Exam 1 – Lecture 4: Dr. Langston Flashcards
What is ATP?
The energy currency of the body
What exists after the digestion of carbohydrates?
Glucose
Fructose
Galactose
What is fructose?
A monosaccahride that is quickly converted to glucose in the liver
What is galactose converted to? Where?
Glucose in the liver
What is glucose?
The final common substrate for transport of carbohydrates to the cells
What do intestinal and renal tubules use active transport for?
Absorbing glucose
What do cells other than intestinal and renal tubules use to absorb glucose?
Facilitated diffusion
What does insulin do?
Increase the rate of facilitated diffusion 10x
Do the liver and brain require insulin for glucose transport?
No
What are neurons and RBCs primarily dependent on as their energy source?
Glucose
What can the brain use to meet energy demands during starvation?
Keto-acids
What are the steps to aerobic conversion of glucose to energy?
Glucose is split into pyruvic acid and then move to the krebs cycle to produce ATP, H, and NADH
What does each glucose molecule produce when it is converted to energy?
38 ATP with CO2 and water
What is an alternate pathway for conversion of glucose to energy independent of TCA cycle?
Pentose phosphate pathway
What is the pentose phosphate pathway especially important in?
The liver and synthesis of fat
Can glycolysis occur without oxygen?
Yes
How can glycolysis occur without oxygen?
Glucose is converted to pyruvic acid which is then converted to lactic acid which is what allows it to continue
What would the “law of mass action” cause?
Stop glycolysis if pyruvic acid accumulated
When oxygen is restored, what happens to lactate?
It is converted back to pyruvic acid
Where does the conversion of lactate back to pyruvic acid occur?
In the liver and heart muscle
What does tying up come from in horses?
The large amounts of lactate that the animal produces
What is consumed by the Cori cycle to convert 2 pyruvates back to glucose
6 ATP
What are small amounts of lactate metabolized into? Where?
Bicarbonate ion
Liver
What can severe lactate accumulation cause?
Metabolic acidosis
What can the liver do with small quantities of lactate?
Generate a carbon ion
What can happen to glucose if not stored immediately?
It can be stored as glycogen, especially in the liver and muscle
What is special about glycogen because of its high molecular weight?
It does not disrupt the osmolarity of the cell
How much glycogen does the body keep in reserve?
About 1-2 days worth
What can muscle store energy in?
Phosphocreatinine
What is unique to phosphocreatinine when compared to ATP?
It contains more energy per molecule
How can phosphocreatinine be released?
Immediately when needed for maximal short bursts of muscle power
What does the use of phosphcreatinine lead to?
Waste product of creatinine
What is creatinine excreted by?
Kidney
What does the brain need in particular?
Glucose
When blood glucose is low, how is glucose obtained?
Gluconeogenesis
What does gluconeogenesis do?
Creates glucose from non-carbohydrate sources
What makes ruminant unique when it comes to making glucose?
They can use propionic acid
How much can volatile fatty acids contribute to energy demands in ruminants?
80%
What can be used as substrates for gluconeogenesis in non-ruminants?
Protein and fats
What percentage of amino acids can be converted to glucose?
About 60%
What can fats do to produce glucose?
They can be broken down into glycerol and fatty acids, with the glycerol converted to glucose
What normally happens to fatty acids?
They are broken down to 2-carbon segments to form acetyl-CoA that enters glycolytic pathways
When does keto-acidosis occur?
When no available carbohydrate exists to recharge oxaloacetate required to bind with acetyl-CoA
What can cause keto-acidosis?
Starvation
High fat, low carb diets
Diabetes mellitus
What are the 3 main keto-acids?
Acetoacetic acid
Acetone
β-Hydroxybutyric acid
What do brown fat deposits contain?
Mitochondria
What can brown fat, via mitochondria, generate?
Thermogenesis
Why is brown fat important in puppies and kittens?
Because they cannot yet shiver to generate heat
What happens if puppies are hypoglycemic and stop nursing?
They no longer have brown fat, so they become hypothermic
What does the catabolism of brown fat for heat generation require?
Glucose
When are proteins used as energy?
Insufficient glucose exists
Excess proteins in the diet
What can proteins be converted to?
Glucose
Fatty acids
What can protein catabolism be used in?
Gluconeogenesis or ketogenesis
What does the microfloral of the rumen do?
Creates all essential and non-essential amino acids
What can ruminants use to create amino acids by their rumen flora?
Non-protein nitrogen
What do cats and some Cocker Spaniels need in their diet? Why?
Greater amount of taurine
To avoid cardiomyopathy
How is CO2 from glycolytic pathways expired?
By the lung via bicarbonate buffer system
What is NH3 from protein catabolosm converted to? How is that excreted?
Coverted by the liver to urea and excreted by the kidney
What is creatinine produced by? How is it excreted?
Muscle metabolism
Kidney
How do aquatic animals excrete ammonia? Why?
Directly
Water is abundant
What is urea the main route of in mammals and sharks?
Nitrogen excretion
What do insects, birds, and reptiles convert ammonia to? Hos is it secreted?
Uric acid
As paste
What is unique about Dalmatians and excretion?
They have a build up of uric acid which causes kidney stones and the blocks the excretion. They must have surgery to create a hole to allow for excretion
