Charlotte Jakes
Quiz por , criado more than 1 year ago

Nutrition and Metabolism Quiz sobre Glycogen Synthesis and Regulation, criado por Charlotte Jakes em 30-12-2019.

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Charlotte Jakes
Criado por Charlotte Jakes mais de 4 anos atrás
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Glycogen Synthesis and Regulation

Glycogen Synthesis and Regulation

Questão 1 de 48

1

Why is there glycogen in the liver?

Selecione uma das seguintes:

  • Glucose homeostasis

  • The liver's only source of glucose

  • Gluconeogenesis

  • Gives structural support to hepatocyte membranes

Explicação

Questão 2 de 48

1

Which is correct of glycogen in the liver?

Selecione uma das seguintes:

  • Anabolism initiated by insulin
    Catabolism initiated by glucagon

  • Anabolism initiated by glucagon
    Catabolism initiated by insulin

Explicação

Questão 3 de 48

1

The only source of glucose to supply the muscles is the glycogen.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 4 de 48

1

Which linkages occur between adjacent glucose monomers in glycogen?

Selecione uma das seguintes:

  • a-1,4 links

  • a-1,6 links

Explicação

Questão 5 de 48

1

Which linkages occur between glucose monomers and their neighbouring molecules in branches in glycogen?

Selecione uma das seguintes:

  • a-1,4 links

  • a-1,6 links

Explicação

Questão 6 de 48

1

The enzymes at the beginning and/or end of a biosynthetic pathway will be tightly regulated.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 7 de 48

1

Why, in biosynthetic pathways, is at least one enzymatic reaction irreversible?

Selecione uma das seguintes:

  • To prevent accumulation of metabolites

  • More finer degree of control

  • To prevent unwanted by-products

  • To increase the rate of the pathway

Explicação

Questão 8 de 48

1

What is the first reaction in the synthesis of glycogen?

Selecione uma das seguintes:

  • Phosphorylation of glucose

  • Formation of UDP glucose

  • Addition of protein primer

  • Addition of UDP glucose

Explicação

Questão 9 de 48

1

Where is hexokinase present?

Selecione uma das seguintes:

  • All tissues

  • The liver only

  • The liver and pancreatic B cells

  • The liver and pancreatic a cells

Explicação

Questão 10 de 48

1

Glucokinase is present in the liver and pancreatic B cells only.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 11 de 48

1

Phosphorylation of glucose to glucose-6-phosphate is carried out by which enzyme(s)?

Selecione uma das seguintes:

  • Glucokinase or hexokinase

  • Glucose phosphorylase

  • Glucokinase only

  • Hexokinase only

Explicação

Questão 12 de 48

1

What is the role of phosphoglucomutase in glycogen synthesis?

Selecione uma das seguintes:

  • Isomerisation of glucose 6-phosphate to glucose 1-phosphate

  • Phosphorylation of glucose to glucose 6-phosphate

  • Phosphorylation of glucose to glucose 1-phosphate

  • Addition of UTP to glucose

Explicação

Questão 13 de 48

1

Which enzyme catalyses the formation of UDP glucose from UTP and glucose 1-phosphate?

Selecione uma das seguintes:

  • UDP-glucose pyrophosphorylase

  • UDP-glucose pyrophosphatase

  • UDP-glucose synthase

  • Gluco-UTPase

Explicação

Questão 14 de 48

1

What is the structure of uridine triphosphate (UTP)?

Selecione uma das seguintes:

  • Ribose, uracil and three phosphates

  • Deoxyribose, uracil and three phosphates

  • Ribose, uracil and two phosphates

  • Ribose, adenine and three phosphates

Explicação

Questão 15 de 48

1

What is a co-product of UDP glucose formation?

Selecione uma das seguintes:

  • PPi

  • Pi

  • UTP

  • ADP

Explicação

Questão 16 de 48

1

What does UTP react with on glucose 1-phosphate to form UDP glucose?

Selecione uma das seguintes:

  • The phosphate group of glucose 1-phosphate

  • The hydroxyl group of the 6th carbon

  • The hydroxyl group of the 2nd carbon

  • The hydrogen of the 3rd carbon

Explicação

Questão 17 de 48

1

What amino acid does glycogenin bind to in the protein primer?

Selecione uma das seguintes:

  • Tyrosine

  • Phenylalanine

  • Threonine

  • Glutamate

Explicação

Questão 18 de 48

1

Which carbon of UDP-glucose does tyrosine bind to in the protein primer?

