Biochemistry Exam (Correct Answers)
What demographic is Type 1 diabetes most prevalent in? Correct AnswersChildren over
10 years HOWEVER this is not always the case. It can occur later on in life.
In Type 2 diabetes, what is a pre-diabetic situation? When is a diagnosis for type 2
given? Correct AnswersWhen the pancreas gets tires trying to keep the glucose under
control and the insulin starts to rise. Type 2 diagnosed when there is insulin resistance.
What does glucagon do? What does it cause? Correct AnswersCauses rapid
metabolism of energy sources into glucose. Causes high blood glucose levels.
What does Insulin do? Correct AnswersPromotes energy storage and therefore causes
lowering of the blood glucose levels. It also stimulates glycogen, lipid and protein
synthesis for storage.
What does somatostatin do? Correct AnswersInhibits release of islet hormones (like
insulin and glucagon).
Hyper glycaemia would encourage the release of what? Correct AnswersBeta cells of
pancreas release of insulin to lower blood glucose levels.
Hypo glycaemia would encourage the release of what? Correct AnswersAlpha cells of
pancreas release of glucagon to increase blood glucose levels.
What does insulin do in terms of regulating glycogenolysis, gluconeogenesis and
ketogenesis? Correct AnswersDownregulates
What is glycogenolysis? Correct AnswersThe breaking down of glycogen to glucose
and glucos-6-phosphate.
What is gluconeogenesis? Where does it occur mainly (2)? And what are its substrates
(4) Correct AnswersThe synthesis of glucose from non-carbohydrate precursors.
Gluconeogenesis mainly occurs in the liver and kidneys.
Its substrates are lactate, glycerol, glucogenic amino acids and ketogenic amino acids
(which we can't use and makes ketone bodies).
What does it mean when we say beta-cell regulation is 'multifaceted'? What are the 3
main regulators of insulin? Correct AnswersIt means many things, apart from lifestyle or
diet can affect it. tumour pushing on the pancreas can affect bet cell regulation. In these
cases, insulin can be over secreted or under secreted. Lifestyle and diet can be risks
but won't necessarily cause it. The three main regulators of insulin are amino acids, fatty
acids and glucose.
How does glycogen affect glycogenolysis, lipolysis and ketogenesis? Correct
AnswersUpregulates.
In a FED state, how is glucose affected? Correct AnswersGlucose is pushed through
glycolysis.
What is glycolysis? Correct AnswersThe breakdown of glycogen from the liver and
skeletal muscles to glucose.
Where is glycogen stored? Correct AnswersIn the liver and skeletal muscles.
What is the difference between hexokinase and glucokinase? What are their
similarities? What reaction do they catalyse? Correct AnswersHexokinase is available in
all cells whereas glucokinase is only in particular cells. (pancreas and liver). Hexokinase
cannot be stimulated and has a saturation level. Once saturation level is reached,
glucokinase deals with the glucose. Both catalyse glucose to glucose-6-phosphate in a
, non-reversible reaction. As they are both kinases, they need ATP. They are non-
reversible because they cause phosphorylation.
What 3 kinases create non-reversible synthesis of glucose from glycogen via
glycolysis? Correct AnswersHexokinase (or glucokinase), phosphofructokinase-1 and
pyruvate kinase.
What can inhibit hexokinase? Correct AnswersSaturation levels of glucose-6-
phosphate.
What is the difference between glycolysis and gluconeogenesis in their pathways? What
replaces them in the reverse pathway? Correct AnswersHexokinase (or glucokinase),
phosphofructokinase-1 and pyruvate kinase are non reversible and therefore in
gluconeogenesis are bypassed.
The gluconeogenesis reaction is the reversed of glycolysis, and pyruvate kinase is
replaced with mitochondrial pyruvate carboxylase with the vitamin biotin as the
coenzyme (still requires ATP).
Phosphofructokinase-1 in glycolysis which converts fructose-6-phosphate to fructose-
1,6-biphosphate is replaced with fructose-1,6-biphosphotase which does the opposite in
gluconeogenesis (catalyses fructose-1,6-biphosphate to fructose-6-phosphate.
