Lecture 1.2 - Energy reactions in cells

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of creatine phosphate in muscle cells?

To rapidly produce ATP for muscle contraction under anaerobic conditions (correct)

To store ATP for muscle contraction under aerobic conditions

To inhibit the production of ATP in muscle cells

To convert ATP into ADP

What is the subunit composition of creatine kinase in heart muscle?

CK-MM at 90% and CK-MB at 10%

CK-MM at 70% and CK-MB at 25-30% (correct)

CK-MM at 30% and CK-MB at 70%

CK-MM at 50% and CK-MB at 50%

What is the primary indicator of kidney function in the body?

CK-MM levels

Blood and urine creatinine levels (correct)

Urine creatinine levels

Blood creatinine levels

What is the relationship between creatine levels and muscle mass?

The rate of production of creatinine is proportional to the concentration of creatine in muscle Signup and view all the answers

What is the diagnostic significance of creatine kinase in myocardial infarction?

It is a diagnostic indicator of myocardial infarction, appearing in blood after a few hours Signup and view all the answers

What is the primary fate of creatinine in the body?

It is efficiently excreted by the kidneys in the urine Signup and view all the answers

What is the primary function of the energy released in exergonic reactions?

To synthesize ATP from ADP and Pi Signup and view all the answers

What is the primary function of ATP production in cell metabolism?

To generate energy for the synthesis of cell components Signup and view all the answers

What is the role of NADH and NADPH in cell metabolism?

To act as carriers of reducing power for ATP production and biosynthesis Signup and view all the answers

What is the characteristic of ATP that enables the flow of energy to be controlled?

Its stability in the absence of specific catalysts Signup and view all the answers

What is the characteristic of oxidation reactions in biological systems?

The removal of electrons or removal of H atoms Signup and view all the answers

What is the term for the energy actually available to do work in biochemical reactions?

Free energy Signup and view all the answers

What is the consequence of a reaction being endergonic?

It requires more energy to take place and is not spontaneous Signup and view all the answers

What is the term for the oxidation reaction accompanied by a reduction reaction?

Redox reaction Signup and view all the answers

What is the role of NADPH in the cell?

To provide reducing power Signup and view all the answers

What is the role of acetyl CoA in cell metabolism?

To allow for the inter-conversion of building block materials Signup and view all the answers

What is the significance of ATP being a high-energy signal?

It signals that the cell has adequate energy levels for its immediate needs Signup and view all the answers

What is the primary function of anabolic reactions in cell metabolism?

To synthesize new molecules using energy Signup and view all the answers

What is the characteristic of ATP in terms of energy storage?

It is a carrier molecule and not a store Signup and view all the answers

What is the term for the energy stored in the chemical bonds of fuel molecules?

Bond energy Signup and view all the answers

What is the classification of reactions that release energy?

Exergonic reactions Signup and view all the answers

What is the characteristic of metabolic pathways in cell metabolism?

They are integrated and interconnected with each other Signup and view all the answers

Study Notes

Carrier Molecules

The total concentration of carrier molecules in cells is constant and consists of both oxidized and reduced forms.
Carrier molecules are complex and contain components from vitamins (B vitamins).
They are converted to reduced form by adding two H atoms (H+ + e-), and H+ dissociates into solution.
NADPH is a carrier molecule.

Bioenergetics

Bioenergetics is the study of energy changes (transfer and utilization) in biochemical reactions.
Reactions are classified as exergonic (energy releasing) and endergonic (energy consuming).
Free energy (G) is the energy available to do work and is related to enthalpy and entropy changes.
Free energy change (ΔG) is the energy change as the system moves from its initial state to equilibrium.
Exergonic reactions are spontaneous and release energy, while endergonic reactions require more energy to take place.

ATP-ADP-AMP

ATP is produced by the energy released in exergonic reactions.
ATP is a high-energy molecule due to the chemical bond energy of its terminal phosphate group.
The concentration of ADP and ATP is limited, making it necessary to cycle.
ATP is stable in the absence of specific catalysts, enabling controlled flow of energy.

Cellular Metabolism

Cell metabolism refers to the chemical reactions that occur within cells.
Many reactions take place in the body, but only a few reaction types are organized into metabolic pathways.
Metabolic pathways are distinct but integrated and occur in all cells, some cell types, or specific compartments.
Anabolism and catabolism are interconnected and make up metabolism.

Catabolic Metabolism

Products of catabolic metabolism include:
- Building block materials (sugars, amino acids, fatty acids)
- Organic precursors (acetyl CoA)
- Biosynthetic reducing power (NADH, NADPH)
- Energy for cell function and synthesis of cell components (ATP)

Biological Oxidation

Biological oxidation is the release of chemical bond energy of fuel molecules through oxidation reactions.
Oxidation involves the removal of electrons (e-) or H atoms (H+ + e-).
Oxidation reactions are accompanied by reduction reactions, forming REDOX reactions.

H-Carrier Molecules

H-carrier molecules, such as NAD+, transfer electrons and protons from fuel molecules during oxidation.
H-carrier molecules cycle between oxidative and reductive processes.
They act as carriers of reducing power for ATP production and biosynthesis.

Clinical Relevance

Creatine phosphate is a high-energy reserve that can rapidly produce ATP for muscle contraction under anaerobic conditions.
Creatine kinase (CK) is a marker of myocardial infarction (heart attack).
CK is released from cardiac myocytes when damaged, and its levels appear in blood after a few hours.
CK is diagnostic of MI and rises approximately 6 hours after MI, remaining elevated for 36-48 hours.
Creatinine levels are indicative of skeletal muscle mass and kidney function.
Increased creatinine levels in urine suggest muscle wasting, while high blood levels and low urine levels indicate reduced kidney function.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Learn about the role of NADPH in bioenergetics, including its conversion to reduced form and its importance in energy changes. Discover the connection between NADPH and vitamins, and how it affects energy transfer and utilization.