'State' Statements for Chemicals of life

'State' Statements for Chemicals of life

1. the most frequently occurring chemical elements in living things are carbon, hydrogen, oxygen and nitrogen

2. a variety of other elements are needed by living organisms, including sulphur, calcium, phosphorus, iron and sodium

   • one role for each of the elements mentioned in 3.1.2
     • Sulphur (S): Found in certain amino acids (cysteine and methionine), allowing proteins to form disulphide bonds
     • Calcium (Ca): Found in bones and teeth, also involved in neurotransmitter release in synapses
     • Phosphorus (P): Component of nucleic acids and cell membranes
     • Iron (Fe): Found in haemoglobin (animals), allowing for oxygen transport
     • Sodium (Na): Involved in the generation of nerve impulses in neurons

3. one function of glucose, lactose and glycogen in animals and of fructose, sucrose and cellulose in plants

   • Animal
     • Glucose
       • A source of energy which can be broken down to form ATP via cellular respiration
     • Lactose
       • A sugar found in the milk of mammals, providing energy for suckling infants
     • Glycogen
       • Used by animals for short term energy storage (between meals) in the liver
   • Plant
     • Fructose
       • Found in honey and onions, it is very sweet and a good source of energy
     • Sucrose
       • Used primarily as a transportable energy form (e.g. sugar beets and sugar cane)
     • Cellulose
       • Used by plant cells as a strengthening component of the cell wall

4. three functions of lipids

   • Structure
     • Phospholipids are a main component of cell membranes
   • Storage of energy
     • Triglycerides can be used as a long-term energy storage source
   • Protection
     • Triglycerides may form a tissue layer around many key internal organs and provide protection against physical injury

5. names of the four bases in DNA

   • Adenine
     • Thymine
   • Guanine
     • Cytosin

6. in cell respiration, glucose in the cytoplasm is broken down by glycolysis into pyruvate, with a small yield of ATP

7. that photosynthesis involves the conversion of light energy into chemical energy

   • chlorophyll is the main photosynthetic pigment

8. light from the Sun is composed of a range of wavelengths (colours

9. light energy is used to produce ATP, and to split water molecules (photolysis) to form oxygen and hydrogen

10. ATP and hydrogen (derived from the photolysis of water) are used to fix carbon molecules to make organic molecules