Molecular biology

Which type of molecule is shown in the diagram below?

• Peptide

• Carbohydrate

• Lipid

• Nucleic acid

Which of the following are connected by hydrogen bonds?

• Hydrogen to oxygen within a molecule of water

• Phosphate to sugar in a DNA molecule

• Base to sugar in a DNA molecule

• Hydrogen to oxygen between two different molecules of water

What is denaturation?

• A structural change of a protein that results in the loss of its biological properties

• A change in the genetic code of an organism

• A change in the amino acid sequence of a protein causing a disruption of its 3D shape

• The process by which amino acids are broken down and ammonia is released

What property of water makes it a good evaporative coolant?

• High latent heat of evaporation

• Relatively low boiling point

• Volatility

• Transparency

A number of different proteins are involved in nerve function. Which of the following does not require a membrane protein?

• Active transport of sodium

• Diffusion of K+ into the cell

• Diffusion of the neurotransmitter across the synapse

• Binding of the neurotransmitter to the post-synaptic membrane

What is the difference between galactose and lactose?

• Lactose is a disaccharide and galactose is a monosaccharide

• Lactose is the product of anaerobic respiration in humans and galactose is the product of anaerobic respiration in yeast

• Lactose is an enzyme and galactose is a hormone

• Galactose is a sugar found in milk but lactose is not found in milk

How many molecules of water are required to completely hydrolyse a polypeptide made up of 23 amino acids?

• 11

• 22

• 23

• 44

Which statement  about water is correct?

• The atoms within a molecule of water are held together by hydrogen bonds

• Water has a low heat capacity allowing enzymatic reactions to happen at a wide range of temperatures

• Water molecules are polar, therefore fatty acids do not dissolve

• Ice has a higher density than liquid water, therefore some organisms can live under the ice

What is a difference between cohesion and adhesion?

• Only adhesion is involved in transpiration pull

• Only cohesion is involved in the movement of water in soil

• Only cohesion involves the interaction of water with soil mineral particles

• Only adhesion involves the interaction of water with xylem

Which describes these molecules correctly?

• I-ribose

  II-amino acid

• I-glucose

  II-amino acid

• I-ribose

  II-fatty acid

• I-glucose

  II-fatty acid