Topic 1:Biological molecules Flashcards
(63 cards)
What are the monomers of carbohydrates?
Monosaccharides (e.g., glucose, fructose, galactose).
What is the difference between α-glucose and β-glucose?
In α-glucose, the hydroxyl (-OH) group on carbon 1 is below the ring; in β-glucose, it is above.
What reaction forms a disaccharide from two monosaccharides?
A condensation reaction, which forms a glycosidic bond and releases water
Name three common disaccharides and their component monosaccharides.
~Maltose = glucose + glucose
~Sucrose = glucose + fructose
~Lactose = glucose + galactose
What test is used for reducing sugars?
Benedict’s test – a brick-red precipitate indicates a positive result.
What are the two main types of lipids?
Triglycerides and phospholipids.
What are triglycerides made of?
One glycerol molecule and three fatty acids.
What is the difference between saturated and unsaturated fatty acids?
Saturated fatty acids have no double bonds, whereas unsaturated fatty acids have one or more double bonds.
What test is used to identify lipids?
The emulsion test – a milky-white emulsion indicates lipids are present.
What are the monomers of proteins?
Amino acids.
What type of bond forms between amino acids?
Peptide bonds.
What are the four levels of protein structure?
~Primary: Sequence of amino acids.
~Secondary: α-helices and β-pleated sheets (formed by hydrogen bonds).
~Tertiary: 3D structure (involves hydrogen, ionic, and disulfide bonds).
~Quaternary: Multiple polypeptide chains joined.
What test is used for proteins?
Biuret test – a purple color indicates the presence of protein.
How do enzymes speed up reactions?
They lower the activation energy required for a reaction to occur.
What is the difference between the “lock and key” and “induced fit” models?
~Lock and key: The enzyme’s active site is a perfect fit for the substrate.
~Induced fit: The enzyme changes shape slightly to fit the substrate more closely.
How does temperature affect enzyme activity?
Increases activity up to the optimum, but too high a temperature denatures the enzyme.
How does pH affect enzyme activity?
Enzymes have an optimum pH; extreme pH changes alter the active site shape and denature the enzyme.
How does substrate concentration affect enzyme activity?
~increases the numbers of substrate molecules that can form enzyme-substrate (ES) complexes at any one time.
~This increases the initial rate of reaction but when all the enzyme molecules are engaged in ES complexes the rate cannot increase any further.
How do competitive and non-competitive inhibitors work?
~Competitive inhibitors bind to the active site, blocking the substrate.
~Non-competitive inhibitors bind elsewhere on the enzyme, changing its shape.
How can you measure the rate of an enzyme-controlled reaction?
Measuring the increase in products or decrease in reactants over time
What does a plateau in a reaction rate graph indicate?
The reaction rate has reached its maximum and no longer increases, even with further increases in the factor being measured
What is a monosaccharide?
The monomer of carbohydrates, e.g., glucose.
What is a glycosidic bond?
A bond formed between two monosaccharides via a condensation reaction.
What is a triglyceride?
A lipid consisting of one glycerol and three fatty acids.