Selecione uma das seguintes:

  • 1st

  • 2nd

  • 3rd

  • 6th

Explicação

Questão 19 de 48

1

When the tyrosine-glycogenin protein primer binds to UDP-glucose, UDP is cleaved off.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 20 de 48

1

Which enzyme catalyses the addition of the tyrosine-glycogenin primer to UDP-glucose causing the cleavage of UDP?

Selecione uma das seguintes:

  • Glucosyltransferase

  • Tyrosine transferase

  • Glycogenin synthase

  • UDP hydrolase

Explicação

Questão 21 de 48

1

How does the chain extend from glucose once it has been bound to the tyrosine-glycogenin primer?

Selecione uma das seguintes:

  • 1,4 linkages between primed glucose and UDP-glucose

  • 1,6 linkages between primed glucose and UDP-glucose

  • 1,4 linkages between primed glucose and primed UDP-glucose

  • 1,6 linkages between primed glucose and primed UDP-glucose

Explicação

Questão 22 de 48

1

Which statement is true of branching in glycogen?

Selecione uma das seguintes:

  • A portion of the long chain is moved to branch up and form 1,6 linkages

  • An initial 1,6 linkage is formed off the core chain and 1,4 linkages are formed from that

  • Branching requires another primed UDP-glucose molecule

  • Branching does not require UDP glucose, only regular glucose

Explicação

Questão 23 de 48

1

Preencha os espaços em branco para completar o texto.

Fill in the blanks below to summarise the synthesis of glycogen.
1. First, is phosphorylated to . This is catalysed by or in the liver.
2. Then, is isomerised to . This is catalysed by .
3. reacts with to form , releasing in the process. This reaction is catalysed by .
4. The enzyme binds a protein primer in the form of the amino acid bound to to the 1st carbon of . This causes the cleavage of .
5. Additional monomers join via linkages in reactions catalysed by .
6. This process repeats to form a chain.
7. Portions of the core chain are transferred to form linkages with the chain itself to form branches.

Explicação

Questão 24 de 48

1

The active form of glycogen synthase is what?

Selecione uma das seguintes:

  • Not phosphorylated

  • Phosphorylated

Explicação

Questão 25 de 48

1

What enzyme do we require to activate glycogen synthase?

Selecione uma das seguintes:

  • Protein phosphatase

  • Protein kinase

Explicação

Questão 26 de 48

1

Insulin activates a protein phosphatase which dephosphorylates glycogen synthase to activate it.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 27 de 48

1

What happens first in glycogen breakdown?

Selecione uma das seguintes:

  • Phosphorylation of glycogen to release glucose 1-phosphate monomers

  • Phosphorylation of glycogen to release glucose 6-phosphate monomers

  • Transfer of branches onto the core chain

  • Cleavage of a-1,6 linkages

Explicação

Questão 28 de 48

1

What enzyme carries out the phosphorylation of glucose monomers in glycogen during breakdown?

Selecione uma das seguintes:

  • Glycogen phosphorylase

  • Glycogen phosphatase

  • Hexokinase

  • Glycogen hydrolase

Explicação

Questão 29 de 48

1

What does glycogen transferase do?

Selecione uma das seguintes:

  • Transfers glycogen chains onto the core chain leaving behind 1 branched monomer with a a-1,6 linkage

  • Transfers glycogen chains entirely onto the core chain

  • Isomerises glucose 1-phosphate to glucose 6-phosphate

  • Catalyses the hydrolysis of a-1,6 linkages

Explicação

Questão 30 de 48

1

Which enzyme cleaves a-1,6 linkages on glycogen?

Selecione uma das seguintes:

  • a-1,6-glucosidase

  • a-1,6-kinase

  • a-1,6-hydratase

  • a-1,6-catalase

Explicação

Questão 31 de 48

1

Glucose 1-phosphate from the breakdown of glycogen is converted to glucose 6-phosphate by phosphoglucomutase

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 32 de 48

1

Glucose-6-phosphate is only converted to glucose in the liver

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 33 de 48

1

Preencha os espaços em branco para completar o texto.

Fill in the blanks below to describe glycogen breakdown.
1. First, an phosphorylates glucose monomers to break their linkages and release them. This is catalysed by .
2. Then, glycogen are removed and added to the core chain by . This leaves behind a single branched glucose monomer with an linkage.
3. This linkage is broken by .
4. is isomerised to by .
5. In the liver, is converted to by the enzyme. The muscle does not have this enzyme, so its enters the pathway.

