Biology: Surface Area and Absorption Efficiency

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Questions and Answers

Why can single-celled organisms rely on diffusion for transporting molecules into their body?

They have a small surface area to volume ratio.

They have a complex transport system.

They have a low metabolic rate.

They have a large surface area to volume ratio. (correct)

Why do multicellular organisms need adaptations for molecule transport instead of relying on diffusion alone?

They have a large surface area to volume ratio.

They have a small surface area to volume ratio. (correct)

They have specialized transport systems.

They have a high metabolic rate.

In the lungs, where does the transfer of oxygen and carbon dioxide take place?

In the diaphragm

In the bronchi

In the alveoli (correct)

In the trachea

What structures in the small intestine aid in the absorption of digested food?

Villi Signup and view all the answers

Why do fish gills have a large surface area?

To facilitate gas exchange Signup and view all the answers

Which organ in plants has a high surface area to volume ratio for efficient gas exchange?

Leaves Signup and view all the answers

Why do fish gills contain lamellae?

To increase the surface area Signup and view all the answers

What role do alveoli play in the lungs?

Increase surface area for gas exchange Signup and view all the answers

What is the function of villi in the small intestine?

Increase surface area for nutrient absorption Signup and view all the answers

Why is a partially permeable membrane essential for osmosis?

To allow the movement of water based on concentration gradients Signup and view all the answers

How do leaves increase the surface area for gas exchange?

By having a flattened shape and air spaces Signup and view all the answers

What maintains a steep concentration gradient in fish for oxygen diffusion?

Water and blood flow in opposite directions Signup and view all the answers

Why do fish have gill lamellae?

To increase the surface area for diffusion of oxygen into the blood and carbon dioxide into the water Signup and view all the answers

How do guard cells in plant leaves affect stomata?

By changing the size of stomata based on the plant's water intake Signup and view all the answers

What is the main function of alveoli in the lungs?

To provide a large surface area for gaseous exchange Signup and view all the answers

Why do roots have root hair cells with large surface areas?

To increase absorption of water and mineral ions from the soil Signup and view all the answers

What is the role of villi in the small intestine?

To increase the surface area for absorption of nutrients into the bloodstream Signup and view all the answers

Why do gill filaments in fish have gill lamellae?

To enhance gas exchange by providing a larger surface area for diffusion Signup and view all the answers

Study Notes

Single-celled vs. Multicellular Organisms

Single-celled organisms rely on diffusion for molecule transport due to their small size and high surface area to volume ratio, allowing efficient nutrient and gas exchange directly across the membrane.
Multicellular organisms require adaptations like circulatory systems for molecule transport because diffusion alone is too slow to meet the metabolic needs of larger bodies.

Gas Exchange in the Lungs

The exchange of oxygen and carbon dioxide occurs in the alveoli, tiny air sacs at the end of bronchioles that maximize gas exchange due to their large surface area and thin walls.

Structure and Function in the Small Intestine

Villi, small finger-like projections in the lining of the small intestine, increase the surface area for absorption of digested food, enhancing nutrient uptake.

Fish Gills

Fish gills possess a large surface area due to the presence of gill lamellae, which are thin, flat structures that facilitate efficient gas exchange in water.
Lamellae increase the fish gills' surface area for oxygen uptake while ensuring effective removal of carbon dioxide.

Plant Gas Exchange

Stomata in leaves allow gas exchange; guard cells control their opening and closing, regulating water loss and gas entry.
The spongy mesophyll in leaves increases surface area for efficient gas exchange with the atmosphere.

Osmosis and Membrane Function

A partially permeable membrane is essential for osmosis, as it allows water to move across the membrane while restricting solute passage, creating different concentrations on either side.

Concentration Gradients in Fish

A steep concentration gradient is maintained in fishes through constant water flow over gill membranes, enhancing oxygen diffusion into the blood and carbon dioxide diffusion out.

Root Adaptations

Roots have root hair cells, which are elongated and increase surface area, enhancing water and nutrient absorption from the soil.

Summary of Key Functions

Alveoli are crucial for maximizing the surface area in the lungs, facilitating efficient gas exchange during respiration.
Villi play a similar role in the small intestine, enhancing nutrient absorption.
Gill lamellae provide a large surface area in fish for effective oxygen uptake and carbon dioxide release.

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Description

This quiz covers the relationship between surface area and absorption efficiency in various organisms and organs. Topics include the adaptations for efficient absorption such as lamellae, flattened shapes, air spaces, thin membranes, and efficient blood supply.