Chemistry & Water Properties
An atom has 6 protons, 7 neutrons, and 6 electrons. What is its net charge and atomic number?
Net charge = 0 (neutral); Atomic number = 6 (protons).
What are the building blocks (monomers) of proteins and lipids?
Proteins = Amino acids; Lipids = Glycerol and fatty acids.
Which sugar is small enough to pass directly into the bloodstream without needing to be digested first?
Monosaccharide
Which type of fat contains double bonds (C=C) in its fatty acid tails and is usually liquid at room temperature?
Unsaturated fat
What do we call the specific reactant that binds to an enzyme's active site?
Substrate
What type of chemical bond is formed when atoms share pairs of valence electrons?
Covalent Bond
Name the polysaccharide that provides structural support in plant cell walls, which humans cannot digest (often called dietary fiber).
Cellulose
When blood glucose levels rise after a meal, which hormone does the pancreas release to bring blood sugar back to normal?
Why are cholesterol and fats unable to dissolve directly in human blood plasma?
They are nonpolar (hydrophobic), while blood plasma is mostly water (polar).
Using the "Lock and Key" model, why won't the enzyme lactase break down sucrose? **DRAW TO SHOW THE ANSWER**
The shape of sucrose does not fit the specific 3D shape of lactase's active site.
Balance the following chemical equation: N2 + H2 --> NH3
N2 + 3 H2 --> 2NH3
Look at a food label with 10g Total Carbohydrates, 2g Dietary Fiber, and 8g Sugars. Which type of carbohydrate will give you quick, immediate energy vs. no usable energy?
Sugars (monosaccharides/disaccharides) give quick energy; Dietary fiber (cellulose) gives no usable energy.
Name the storage polysaccharide found in animal liver/muscle tissue, and contrast it with where plants store surplus glucose.
Animals store glycogen; Plants store starch (amylose) in roots/tubers.
What specialized package does the body use to transport nonpolar lipids through the bloodstream?
Lipoprotein (HDL or LDL)
What happens to an enzyme's structure and function when exposed to extreme heat or severe pH changes?
It denatures (unfolds/changes shape) and loses its function.
Explain on a molecular level why water creates surface tension that allows small insects to walk across it.
Water molecules are polar and form hydrogen bonds with each other, creating cohesion at the surface.
What chemical reaction joins two monosaccharides together by removing a water molecule?
Dehydration synthesis
A patient exhibits high blood glucose levels AND high insulin levels in their blood. What metabolic condition do they likely have, and why is insulin not working?
Type 2 Diabetes; their body cells have become resistant/insensitive to insulin.
Compare HDL and LDL: Which one is considered "good" cholesterol, and what does it do with excess cholesterol in the blood?
HDL is "good"; it carries excess cholesterol back to the liver for breakdown/elimination.
If Human Enzyme A has an optimal temperature of 37 oC and Bacterial Enzyme B has an optimal temperature of 75 oC, what happens to Enzyme A at 60 oC?
Enzyme A denatures and its rate of reaction drops to zero.
Why is water's high specific heat crucial for maintaining homeostasis in living organisms?
It allows organisms (and environments) to resist drastic, sudden temperature changes when heat is absorbed or lost.
Identify which macromolecule family contains nitrogen in its functional amine group, and name the organelle that builds it.
Proteins; built by ribosomes.
Describe the reaction called hydrolysis and explain why an enzyme is required for it to occur during digestion.
Hydrolysis breaks down polymers into monomers by adding water; the enzyme acts as a catalyst to lower the activation energy needed for digestion.
Name two major sources of cholesterol in the human body, and list two ways a person can lower high cholesterol levels.
Sources: Genetics/liver production and diet (saturated/trans fats).
Ways to lower: Exercise, diet modification (less saturated fat), or medication (statins).
True or False: Enzymes are consumed/destroyed during a chemical reaction and must be remade every time. Explain why.
False; enzymes are reusable catalysts that remain unchanged after releasing the products.