Lecture 12 Energy Flashcards
what do glucose, fructose, and galactose have in common?
all hexose sugars
all can be phosphorylated
all interconvertible
What does delta G equal in normal conditions in the body?
-12,000 cal/mol
how is glucose uptaken?
active sodium-glucose co-transport against [ ] gradient
facilitated diffusion from higher to lower [ ]
what does the presence of insulin do?
increases glucose transport 10x
where can phosphorylation be reversed?
liver, renal, intestinal cells
What does glucokinase do?
converts glucose to G6P
what does phosphatase do?
converts G6P to glucose
what does phosphorylase do?
converts glycogen to G1P
what factors activate phosphorylase and from where?
Epi from adrenal medulla
glucagon from alpha cells in pancreas
what is the effect of phosphorylase?
promotes the conversion of glycogen to glucose
glucose can be released into the blood
what are the end products of glycolysis?
2 ATP
2 pyruvic acid
4 H+
what are the end products of pyruvic acid –> acetyl-CoA
2 acetyl-CoA
2 CO2
4 H+
where does the citric acid cycle occur?
mitochondrial matrix
what are the end products of the citric acid cycle?
2 ATP
4 CO2
16 H+
where does Ox Phos occur?
mitochondrial cristae
where do electrons removed from hydrogen ions end up?
ETC
What are the major components of the ETC
flavoprotein
iron sulfide proteins
ubiquinone (q)
cytochrome A3
how many ATPs are formed per glucose and where do they come from?
38 total
2 ATP from glycolysis
2 ATP from CAC
34 ATP from ox phos
what is the glucose efficiency?
66%
456,000 cal/mol
For every 6 molecules of glucose that enter the pathway, how many are resynthesized?
5
what is this pathway mostly used for?
what is the major H+ carrier?
synthesis of fats and carbs
NADP+
when there is excess glucose in ________ , it is broken down by the pentose phosphate pathway
the liver
What is the net reaction of the pentose phosphate pathway?
Glucose + 12NADP+ + 6H20 –> 6CO2 + 12H + 12NADPH
most triglycerides are digested into what?
monoglycerides and fatty acids
what resythesizes these into triglyercides that will enter the lymph as chylomicrons?
intestinal epithelial cells
what is absorbed to the chylomicron surfaces?
apoprotein B
how are chylomicrons transported?
thoracic duct to venous system
what tissue removes chylomicrons from the blood?
adipose, skeletal, heart
what does lipoprotein lipase do?
hydrolyzes chylomicron triglycerides, releasing fatty acids and glycerol
what conditions increase utilization of fat for energy?
diabetes mellitus
starvation
what lipoproteins are synthesized by the liver?
VLDLs
IDLs
LDLs
HDLs
10 NADH produces how many H+ and how many ATP?
20 H+
30 ATP
2 FADH2 produces how many H+ and ATP?
4 H+ and 4 ATP
what do lipoproteins do?
transport lipids in the blood
what are vldls made of?
Where do they transport lipids?
high [ ] of triglycerides, some cholesterol and phospholipids
from liver to adipose tissue
what are LDLs made of
high cholesterol, moderate [phospholipids]
what are HDLs made of?
high [proteins], low [cholesterol] and [fatty acids]
which 2 types of cells do not use fatty acids for energy?
brain cells
RBCs
fatty acids are converted to ______ in the _____?
This process is called what?
acetyl-CoA
mitochondria
Called Beta-oxidation
what is used as a carrier molecule into the mitochondria?
carnitine
how does acetyl-CoA enter the CAC?
by binding to oxaloacetic acid
what are the products from beta oxidation of one molecule of stearic acid?
9 acetyl-CoA
146 ATP
what are 3 ketone bodies?
acetoacetic acid, acetone, Beta-hydroxybutyric
ketone bodes diffuse back into cells and are converted to what?
acetyl-CoA
what conditions favor ketosis?
fatty diet
starvation
diabetes
Synthesis of fatty acids is a 2 step process that requires what?
malonyl-CoA and NADPH
fat contains how much energy compared to carbs?
2.5x as much
Give the steps to the development of atherosclerotic plaque!
- Damage to vascular endothelium
- Monocytes and LDLs accumulate at injury site
- Monocytes cross endothelium and enter intima
- Macrophages ingest lipoproteins and become foam cells
- Fatty streaks develop and grow larger
- Surrounding fibrous and smooth m. tissue proliferates and forms large plaques
what are the basic causes of athersclerosis?
increased LDLs
familial hypercholesterolemia
What may be able to absorb cholesterol crystals that are being deposited into the arterial walls?
HDLs
