Biological Molecules Flashcards
- Proteins - Carbohydrates - Lipids - Enzymes
What are proteins made of?
Proteins are made of amino acids. Proteins are composed of long chains of amino acids. There are 20 different amino acids used in proteins.
What do proteins contain?
They all contain carbon, hydrogen, oxygen and nitrogen, and some contain sulfur.
How many different types of amino acids are there?
20
Describe how proteins are held together.
1) The amino acids in a protein chain are attached to each other by strong peptide bonds.
2) The amino acids can be arranged in any sequence and proteins can be up to several hundred amino acids long.
3) The number of different proteins that are possible is almost unimaginable. Consider that there are several thousand ways of arranging a chain of just 3 amino acids, with each combination forming a different protein.
4) It’s the order of the amino acids in a protein that determines its structure and it’s the structure of a protein that determines how it works
What is the primary structure of a protein?
The order in which the amino acids are arranged in a protein chain
What type of bond holds together the secondary structure of a protein?
Hydrogen bonds (weak forces of chemical attraction)
Give an example of a carbohydrate.
Sugars, starch, cellulose
Finish the equation:
GLUCOSE + GLUCOSE –>
MALTOSE (a disaccharide) + WATER
Finish the equation:
GLUCOSE + FRUCTOSE –>
SUCROSE (a disaccharide) + WATER
What are polymers?
Large molecules made up of monomers (smaller units). The monomers of polysaccharides are monosaccharides.
Is starch a monosaccharide or a polysaccharide?
Polysaccharide
Is cellulose a monosaccharide or a polysaccharide?
Polysaccharide
What are two physical factors of Cellulose molecules?
Cellulose molecules are long and straight.
Name two monosaccharides.
Fructose, glucose
Which disaccharide is composed of two molecules of glucose?
Maltose
Name two polysaccharides?
Starch, cellulose, amylose and amylopectin.
What elements do lipids contain?
Carbon, hydrogen and oxygen
What are Lipids?
Oils and fats. Plant oils are mostly made up of a group of lipids called triglycerides.
What does a triglyceride?
Molecule of glycerol with three fatty acids attached to it.
What are phospholipids?
A molecule of glycerol, with two fatty acids and a phosphate group.
Cell membranes are made of what?
A double layer of phospholipids.
Which elements are fatty acids composed of?
Carbon, hydrogen and oxygen.
What’s the difference between saturated fatty acids and unsaturated fatty acids?
Every carbon atom is saturated fatty acid chains is joined by a single bond. Unsaturated fatty acids have one or more double bonds in their carbon chains.
What’s the difference between triglycerides and phospholipids?
A triglyceride is made up of one glycerol molecule and three fatty acid molecules but a phospholipid is made of one glycerol molecule, two fatty acid molecules and a phosphate group.
Enzymes speed up what?
Biochemical reactions.
Enzymes are…?
Globular proteins
What is the function of enzymes?
Speed up the rate of biochemical reactions.
What is activation energy?
The energy required to get a reaction started.
What do digestive enzymes do?
Digestive enzymes break down food into smaller molecules.
How does temperature affect enzyme activity?
As temperature increases, the rate of reaction also increases.
Why are enzymes described as ‘specific’?
The substrate molecule must be the correct shape to fit into the active site.
Explain why a denatured enzyme will not function.
The shape of the active site has changed and the substrate will no longer fit.
Describe the effect of pH on enzyme activity.
Acids and alkalis can denature enzymes by disrupting the weak hydrogen bonds in the enzymes’ tertiary structure and changing the shape of their active sites.
