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WorksheetsCarbohydrates and Energy Metabolism
Total questions: 20
Worksheet time: 21mins
One of the most important metabolic regulators in most cells is ______
the relative levels of NAD+ and NADP+ in the cell
the level of glucose 1-phosphate in the cell
the level of coenzyme A in the cell
the relative levels of ATP and ADP/AMP in the cell
In the electron transport chain, which of the following complexes does not pump protons?
complex I
complex III
complex II
complex IV
Which of the following lists shows the enzymes responsible for using ATP in the first stage of glycolysis?
hexokinase or glucokinase; phosphofructokinase-1
phosphofructokinase-2; pyruvate kinase
phosphoglycerate kinase; pyruvate kinase
triose phosphate isomerase; phosphoglucomutase
T or F. Fructose 2,6-bisphosphate is an allosteric modulator that can stimulate either glycolysis or gluconeogenesis, depending on cellular glucose concentration
(a)
The enzymes catalysing the glycolysis pathway are located in _______
the mitochondria
the nucleus
the cytosol
the endoplasmic reticulum
The most important regulatory step in the glycolytic pathway is _______
the formation of phosphoenolpyruvate
the formation of fructose 6-phosphate
the formation of glucose 6-phosphate
the formation of fructose 1,6-bisphosphate
The importance of the glycolysis pathway, particularly in muscle, is that ______
cells can produce energy aerobically
cells can convert other nutrients to glucose
cells can produce more energy when exercising
cells can produce energy anaerobically
Allosteric regulation of which of the following enzymes is important in the regulation of glycolysis?
pyruvate kinase
hexokinase
phosphofructokinase-1
Which of the following is not involved in the pyruvate dehydrogenase reaction?
biotin
coenzyme A
NAD
thiamine pyrophosphate
Which of the following are the primary substrates for the synthesis of glucose by gluconeogenesis?
lactate and alanine
lactose and lactate
fructose and alanine
pyruvate and oxaloacetate
The TCA cycle is regulated by ______
allosteric effects of ATP and AMP on isocitrate dehydrogenase
feedback inhibition by ATP on the electron transport chain
the availability of acyl CoA from the pyruvate dehydrogenase reaction
allosteric effects of acetyl CoA on citrate synthase
Compare the pH of the mitochondrial matrix and the intermembrane space in a metabolically active cell. Which of the following statements are correct?
the pH in both regions is the same
the pH is lower in the intermembrane space
the pH is lower in the matrix
the comparison of pH varies from moment to moment depending on energy needs of the cell
Electron flow down the electron-transport chain leads to the ______
coupled synthesis of GTP
transport of protons across the inner mitochondrial membrane from the intermembrane space into the matrix
a dangerous imbalance of K+ ions across the mitochondrial membrane
transport of protons across the inner mitochondrial membrane from inside the matrix to the intermembrane space
In a eukaryotic cell, most of the enzymes of the TCA cycle are located in the _______
outer mitochondrial membrane
cytosol
inner mitochondrial matrix
mitochondrial matrix
Which of the following will happen to pyruvate when oxygen is present and the cell needs to produce ATP?
pyruvate will be converted back to glucose via gluconeogenesis
pyruvate will be converted to lactate
pyruvate will be oxidised via pyruvate dehydrogenase and the tricarboxylic acid cycle
pyruvate will be converted to fatty acids via acetyl CoA
T or F. More energy in the form of ATP is required to synthesise glucose than can be obtained from it by glycolysis alone
(a)
Gluconeogenesis must use “bypass reactions” to circumvent three reactions in the glycolytic pathway that are highly exergonic and essentially irreversible.
Reactions carried out by which three of the enzymes listed must be bypassed in the gluconeogenic pathway?
1. Hexokinase
2. Phosphoglycerate kinase
3. Phosphofructokinase-1
4. Pyruvate kinase
5. Triosephosphate isomerase
1, 3, 4
1, 2, 4
2, 4, 5
1, 3, 5
1, 2, 3
Which of the following lists shows the enzymes responsible for producing ATP in the third stage of glycolysis?
phosphoglycerate kinase, pyruvate kinase
phosphofructokinase-2, pyruvate kinase
glyceraldehyde phosphate dehydrogenase, phosphoglyceromutase, enolase
hexokinase, glucokinase, phosphofructokinase-1
How are the enzymes of glycolysis regulated?
reversible phosphorylation
transcriptional control
allosteric control
In the TCA cycle, the reaction sequence from succinate to oxaloacetate and involving hydrogen and water is ______
addition, condensation, elimination
condensation addition, elimination
elimination, addition, elimination
addition, elimination, addition
