A level - gas exchange in fish

What is the primary gas exchange surface in fish?

• Fins

• Gills

• Lungs

• Skin

Why can't fish simply diffuse oxygen across their surface?

• They live in air

• They are not waterproof

• They have a large surface area to volume ratio

• They have a small surface area to volume ratio

How much less oxygen does water contain compared to air?

• 40 times less

• 20 times less

• 10 times less

• 30 times less

What is one of the key features of every gas exchange surface?

• Thick diffusion distance

• Large surface area to volume ratio

• No concentration gradient

• Low permeability

What structure in fish gills increases the surface area for gas exchange?

• Gill filaments

• Gill scales

• Gill muscles

• Gill bones

What is the function of the gill lamellae?

• To protect the gills

• To provide a large surface area for gas exchange

• To increase diffusion distance

• To store oxygen

What is the purpose of the counter current exchange principle?

• To increase water flow speed

• To reduce oxygen levels in blood

• To maintain a diffusion gradient across the entire length of the lamellae

• To reach equilibrium quickly

In counter current flow, how does water flow in relation to blood?

• In the same direction

• In the opposite direction

• Perpendicular to blood flow

• In a circular motion

What happens if equilibrium is reached in the gills?

• Oxygen levels rise

• Diffusion increases

• Diffusion stops

• Water flow stops

What is the role of capillaries in the gill lamellae?

• To protect the gills

• To store water

• To increase water flow

• To transport blood close to the surface for gas exchange and maintain a diffusion gradient