week 13.0 Flashcards
Why is glucose considered a central fuel for our bodies?
Glucose is considered a central fuel for our bodies because when fully broken down, it provides a significant amount of energy. It can also be stored efficiently in a polymer form and can be used to create other important molecules such as amino acids, membrane lipids, and DNA and RNA components.
How does the oxygen requirement for breaking down glucose compare to breaking down fat?
When fully breaking down glucose, less oxygen is required compared to breaking down fat. While fat provides more energy in the form of calories, it requires more oxygen to convert into energy.
Why is glycolysis the primary metabolic pathway when there is an abundance of nutrients or a lack of oxygen?
When there is an abundance of nutrients or a lack of oxygen, the primary metabolic pathway is glycolysis because it breaks down glucose, requiring less oxygen to produce energy.
Why is brisk walking more effective for burning fat compared to intense running?
Brisk walking can be more effective for burning fat compared to intense running because fat metabolism requires more oxygen. When food is not available, the body relies on fat as an energy source, but it requires a higher oxygen supply.
How is glucose stored in plants and in our bodies?
In plants, glucose is stored as starch, which provides nutrients during digestion. In our bodies, glucose is stored as glycogen for later use.
Which tissues in our bodies rely mainly on glucose for their energy needs?
Tissues such as the liver, red blood cells, and some other cells rely mainly on glucose for their energy needs.
How does glucose utilization differ in Escherichia coli bacteria?
Escherichia coli bacteria have the ability to convert glucose into any molecule they need for growth. They can use glucose in various ways for different metabolic processes.
What are the two main pathways of glucose utilization mentioned in the text?
The two main pathways of glucose utilization mentioned in the text are glycolysis and the pentose phosphate pathway.
What is the primary outcome of glycolysis?
pyruvate and ATP
What is the function of the pentose phosphate pathway?
The pentose phosphate pathway uses glucose as an alternative source of energy and specifically produces riboses, which are important components of RNA, DNA, and other essential molecules in our body.
How is glucose stored for later use?
Glucose is stored in a polymer form known as glycogen
Besides energy production and storage, what other role does glucose play in the body?
Glucose is involved in the synthesis of polymers such as the extracellular matrix and cell wall polysaccharides.
Can you summarize the main uses of glucose in the body?
Glucose is primarily used for glycolysis to produce energy, but it can also be used through the pentose phosphate pathway for the production of important molecules. It can be stored as glycogen for later use and is involved in the formation of various polymers in the body.
What is the main goal of glycolysis?
The main goal of glycolysis is to produce energy in the form of ATP and NADH+H+.
What is the composition of ATP?
ATP is composed of three phosphate groups, ribose (a sugar molecule), and adenine (a component of DNA and RNA).
How is the energy stored in ATP released?
The energy stored in ATP is released by breaking the high-energy bonds between the phosphate groups.
What are some of the cellular processes that utilize the energy released from ATP?
The energy released from ATP is used for various cellular processes such as muscle contraction.
Besides ATP, what other molecules are synthesized from glucose during glycolysis?
Ribose and adenine are also synthesized from glucose during glycolysis.
What happens to pyruvate, the end product of glycolysis?
- In the presence of oxygen, pyruvate can enter the mitochondria where it undergoes further reactions to produce energy in a process called cellular respiration.
- Alternatively, pyruvate can be used as a building block to create important molecules needed by the body, such as amino acids, proteins, fats, nucleic acids and glucose.
How is energy stored during glycolysis?
Some of the energy released during glycolysis is stored in the form of ATP and NADH+H+.
Can you summarize the importance of glycolysis?
Glycolysis is important because it converts glucose into pyruvate, producing energy in the form of ATP and NADH+H+. ATP provides energy for cellular processes, while pyruvate can be used for further energy production and can be used as a building block to create important molecules in the body, such as proteins, fats, and nucleic acids.
Where does glycolysis take place in the cell?
