Thompson 1 Flashcards
In ATP, which bonds are ‘high energy’ and what type of bond are they?
Phosphoanhydride bonds between alpha/beta and beta/gamma phosphates.
(The phosphoester bond between the alpha phosphate and adenosine releases about half as much energy)
Give a general overview of how the TCA cycle and oxidative phosphorylation turn food into energy.
Most of the carbons from our diet are ultimately converted to Acetyl CoA. In the TCA cycle, Acetyl CoA is oxidized (to CO2) and NAD+ and FAD are reduced to NADH and FADH2. The electrons gained by NADH and FADH2 are transferred to O2 by the ETC, and ATP is produced from this electron transfer through oxidative phosphorylation.
Phosphoenolpyruvate, 1,3-BPG, and ATP (among others) are good phosphate donors because…?
…their standard free energy of hydrolysis (the energy released when their phosphate group is hydrolyzed) is greater (more negative) than the compounds that receive them. I.e., they have a greater phosphoryl transfer potential.
In metabolism, coupling energetically unfavorable reactions with _____ is a common way to make them energetically favorable.
Hydrolysis of ATP
Reducing agents ____ electrons and become _____. Oxidizing agents ______ electrons and become ______.
Donate, oxidized; Receive, reduced
Oxidation of biological carbon atoms is done through _______.
Dehydrogenation (loss of electrons tied to hydrogen atoms)
The C1 carbon of cyclic sugars is known as the ______ and has a free _____ in reducing sugars.
anomeric carbon, hydroxyl group
Where do glycosidic bonds occur on amino acids?
OH of serine, N of asparagine
Plants store glucose as polymers called _____ which utilize ______ linkages.
Amylose, alpha 1-4
Amylopectin is a polymer of glucose with alpha 1-4 linkages and branches created by alpha 1-6 bonds
Why is amylopectin more soluble than amylose (why is it broken down faster)?
Its alpha 1-6 linkages create branch points and therefore many reducing ends on the molecule. Amylose only has one reducing end.
How do SGLT proteins transport glucose from the intestinal lumen into the mucosa?
Secondary active transport. Na-K pumps create a sodium concentration gradient with more Na outside of the cell and glucose hitches a ride with sodium as it travels down its gradient. (SGLT = Sodium GLucose coTransporter)
Which glucose transporter is responsible for the baseline (basal) level of glucose uptake required to sustain respiration in most tissues?
GLUT 1
_____ is a bidirectional transporter found in the basolateral membrane of small intestinal epithelial cells, in liver cells, and in pancreatic beta cells. All three monosaccharides (glucose, galactose and fructose) are transported from the intestinal mucosa into the portal circulation by it.
GLUT 2
____ is a high-affinity glucose transporter found mostly in neurons, where it can transport glucose even when concentrations are low.
GLUT 3
______ is the glucose transporter found in striated muscle (cardiac and skeletal) and adipose tissue.
GLUT 4
