water Particles from an area of low to high concentration
Why does pure water have the highest water potential
Water molecules are more free to move so this means the concentration is really low
What is active transport
Allows substances to move from a low to high concentration. Energy must be transferred from an energy store.
What are the 3key features of active transport
Particles are transported against the concentration gradient
ATP is required and that comes from respiration
The process makes use of carrier proteins in the cell membrane
What do cells that carry out a lot of active transport contain?
They contain many mitchondria so they respire rapidly to produce large quantities of ATP
What are carrier proteins
They’re special proteins that span across the width of a membrane. A particular molecule the cell requires binds to a specific carrier protein. It can change shape or rotate so the carrier protein transports the molecule into the cell
Active transport during digestion
During digestion the small intestine carbohydrates are broken into glucose. The glucose is then actively transported into the bloodstream through the villi and the blood takes the glucose wherever it’s needed in the body.
Active transport in nerve cells
A carrier protein actively pumps sodium ions out of the cell. At the same time potassium ions are pumped back in. The sodium potassium pumps plays an important role in creating nerve impulses
Plants using active transport
They take in minerals from the soil. P,ants need nitrate ions to make protein for growth. There is normally a Lower concentration of nitrate ions in the soil water surrounding the roots than in the plant. The root hair cells use active transport to move these ions across the cell membrane and into the root cell
What is mitosis?
It’s where body cells divide. They divide to produce two daughter cells.
