Exam 4 Flashcards
What happens to most of the glucose-6-phosphate in liver versus muscle tissue?
In the muscle it is used for energy, in liver it is converted to glucose to be transported in the blood to other cells. It can be converted back to glycogen in the muscle and liver if not needed
What hormone is released from the pancreas in response to low blood glucose levels?
glucagon
T/F Insulin can enter the cell but glucagon cannot
False
The hydrolysis of ATP is: ATP ADP + ? + 7kcal/mole. What is the missing product?
inorganic phosphate (Pi)
Where does gluconeogenesis take place?
liver
What effect does insulin have on gluconeogenesis?
inhibits
What is the final product of glycolysis in humans in anaerobic conditions?
lactic acid
T/F The rate of glycolysis decreases when the cell’s ATP concentration is high
True
What hormone or hormones will stimulate glycogenolysis in muscle?
only epinephrine
What compounds can be converted into new glucose in gluconeogenesis?
gylcerol, lactic acid, and some amino acids
What two enzymes are needed by a yeast cell to convert pyruvic acid to ethanol?
decarboxylase and dehydrogenase
Why are there no receptor sites on muscle for glucagon?
Glycogen in the muscle is only for the muscle and is not affected by low blood sugar
What hormone is called “The famine hormone”
glucagon
What functional group or groups are found in a pyruvic acid molecule?
ketone and carboxylic acid
Which of these hormones cannot get into the cell?
insulin, glucagon, and epinephrine
The enzyme for step 9 in glycolysis is called “Enolase”. What type of enzyme is this?
lyase
T/F Without oxygen, a cell cannot do gycolysis
False
When glucagon affects a liver cell, a phosphate is attached to both glycogen synthetase and glycogen phosphorylase. Which enzyme is activated?
glycogen phosphorylase
Where does gluconeogenesis occur?
only liver
Which statement concerning glycogenolysis is FALSE?
It is activated by the secretion of insulin into the bloodstream
Where does glucose to CO2 + H2O take place?
all cells
What hormone or hormones will stimulate entry of glucose into the muscle?
only insulin
T/F Glucose-6-phosphate (in glycolysis) is always converted into pyruvic acid in both liver and muscle
False
What type of enzyme catalyzes step 2 of glycolysis?
mutase
T/F Digestion cannot take place within a cell
True
Where is galactose converted to glucose?
liver
T/F the main source of energy for the liver is glycolysis of its own glycogen
False
What type of enzyme catalyzes step 6 of glycolysis?
dehydrogenase
What process converts glycerol to glucose?
gluconeogenesis
What reaction in step 6 of glycolysis is endothermic?
synthesis of a phosphate ester from inorganic phosphate
Which is true of fatty acids?
They can be stored in adipose tissue as triglycerides. They cannot be used by the brain for energy because of the blood/brain barrier and they cannot be used by red blood cells for energy because they have no mitochandria.
How much ATP is produced from glycolysis of 2 glucose molecules?
4 ATP
Where is insulin made?
pancreas
Glycogenesis occurs under which of the following conditions
When digestion of polysaccharides provides high levels of blood glucose
Why is pyruvic acid converted to lactic acid in muscle cells doing anerobic work?
To convert NADH back to NAD and muscle cell can only do glycolysis in these conditions, and needs more oxidizing agent for step 6
Which statements about glycolysis are correct?
It is found in the cytoplasm, all cells can do it, muscles will do a lot of glycolysis during strenuous exercise and it occurs in aerobic and anaerobic conditions
T/F Fructose needs two phosphates on it before entering step 4 of glycolysis, so that each 3 carbon product will contain a phosphate
True
Which statements are true concerning the reaction: glucose-1-phosphate to glycogen?
the enzyme needed is glycogen synthetase and the energy needed to synthesize glycogen comes from breaking the high energy phosphate bond on glucose
Where does glycogen to glucose take place?
only liver and muscle cells
What is the starting point of glycolysis in a red blood cell?
glucose
Which is the highest energy compound?
ATP
Which cells need insulin to help the passage of glucose into the cell?
liver, muscle, and adipose tissue
T/F The rate of glycolysis decreases when the cell’s ATP concentration is high
True
Which of the following is a possible “fate” of pyruvic acid in humans?
conversion to acetyl-CoA and reduction to lactic acid in muscle
What effect does insulin have on entry of glucose into a red blood cell?
have no effect
How does glucose accumulate in the liver for storage?
active transport
Where is the energy coming from to convert fructose-6 phosphate + P1 to fructose-1,6 bisphosphate in step 3 of glycolysis?
The hydrolysis of ATP to ADP + P1 which is exothermic
What hydrolysis product of fat digestion can enter the glycolysis pathway?
glycerol
What effect does insulin have on glycogenesis?
activates
Where is glucagon made?
pancreas
What hormone or hormones will inhibit gluconeogenesis?
only insulin
What type of enzyme catalyzes step 8 of glycolysis?
mutase (isomerase)
What type of enzyme catalyzes step 7 of glycolysis?
kinase
T/F Oxidation reactions produce energy, which can be used to drive an endothermic reaction.
True
What is the “starting point” of glycolysis for muscle?
muscle glycogen and blood sugar after its own glycogen is used up
T/F glucagon will activate triglyceride hydrolysis in adipose tissue.
True