Bio 101 Glycolysis Steps
38 flashcards covering Bio 101 Glycolysis Steps for the BIOLOGY-101 Energy & Metabolism section.
Glycolysis is a fundamental metabolic pathway that breaks down glucose to produce energy in the form of ATP. It consists of a series of ten enzyme-catalyzed reactions, regulated by various factors, and is outlined in the curriculum for Introductory Biology I courses, such as those defined by the College Board's AP Biology framework. Understanding glycolysis is essential for grasping cellular respiration and energy production in both prokaryotic and eukaryotic organisms.
On practice exams and competency assessments, questions about glycolysis often focus on identifying the steps of the pathway, the enzymes involved, and the energy yield. Common traps include confusing the order of reactions or misidentifying the roles of specific enzymes. It's important to pay close attention to the differences between substrate-level phosphorylation and oxidative phosphorylation, as this distinction frequently appears in exam questions. A practical tip to remember is that many learners overlook the importance of intermediates in glycolysis, which can lead to misunderstandings about the overall process.
Terms (38)
- 01
What is the first step of glycolysis?
The first step of glycolysis is the phosphorylation of glucose to form glucose-6-phosphate, catalyzed by the enzyme hexokinase. This step requires one molecule of ATP (Campbell Biology, glycolysis chapter).
- 02
How many ATP molecules are consumed in the preparatory phase of glycolysis?
A total of 2 ATP molecules are consumed in the preparatory phase of glycolysis, specifically in steps 1 and 3 (Campbell Biology, glycolysis chapter).
- 03
What is produced during the energy payoff phase of glycolysis?
During the energy payoff phase of glycolysis, 4 ATP and 2 NADH molecules are produced per molecule of glucose (Campbell Biology, glycolysis chapter).
- 04
Which enzyme catalyzes the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate?
The enzyme phosphofructokinase catalyzes the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate, using one ATP molecule (Campbell Biology, glycolysis chapter).
- 05
What is the net gain of ATP from glycolysis?
The net gain of ATP from glycolysis is 2 ATP per molecule of glucose, after accounting for the 2 ATP used in the preparatory phase (Campbell Biology, glycolysis chapter).
- 06
What happens to glyceraldehyde-3-phosphate during glycolysis?
Glyceraldehyde-3-phosphate is oxidized and phosphorylated to form 1,3-bisphosphoglycerate, producing NADH in the process (Campbell Biology, glycolysis chapter).
- 07
What is the role of NAD+ in glycolysis?
NAD+ acts as an electron carrier in glycolysis, being reduced to NADH during the oxidation of glyceraldehyde-3-phosphate (Campbell Biology, glycolysis chapter).
- 08
Which step of glycolysis involves substrate-level phosphorylation?
Substrate-level phosphorylation occurs in steps 7 and 10 of glycolysis, resulting in the direct synthesis of ATP from ADP (Campbell Biology, glycolysis chapter).
- 09
What is the final product of glycolysis?
The final product of glycolysis is pyruvate, which can be further processed in aerobic or anaerobic conditions (Campbell Biology, glycolysis chapter).
- 10
How many molecules of pyruvate are produced from one glucose during glycolysis?
One molecule of glucose is converted into two molecules of pyruvate during glycolysis (Campbell Biology, glycolysis chapter).
- 11
What is the significance of the enzyme hexokinase in glycolysis?
Hexokinase is significant because it catalyzes the first step of glycolysis, phosphorylating glucose and trapping it in the cell (Campbell Biology, glycolysis chapter).
- 12
What is the function of phosphoglycerate kinase in glycolysis?
Phosphoglycerate kinase catalyzes the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate, producing ATP in the process (Campbell Biology, glycolysis chapter).
- 13
What are the two main phases of glycolysis?
The two main phases of glycolysis are the preparatory phase and the energy payoff phase (Campbell Biology, glycolysis chapter).
- 14
What is the role of aldolase in glycolysis?
Aldolase catalyzes the cleavage of fructose-1,6-bisphosphate into two three-carbon sugars: dihydroxyacetone phosphate and glyceraldehyde-3-phosphate (Campbell Biology, glycolysis chapter).
- 15
How does glycolysis relate to cellular respiration?
Glycolysis is the first step in cellular respiration, breaking down glucose to produce pyruvate, which enters the citric acid cycle (Campbell Biology, glycolysis chapter).
- 16
What is the purpose of the enzyme enolase in glycolysis?
Enolase catalyzes the conversion of 2-phosphoglycerate to phosphoenolpyruvate, facilitating the final steps of glycolysis (Campbell Biology, glycolysis chapter).
- 17
Which step of glycolysis is considered irreversible?
The conversion of fructose-6-phosphate to fructose-1,6-bisphosphate, catalyzed by phosphofructokinase, is considered irreversible (Campbell Biology, glycolysis chapter).