The conversion of glucose to glucose-6-phosphate in glycolysis which is catalysed by
hexokinase (or glucokinase after saturation of glucose-6-phosphate is reached) is
replaced with glucose-6-phosphotase in gluconeogenesis to produce glucose.
What is fructose-1,6-biphosphotase, what does it determine and where is it present?
Correct AnswersFructose-1,6-biphosphotase determines whether a tissue can catalyse
glucose (or glycogen) from pyruvate in gluconeogenesis. If so, it catalyses fructose-1,6,-
biphosphate to fructose-6-phosphate. Present in liver, kidneys and skeletal muscle.
What is GLUT 2 and GLUT 4? What are the differences between GLUT 2 and GLUT 4?
Correct AnswersGLUT 2 and GLUT 4 are both glucose transporters (carrier trans-
membrane proteins). GLUT 2 is fast acting and is not affected by insulin. It responds to
glucose receptors in the level when there is high BGL. It causes the rapid uptake and
release of glucose into cells. It is located in the liver, pancreatic beta cells, small
intestine and kidneys. GLUT 4 is insulin stimulated and also promoted the uptake of
glucose by the cells. Found in the adipocytes, heart and skeletal muscles.
What happens when insulin binds to a receptor in the cell membrane (not in the liver)?
Correct Answers1) Activated receptor (activated by the binding of insulin to the insulin
receptor on the membrane) promotes the glucose transporters to come from the
intracellular pool (inside the cell) and attach to the cell membrane.
2) The Glucose transporters increase the insulin-mediated uptake of glucose into the
cell (GLUT 4), meaning glucose comes into the cell through them.
3) Once the insulin levels decrease, the glucose transporters are taken back by the cell
into the intracellular storage pool again where they can be recycled.
4) Vesicles with the transporters fuse to form an endosomes and the transporters wait in
the cytosol to be utilised again.
What is the bifunctional enzyme, fructose-2,6-biphosphate? Correct AnswersLocated in
the cytosol of liver cells, it forms when phosphorylated i.e. when there is high blood
glucose levels outside the cell and lots of insulin trying to bring that glucose into the cell.
What demographic is Type 1 diabetes most prevalent in? Correct AnswersChildren over
10 years HOWEVER this is not always the case. It can occur later on in life.
In Type 2 diabetes, what is a pre-diabetic situation? When is a diagnosis for type 2
given? Correct AnswersWhen the pancreas gets tires trying to keep the glucose under
control and the insulin starts to rise. Type 2 diagnosed when there is insulin resistance.
What does glucagon do? What does it cause? Correct AnswersCauses rapid
metabolism of energy sources into glucose. Causes high blood glucose levels.
What does Insulin do? Correct AnswersPromotes energy storage and therefore causes
lowering of the blood glucose levels. It also stimulates glycogen, lipid and protein
synthesis for storage.
What does somatostatin do? Correct AnswersInhibits release of islet hormones (like
insulin and glucagon).
Hyper glycaemia would encourage the release of what? Correct AnswersBeta cells of
pancreas release of insulin to lower blood glucose levels.
Hypo glycaemia would encourage the release of what? Correct AnswersAlpha cells of
pancreas release of glucagon to increase blood glucose levels.
What does insulin do in terms of regulating glycogenolysis, gluconeogenesis and
ketogenesis? Correct AnswersDownregulates
What is glycogenolysis? Correct AnswersThe breaking down of glycogen to glucose
and glucos-6-phosphate.
What is gluconeogenesis? Where does it occur mainly (2)? And what are its substrates
(4) Correct AnswersThe synthesis of glucose from non-carbohydrate precursors.
Gluconeogenesis mainly occurs in the liver and kidneys.
Its substrates are lactate, glycerol, glucogenic amino acids and ketogenic amino acids
(which we can't use and makes ketone bodies).
What does it mean when we say beta-cell regulation is 'multifaceted'? What are the 3
main regulators of insulin? Correct AnswersIt means many things, apart from lifestyle or
diet can affect it. tumour pushing on the pancreas can affect bet cell regulation. In these
cases, insulin can be over secreted or under secreted. Lifestyle and diet can be risks
but won't necessarily cause it. The three main regulators of insulin are amino acids, fatty
acids and glucose.