Glycolysis takes place in the cytosol, which is the fluid part of the cell.
In which cells does glycolysis occur at a particularly high rate?
Glycolysis occurs at a particularly high rate in the brain and muscles.
Why does the brain require a lot of energy?
The brain requires a lot of energy for neuronal signaling.
Why do muscles need energy?
Muscles need energy to maintain contractions and perform their functions.
What is gluconeogenesis?
Gluconeogenesis is the synthesis of glucose from pyruvate.
Where does gluconeogenesis take place?
Gluconeogenesis takes place in the cytosol, similar to glycolysis.
How does glycolysis regulate the conversion of substrates?
Glycolysis has three regulatory reactions that determine the direction of the conversion process, ensuring whether glucose is used or synthesized within the cells.
Glykolys är en process där glukos bryts ner för att producera energi i cellerna. För att kontrollera denna process och avgöra om glukos ska användas eller bildas, finns det tre reglerande reaktioner. Dessa reaktioner fungerar som vägskäl och bestämmer vilken riktning omvandlingen tar. Om cellen behöver energi kommer processen att gå framåt och glukos kommer att brytas ner för att generera ATP. Å andra sidan, om cellen har tillräckligt med energi och behöver lagra glukos, kommer processen att gå bakåt och glukos kommer att bildas för att lagras för framtida användning. Dessa reglerande reaktioner säkerställer att glukosmetabolismen är anpassad efter cellens energibehov.
Can you summarize the key points about glycolysis and gluconeogenesis?
Glycolysis occurs in all cells, with higher rates in the brain and muscles. It takes place in the cytosol and is responsible for producing energy. Gluconeogenesis, also occurring in the cytosol, is the synthesis of glucose from pyruvate. Glycolysis has three regulatory reactions that control the conversion of substrates and determine the use or synthesis of glucose in the cells.
How can glycolysis be divided?
Glycolysis can be divided into two phases: the preparatory phase and the payoff phase.
What happens in the preparatory phase of glycolysis?
In the preparatory phase, some energy is invested to prepare the glucose molecule for further breakdown and energy production.
How many reactions are involved in the preparatory phase of glycolysis?
The preparatory phase consists of the first five reactions in the glycolysis pathway.
What is the purpose of the investment of ATP in the preparatory phase?
The investment of ATP in the preparatory phase helps prepare the glucose molecule for further breakdown and energy production.
How many ATP molecules are used up in the initial reactions of the preparatory phase?
Two ATP molecules are used up in the first and third reactions of the preparatory phase.
What is the purpose of the payoff phase in glycolysis?
The purpose of the payoff phase is to generate energy.
What molecules are produced in the payoff phase of glycolysis?
The payoff phase produces ATP and NADH+H+.
In which reactions of glycolysis is ATP generated?
ATP is generated in the 7th and 10th reactions of glycolysis.
What is the role of NADH+H+ in glycolysis?
NADH+H+ is a cofactor that is generated in the 6th reaction of glycolysis and plays a crucial role in various cellular functions and processes.
Why are ATP and NADH+H+ important?
ATP and NADH+H+ are energy-rich molecules that provide the energy necessary for cellular functions and processes.
Why do phosphorylated intermediates play an important role in glycolysis?
Phosphorylated intermediates in glycolysis are important because they are not easily transported out of the cell, saving energy for the cell and allowing them to be used for various cellular functions.
What is the advantage of phosphorylation in glycolysis?
Phosphorylation forms high-energy bonds with molecules, and when these bonds are broken, they release a significant amount of potential energy that can be utilized for processes like muscle contraction.
How does phosphorylation affect enzyme reactions in glycolysis?
When molecules are phosphorylated, it makes enzymes better at their job. It lowers the energy needed to start reactions and helps enzymes pick the right molecules to work on. This makes the reactions happen more efficiently.
What are the benefits of phosphorylated intermediates in glycolysis?
