Biochemistry Glycolysis and Reactions Quiz

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Questions and Answers

What is produced along with pyruvate during aerobic metabolism?

Lactate

Eight ATP molecules (correct)

Triglycerides

Two ATP molecules

Which enzyme secreted in saliva initiates the digestion of carbohydrates?

Lipase

Amylase (correct)

Protease

Glycogenase

During anaerobic metabolism in muscles, what is the final product generated?

Pyruvate

Lactate (correct)

ATP

Fatty acids

Which of the following fates of glucose produces the least amount of ATP?

Anaerobic glycolysis Signup and view all the answers

What is the primary role of mitochondria in aerobic metabolism?

To convert glucose to pyruvate and ATP Signup and view all the answers

What is the primary product formed after the conversion of 1,3-bisphosphoglycerate?

3-phosphoglycerate Signup and view all the answers

Which enzyme is responsible for the conversion of 1,3-bisphosphoglycerate in glycolysis?

Phosphoglycerate kinase Signup and view all the answers

How many molecules of ATP are produced per cycle during this step of glycolysis?

1 Signup and view all the answers

What happens to the phosphate group lost from 1,3-bisphosphoglycerate during the reaction?

It is transferred to ADP, forming ATP Signup and view all the answers

What is the net ATP yield at the end of glycolysis after accounting for the ATP used?

0 ATP Signup and view all the answers

Why is this step of glycolysis considered a substrate-level phosphorylation?

It occurs without the aid of an electron transport chain Signup and view all the answers

What is the significance of producing two glyceraldehyde-3-phosphate molecules at this stage?

They allow for the completion of glycolysis Signup and view all the answers

What is the reason for the reversible nature of the reaction converting 1,3-bisphosphoglycerate to 3-phosphoglycerate?

To allow alternate pathways for glucose metabolism Signup and view all the answers

What type of reaction converts D-glucose into D-arabinose while incorporating an amino group?

Interconversion process Signup and view all the answers

Which product is formed from the osazone reaction involving aldose?

Osazone crystal Signup and view all the answers

What is the other name for sucrose?

Table sugar Signup and view all the answers

Which of the following statements about sucrose is true?

It is a non-reducing sugar. Signup and view all the answers

Which disaccharide is referred to as malt sugar or beer sugar?

Maltose Signup and view all the answers

Which reaction involves the addition of oxygen or removal of hydrogen from a molecule?

Oxidation reaction Signup and view all the answers

What type of linkage allows for the digestion of maltose by humans?

Alpha-1,4-linkages Signup and view all the answers

Which of the following compounds is classified as an amino sugar?

Mannosamine Signup and view all the answers

What occurs during the reduction reaction?

Addition of hydrogen to a molecule Signup and view all the answers

Which substance can contain up to 20% by mass of sucrose?

Sugar cane Signup and view all the answers

What is the primary enzyme responsible for breaking down starches in the mouth?

Ptyalin Signup and view all the answers

What is the product formed during the phosphorylation of fructose-6-phosphate?

Fructose-1,6-bisphosphate Signup and view all the answers

Which enzyme acts as the rate-limiting factor during the phosphorylation process in glycolysis?

Phosphofructokinase (PFK) Signup and view all the answers

What is the role of ATP in the phosphorylation of fructose-6-phosphate?

To donate a phosphate group to fructose-6-phosphate Signup and view all the answers

Which metabolic pathway can fructose-1,6-bisphosphate exclusively enter?

Glycolysis Signup and view all the answers

What happens to excess glucose in the body?

It is converted into glycogen Signup and view all the answers

What is required for the activity of phosphofructokinase (PFK)?

Mg2+ ions Signup and view all the answers

What characterizes the reaction during phosphorylation of fructose-6-phosphate?

It is irreversible Signup and view all the answers

What is produced during the oxidation and decarboxylation of alpha-ketoglutarate?

NADH and CO2 Signup and view all the answers

What inhibits the alpha-ketoglutarate dehydrogenase complex?

Succinate Signup and view all the answers

What is the outcome of the reaction catalyzed by succinyl CoA synthetase?

Formation of succinate and GTP Signup and view all the answers

Which component acts as an electron acceptor during the alpha-ketoglutarate oxidation?

NAD+ Signup and view all the answers

What type of pathway is the citric acid cycle classified as?

Aerobic pathway Signup and view all the answers

What does the term 'substrate-level phosphorylation' refer to in the context of the citric acid cycle?

