B2.2 Flashcards
Why is surface area to volume ratio important ?
To see how nutrients can diffuse directly into the organism to sustain life as diffusion distances are small. The larger the animal, the lower the SA to volume ratio
How can you maximise the rate of diffusion of oxygen into the bloodstream
Have many alveoli in the lungs to increase the S.A. of it
Where is digested food molecules absorbed into
Into the blood from the small intestine
How do you maximise the rate of diffusion for the small intestine
The walls of the small intestine contain fingerlike villi to increase S.A. of the intestine wall.
Why are transport systems needed in animals?
The circulatory system is the main transport system. The blood carried materials to where they’re required. The liver produces urea when it breaks down the excess amino acids. Urea is toxic so it is transported to the kidney where it’s removed
Why are transport systems needed in plants?
Xylem tubes carry water and mineral ions around a plant and phloem tubes transport sugars and amino acids
What is the circulatory system made up of?
Your heart and your blood vessels
Why is the circulatory system known as a closed system
Because the blood remains within the structures
Where does the blood transport to
It transports around the body to the cells that need them
Oxygen and glucose for respiration
Co2as a waste product
How many times does the blood circulate the heart in one circuit?
Twice
Called the double circulatory system
What does oxygenated blood mean
High levels of oxygen
What does deoxygenated blood mean
Low levels of oxygen
Where does your heart pump blood to.
Body organs and tissues
Where does co2, glucose and oxygen diffuse to.
Co2 -out of the cells into the blood
Glucose and oxygen- out of the blood and into the cells
What does the lungs do to co2, glucose and oxygen ?
It diffuses co2out of the blood and into the body
It diffuses in the other two into the blood
What are the three main blood vessels
Arteries, capillaries and veins
What do arteries do?
They carry blood vessels away from the heart under high pressure
What do veins do
They return blood back to the heart and they have valves to stop blood flowing the wrong way
What do capillaries do
They link the arteries and veins in tissues and organs. They then form a network so every cell is close to a capillary. Their semi permeable walls are one cell thick so substances can move easily through them
What do strong contractions of the heart cause
High blood pressure
What Is your heart made up of
Cardiac muscle. They contract without receiving a nerve impulse from your brain.
What are the four chambers called
The two top ones are the atria
The two bottom ones are the ventricles
What separates the Chambers
Valves
What are the four things found in the blood
Red blood cells
White blood cells
Plasma
Platelets
What does the xylem tissue transport
Water and mineral ions from the roots to the stem, leaves and flowers. Water diffuses into roots via osmosis. Mineral ions are taken by active transport
What does the phloem tissue transport
Dissolved sugars produced during photosynthesis and other soluble food molecules from the leaves to all other areas of the plant. This is called translocation.
What do the phloem and the xylem tissue form a structure called
A vascular bundle
What are xylem vessels made up from
Dead xylem cells. No cell walls at the endz of these cells.
Structure of the phloem
Phloem vessels are made form living cells. The cell walls of these cells don’t completely break down. Instead plates are formed- small holes in the end wall which allows the dissolved sugars to pass through. The connection of the phloem cells effectively forms a tube which allows dissolved sugars to be transported
How do vascular bundles provide support in the leaf
They form a network that supports the softer leafy tissue
How do vascular bundles provide support in the stem
They’re located around the outer edge providing the stem with strength to resist the bending in the breeze
How do vascular bundles provide support in the root
Found in the centre to enable the root to act as an anchor so the plant can bend as the plant moved int he wind
What is transpiration
The loss of water in a plant’s leaves
Transpiration Stream
The constant flow of water from the roots to the xylem and out if the Leaves
How does the water enter the xylem
Water diffuses from the soil into the root hairs by osmosis. Before the water can enter a xylem vessel it must travel from cell to cell till it reaches the centre of the root. Once inside the xylem, the water can be transported through the plant
How is water lostfrom leaves
The stomata on the surface of the leaves allows co2 to diffuse in for photosynthesis. Guard cells allow the stomata to open and close
When the stomata is open the water evaporates from cells inside the leaf’s air spaces . This creates a concentration gradient between the air inside the leaf and the surrounding air. Water vapour then diffuses out of the leaf into the air.
How does light intensity affect the rate of transpiration ?
Stomata open in the light and close in the dark and if u increase the light intensity more water evaporates. The rate of transpiration increases u TIL all the stomata are open. Transpiration is now at its maximum rate
How does temperature affect the rate of transpiration ?
If you increase temperature the water evaporates more quickly from the leaf. Diffusion of water vapour our of the leaf becomes more rapid. This increase the rate of transpiration
How does wind affect the rate of transpiration ?
When Air moves over the surface of the leaf, it moves evaporated water molecules away from the leaf. The faster the wind the fast the rate of transpiration
How does humidity affect the rate of transpiration ?
The higher the humidity the more water it contains