The benefits include energy conservation, release of potential energy, and enhanced enzyme efficiency through lowered activation energy and increased specificity.
Which step of glycolysis involves the phosphorylation of glucose?
Step 1 of glycolysis involves the phosphorylation of glucose.
Why is glucose phosphorylated in the first step of glycolysis?
In the first step of glycolysis, glucose gets a phosphate group added to it. This helps to keep glucose inside the cell and starts the process of breaking it down.
What is the purpose of phosphorylating glucose in glycolysis?
During glycolysis, a phosphate group is added to glucose, which prepares it for other reactions and allows the release of energy.
What molecule is used to phosphorylate glucose in the first step of glycolysis?
ATP (adenosine triphosphate) is used to phosphorylate glucose in the first step of glycolysis.
How does the phosphorylation of glucose contribute to the overall energy production in glycolysis?
The phosphorylation of glucose in step 1 of glycolysis helps to initiate the breakdown of glucose and ultimately leads to the production of ATP, which is a crucial energy molecule.
Why is the induced fit conformational change in hexokinase important when glucose is being phosphorylated?
Varför är den inducerade förändringen i hexokinas viktig när glukos blir fosforylerad?
The induced change brings glucose and ATP magnesium closer together and helps phosphorylate glucose, while preventing ATP from being broken down incorrectly.
Den inducerade förändringen gör att glukos och ATP-magnesium kommer närmare varandra och hjälper till att fosforylera glukos, samtidigt som det förhindrar att ATP bryts ner på fel sätt.
How does the phosphorylation of glucose contribute to the regulation of glycolysis?
The product of the phosphorylation reaction, glucose-6-phosphate, negatively regulates hexokinase through a feedback mechanism, ensuring that glycolysis is tightly controlled.
Why is the phosphorylation of glucose in step 1 of glycolysis considered an irreversible reaction?
The phosphorylation of glucose in step 1 is an irreversible process that helps keep glucose inside the cell and prevents its escape.
What is the role of hexokinases in the phosphorylation of glucose?
Hexokinases are special enzymes that help attach a phosphate group from ATP to glucose. This creates a new molecule called glucose-6-phosphate.
Which step of glycolysis involves the phosphorylation of glucose?
Step 1 of glycolysis involves the phosphorylation of glucose.
Which step of glycolysis is responsible for the phosphorylation of glucose?
Step 1 of glycolysis is responsible for the phosphorylation of glucose.
What is the purpose of phosphorylating glucose in step 1 of glycolysis?
When glucose is phosphorylated in step 1 of glycolysis, it means that a phosphate group is added to the glucose molecule. This makes glucose more reactive and can be broken down more easily to produce energy. The phosphorylation also helps keep glucose inside the cell by reducing its concentration outside the cell. by phosphorylating glucose in step 1 of glycolysis, it ensures that there is enough glucose available for the cell to produce energy. This helps maintain a steady supply of fuel for energy production within the cell.
What molecule provides the energy required for the phosphorylation of glucose in step 1?
ATP provides the energy needed for the phosphorylation of glucose in step 1 of glycolysis.
How does the presence of Mg2+ assist in the phosphorylation of glucose in step 1?
The presence of Mg2+ bound to ATP helps shield the negative charges on ATP, facilitating the attack of the oxygen atom at the 6th carbon of glucose during phosphorylation.
Which step of glycolysis involves the conversion of glucose 6-phosphate into fructose 6-phosphate?
Step 2 of glycolysis, known as phosphohexose isomerization, involves the conversion of glucose 6-phosphate into fructose 6-phosphate.
What is the purpose of the phosphohexose isomerization step in glycolysis?
In glycolysis, there is a step called phosphohexose isomerization. Its purpose is to make the next steps in the process easier and require less energy. It does this by changing a molecule called glucose 6-phosphate into another molecule called fructose 6-phosphate. This helps the rest of the glycolysis process go more smoothly and saves energy.
