Initial Definitions

Question 1

Define an atom

Answer 1

A basic unit of matter that consists of a dense, central nucleus surrounded by a cloud of negatively charged electrons.

Question 2

Define a molecule

Answer 2

a group of at least two atoms held together by covalent bonds

Question 3

Define organic

Answer 3

molecules containing carbon, except those containing only carbon and oxygen (eg CO2)

Question 4

Define inorganic

Answer 4

molecules that do not contain carbon, plus the carbon oxides (eg CO2)

Question 5

What are magnesium, phosphate, nitrate and calcium used for in plants?

Answer 5

chlorophyll, nucleic acids, nucleic acids/amino acids and the cell wall

Question 6

What are magnesium, iron, phosphate, nitrate and calcium used for in animals?

Answer 6

bones, haemoglobin, nucleic acids, nucleic acids/amino acids and bones/teeth

Question 7

How would you draw and label two bonded water molecules?

Answer 7

Each molecule should have two H (delta +), one O (delta -). They should be joined with a dashed line labelled H bond

Question 8

Describe the food test and positive result for starch

Answer 8

Add iodine, colour change from yellow to blue/black

Question 9

Give the food test and positive result for a reducing sugar

Answer 9

Add benedicts reagant and BOIL, colour change from blue to brick red (or green to yellow to orange to red)

Question 10

Give the food test and positive result for a non reducing sugar

Answer 10

Add acid and boil, then neutralise. Add benedicts reagant and BOIL, colour change from blue to brick red (or green to yellow to orange to red)

Question 11

Give the food test and positive result for protein

Answer 11

Add biuret reagant, colour change from blue to lilac/purple

Question 12

Give the food test and positive result for lipid

Answer 12

Add ethanol, shake, add water, shake. Forms a milky white emulsion