- 18
What is the importance of the energy investment phase in glycolysis?
The energy investment phase is important because it prepares glucose for subsequent breakdown, requiring an initial investment of ATP (Campbell Biology, glycolysis chapter).
- 19
What is the role of pyruvate kinase in glycolysis?
Pyruvate kinase catalyzes the final step of glycolysis, converting phosphoenolpyruvate to pyruvate and generating ATP (Campbell Biology, glycolysis chapter).
- 20
How is glycolysis regulated?
Glycolysis is regulated by key enzymes such as hexokinase, phosphofructokinase, and pyruvate kinase, which respond to the energy needs of the cell (Campbell Biology, glycolysis chapter).
- 21
What types of organisms perform glycolysis?
Glycolysis occurs in nearly all organisms, including bacteria, plants, and animals, as it is a fundamental metabolic pathway (Campbell Biology, glycolysis chapter).
- 22
What is the role of ATP in glycolysis?
ATP serves as both an energy source and a substrate for phosphorylation reactions during glycolysis (Campbell Biology, glycolysis chapter).
- 23
What is the end product of glycolysis under anaerobic conditions?
Under anaerobic conditions, the end product of glycolysis is lactate in animals or ethanol and carbon dioxide in yeast (Campbell Biology, glycolysis chapter).
- 24
What is the function of triose phosphate isomerase in glycolysis?
Triose phosphate isomerase catalyzes the interconversion of dihydroxyacetone phosphate and glyceraldehyde-3-phosphate, allowing for the continuation of glycolysis (Campbell Biology, glycolysis chapter).
- 25
What happens to NADH produced in glycolysis?
NADH produced in glycolysis can be used in oxidative phosphorylation or converted back to NAD+ during fermentation processes (Campbell Biology, glycolysis chapter).
- 26
What is the role of phosphoglycerate mutase in glycolysis?
Phosphoglycerate mutase catalyzes the conversion of 3-phosphoglycerate to 2-phosphoglycerate, facilitating the rearrangement of phosphate groups (Campbell Biology, glycolysis chapter).
- 27
What is the significance of the enzyme lactate dehydrogenase?
Lactate dehydrogenase is significant because it catalyzes the conversion of pyruvate to lactate under anaerobic conditions, regenerating NAD+ (Campbell Biology, glycolysis chapter).
- 28
What is the effect of high ATP levels on glycolysis?
High ATP levels inhibit key enzymes in glycolysis, particularly phosphofructokinase, thus slowing down the pathway (Campbell Biology, glycolysis chapter).
- 29
How many steps are there in glycolysis?
Glycolysis consists of 10 enzymatic steps that convert glucose into pyruvate (Campbell Biology, glycolysis chapter).
- 30
What is the role of the enzyme aldose reductase in glycolysis?
Aldose reductase is not directly involved in glycolysis; it is involved in the conversion of glucose to sorbitol in the polyol pathway (Campbell Biology, glycolysis chapter).
- 31
What is the primary substrate for glycolysis?
The primary substrate for glycolysis is glucose, which is broken down to generate energy (Campbell Biology, glycolysis chapter).
- 32
What is the difference between aerobic and anaerobic glycolysis?
Aerobic glycolysis occurs in the presence of oxygen and leads to complete oxidation of glucose, while anaerobic glycolysis occurs without oxygen and produces lactate or ethanol (Campbell Biology, glycolysis chapter).
- 33
What happens during the isomerization step of glycolysis?
During the isomerization step, glucose-6-phosphate is converted to fructose-6-phosphate, allowing for further processing in glycolysis (Campbell Biology, glycolysis chapter).
- 34
What is the significance of the enzyme pyruvate carboxylase?
Pyruvate carboxylase is not involved in glycolysis but plays a role in gluconeogenesis by converting pyruvate to oxaloacetate (Campbell Biology, glycolysis chapter).
- 35
What is the energy yield of glycolysis in terms of NADH?
Glycolysis yields 2 NADH molecules per molecule of glucose, which can be used for ATP production in oxidative phosphorylation (Campbell Biology, glycolysis chapter).
- 36
What is the role of the enzyme glyceraldehyde-3-phosphate dehydrogenase?
Glyceraldehyde-3-phosphate dehydrogenase catalyzes the oxidation and phosphorylation of glyceraldehyde-3-phosphate to form 1,3-bisphosphoglycerate (Campbell Biology, glycolysis chapter).
- 37
What is the impact of low glucose levels on glycolysis?
Low glucose levels can lead to decreased glycolytic activity as the substrate for the pathway is limited (Campbell Biology, glycolysis chapter).
- 38
How does glycolysis contribute to cellular metabolism?
Glycolysis contributes to cellular metabolism by providing ATP and metabolic intermediates for other pathways (Campbell Biology, glycolysis chapter).