Structures + Functions In Living Organisms

Question 1

How do most animals store carbohydrates

Answer 1

As glycogen

Question 2

What is meant by the term saprotophic nutrition

Answer 2

They (can be fungi) secrete extracellular enzymes into the area outside their body to dissolve their food, so they can then absorb the nutrients

Question 3

Give two examples of protoctists

Answer 3

Chlorella

Amoeba

Question 4

What are pathogens and give two examples

Answer 4

Pathogens are organisms that cause disease
They include some fungi, protoctists, bacteria and viruses.
E.g. Plasmodium,causes malaria
Influenza virus causes flu

Question 5

Give two examples of fungi

Answer 5

Mucor

Yeast

Question 6

Briefly describe an experiment to show how the temperature can affect the enzyme activity

Answer 6

1) the enzyme catalase catalyses the breakdown of hydrogen peroxide into O and H2O
2) collect the oxygen produced and measure how much is given off at set period of time (using water bath)
3) you can run a series of experiments using different temperature water baths and see how the temperature affects the activity of catalase

Question 7

State what happens to the relative rate of reaction at the extremes of the pH

Answer 7

pH also affects enzymes. If it’s too high or too low the pH interferes with the bonds holding the enzyme together. This changes the shape of the active site and denatures the enzyme

Question 8

Why are turgid cells important to plants

Answer 8

When a plant is well watered all its cells will draw water in osmosis and become plump and swollen. This means the cells are turgid. The contents of the cell push against the cell wall(this is called turgor pressure). Turgor pressures helps support the plant tissues

Question 9

Describe an experiment using a non living system that shows diffusion taking place

Answer 9

Phenolphthalein is pH indicator - it’s pink in alkaline solutions and colourless in acidic solutions.
1)Make agar jelly using phenolphthalein and dilute sodium hydroxide (pink)
2)fill beaker with dilute hydrochloric acid. Place cubes in the beaker of acid
3) eventually they’ll turn colourless
You can investigate the rate of diffusion by using different sized cubes of agar jelly and timing how long it takes for each to go colourless. The cube with the largest surface area:volume ration will lose its colour quickest

Question 10

Describe an experiment using a non living system that shows osmosis taking place

Answer 10

1) cut up a potato into identical cylinders
2) place them in beakers with different sugar solutions in them: one should be pure water, another should be very concentrated sugar solution, then a few in between
3) you can measure the length of the cylinders, then leave a few cylinders in each Beamer for an hour or so
4) remeasure the potatoes. If the cylinders have in water by osmosis, they’ll be a bit longer. If water have been drawn out, they’ll have shrunk a bit

Question 11

How is active transport different from diffusion in terms of energy requirements and concentration gradients

Answer 11

Active transport requires energy from respiration to make it work
Active transport moves from an area of high conc into an area of low conc