Download 2.3 Obtaining nutrients – Further questions and

2.3 Obtaining nutrients – Further questions and answers
Q1.
Bk Ch2 S2.3 FQ1
Visit your local nursery or consult an encyclopaedia of plants to find out the answers to each of the
following.
a
What is the difference between macronutrients and micronutrients?
b
Packets of fertiliser purchased from nurseries often list ‘NPK’ as major ingredients.
i For what nutrients are these letters an abbreviation?
ii How are each of these nutrients important to plants?
A1.
Bk Ch2 S2.3 FA1
a
b
Macronutrients are those that are required in relatively large amounts, for example nitrogen.
Micronutrients are needed in much smaller amounts; iron is an example.
i N: nitrogen; P: phosphorus; K: potassium
ii Nitrogen is needed to manufacture proteins that make up a large part of plant structure as
well as nucleic acids. Phosphorus is a component of ATP used in energy transformations as
well as an important part of the structure of nucleic acid molecules. Potassium is a mineral
involved in many cellular processes, for example the manufacture of chlorophyll.
Q2.
Bk Ch2 S2.3 FQ2
A green pot-plant was placed in a position to receive plenty of sunlight during the day. It was watered
regularly. Very little new growth occurred, and the plant soon began to lose its leaves and turn brown.
Suggest a possible explanation for this observation.
A2.
Bk Ch2 S2.3 FA2
These symptoms are consistent with a mineral deficiency. Plant cells need a range of minerals to ensure
the adequate functioning of different metabolic processes, including cellular respiration and
photosynthesis. When one or more of these minerals are missing from the plant’s soil a range of
symptoms specific to the mineral in question arises. Also, by elimination the plant was supplied with
an adequate supply of water, sunlight and carbon dioxide.
Q3.
Bk Ch2 S2.3 Q3
Complete the table, which summarises actions of enzymes.
Food
Type of enzyme
Final product of chemical digestion
Carbohydrate
Lipid
Protein
A3.
Bk Ch2 S2.3 A3
Food
Type of enzyme
Final product of chemical digestion
Carbohydrate
Amylase
Simple sugars
Lipid
Lipase
Fatty acids and glycerol
Protein
Protease
Amino acids
2.3 Obtaining nutrients FQA
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Q4.
Bk Ch2 S2.3 FQ4
Examine the following graph, which shows the rate of photosynthesis occurring at a fixed level of light
intensity.
a
b
c
d
What is happening to the rate of photosynthesis between the points X and Y? Explain.
Why does the graph level off after point Y?
What is the limiting factor in this experiment? Why do you think so?
List two factors that are being controlled in this experiment.
A4.
Bk Ch2 S2.3 FA4
a
b
c
d
The rate of photosynthesis is increasing. As carbon dioxide concentration increases so does the
rate of photosynthesis.
This represents the optimum rate of photosynthesis at this level of light intensity.
Light intensity. Initial information indicates that light intensity is at a fixed level; this means that
the level of light intensity limits the rate at which photosynthesis proceeds.
Any two of light, temperature, pH.
Q5.
Bk Ch2 S2.3 FQ5
Design a simple experiment to test the effect of temperature on photosynthesis.
A5.
Bk Ch2 S2.3 FA5
Set up two similar plants (same species, size, age, etc.) in bell jars fitted with a constant supply of
carbon dioxide as well as oxygen probes. The oxygen probes will measure the concentration of oxygen
and therefore serve as an indicator of the rate at which photosynthesis is proceeding. Keep all factors in
the experiment constant (e.g. soil type, amount of water) except temperature, which will remain
constant in the control plant and be the only factor that is varied for the experimental plant. Any change
in the rate of photosynthesis in the experimental set-up will be attributable to the variable of
temperature.
Q6.
Bk Ch2 S2.3 FQ6
Explain the importance of the liver in relation to the products of digestion.
A6.
Bk Ch2 S2.3 FA6
First, the liver stores excess glucose as glycogen. Second, some of the foods we ingest can be toxic to
the body and an important role of the liver is to receive blood leaving the small intestine after the
absorption of digested materials and process it for harmful substances such as alcohol, drugs and
poisons. Detoxification of such substances occurs at the liver so they can be made less harmful before
being sent to the heart and then to the rest of the body cells.
2.3 Obtaining nutrients FQA
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Q7.
Bk Ch2 S2.3 FQ7
Use a reference book to find out about the appendix in humans. What role, if any, does it play? How
does it compare with similar structures in herbivorous animals? What does the presence of the
appendix in humans suggest about our relationship to other species?
A7.
Bk Ch2 S2.3 FA7
The appendix in humans has no role to play in the digestion of foodstuffs. It is a redundant structure
found as a rudimentary pocket at the base of the caecum. In herbivorous animals the appendix and
caecum are much more developed, forming the site at which cellulose is digested by bacteria. The very
presence of the appendix in humans suggests that it did have a role at some time in our evolutionary
history. Vestigial structures such as the appendix in humans that are like similar functional structures in
other animals suggest that organisms are related in the evolutionary sense.
Q8.
Bk Ch2 S2.3 FQ8
Prepare a poster that would appeal to your classmates, providing information about diet. Include
 a summary of what is meant by the term ‘balanced diet’
 the five major food groups, with examples of the kinds of foods offered by each and the
recommended daily allowance of each.
A8.
Bk Ch2 S2.3 FA8
A balanced diet is one that includes an adequate daily quantity of food items from each of the five
recognised food groups. Regular exercise is an important addition to a balanced diet.
Food group
Examples
Recommended daily allowance
Breads and cereals
Bread, breakfast cereals, rice,
pasta
4 servings
Fruits and vegetables
Apple, oranges, any fruits;
carrots, broccoli, any vegetables
4 servings
Meat and meat substitutes
Red meat, chicken, fish, lentils,
nuts
1–2 servings
Dairy products
Milk, cheese, yoghurt
Equivalent of 600 mL milk for
children/300 mL for adults
Fats and oils
Butter, margarine, vegetable oil
15–30 g
2.3 Obtaining nutrients FQA
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