Osmosis, Gas and Solute Exchange and Breathing System

Question 1

What is the definition of osmosis?

Answer 1

The movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration.

Question 2

What is a partially permeable membrane?

Answer 2

A membrane with very small holes in it so only small molecules can pass through it.

Question 3

If a cell has lot of water, the solution inside will be …?

Answer 3

Dilute

Question 4

If a cell is short of water, the solution inside will be ….?

Answer 4

Concentrated

Question 5

What fluid surrounds the cells in the body?

Answer 5

Tissue fluid

Question 6

What is diffusion?

Answer 6

When particles move from an area of high concentration to an area of low concentration.

Question 7

Which way to particles move in active transport?

Answer 7

From an area of low concentration to an area of high concentration?

Question 8

In what ways are exchange surfaces adapted and why?

Answer 8

• They are thin so substances only have a short distance to move.
• They have a large surface area so lots of a substance can diffuse at once.
• Exchange surfaces in animals contain many blood cells , to move substances in and out of cells quickly.
• Gas exchange cells are often ventilated so air moves in and out.

Question 9

What are the small holes underneath the leaf, that carbon dioxide diffuses in through, called?

Answer 9

Stomata

Question 10

What diffuses out through the stomata?

Answer 10

Oxygen (produced in photosynthesis) and water vapour

Question 11

What do guard cells do?

Answer 11

Regulate the opening and closing of the stomata.

Question 12

When will the guard cells close the stomata?

Answer 12

If the plant is losing water faster than it is being replaced by the roots.

Question 13

Why is the flattened shape of the leaf useful?

Answer 13

It increases the area of the exchange surface, making it more effective.

Question 14

What diffuses into the leaf?

Answer 14

Carbon dioxide

Question 15

What conditions is evaporation quickest?

Answer 15

Hot, dry, windy conditions

Question 16

What happens to the water vapour in the leaf?

Answer 16

The water vapour evaporates from the cells inside the leaf, then it escapes by diffusion as there is less water vapour in the air outside.

Question 17

What is the thorax?

Answer 17

The top part of the body.

Question 18

What separates the thorax from the lower part of the body (abdomen)?

Answer 18

The diaphragm.

Question 19

What does the air that you breath in go through?

Answer 19

The trachea.

Question 20

Describe the route of the air flow.

Answer 20

The trachea to the bronchi which splits into two tubes, each one called the bronchus. These split into smaller tubes called the bronchioles then finally to the small bags called the alveoli.

Question 21

What is ventilation?

Answer 21

The movement of air into and out of the lungs.

Question 22

What happens when you breath in?

Answer 22

• Intercostal muscles and diaphragm contract
• Thorax volume increases
  (this decreases pressure, drawing air in)

Question 23

What happens when you breath out?

Answer 23

• Intercostal muscles and diaphragm relax
• Thorax volume decreases
  (This increases the pressure so air is forced out)

Question 24

What are artificial ventilators?

Answer 24

Machines that move air (often with extra oxygen) into and out of lungs.

Question 25

How do artificial ventilators work?

Answer 25

By pumping air into the lungs - this expands the ribcage so when they stop pumping, the ribcage relaxes and pushes air back out of the lungs.

Question 26

How does water enter a plant'?

Answer 26

Through the roots by osmosis

Question 27

What happens to the water in the plant not used in photosynthesis?

Answer 27

It evaporates from the underside of the leaf

Question 28

What is transpiration?

Answer 28

The process of water evaporating away from the leaves

Question 29

Why does hot weather cause more evaporation of water in plants?

Answer 29

The heat energy gives energy to the water particles enabling them to escape the force of attraction and evaporate quicker.

Question 30

Why does dry weather increase evaporation in plants?

Answer 30

Because there is low humidity outside the plant so the concentration of water particles will be greater inside the plant.

Question 31

Why do windy conditions increase evaporation in plants?

Answer 31

Because the wind pushes the particles away from the plant.

Question 32

What happens to a plant if evaporation rate is to high?

Answer 32

The plant will wilt as there isn't a great enough water supply to the plant.

Question 33

What test can you do to see rate of transpiration in a plant?

Answer 33

Use cobalt chloride paper it will start out a blue colour but when it comes in contact with water turns pink so see how long it takes for the colour to change.

Question 34

Why won't a plant cell burst when it is full of water?

Answer 34

Because it has a cell wall which allows it to maintain its shape.

Question 35

How is a villi adapted to be an effective exchange surface?

Answer 35

They increase the surface area of the small intestine so digested food is absorbed quickly into the blood. They have a single layer of surface cells so there is a small distance for substances to travel. They have a good blood supply to assist quick absorption.

Question 36

What are the cells on the surface of the villi called and why are they useful?

Answer 36

Micro villi They are finger like projections which increases the surface area even more. They also contain many mitochondria which release energy for the process of active transport.

Question 37

What is the villi?

Answer 37

They are tiny projections that cover the inside of the small intestine.

Question 38

What is the job of the lungs?

Answer 38

To transfer oxygen to the blood and to remove waste carbon dioxide from it by gas exchange.

Question 39

How are the alveoli specialised to maximise diffusion of oxygen and carbon dioxide?

Answer 39

A huge surface area to allow lots of oxygen or carbon dioxide to diffuse at once. A moist lining which is good for dissolving gases. Very thin walls meaning diffusion is quicker. A good blood supply to assist the movement of substances. Well ventilated mean oxygen is regulated breathed in an carbon dioxide is taken out.

Question 40

When is active transport used in the gut?

Answer 40

When there is a low concentration of nutrients in the gut but a high concentration in the blood. It nutrients and amino acids are kept in the gut we could starve.