How does glycogen affect glycogenolysis, lipolysis and ketogenesis? Correct
AnswersUpregulates.
In a FED state, how is glucose affected? Correct AnswersGlucose is pushed through
glycolysis.
What is glycolysis? Correct AnswersThe breakdown of glycogen from the liver and
skeletal muscles to glucose.
Where is glycogen stored? Correct AnswersIn the liver and skeletal muscles.
What is the difference between hexokinase and glucokinase? What are their
similarities? What reaction do they catalyse? Correct AnswersHexokinase is available in
all cells whereas glucokinase is only in particular cells. (pancreas and liver). Hexokinase
cannot be stimulated and has a saturation level. Once saturation level is reached,
glucokinase deals with the glucose. Both catalyse glucose to glucose-6-phosphate in a
, non-reversible reaction. As they are both kinases, they need ATP. They are non-
reversible because they cause phosphorylation.
What 3 kinases create non-reversible synthesis of glucose from glycogen via
glycolysis? Correct AnswersHexokinase (or glucokinase), phosphofructokinase-1 and
pyruvate kinase.
What can inhibit hexokinase? Correct AnswersSaturation levels of glucose-6-
phosphate.
What is the difference between glycolysis and gluconeogenesis in their pathways? What
replaces them in the reverse pathway? Correct AnswersHexokinase (or glucokinase),
phosphofructokinase-1 and pyruvate kinase are non reversible and therefore in
gluconeogenesis are bypassed.
The gluconeogenesis reaction is the reversed of glycolysis, and pyruvate kinase is
replaced with mitochondrial pyruvate carboxylase with the vitamin biotin as the
coenzyme (still requires ATP).
Phosphofructokinase-1 in glycolysis which converts fructose-6-phosphate to fructose-
1,6-biphosphate is replaced with fructose-1,6-biphosphotase which does the opposite in
gluconeogenesis (catalyses fructose-1,6-biphosphate to fructose-6-phosphate.
The conversion of glucose to glucose-6-phosphate in glycolysis which is catalysed by
hexokinase (or glucokinase after saturation of glucose-6-phosphate is reached) is
replaced with glucose-6-phosphotase in gluconeogenesis to produce glucose.
What is fructose-1,6-biphosphotase, what does it determine and where is it present?
Correct AnswersFructose-1,6-biphosphotase determines whether a tissue can catalyse
glucose (or glycogen) from pyruvate in gluconeogenesis. If so, it catalyses fructose-1,6,-
biphosphate to fructose-6-phosphate. Present in liver, kidneys and skeletal muscle.
What is GLUT 2 and GLUT 4? What are the differences between GLUT 2 and GLUT 4?
Correct AnswersGLUT 2 and GLUT 4 are both glucose transporters (carrier trans-
membrane proteins). GLUT 2 is fast acting and is not affected by insulin. It responds to
glucose receptors in the level when there is high BGL. It causes the rapid uptake and
release of glucose into cells. It is located in the liver, pancreatic beta cells, small
intestine and kidneys. GLUT 4 is insulin stimulated and also promoted the uptake of
glucose by the cells. Found in the adipocytes, heart and skeletal muscles.
What happens when insulin binds to a receptor in the cell membrane (not in the liver)?
Correct Answers1) Activated receptor (activated by the binding of insulin to the insulin
receptor on the membrane) promotes the glucose transporters to come from the
intracellular pool (inside the cell) and attach to the cell membrane.
2) The Glucose transporters increase the insulin-mediated uptake of glucose into the
cell (GLUT 4), meaning glucose comes into the cell through them.
3) Once the insulin levels decrease, the glucose transporters are taken back by the cell
into the intracellular storage pool again where they can be recycled.
4) Vesicles with the transporters fuse to form an endosomes and the transporters wait in
the cytosol to be utilised again.
What is the bifunctional enzyme, fructose-2,6-biphosphate? Correct AnswersLocated in
the cytosol of liver cells, it forms when phosphorylated i.e. when there is high blood
glucose levels outside the cell and lots of insulin trying to bring that glucose into the cell.
