Lecture 11

Front 1

1. Is there storage for amino acids?

2. Why is this model good?

Back 1

1. No, amino acids are constantly turned over and degraded.

2. Eliminates damaged amino acids, regulation is easier and we can utilize amino acids for energy

Front 2

1. What are the two mechanisms of degradation?

2. Describe lysosome degradation.

3. Describe proteosome degradation.

Back 2

1. Lysosome and proteosome

2. Proteins bind to a ligand on the surface of the cell, fuse with a lysosome (pH of 5) and are broken down. Nonspecific.

3. Tagged with a marker which goes through a proteosome which chews up into approximately 8 parts; cytosol finishes up. Very specific.

Front 3

1. What is added to proteins to designate them as a proteosome?

2. What is the structure of a proteosome?

Back 3

1. Ubiquitin by ubiquitination. Note the protein needs at least four to be marked for destruction and ubiquitin is recycled, not destroyed.

2. Has caps and a middle section. Cleaving is done in the middle; caps are responsible for recognizing ubiquitinated proteins and unfolding them.

Front 4

1. What are some uses from the amino acids our body digests?

2. What is transamination?

Back 4

1. Carbon skeleton of glucose, acetyl-CoA, ketone bodies. NH3 is gotten rid of in the form of urea.

2. Transfer of amino group to alpha-keto acid. Typically amino is transferred to glutamate (important so waste excretion only has to recognize one molecule).

Front 5

1. What is oxidative deamination?

2. What is special about glutamate dehydrogenase?

Back 5

1. When glutamate is transformed to an alpha-keto acid by glutamate dehydrogenase. This is the way to get rid of them if too many.

2. Can use either NADH or NADPH

Front 6

1. What are the three molecules organisms can use to secrete excess nitrogen?

2. What are the basic inputs/outputs of the urea cycle?

Back 6

1. Urea, ammonia, uric acid.

2. Inputs are aspartate, ATP and bicarbonate, outputs are urea and fumarate.

Front 7

1. What is Kreb's bicycle?

Back 7

1. Fumarate (a product of the urea cycle) is needed by TCA. Forms sort of a bicycle looking dependency chart.

Front 8

1. How are essential amino acids acquired by our body?

2. How about the rest of the amino acids?

3. Is Vitamin C a vitamin for guinea pigs considering they can make it?

Back 8

1. We have to eat them.

2. Synthesized from common intermediates by a transamination reaction (most often the amino group from the glutamate is used).

3. No.

Front 9

1. What are the six major elements in living systems?

2. What are diazotrophs and why are they important?

3. Does nitrogen fixation take a lot or little of energy?

Back 9

1. CHNOPS

2. Marine cyanobacteria that fix nitrogen! Nitrogen is rare and hard to come by otherwise.

3. Very expensive.

Front 10

1. Why is anammox bacteria important?

Back 10

1. Used to be very difficult and expensive to get from ammonia to atmospheric nitrogen. Cost is reduced by 90% with anammox. Also are unique in that they have a membrane bound organelle ammoxosome to prevent N2H4 from evaporating.

Front 11

Describe the basic ways fat cells are ingested and get to the cells.

Back 11

Bile salts emulsify fats in small intestines to make it a mixed micelle. Lipases degrade tracylglycerols. Free fatty acids are absorbed by intestinal mucosa. Made back into triacylglycerols and packaged into chylomicrons. Goes through lymph, into blood. Broken down into FFA again and eventually absorbed into cells.

Front 12

1. Why do triacylglycerols give us lots of energy?

2. What do bile salts do?

Back 12

1. Very reduced, high energy/weight, relatively inert, water insoluble.

2. Increase solubility of fats, made from cholesterol derivatives. Surround the fats. Help fatty acids go into cells.

Front 13

1. How do pancreative lipases work?

2. What is I-FABP?

Back 13

1. Water soluble enzymes that can act on hydrophobic molecules at lipid water interface. Called interfacial activity.

2. Intestinal fatty acids binding protein which is found inside intestinal cells and binds fatty acids until converted back to TAGs

Front 14

1. What is the difference between chylomicron and albumin?

2. What is the composition of a lipoprotein?

3. What is a apolipoprotein?

Back 14

1. Chylomicrons transport TAGs, while albumin transports FAs.

2. Cholesterol, triacylglycerols, lipoproteins, phospholipids.

3. A lipoprotein when it is not associated with a lipoprotein.

Front 15

1. What is the order of fat transporters in density?

2. Which is bigger, chylomicrons or HDL?

Back 15

1. Chylomicrons to VLDL to IDL to LDL to HDL.

2. Chylomicrons

Front 16

1. Where do VLDL, IDL and LDL come from?

2. What is HDL?

Back 16

1. Synthesized in liver, transport endogenous lipids, from liver to tissues. Bad cholesterol.

2. Transports cholesterol (and other fats) from tissue back to liver

Front 17

1. What are TAGs broken down into?

2. What is the fate of our fatty acids?

3. What about the glycerol?

Back 17

1. Glycerol backbone and fatty acids.

2. Beta oxidation (most of our energy)

3. Recycled or enters glycolysis at DHAP.

Front 18

1. What is fatty acyl-CoA?

2. What is the fate of acyl CoA?

Back 18

1. Forms acyl-CoA from a fatty acid using two phosphates. Priming step to get ready for oxidation.

2. Either can be used to make ATP in mitochondria or to make membrane lipids

Front 19

1. What is the next step of beta oxidation?

2. Fatty acids are broken down in what units?

Back 19

1. Transported into the mitochondria. Regulatory step, it is committed after this. "Shuttle system"

2. Units of two carbons.

Front 20

What are the four steps of beta oxidation?

Back 20

1. Create a double bond between two carbons; dependent on FAD+.
2. Hydrate the double bond.
3. NAD+ dependent formation of a ketone.
4. C-C bond cleavage (loses two carbons)

Front 21

1. Where does beta oxidation take place?

2. What does it produce each round of beta oxidation?

3. Is beta oxidation exergonic or endergonic?

Back 21

1. Mitochondria.

2. 1 NADH, 1 FADH2 and 1 acetyl CoA (1 FADH2, 3 NADH, 1 GTP)

3. Exergonic.

Front 22

1. What causes problems in oxidation of fatty acids?

2. What are trans fats bad?

Back 22

1. Unsaturated have cis bonds instead of trans bonds. EH enzyme can't bond to these. So we need extra enzymes, isomerase and reductase.

2. Trans fats breakdown are a problem in digestion. Lipase doesn't work on them. In oxidation, this is breakdown for energy, not digestion.

Front 23

How are VLCF broken down?

Back 23

Oxidized in peroxisomes. VLCFs are less common. Peroxisomes output acetyle-CoA, entire beta oxidation happens inside.