Macromolecules & Cells
Which macromolecule is the main component of membranes?
Lipids (Phospholipids)
DNA strands are antiparallel. What does that mean?
One runs 5' to 3' and the other 3' to 5'
Which type of bond stabilizes alpha-helices and Beta-Sheets
Hydrogen Bonds
What is the cell's main energy currency?
ATP
Purines have how many rings? Name one
two rings, Adenine or Guanine
Give one function of carbohydrates
Energy storage, cell identity, or structure.
Which enzyme transcribes DNA into RNA?
RNA Polymerase
Enzymes lower what barrier to speed up reactions?
Activation Energy
Glycolysis breaks one glucose into how many pyruvate?
Two
What is the difference between the coding strand and the template strand?
Coding strand matches RNA (except U instead of T)
Template strand is the one read by RNA Polymerase
What is the difference between a phospholipid bilayer & a cell membrane?
Bilayer = phospholipids only
Membrane = lipids, proteins & carbs
What role does the sigma factor play in prokaryotes?
Helps RNA polymerase bind to promoters
What is an allosteric inhibitor?
A molecule that binds away from the active site, changes enzyme shape
Why is ATP synthase not a primary active transporter?
It uses H+ gradient (Facilitated diffusion)
What is the difference between DNA Polymerase & RNA Polymerase
DNA Pol replicates DNA (needs a primer)
RNA Pol transcribes RNA (no primer)
What is one difference between yeast & E. coli?
Yeast has some membrane bound organelles
E.coli does not
What is one key difference in gene expression between prokaryotes & eukaryotes?
Prokaryotes couple transcription & Translation
Eukaryotes do this separately
Why would Valine, not Glutamate, be in the lipase active site?
Valine is non-polar, matches hydrophobic lipid substrate
Why might a cell down-regulate glycolysis when ATP is high?
To store glucose instead (glycogen/starch)
During transcription initiation in prokaryotes, what are the names of the two consensus sequences in the promoter?
The -10 box and -35 box