3 marksThe butterfly is an insect that feeds on nectar produced by flowers.
The photograph shows a butterfly feeding on a flower.
Photo (c)2006 Derek Ramsey (Ram-Man), GFDL 1.2 , via Wikimedia Commons
The nectar in flowers contains nutrients including sugars, amino acids and lipids.
(i) The sugars in the nectar are fructose, glucose and sucrose.
Which of these contain glycosidic bonds?
(1)
☐ | A | fructose only |
☐ | B | sucrose only |
☐ | C | fructose and glucose |
☐ | D | fructose and sucrose |
(ii) Which row of the table describes how amino acids are joined together to form a protein?
(1)
|
| name of bond | type of reaction |
☐ | A | ester | condensation |
☐ | B | ester | hydrolysis |
☐ | C | peptide | condensation |
☐ | D | peptide | hydrolysis |
(iii) Which row of the table describes a saturated lipid?
(1)
|
| carbon-carbon double bonds | carbon : hydrogen ratio |
☐ | A | absent | higher than in an unsaturated |
☐ | B | absent | lower than in an unsaturated |
☐ | C | present | higher than in an unsaturated |
☐ | D | present | lower than in an unsaturated |
6 marksThe circulatory system of an insect is described as an open system. This means that the blood is not contained inside blood vessels but flows through cavities called sinuses.
The diagram shows part of the circulatory system of an insect.
(i) The length of the head of a butterfly is 4mm, the thorax is 6mm and the abdomen is 18mm.
Estimate the surface area to volume ratio of the butterfly.
Assume that the insect is a cylinder of diameter 4mm and the surface area is 360mm2
(2)
(ii) Explain why the circulation of a butterfly is different from the circulation of a mammal.
(2)
(iii) The blood flowing through the sinuses of the butterfly is separated from the organs by collagen.
Describe the structure of collagen.
(2)
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