5. Nutritional energy and role of ATP Flashcards
Energy sources that blood contains?
Glucose
Ketone bodies
Fatty acids
Lactic acid
Amino Acids
Energy sources:
Brain mostly uses..
Skeletal muscle mostly uses..
Liver mostly uses..
Heart mostly uses..
- Glucose
2,3, 4 Fatty acids
ATP formation = ?
- ADP + Pi <-> ATP (33 kJ/mol)
- ATP formation requires input of energy
- ATP -> ADP + Pi
- ADP -> AMP + Pi
- ATP -> AMP
How much ATP yield?
- 1 ATP
- 1 ATP
- 2 ATP
GE =? DE=? ME = ?
GE = gross energy (kj/gram)
DE = Digestible energy (kj/gram) (=GE-faeces). Amount of energy that is absorbed. (98,95, or93%)
ME = MEtabolizable energy (kj/gram) 9= DE - Urine & gas). What is left after accounting for energy in faeces and urine. Used to calculate caloric content.
How is GE measured? By what machine(s) and based on what principle?
GE (kj/gram) = total amount of heat released during oxidation (=combustion)
Bomb calorimeter: measure heat released during the burning of food
Bio calorimeter: animal + glucose, measure its heat production
Glucose is fully absorbed, thus same amount of heat released
Fat, protein, cho: how many kcal/gr?
cho: 4
Fat: 9
Protein: 4
GE is not the same/the same for animals and humans. In descending order of energy:
glucose
Maltose
Cellulose
Amylose
- Cellulose = amylose
- Maltosee
- Glucose
ME: same/not same for animals/humans?
Descending order of energy:
glucose
Maltose
Cellulose
Amylose
- Amylose
- Maltose
- Glucose
- Cellulose
How much energy is in ATP (kj/mol)?
33 kj/mol
There are two ways to form ATP by oxidation of nutrients. Name them + example.
2 ways:
Direct: substrate phosphorylation (anaerobic). Example: glycolysis
Indirect: oxidative phosphorylation (aerobic), mitochondria. Example: oxidation of metabolic fuels
Five ways ATP can be used?
- Endothermic (metabolic) reactions
- Linked to H+ gradient, and cellular transporters
- ABC transporters
- Metabolic trapping
- Protein regulation
How is ATP needed for endothermic reactions?
In an endothermic reaction, less energy than the activation energy is released when the new bond is formed.
Endothermic reactions proceed with overall 1 ATP used
How is ATP needed in transporting materials across cell membranes with generation of a proton gradient?
- Water = H+ (proton) + OH- (hydroxyl group). They do not have to come from the same compartment within a cell.
- Membrane ATPase uses H+ from inside and OH- from outside.
ATP -> ADP + P, releasing energy. - Excess H+ on outside is used for the sodium pump. Sodium is used for co-transport with substrates, or counter transport to get waste products outside of the cell. (e.g. amino acid absorption)
How is ATP needed in ABC transporters?
ABC-type transporters have to be phosphorylated to allow transport, which happens with ATP
How is ATP needed in metabolic trapping?
Phosphorylation of glucose (= gl-6-p) requires one ATP.
How is ATP needed in protein regulation?
Phosphorylation of the enzyme: may activate or inactivate the protein. Depends on the protein and where the phosphorylation takes place.
Requires ATP
How is creatin used in terms of ATP?
To store energy.
There are difficulties of storing a large excess of ATP in a cell.
ATP = used to phosphorylate creatin into creatin phosphate. That is a way to store energy. Dephosphorylation releases ATP again for contraction.
Oxidation of glucose: how much % efficiency?
35
What are 5 sphincters that border compartments of digestive tract from mouth to anus?
- Upper oesophagus sphincter
- Lower oesophagus sphincter
- Pylorus
- Ileal cecal valve
- Anal sphincter
Which sphincter borders the
1. Oesophagus
2. Small intestine
3. Stomach
4. Large intestine
- Upper oesophagus sphincter + lower
- Pylorus + ileal ecal valve
- Lower oesophageal sphincter + pylorus
- Ileal cecal valve + Anal sphincter
What nutrients are not digested by the brush border enzymes?
Fat + oils (simply absorbed)
Main determinant of the timespan of arrival of food components at the ileo-caecal valve after a meal?
The rate of gastric emptying. This can range to 1-5 hrs. Small intestinal passage rate is 1.5 hr and that’s it.
Assuming normal nutritional conditions, what is true with respect to anabolic and catabolic processes during the post absorptive phase of a meal?
There is always a net catabolic situation
(Catabolism: to break down, anabolism: to build up (think: anabolen))