2.1.2 Biological Molecules

• What type of bond forms between hydrogen and oxygen in a water molecule?

  Covalent
• Why is ice less dense than water?

  As water cools, more hydrogen bonds form, causing molecules to spread out, and resulting in ice being less dense.
• What percentage of the cytoplasm is water?

  70 %
• Why is it important that cells maintain stable temperatures?

  Enzyme function
• Oxygen atoms are _____ charged

  Negatively
• Hydrogen atoms are slightly ______ charged

  Positively
• Properties of Water

  A) transport

  B) Solvent

  C) stable

  D) optimal

  E) hydrogen

  F) less

  G) habitats

  H) insulating

  
• How do hydrogen bonds form between water molecules?

  The positive hydrogen atoms are attracted to the negative oxygen atoms of another water molecule, forming a hydrogen bond.
• What is cohesion?

  Attraction between water molecules
• Name two processes where water acts as a reactant

  Photosynthesis, hydrolysis
• Cohesion produces surface tension
• Surface tension provides habitats
• What animal may use surface tension as a habitat?

  Pond skaters
• What is the benefit of water being transparent?

  Aquatic plants can photosynthesise
• Are hydrogen bonds solely found in water molecules?

  No -> alpha helices, beta pleated sheets etc.
• What is a monomer?

  A small molecule which binds to many other identical molecules to form a polymer
• What is a polymer?

  A large molecule made from many smaller molecules called monomers
• What is a hydrolysis reaction?

  A reaction that occurs when a molecule is split into two smaller molecules with the addition of water
• What is a condensation reaction?

  A reaction that occurs when two molecules are joined together with the removal of water
• What elements make up carbohydrates?

  Carbon, Hydrogen, Oxygen

  (alphabetical)
• What elements make up lipids?

  Carbon, Hydrogen, Oxygen

  (alphabetical)
• What elements make up Proteins?

  Carbon, Hydrogen, Oxygen, Nitrogen, Sulfur
• What elements make up Nucleic Acids?

  Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus
• Glucose is a hexose monosaccharide
• What is an isomer?

  Isomers have the same molecular formula, but a different arrangement of atoms.
• Name the two glucose isomers

  Alpha

  Beta
• Why is glucose easy to transport?

  It is small and soluble
• Monosaccharides are soluble and sweet reducing sugars
• How many carbons do hexose sugars have?

  6
• How many carbons do pentose sugars have?

  5
• What is the main role of glucose?

  Energy source. It is used as a respiratory substrate to provide energy for the formation of ATP
• What bond joins two monosaccharides together?

  Glycosidic bond
• On which carbon does deoxyribose lose an oxygen compared to ribose?

  Carbon 2
• What is a disaccharide?

  Two monosaccharides
• What is the polymer of carbohydrates?

  Polysaccharides
• Alpha glucose

  A) CH2OH

  B) H

  C) OH

  D) H

  E) OH

  F) OH

  G) H

  H) H

  I) OH

  
• Alpha v Beta glucose

  A) alpha

  B) beta

  
• Ribose v Deoxyribose

  A) ribose

  B) Deoxyribose

  
• Which disaccharide is a non-reducing sugar?

  Sucrose
• How do you make maltose?

  a Glucose + a Glucose