Transport Flashcards
What does the xylem transport?
Water and dissolved mineral ions
Explain how plants absorb water and transport the water to their leaves
1) water moves into the root hair cell via osmosis
2) the water continues to diffuse along the cell from a dilute solution to a concentrated solution until it eventually reaches the xylem
3) water then gets sucked up to the leaves in the transpiration stream
What is transpiration?
The evaporation of water from the surface of a plant
What is the xylem made up of?
Lignifies cells which are very strong so can withstand the high pressure
How does high humidity affect the rate of transpiration?
1) decreases the rate of transpiration
2) decreases the concentration gradient
How does light intensity affect the rate of transpiration?
When it is light the guard cells surrounding the stomata fill with water, opening the stomata and when it is dark they become flaccid closing the stomata
How does high temperature affect the rate of transpiration?
1) increases the rate of transpiration
2) water particles have more kinetic energy so there is more evaporation
How does increased wind affect the rate of transpiration?
1) increases the rate of transpiration
2) increases the concentration gradient as moves moist air away
Describe an experiment to investigate the role of environmental factors on the rate of transpiration
Use a potometer to measure the rate of uptake of water (the time taken for the air bubble to move along the scale is measured and the plant can be exposed to different conditions to see how this affects the rate of transpiration)
Why do unicellular organisms not require a transport system?
They have a very high surface are to volume ratio so materials can simply diffuse in and out of the cell
What is the plasma?
The liquid part of the blood (mainly composed of water)
How are red blood cells adapted to store oxygen?
1) biconcave shape to increase surface area
2) no nucleus to increase capacity for haemoglobin
3) thin cell surface membrane to increase the rate of diffusion
What is the function of the plasma?
1) Carries the blood cells, dissolved nutrients, carbon dioxide and urea around the body
2) distributes heat around the body
What is the function of red blood cells?
To transport oxygen around the body (load in the lungs and unload in other parts of the body)
What is the compound formed when oxygen bonds with haemoglobin?
Oxyhaemoglobin
What is the function of lymphocytes?
1) produce antibodies to destroy microorganisms
2) memory lymphocytes provide immunity to certain diseases
What is the function of phagocytes?
To engulf and digest bacteria and other microorganisms which have entered the body
What do antibodies stick to?
Antigens on the surface of pathogens
How do antibodies destroy pathogens?
1) make the pathogens stick together so the phagocytes can engulf them more easily
2) act as a label so the phagocytes can recognise the pathogen more easily
3) cause the bacterial cell to burst open
4) neutralise toxins produced by the bacteria
What are platelets?
Small fragments of other cells
What happens in a double circulatory system?
1) pulmonary circulation (blood piped to lungs to pick up oxygen)
2) systemic circulation (heart pumps oxygenated blood around the body)
What happens in a single circulatory system?
Blood is pumped from the heart to the gas exchange organ and then directly to the rest of the body
Why are double circulatory systems better?
A higher blood pressure can be maintained meaning that blood travels more quickly to the organs
Give an example of an organism with a single circulatory system
Fish
What so the name of the blood vessel which goes from the heart to the lungs?
Pulmonary artery