A Few Review Questions

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A Few Review Questions
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Question 1

• Say that your cells have met all of their ATP
  needs. If you eat glucose in excess of your
  cells ATP needs, what is/are the fates of this
  glucose, in order of priority?

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Answer Question 1

• If your cells have met all of their energy needs,
  the glucose will not go through ATP production
  (glycolysis -gt citric acid cycle -gt ETC).
  Instead
• The first thing that will happen is glycogen
  formation -- storage of this energy supply in
  liver and muscle cells. But the glycogen tanks
  are also limited in size.
• When the glycogen tanks get full, the excess
  glucose gets synthesized into fatty acids. The
  first step of this pathway involves glycolysis,
  but only to form acetyl-CoA, involved in fatty
  acid formation.

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Question 2

• Protein monomers and lipid monomers are both
  absorbed into the bloodstream from the small
  intestine. The method by which each molecule
  type travels through the blood to the cells is
  different, however. Explain why this is, and how
  the above molecule types are transported through
  the bloodstream.

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Answer Question 2

• Amino acids are zwitterionic at neutral pH and
  therefore water soluble -- once they are absorbed
  across the small intestine lining, they can be
  transported through the water-based blood.
• However, lipids are nonpolar. They have to be
  attached to a protein, forming a lipoprotein
  (specifically in the digestive system, a special
  lipoprotein called a chylomicron is formed) which
  is then polar enough to be transported through
  the bloodstream.

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Question 3

• Explain what is involved in designing primers for
  PCR. (or, as its often referred to, PCRing up
  a gene)

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Answer Question 3

• Decide what the boundaries/ends will be of the
  region you wish to amplify.
• Each primer will be a short nucleotide sequence
  (typically 12-15 NT -- you dont need to know
  this) that will bind to your template DNA.
• The 5-gt3 orientation of each primer should be
  such that new nucleotides get added moving in
  toward the center of your gene after the two
  strands have been separated.
• In a real-life situation, youd consider
  re-annealing temperature (which is dependent on
  AT vs. GC) as well

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Question 4

• You just ate a big, yummy dinner. Describe what
  is happening to your blood glucose levels and
  hormones released by the pancreas.
• (YES, we are assuming that you are not diabetic,
  and we are assuming that your meal was reasonably
  balanced in terms of carbs/proteins/fats!)

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Answer Question 4

• Big meal blood glucose levels are high.
• If you are normal (well metabolically so), your
  pancreas is releasing insulin. This will allow
  the glucose to enter your cells for processing in
  whatever capacity it decides is proper for the
  cells current metabolic and energy needs.

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Question 5

• Some of the proteolytic (protein-digesting)
  enzymes are produced by glands found in the
  lining of the stomach. However, they are
  produced as zymogens and not active until they
  make contact with HCl inside the cavity of the
  stomach. Why do you think this form of
  regulation is used by these particular
  proteolytic enzymes?

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Answer Question 5

• The walls of the stomach contain structural
  proteins. If the enzymes were produced from
  their glands already in an active form, they
  would digest the stomach lining.
• Since they are produced in an inactive form, they
  will not digest the stomach lining upon release,
  and they will not start doing their business
  until they make contact with HCl, which cleaves
  off the inactive part of the zymogen.