Which enzyme catalyzes the conversion of glucose 6-phosphate to fructose 6-phosphate in Step 2 of glycolysis?
The conversion of glucose 6-phosphate to fructose 6-phosphate in Step 2 of glycolysis is catalyzed by the enzyme phosphohexose isomerase.
How does the rearrangement of glucose 6-phosphate to fructose 6-phosphate in Step 2 conserve energy?
The rearrangement of glucose 6-phosphate to fructose 6-phosphate in Step 2 of glycolysis conserves energy by making the subsequent reactions more favorable, thus requiring less energy.
What type of catalysis is involved in the phosphohexose isomerization reaction in Step 2 of glycolysis?
The phosphohexose isomerization reaction in Step 2 of glycolysis involves acid-base catalysis, where certain molecules act as catalysts to facilitate the conversion of glucose 6-phosphate to fructose 6-phosphate.
Which step of glycolysis is referred to as the “Second Priming Phosphorylation”?
Step 3 of glycolysis is known as the “Second Priming Phosphorylation.”
What is the purpose of the Second Priming Phosphorylation step?
The purpose of the Second Priming Phosphorylation step is to further activate glucose and prepare it for the subsequent reactions in glycolysis.
What is the role of fructose 6-phosphate in the Second Priming Phosphorylation step?
In the Second Priming Phosphorylation step, fructose 6-phosphate acts as a feed-forward activator for the enzyme phosphofructokinase-1.
What is the product of the Second Priming Phosphorylation step?
The product of the Second Priming Phosphorylation step is fructose 1,6-bisphosphate.
Why are the phosphate groups in fructose 1,6-bisphosphate important for glycolysis?
The phosphate groups in fructose 1,6-bisphosphate allow for the formation of two three-carbon sugars with one phosphate group each, enabling energy production in later steps of glycolysis.
How is the Second Priming Phosphorylation step regulated?
The Second Priming Phosphorylation step is regulated through activation and inhibition via allosteric regulation. Activators such as adenosine monophosphate (AMP), adenosine diphosphate (ADP), and ribulose 5-phosphate enhance the activity of phosphofructokinase-1, while inhibitors like high concentrations of ATP, phosphoenolpyruvate, and citrate suppress its activity.
What is the significance of the Second Priming Phosphorylation step being considered the committed step and the rate-limiting step of glycolysis?
Being the committed step and the rate-limiting step, the Second Priming Phosphorylation step exerts significant control over the flux of glucose through glycolysis, ensuring efficient management of glucose concentration and energy utilization within the cell.
How does the regulation of the Second Priming Phosphorylation step ensure efficient energy utilization?
The regulation of the Second Priming Phosphorylation step allows for adjustments in response to signals of energy availability and demand in the cell. Activators and inhibitors help maintain appropriate glycolytic activity based on the cell’s immediate energy needs.
What are the possible fates of glucose regardless of the cell’s immediate energy needs?
Regardless of the cell’s immediate energy needs, glucose can be stored as glycogen or converted into fatty acids through the breakdown of pyruvate into acetyl coenzyme A.
How does the Second Priming Phosphorylation step set the stage for greater energy gain later on in glycolysis?
By utilizing ATP at this early stage, the Second Priming Phosphorylation step sets the stage for greater energy gain in later steps of glycolysis by activating glucose and preparing it for further breakdown.
Which step of glycolysis involves the cleavage of fructose 1,6-bisphosphate?
Step 4 of glycolysis, known as the Aldol Cleavage of F-1,6-bP, involves the cleavage of fructose 1,6-bisphosphate.
What enzyme is responsible for the cleavage of fructose 1,6-bisphosphate?
The enzyme aldolase is responsible for the cleavage of fructose 1,6-bisphosphate.
What are the products of the Aldol Cleavage of F-1,6-bP?
The products of the Aldol Cleavage of F-1,6-bP are dihydroxyacetone phosphate and glyceraldehyde 3-phosphate.
