Transport Flashcards
What does the phloem transport
sugars such as sucrose and amino acids
What does the xylem transport
water and mineral salts from the roots in the transpiration stream
Give the structure and functions of the xylem
- Only flows one way (up)
- Made of dead cells that have lot their cytoplasm
- Thick walls stiffened with lignin
- The inner of the vascular bundle
- Transports water and minerals
Give the structure of the phloem
- Flows both
- Made of live cells with perforations
- Uses translocation
- Outside of the vascular bundle
- cell wall made of cellulose
- cell walls permeable
How does water move into plant roots
The movement of water into plant roots is via osmosis from an area of high water potential (the soil) to and area of low water potential (the cell) it is then moved through the root cell to the xylem to keep the water potential in the cell low
How do minerals move into plant roots
Via active transport which requires energy, which lowers the water potential so increases osmosis
How are root hair cells adapted for absorption
- Large SA
- Thin wall so low transport distance
How does water get transported from soil to leaves
- Water enters roots by osmosis from high water potential (soil) to low water potential (cell)
- Water crosses the endodermis cortex into the xylem via osmosis
- Leaves lose water (evaporation) this is called transpiration
- Water is pulled up the xylem by the transpiration stream
- Water moves out the xylem into the leaves
What is transpiration
Evaporation and diffusion from a plants surface
How does temperature affect transpiration
The higher the temperature the more kinetic energy so particles move faster, therefore greater rate of transpiration
How does light intensity affect transpiration
- The more light the greater the rate of transpiration because there would be more photosynthesis so more gas exchange so the stomata are open
- When dark the stomata are closed so there is less or no transpiration
How does humidity affect transpiration
More humidity means more water vapour in the air, so there would be a low concentration gradient therefore less transpiration
How does wind affect transpiration
The more wind the more the water in the air moves which maintains are high concentration gradient so there is more transpiration
What are the 4 major components of blood
- Plasma
- Red blood cells
- White blood cells
- Platelets
Explain the role of plasma
Plasma is the liquid part of blood which carries dissolved substances around the body:
- Digested food
- Red and white blood cells and platelets
- Carbon dioxide
- Urea
- Hormones
- Heat energy
Describe the role of the red blood cells
They carry oxygen from the lungs to all the cells in the body for the process of respiration
How are red blood cells adapted to their function
- They have a biconcave shape to give them a larger surface area for the absorption of oxygen
- They contain haemoglobin which binds with oxygen
- They do not have a nucleus which means they have mor space to carry haemoglobin so they can carry more oxygen
What is the role of platelets
- They clump together to form blood clots
- This prevents excessive blood loss and prevents pathogens entering the wound
- In a clot the platelets are held together in a mesh of protein called fibrin
What are the 2 types of white blood cell
Phagocytes and lymphocytes
How to phagocytes deal with bacteria
They have a non specific response
They engulf pathogens and break them down by secreting digestive enzymes
How do lymphocytes respond to pathogens
They have a specific response
- They produce antibodies which are specific to the antigen on the surface of the pathogen
- Antibodies cause pathogens to clump together
- Produces memory cells with remember a specific antigen
How do vaccines work
- Dead or inactive pathogens are inserted into the body
- This triggers an immune response so your lymphocytes produces antibodies
- Memory cells are produced which stay in the blood so if the same pathogens appear again they will be killed quickly
Describe the structure of the mammalian heart
The vena cava is connected to the right atrium which is connected to the right ventricle through the tricuspid valve. The blood is then taken to the lungs through the pulmonary artery and returns through the pulmonary vein which is connected to the left atrium then the blood flows through the the left ventricle into the aorta which pumps blood around the body
Which side of the heart is oxygenated and which side is deoxygenated
Right side : deoxygenated
Left side: oxygenated
Explain the cardiac cycle
- Deoxygenated blood enters the right atrium through the vena cava
- Right Atriums contract and push the blood in the right ventricle
- The atrium relaxes and the ventricles start to relax this closes the tricuspid valve to prevent blood going back
- Right ventricle contacts which pushes the blood into the pulmonary artery
- Blood enters back into the heart through the pulmonary vein
- Goes into the left atrium and ventricle
- Into the aorta
How does the heart know to increase its rate with exercise
- Exercise increases the amount of carbon dioxide in the blood because you are respiring more bc your muscles need more energy .
- High levels of blood CO, are detected by receptors in the aorta and carotid artery
- These receptors send signals to the brain.
- The brain sends signals to the heart, causing it to contract more frequently and with more force.
How do hormones effect heart rate
1) When an organism is threatened the adrenal glands release adrenaline.
2) Adrenaline binds to specific receptors in the heart. This causes the cardiac muscle to contract more frequently and with more force, so heart rate increases and the heart pumps more blood.
3) This increases oxygen supply to the tissues, getting the body ready for action.
How does coronary heart disease occur
- There is build up of lipids and cholesterol in the coronary artery
- This means that the vessel is narrower - this could lead to an increase in blood pressure
- If the build up becomes a blockage this means there is less oxygen to the heart muscles so heart rate increase
- Eventually lead to a heart attack
What factors could lead to coronary heart disease
- Smoking: Increases blood pressure, this could lead to damage in the coronary arteries which make it more likely for fatty acids to build up
- Diet in high saturated fats: higher chance of fatty deposits forming
- Lack of exercise: increased blood pressure, damage to coronary arteries, likely for fatty deposits to build up
Explain the consequences of a blockage in the coronary artery
- Increased blood pressure
- Damage to the coronary arteries
- Lack of oxygen
- Less aerobic respiration
- More anaerobic respiration
- Less ATP energy
- Heart muscle can’t contract
- Heart muscle die
- Cardiac arrest
Explain the structure and the function of an artery
- Carry blood away from the heart (oxygenated blood)
- The blood is under high pressure so the the walls are very thick with lots of muscle fibres and elastic tissue
- Small lumen
Explain the structure and the function of a capillary
1) Arteries branch into capillaries.
3) They carry the blood close to cells in the body to exchange substances
4) They have permeable walls, so substances can diffuse in and out
6) Their walls are usually only one cell thick. This increases the rate of diffusion by decreasing the distance over which it happens.
Explain the structure and the function of a vein
- Carry blood back to the heart
- Under low pressure so have thin walls made up of little muscle and elastic tissue
- Large lumen
- Contains valves to prevent back flow
Give the major blood vessels
- Lungs: pulmonary artery and pulmonary vein
- Heart: Vena cava and aorta
- Liver: Hepatic artery, hepatic vein and hepatic portal vein
- Kidney: renal artery, renal vein
