Download 3.3 Procaryotes – Further questions and answers Q1. Bk Ch3 S3.3

3.3 Procaryotes – Further questions and answers
Q1.
Bk Ch3 S3.3 FQ1
Identify the procaryotic and eucaryotic cells from the following illustrations.
A1.
Bk Ch3 S3.3 FA1
Procaryotic cells: d; eucaryotic cells: a, b, c, e, f.
Q2.
Bk Ch3 S3.3 FQ2
a
b
c
Nitrogen is abundant in the atmosphere as a gas (N2), but plants and animals cannot use it in this
form.
i Why is nitrogen an important nutrient for plants and animals?
ii Explain how plants obtain nitrogen.
iii How do animals obtain nitrogen?
How are legumes such as peas, beans and lentils different from other plants?
Legumes are beneficial plants to grow in domestic vegetable gardens and in larger scale farming
practice. Explain the benefits offered by growing legumes.
A2.
Bk Ch3 S3.3 FA2
a
b
c
i Nitrogen is a component of protein, including enzymes, and nucleic acids, both complex
organic compounds. Proteins make up a large part of living organisms and nucleic acids are
contained in the nucleus—they direct the activities of cells and are involved in heredity.
ii Plants obtain nitrogen in the form of nitrates, which they obtain from nitrogen-fixing
bacteria (a kind of eubacteria) in the soil or living in close relationship with the roots of
certain plants.
iii Animals obtain nitrogen by consuming plants or by eating other animals that eat plants.
Legumes such as peas, beans and lentils contain nitrogen-fixing bacteria in their roots, that is, the
bacteria and the plant live in a symbiotic relationship. Such plants have a ready source of nitrogen
available to them. Most plants do not live in such an association and rely on nitrogen-fixing
bacteria in the soil to obtain nitrogen.
Legumes are important plants to have in domestic and commercial gardens because they improve
the fertility of the soil due to the activity of the nitrogen-fixing bacteria in their roots. The bacteria
absorb nitrogen from the air and convert it into nitrates that can be used by the legumes and are
also released into the soil where it becomes available to other plants.
3.3 Procaryotes FQA
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