Exchange and transport in plants Flashcards
What three factors affect diffusion?
Distance, concentration difference and surface area
How does distance affect diffusion?
Substances diffuse more quickly when they haven’t as far to move.
How does the concentration difference affect diffusion?
Substances diffuse faster if there’s a big difference in concentration between the area they are diffusion from and the area they are diffusing to.
How does the surface area affect diffusion?
The more surface there is available for molecules to move across, the faster they can get from one side to another
Where does gas exchange take place in mammals?
Alveoli
What is the function of the red blood cells?
Carry oxygen from the lungs to all the cells in the body.
What are the adaptations of the red blood cells?
- Biconcave disc shape
- No nucleus
- Red pigment called haemoglobin
Why does the red blood cell have a biconcave disc shape?
To give a large surface area for absorbing oxygen
Why does the red blood cell have no nucleus?
More room to carry oxygen
Why does the red blood cell have haemoglobin?
- Contains iron
- Binds to oxygen in the lungs
What is the function of white blood cells?
- Defend against infection.
- Two types are lymphocytes and phagocytes
What is the function of the lymphocytes?
Produce antibodies against microorganisms. Some produce antitoxins to neutralise any toxins produced by the microorganism
What is the function of phagocytes?
They change shapes to engulf unwelcome mircoorganisms
What is the function of platelets?
Help blood clot at wounds. They also stop blood pouring out an d microorganisms getting in.
What are the adaptations of platelets?
Small fragments of cells and have no nucleus.
What is the function of the plasma?
The liquid that carries everything in blood.
What does the plasma carry?
- Red and white blood cells and the platelets
- Nutrients like glucose and amino acids
- Carbon dioxide
- Urea
- Hormones
- Proteins
- Antibodies and antitoxins