Explicação

Questão 34 de 48

1

The active form of glycogen phosphorylase is what?

Selecione uma das seguintes:

  • Phosphorylated

  • Not phosphorylated

Explicação

Questão 35 de 48

1

What enzyme do we require to activate glycogen phosphorylase?

Selecione uma das seguintes:

  • Protein kinase

  • Protein phosphatase

Explicação

Questão 36 de 48

1

By what mechanism is glycogen protein kinase activated?

Selecione uma das seguintes:

  • Secondary messenger with cAMP signalling

  • Secondary messenger with IP3 signalling

  • Increase in cytosolic Ca2+

  • Cytosolic receptor signalling

Explicação

Questão 37 de 48

1

Preencha os espaços em branco para completar o texto.

Adrenaline activates glycogen breakdown in the .
Glucagon activates glycogen breakdown in the .
Insulin activates glycogen breakdown in .

Explicação

Questão 38 de 48

1

Where does calcium released from the sarcoplasmic reticulum bind on glycogen phosphorylase kinase?

Selecione uma das seguintes:

  • Calmodulin domain

  • Histidine residues

  • Active site

  • Tyrosine residues

Explicação

Questão 39 de 48

1

What effect does calcium in muscle cells have on glycogen breakdown?

Selecione uma das seguintes:

  • Activates glycogen phosphorylase kinase to activate glycogen phosphorylase to initiate glycogen breakdown

  • Activates glycogen phosphorylase phosphatase to deactivate glycogen phosphorylase and prevent glycogen breakdown

Explicação

Questão 40 de 48

1

Why is it important that calcium can regulate glycogen breakdown in the muscles?

Selecione uma das seguintes:

  • Our muscles need energy to contract but we don't always need adrenaline and our blood glucose isn't always low

  • Provides more powerful contraction

  • Provides more resistance to fatigue

  • In case glycogen concentration is low

Explicação

Questão 41 de 48

1

What effect does AMP have on glycogen phosphorylase?

Selecione uma das seguintes:

  • Allosteric activation

  • Allosteric inhibiton

  • Competitive inhibition

  • Covalent activation

Explicação

Questão 42 de 48

1

Why is it important that AMP concentration regulates glycogen breakdown?

Selecione uma das seguintes:

  • High AMP indicates low ATP so glycogen breakdown is necessary

  • Provides more powerful contraction

  • AMP is present in all cells all the time

  • AMP can cross the cell membrane

Explicação

Questão 43 de 48

1

ATP is an allosteric inhibitor of glycogen phosphorylase.

Selecione uma das opções:

  • VERDADEIRO
  • FALSO

Explicação

Questão 44 de 48

1

Preencha os espaços em branco para completar o texto.

Fill in the blanks to describe each glycogen storage disease.
disease is caused by defective glucose 6-phosphatase.
disease is caused by defective lysosomal glycosidase.
disease is caused by defective glycogen phosphorylase.

Explicação

Questão 45 de 48

1

Which of the following are logical symptoms of Von Gierke's disease?

Selecione uma das seguintes:

  • Hypoglycaemia, lactic acidosis, enlarged liver

  • Accumulation of glycogen in lysosomes, muscle weakness, cardiac failure

  • Exercise intolerance, red/brown urine following excercise

Explicação

Questão 46 de 48

1

Which of the following are logical symptoms of Pompe's disease?

Selecione uma das seguintes:

  • Accumulation of glycogen in lysosomes, muscle weakness, cardiac failure

  • Hypoglycaemia, lactic acidosis, enlarged liver

  • Exercise intolerance, red/brown urine following exercise

Explicação

Questão 47 de 48

1

Which of the following are logical symptoms of McArdle's disease?

Selecione uma das seguintes:

  • Exercise intolerance, red/brown urine following exercise

  • Accumulation of glycogen in lysosomes, muscle weakness, cardiac failure

  • Hypoglycaemia, lactic acidosis, enlarged liver

Explicação

Questão 48 de 48

1

What causes red/brown urine following exercise in those with McArdle's disease?

Selecione uma das seguintes:

  • Myoglobin excretion due to muscle breakdown

  • Haemoglobin excretion due to vessel rupture in muscles

  • Myoglobin excretion due to use in respiration

  • Myoglobin excretion due to use in removal of lactate

Explicação

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