Topic 8 - Exchange And Transport In Animals Flashcards
What do cells take in and get rid of?
Need oxygen for aerobic respiration, produces Co2 as waste product.
How do oxygen and carbon dioxide move between cells and the environment?
By diffusion
What is water taken up by?
Cells by osmosis
What do animals take in and remove?
Dissolved food molecules + mineral ions diffuse along with it. Urea is a waste product.
What does urea do in the body?
Diffuses from cells to the blood plasma for removal from the body by the kidneys.
What calculation is used to find how easy it is for an organism to exchange substances with its environment?
Surface area to volume ratio (SA:V)
Why do multicellular organisms need exchange surfaces?
For efficient diffusion and a mass transport system to move substances between exchange surfaces + rest of body.
Explain the need for exchange surfaces on multicellular organisms linking to their surface area + volume
Eg animals have a smaller surface area compared to their volume, so difficult to exchange enough substances to supply their entire volume across outside surface area.
How are the alveoli adapted for efficient gas exchange to maximise the diffusion of O2 + CO2?
- Moist lining for dissolving gasses
- Good blood supply to maintain concentration gradients of O2 + CO2
- Thin walls minimising distance gases have to move
- huge surface area
Explain how the structure of red blood cells (erythrocytes) is related to its function:
Biconcave disc shape for large SA for absorbing oxygen. No nucleus, more room for oxygen.
Explain how the structure of white blood cells (phagocytes + lymphocytes) is related to its function:
Phagocytes can change shape to engulf unwelcome microorganisms. Lymphocytes can produce antibodies against microorganisms, some produce antitoxins to neutralise toxins produced by microorganisms.
Explain how the structure of platelets are is related to its function.
They’re small fragment of cells without a nucleus to help blood clot + stop microorganisms getting in.
Explain how the structure of plasma is related to its function.
It’s a liquid that’s able to transport large amounts of nutrients around the body in one time: CO2 from organs to lungs Urea from liver to kidneys Hormones Red, white blood cells
What does an artery do?
Carry the blood away from the heart
What do capillaries do?
They are involved in the exchange of materials at the tissues
