Download Biomolecules Worksheet

Part 1: Carbohydrates (p29-34)
1). List 4 uses of carbohydrates in living organisms.
2) Give the general formula for carbohydrates and explain how sugars with the same formulas
(eg glucose and fructose) are different.
3). Identify the following common sugars as hexoses, pentoses, aldoses or ketoses. Briefly
describe how you can tell: glucose, ribose, fructose, ribulose, galactose.
4). Describe what α- and β-glucose are, and how they are formed from straight chain forms.
5). Oligosaccharides such as sucrose and maltose are formed when two simple sugars bond
together. Using a diagram, show how this reaction can occur.
6). Polysaccharides are long chains of simple sugars. There are several different types, each
with its own purpose for the cell. For each of the four main polysaccharides, starch, glycogen,
cellulose and chitin, state its uses and briefly describe its structure.
Part 2: Lipids (p35-40)
1). Lipids are non-polar, hydrophobic molecules that are insoluble in water. Explain chemically
why this happens.
2). List the four main types of lipids, and the main purpose of each.
3). Triglycerides are the most common type of lipid. Describe the parts of a triglyceride, and the
process by which they are made.
4). Fats can be both saturated and unsaturated. Explain what this means, and describe the
properties of each.
5). Phospholipids are the major molecules in the cell membrane. They have special properties
that make them suited for their task. List the different components / functional groups in a
phospholipid and properties they give.
Part 3: Proteins (p40-50)
1). In diagram form, give the general structure of an amino acid, and label any functional groups.
Since amino acids have the same general structure, what makes them all different?
2). Proteins are the most diverse and prevalent molecules in the cell. Describe some of the roles
proteins perform for the cell.
3). There are 3 main groups of amino acids in cells: non-polar, polar, charged. Explain what you
would look for in an amino acid to identify it as one of these types.
4). Peptide bonds are the bonds that link amino acids together to form proteins. Diagram the
formation of a peptide bond using alanine and serine. What type of reaction is this?
5). All enzymes and proteins are chains of specific amino acids, but in order for them to perform
their specific tasks, they must also have the correct 3D shape.
a) There are a number of structural levels in a protein, describe what is meant by primary,
secondary, tertiary, and quaternary structure.
b) What are α-helixes and β-pleated sheets, and disulfide bridges?
c) Denaturation is when the 3D shape of an enzyme is changed. What might cause this,
and why is it important?
Part 4: Nucleic Acids (p52-54)
1). Nucleic acids are the most important biological molecules because they can store hereditary
information. Draw the generalized structure of a nucleotide, and label the subunits.
2). Both DNA and RNA have nitrogen bases, but DNA has two strands linked by hydrogen
bonds in anti-parallel directions. Describe how the two strands are paired to each other.
3). Besides storing information in DNA and RNA, nucleotides also have several other functions.
Give 3 examples.