1 life processes - respiration and movement, page 12-18, 23-24

Question 1

What is respiration?

Answer 1

A chemical reaction which taking place in cells, where glucose is broken down to release energy.

Question 2

What can ATP be used for?

Answer 2

• Contraction of muscle cells, producing movement.
• Active transport of molecules and ions.
• Building large molecules, such as proteins.
• Cell division.

Question 3

What is ATP also known as?

Answer 3

Energy. It provides energy for cells.

Question 4

What is aerobic respiration?

Answer 4

A reaction that releases energy from food. Uses oxygen and produces carbon dioxide and water.

Question 5

What is the word equation for aerobic respiration?

Answer 5

Glucose + Oxygen —> Carbon dioxide + water + energy

Question 6

What is the chemical equation for aerobic respiration?

Answer 6

C6H12O6 + 6O2 —> 6CO2 + 6H2O

Question 7

Where does aerobic respiration occur?

Answer 7

In the cells of humans, animals, plants and many other organisms. More specifically, in the mitochondria.

Question 8

How is ATP used during respiration?

Answer 8

There is ADP, meaning that there are only 2 phosphate groups. Respiration adds the final phosphate group; turning it into ATP - with three phosphate groups.

Question 9

How is ATP used by other cells?

Answer 9

The ATP is composed of three phosphate groups. When energy is needed; this ATP loses one phosphate group and gets turned into ADP.

Question 10

What is anaerobic respiration?

Answer 10

The reaction that releases energy from food, without using oxygen. Produces lactate in mammals, carbon dioxide and ethanol in yeast.

Question 11

What is anaerobic respiration in terms of glucose?

Answer 11

Not all the glucose is broken down, so less energy is released. It can occur in situations when oxygen is in short supply.

Question 12

What kind of organisms use anaerobic respiration?

Answer 12

• Muscle cells.
• Yeast.

Question 13

What is yeast?

Answer 13

Single-celled fungi.

Question 14

How does yeast respire anaerobically?

Answer 14

When yeast cells are prevented in getting enough oxygen, they stop respiring aerobically and start to respire anaerobically instead. The glucose is broken down into ethanol and carbon dioxide.

Question 15

What is the word equation for anaerobic respiration in yeast?

Answer 15

Glucose —> Ethanol + Carbon dioxide (+ some energy)

Question 16

How do muscle cells respire anaerobically?

Answer 16

When they are short of oxygen. If the muscles are overworked, the blood cannot reach the cells fast enough to deliver enough oxygen for respiration. So when someone does a ‘burst’ activity; like a sprint or quickly lifting a heavy weight.

Question 17

What is the word equation for anaerobic respiration in muscle cells?

Answer 17

Glucose —> Lactic acid (+ some energy)

Question 18

What happens to the lactate after the excersise?

Answer 18

The lactate is respired aerobically in the mitochondria.

Question 19

What is oxygen debt?

Answer 19

The volume of oxygen that is needed to completely oxidise the lactate built up during a period of anaerobic respiration.

Question 20

What is the practical that investigate the production of carbon dioxide by small living organisms?

Answer 20

Uses hydrogen carbonate solution which is orange - it turns yellow if carbon dioxide is added to it. The indicator is sensitive to small changes in carbon dioxide levels making it suitable for small living organisms.

Question 21

What is the method used?

Answer 21

• The living organisms are placed in a stoppered boiling tube.
• The small organisms are placed on a gauze platform.
• Below them is hydrogen carbonate indicator solution which will turn yellow when they respire as it has sensed carbon dioxide.

Question 22

Why are the living organisms placed on a gauze platform?

Answer 22

To avoid their exposure to the chemical.

Question 23

What is the investigation used to demonstrate that heat is produced by respiration?

Answer 23

• Peas are soaked in water for 24 hours.
• One batch of peas are boiled - to kill them.
• Both batches are placed in a bleach solution to act as a disinfectant and then they are washed twice with distilled water to get rid of any traces of bleach.

Question 24

What is the method used to demonstrate that heat is produced by respiration?

Answer 24

Each batch is placed into an inverted vacuum flask and some air will be left in it. The inverted flash and cotton wool allow carbon dioxide to escape as it might kill the peas.

Question 25

How long does this experiment take?

Answer 25

The peas are left to sit for a couple of days. The temperature at the beginning and end of the experiment are recorded. The peas which were alive had a higher temperature in the vacuum flask.

Question 26

What is diffusion?

Answer 26

The net movement of particles from a region where they are of high concentration to a region with a lower concentration due to the random movement of particles. They move down the concentration gradient so no energy is needed.

Question 27

What are examples of substances that diffuse into cells?

Answer 27

• Oxygen.
• Glucose.

Question 28

What are examples of substances that diffuse out of cells?

Answer 28

• Urea.
• Carbon dioxide.

Question 29

What are the factors affecting diffusion?

Answer 29

• The concentration gradient.
• The SA:V ratio.
• The distance.
• The temperature.

Question 30

How does the concentration gradient affect diffusion?

Answer 30

The greater concentration gradient means a greater rate of diffusion. This is when there is a big difference in concentrations between two areas.

Question 31

How does the SA:V affect diffusion?

Answer 31

The greater the surface area the faster the rate of diffusion. A larger surface area and proportion to the volume will increase the rate of diffusion.

Question 32

How does the distance affect diffusion?

Answer 32

The shorter the distance, the quicker and easier a particle can move from one place to another So the faster the rate.

Question 33

How does the temperature affect difffusion?

Answer 33

The higher the temperature, the more kinetic energy particles have - so the rate of diffusion will be faster.

Question 34

What is active transport?

Answer 34

Movement of molecules or ions against a concentration gradient, using energy from respiration. So from an area of low concentration to an area of high concentration.

Question 35

Does active transport need energy?

Answer 35

Yes, this is because it goes against a concentration gradient. So essentially, ‘up’ it.

Question 36

What is an example of where active transport is used?

Answer 36

The roots of plants also take up certain mineral ions this way.

Question 37

What is osmosis?

Answer 37

It is the movement of water particles across a semi-permeable membrane. From an area of high water concentration to an area of low water concentration.

Question 38

Does osmosis need energy?

Answer 38

No, it is moving down a concentration gradient.

Question 39

What is an example of when osmosis is used?

Answer 39

Movement of water particles between neighbouring cells.

Question 40

What is the practical to demonstrate diffusion in a jelly?

Answer 40

Agar can be used for growing culture of bacteria and similar to the cytoplasm of a cell. It has high water content. This is between HCI and potassium permanganate.

Question 41

What happens when HCI comes into contact with potassium permanganate?

Answer 41

The purple colour of the permanganate dissapears.

Question 42

What is the method used to demonstrate diffusion in a jelly?

Answer 42

• A petri dish is prepared containing 2cm of agar jelly which is dyed purple with potassium permanganate.
• Three cubes are cut out of this jelly with the side lengths of 0.5,1 and 2.
• These cubes have different volumes and surface areas.

Question 43

When do we know when to stop the experiment?

Answer 43

The cubes are then dropped into hydrochloric acid and we will stop when the agar which is dyed with potassium manganate has turned colourless. The cube with the side lengths of 0.5 has a higher SA:V ratio meaning that diffusion will happen quickest.