IGCSE marine science 4.1

The syllabus states in 4.1:

Candidates should be able to: 

1 describe nutrients as substances that are required by an organism for growth, repair and to provide chemical energy 

including: 

• gases such as carbon dioxide 

• dissolved salts 

• organic compounds including carbohydrates (starch, and sugars such as glucose), lipids (fats and oils) and proteins

2 investigate a variety of foods to test for the (PA) presence of starch, sugars, proteins and lipids

3 describe the functions of major nutrient group

limited to:

(a) protein used for tissue repair and growth, and energy supply 

(b) carbohydrate as an energy supply

(c) lipids as insulation, energy supply, source of lipid-soluble vitamins

(d) vitamins as micronutrients 

(e) mineral salts as micronutrients

4 state that some nutrients supply marine organisms with a source of essential elements and these elements have important biological roles

(a) nitrogen, which is used to make proteins 

(b) carbon, which is used to make organic compounds 

(c) magnesium, which is used to make chlorophyll 

(d) calcium, which is used to make bones, shells and coral skeletons 

(e) iron, which is used to make haemoglobin in the blood of vertebrates and some invertebrates, to carry oxygen around the body

5 explain how nutrients cycle through marine ecosystems 

• taken up by organisms and passed up food chains 

• become available again after death and decay 

 • sink through the water column as marine snow 

 • return to the surface by upwelling

6 outline the role of bacteria as decomposers in cycling nutrients