How is dihydroxyacetone phosphate different from glyceraldehyde 3-phosphate?
Dihydroxyacetone phosphate is a ketose due to the presence of a keto group, while glyceraldehyde 3-phosphate is an aldose due to the presence of an aldehyde group.
Is the cleavage of fructose 1,6-bisphosphate thermodynamically favorable?
No, the cleavage of fructose 1,6-bisphosphate is not thermodynamically favorable. It requires an input of energy.
How are the concentrations of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate regulated in the cell?
The concentrations of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate are kept low in the cell. They are rapidly utilized, which drives the reaction forward and promotes the production of these products.
What is the significance of the cleavage of fructose 1,6-bisphosphate into dihydroxyacetone phosphate and glyceraldehyde 3-phosphate?
The cleavage of fructose 1,6-bisphosphate into dihydroxyacetone phosphate and glyceraldehyde 3-phosphate is an essential part of glucose breakdown in our cells. These molecules serve as intermediates in further metabolic processes.
How is dihydroxyacetone phosphate utilized in cellular metabolism?
Dihydroxyacetone phosphate can be further used for the synthesis of glycerol, which serves as the backbone for storing fat in the form of triacylglycerides.
How does the breakdown of glucose into triacylglycerides relate to the consumption of sugary foods?
The breakdown of glucose into triacylglycerides involves synthesizing the glycerol backbone and the fatty acids derived from pyruvate conversion to acetyl-CoA. The consumption of sugary foods can contribute to the production of these fat components and has been linked to the rise in obesity rates.
What does the interconnectedness of glucose metabolism and various physiological outcomes emphasize?
The interconnectedness of glucose metabolism and various physiological outcomes highlights the importance of understanding the relationships between glucose metabolism and its impact on overall health and physiological processes.
Which step of glycolysis involves the interconversion of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate?
Step 5 of glycolysis, known as the Triose Phosphate Interconversion, involves the interconversion of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate.
Why do we need to create two identical molecules of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate?
Creating two identical molecules of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate ensures the efficiency of the glycolysis process.
What does it mean for dihydroxyacetone phosphate and glyceraldehyde 3-phosphate to be isomers?
Being isomers means that dihydroxyacetone phosphate and glyceraldehyde 3-phosphate have the same composition but different structures.
Why is it important to keep the concentration of glyceraldehyde 3-phosphate low?
The concentration of glyceraldehyde 3-phosphate is kept low to ensure the thermodynamically unfavorable reaction of creating two identical molecules occurs efficiently.
What does the completion of the preparative phase of glycolysis signify?
The completion of the preparative phase of glycolysis is signified by the creation of two identical molecules of glyceraldehyde 3-phosphate.
How does the metabolic pathway ensure the efficiency of glycolysis in terms of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate?
The metabolic pathway ensures efficiency by interconverting dihydroxyacetone phosphate and glyceraldehyde 3-phosphate to create two identical molecules of glyceraldehyde 3-phosphate.
What would happen if dihydroxyacetone phosphate and glyceraldehyde 3-phosphate were not converted into two identical molecules?
If dihydroxyacetone phosphate and glyceraldehyde 3-phosphate were not converted into two identical molecules, it would lead to different reactions and pathways, disrupting the efficiency of glycolysis.
How does the interconversion of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate contribute to the overall efficiency of glycolysis?
The interconversion ensures that both dihydroxyacetone phosphate and glyceraldehyde 3-phosphate can proceed through the subsequent steps of glycolysis in a synchronized manner, optimizing the overall efficiency of the process.
What is the significance of the thermodynamic favorability of the reaction involving glyceraldehyde 3-phosphate?
The thermodynamic favorability of the reaction involving glyceraldehyde 3-phosphate ensures that the conversion of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate into two identical molecules occurs efficiently, despite it being thermodynamically unfavorable otherwise.
