2h) Transport

Flowering Plants 

Phloem tubes transport food 

• living cells with perforated end plates to allow stuff through 
• transport food made in the leaves to all other parts of the plant in BOTH directions

Xylem tubes 

• not living cells 
• thick strong walls- lignin give support 
• carries water and mineral ions from the soil around the plant 
• hollow 

Root hair cell: 

• long hairs
• big surface area- absorbing water and minerals
• water taken almost entirely at the root hairs
• minerals also taken up- against a concentration gradient: 'active uptake' 

Transpiration:

loss of water from aerial parts of a plant leaves by evaporation and diffusion 

Rate of transpiration:

1. Light intensity: the brighter the light, the greater rate of transpiration
2. Temperature: the warmer, the faster transpiration happens due to more energy
3. Wind speed: higher the wind speed, the greater the transpiration rate 
4. Humidity: the drier air around the leaf, the faster transpiration happens

A Potometer can be used to estimate transpiration rates

• use stopwatch to record the distance moved by bubble per unit time
•  

Humans 

Blood has four main components:

1. plasma 
2. platelet
3. red blood cells 
4. white blood cells 

Plasma:

• Pale yellow liquid 
• Carries:
• other components in blood 
• CO2 
• Urea 
• Digested food products
• Hormones 
• Heat energy 

Platelets:

• help blood clot when a vessel is damaged 
• stop you from losing too much blood and other microorgansims from entering the wound 
• mesh of protein called fibrin  

Red blood cells: 

• transport oxygen from lungs to all respiring tissues 
• adaptations:
• biconcave shape- large surface area to release and absorb oxygen 
• haemoglobin- contains iron
• no nucleus- more space 

White blood cells:

Two types: 

1. Lymphocytes
• make antibodies to destroy microorgansims, some persists in blood after disease and give us immunity  
2. Phagocytes 
• Engulf bacteria (pathogens) and are non specific so attack anything that's not meant to be there 

http://www.bbc.co.uk/schools/gcsebitesize/science/21c_pre_2011/disease/diseaseresistancerev5.shtml

Vaccinations:

To avoid some diseases like polio, measles and rubella you can be vaccinated 

Involves-

Injecting dead or inactive pathogens 

Trigger immune response and lymphocytes produces antibodies to attack them 

Some lymphocytes remain in the blood as memory cells so if live pathogens of same types of disease appears the antibodies will kill them at a faster because they (antibodies) will be produced at a quicker rate 

The structure of the heart

The Heart rate;

• when you exercise, your muscles need more energy so you can respire more 
• blood has to flow faster, so the heart rate increases 
• exercise increases the amount of CO2 in your blood
• when receptors in the aorta and carotid artery detect high levels of Carbon dioxide, the brain sends signals to the heart -----> moves more frequently and with more force 
• Adrenaline is the specific receptor of the heart 

Blood vessels:

Artery carries the blood away from the heart 

• have thick walls with elastic fibres and smooth muscles 
• have a small lumen for the passageway of blood 
• contains blood under high pressure 

Vein carries blood to the heart 

• have thin walls with little muscle and elastic tissue 
• have a large lumen for a big passageway for blood 
• contain blood under low pressure
• has valves to prevent the back-flow of blood 
•  

Capillary exchange materials 

• one cell thick to allow quick gas exchange 
• have tiny holes to allow gas exchange 
• a tiny lumen 
• very low pressure 

The circulatory system:

Things for Paper Two are in bold, italics