Exchange of Materials Flashcards
What does it mean when we say against a concentration gradient?
From an area of low concentration to an area of high concentration.
What is active transport?
The movement of a substance against a concentration gradient or across partially permeable membrane.
What does active transport need and where does it come from?
Active transport needs energy, this energy comes from cellular respiration.
What is the relationship between the rate of respiration and the rate of active transport and why?
As the rate of respiration increases the rate of active transport also increases this is because if a cell is making lots of energy it can carry out lots of active transport.
What cells involved in a lot of active transport usually have lots of?
Mitochondria.
What is the importance in active transport in plants?
Minerals and ions come in very dilute solutions soil (more dilute than the ones already in the plant cells)
By using active transport cells can absorb the mineral ions even thought it’s against a concentration gradient.
Why is active transport so important for animals that live in the sea?
Animals that live in the sea take in a lot of salt when they drink.
The sodium ions are moved out of the body to special salt glands found near the eyes and nostrils.
The salt glands them product a very salty solution
Active transport allows the sodium ions to be moved against a concentration gradient.
What does breathing do?
It brings oxygen into your body and removes the waste Carbon Dioxide produced by your cells.
What happens when you breathe in?
When you breathe in your ribs move up and out and your diaphragm flattens from its normal domed shape. This pulls air into your lungs.
What happens when you breathe out?
When you breathe out your ribs move down and in. The diaphragm returns to its original domed shape, forcing air out of your lungs again.
How are your lungs specially adapted to make gas exchange more efficient?
They are made up of clusters of alveoli which are tiny air sacs which always have a large surface area which Is kept moist. The alveoli always have a rich blood supply which maintains the concentration gradient in the both directions.
What is your thorax?
Your chest.
How can you see if carbon dioxide is present?
When it is bubbled through limewater the limewater turns cloudy.
Why and how do the products of digestion get into your bloodstream?
They must get into your bloodstream so they can provide fuel for respiration and be the building blocks for all the tissues of your body.
They do this by using a combination of diffusion and active transport to move from inside your small intestine to your bloodstream
Why is it so important that your food is broken down into smaller molecules?
Because diffusion can only take place if the molecules are dissolved in water.
Where do the digested food molecules move to and from, how and why?
They move from the small intestine to the blood.
They do this because there is a very high concentration of food molecules in the gut and a lower concentration in the blood. So they move into the blood along a steep concentration gradient.
What is the small intestine lined with?
Villi
What does villi do to the uptake of digested food by diffusion and how?
They increase it because they increase the surface area which means there is more room for diffusion to take place.
Why do you fish have gills?
Because the fish can’t get oxygen directly from the water they live in because there body is covered and protected scales.
How are fish gills adapted for gas exchange?
They have a rich blood supply.
They are thin so there is only a short distance for the gases do diffuse across.
There surface is always moist as they are always in water.
How are leaves adapted for efficient diffusion for carbon dioxide?
There leaves are thin so the distance for the carbon dioxide to get from the outside of the plant inside the photosynthesis get cells is short.
Also there are many air spaces inside the leave which allows lots of carbon dioxide in contact with lots of cells this provides lots of surface area for diffusion.
Why don’t leaves need carbon dioxide all the time?
Because they are not photosynthesising all the time. E.g when it’s dark they ain’t.
How are leaves adapted to allow carbon dioxide in only when it’s needed?
They have small openings called stomata which can be opened and closed when the plant needs to allow air into the leaves so carbon dioxide enters the cell.
What are the stomata controlled by?
The guard cells.
