B2 Flashcards
Definition of diffusion
Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration
Definition of active transport
Movement of particles across a membrane against a concentration gradient
Using ATP released during respiration
Osmosis
Net movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration
Define turgid
Plump and Swollen
Define Flaccid
Droopy
How do you investigate osmosis
Cut equal cylinders of potato
Divided into groups of three
Place one group in each solution
Leave cylinders in solution at least 40 minutes
Remove cylinders and pat dry gently with paper towel
We each group again and record your results
Calculate percentage change in mass for each group
Ideal exchange surface
The rate of diffusion osmosis and active transport is higher in cells with a larger surface area to volume ratio
How does concentration gradient affect speed of exchange
Substances move in an hour or so faster if there’s a big difference in concentration between inside and outside of cell
Properties of exchange surfaces
Thin (short travel distance)
Light surface area so lots of services can move at once
Exchange surfaces in animals have a lots of blood vessels to get stuck into and out of blood quickly
Gas exchange surfaces and animals that are often ventilated
Examples of exchange surfaces
Alveoli And villi
How are you specialise to maximise the diffusion of oxygen and carbon dioxide
Lives abroad so there is a large surface area for diffusion
They are also doing which means gases only have to travel a short distance
There are spaces inside of the leaf this lets gases to move easily between cells
In the lower surface is full of little holes called stomata
How do you fruit has taken the water and mineral ions
Each branch of a route is covered in millions of microscopic routers which gives the blinds a big surface area for absorbing water and mineral ions from the soil water is absorbed through osmosis and minerals move in active transport
Advantages of double circulatory system
Returning oxygenated blood to the heart means blood can be pumped around the body high-pressure
Increases bloodflow to tissues
Important for mammals because they use up a lot of oxygen maintain body temperature
How is the heart provided to this energy
Muscle cells contain loads of mitochondria to provide cells of ATP
What are all the vessels of the heart
On the right:Pulmonary artery and Veena Carver
On the left:Aorta and pulmonary vein
Arteries
These carry blood away from the hear Strong and elastic walls due to high pressure Thick walls in comparison to lumen Contain thick muscle layer Branch into arterioles
Capillaries
These are involved in the exchange of materials at the tissues
Arterial is branch into capillaries
Thin wall only one cell thick
Very small lumen
Veins
Carry blood to the heart
Contain valves
Large lumen
Elastic fibres and smooth muscle
What is inside blood
Red blood cells
White blood cells
Platelets
Plasma
What does does plasma carry
Red blood cells Water Food products CO2 Urea Hormones Antibodies
Phloem
Made of columns of living cells called tube elements these have perforated end-plates to allow stuff to flow through
Drive tube elements have no nucleus this means they can’t survive on their their own nu so each sieve tube elements has a companion cell.
Transport food substances both up and down the stem to growing and storage tissues. This movement of food substances around plant is known as translocation
Xylem
Made of dead cells with one hole
Thick side walls are made of cellulose. They’re strong and stiff which gives plant support
They carry water and minerals from roots up the shoot to leaves in the transpiration stream
What affects transpiration
Light intensity (increases rate of photosynthesis so stomata open) Temperature (water particles move more) Air movement (if air still water vapour surrounds leaf which means slower diffusion)
How do Plants control water loss
Leaves usually have waxy cuticle
Stomata on underside of leaf where it’s darker and cooler
Plants that need to conserve water have smaller and fewer stomata