Direct generation of GTP from GDP Signup and view all the answers

Which enzyme is responsible for the conversion of alpha-ketoglutarate to succinyl CoA?

Alpha-ketoglutarate dehydrogenase Signup and view all the answers

How does alpha-ketoglutarate dehydrogenase resemble pyruvate dehydrogenase?

Both produce NADH. Signup and view all the answers

Which product is obtained after the cleavage of succinyl CoA?

GTP Signup and view all the answers

What role does calcium play in the activity of the alpha-ketoglutarate dehydrogenase complex?

Calcium activates the complex. Signup and view all the answers

Study Notes

Glycolysis - Step 5

1,3-biphosphoglycerate is converted to 3-phosphoglycerate
enzyme: phosphoglycerokinase
loss of phosphate group from 1,3-biphosphoglycerate
phosphate is transferred to ADP, yielding the first ATP in this process
two ATPs are produced as there are two molecules of 1,3-biphosphoglycerate
this is a substrate-level phosphorylation where ATP is produced without the electron transport chain

Lobry de Bruyn Degradation

interconversion or transformation from aldose to ketose or from ketose to aldose
produces unsaturated alcohol

Osazone Reaction

carbonyl group of aldose is linked to phenylhydrazine
product is called osazone

Oxidation Reaction

addition of oxygen to a molecule or removal of hydrogen from a molecule
produces sugar acid

Reduction Reaction

addition of hydrogen to a molecule or removal of oxygen from a molecule

Disaccharide

contains two monosaccharide units
covalently bonded to each other

Sucrose

table sugar
most abundant disaccharide
produced commercially from sugarcane and sugar beets
non-reducing sugar
head to head linkages
glucose + fructose

Maltose

malt sugar, beer sugar
easily digested by humans due to enzymes that break alpha-1,4 linkages
not beta-1,4-linkages of cellobiose

Fates of Glucose

ATP production
amino acid and triglyceride synthesis
glycogen synthesis
digestion of carbohydrates begins in the mouth with saliva
saliva contains an enzyme called amylase that begins the breakdown of sugars to carbohydrates
excess glucose is converted to glycogen, which is sometimes stored in fats and proteins

Ptyalin

starch hydrolyzing enzyme produced by the salivary glands, particularly from salivary amylase

Glycolysis - Step 3

phosphorylation using ATP
fructose-6-phosphate is converted to fructose-1,6-bisphosphate
second mol of ATP is consumed
enzyme: phosphofructokinase (PFK), rate-limiting enzyme, requires Mg2+ ion for activity
irreversible reaction
product: fructose-1,6-bisphosphate

Krebs Cycle

also known as the citric acid cycle, named after Hans Adolf Krebs
aerobic pathway requiring oxygen
final pathway where the oxidative catabolism of carbohydrates, amino acids, and fatty acids converge
carbon skeletons are converted to CO2

Krebs Cycle - Step 4

oxidation of alpha-ketoglutarate and formation of CO2
via oxidation and decarboxylation
second step to produce NADH and CO2
alpha-ketoglutarate is oxidatively decarboxylated to succinyl CoA by alpha-ketoglutarate dehydrogenase complex
alpha-ketoglutarate dehydrogenase complex is activated by calcium and inhibited by NADH and succinyl CoA

Krebs Cycle - Step 5

thioester bond cleavage in succinyl CoA and phosphorylation of GDP
via phosphorylation
substrate-level phosphorylation
step producing GTP
succinyl CoA acts by the enzyme succinyl CoA synthetase, forming succinyl phosphate then acting by succinyl CoA synthetase, forming succinate and GTP (guanosine triphosphate)

Aerobic Respiration (Mitochondria)

involves oxygen
converts glucose to pyruvate and ATP
pyruvate is burned for energy and then converted into fats via fatty acid synthesis
could undergo TCA or Krebs cycle
final product is pyruvate along with the production of eight ATP molecules

Anaerobic Respiration (Cytoplasm)

includes ATP production and has recycled NADH by making the product lactate (muscles)
final product is lactate along with the production of two ATP molecules

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Description

This quiz covers key biochemical processes including glycolysis, specifically focusing on Step 5, and various reactions such as the Lobry de Bruyn degradation and osazone formation. Understand the transformations and the production of ATP in cellular metabolism along with the concepts of oxidation and reduction reactions. Test your knowledge on disaccharides and their properties.