Metabolism and Photosynthesis Overview

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Questions and Answers

What is produced when carbon dioxide reacts with ribulose-1,5-bisphosphate (RuBP)?

Acetyl-CoA

Glyceraldehyde-3-phosphate (G3P)

A six-carbon sugar

Two molecules of 3-phosphoglyceric acid (3-PGA) (correct)

Which enzyme catalyzes the reaction between RuBP and CO2?

Phosphofructokinase

RuBP carboxylase/oxygenase (rubisco) (correct)

ATP synthase

Glyceraldehyde-3-phosphate dehydrogenase

What is the main function of NADPH in the conversion of 3-phosphoglyceric acid (3-PGA) during the reduction stage?

To donate electrons and reduce the three-carbon intermediate (correct)

To regenerate RuBP

To oxidize 3-PGA into glucose

To produce ATP from ADP

What is the primary output of the glycolysis pathway?

Pyruvate Signup and view all the answers

What is primarily regenerated in the Calvin cycle to allow continuous carbon fixation?

Ribulose-1,5-bisphosphate (RuBP) Signup and view all the answers

What is a characteristic of primary metabolites?

Directly involved in normal growth and reproduction Signup and view all the answers

Which of the following is an example of a primary metabolite?

Citric acid Signup and view all the answers

How are secondary metabolites typically produced?

From the modification of primary metabolite synthases Signup and view all the answers

What role do many secondary metabolites serve in ecological function?

Serving as defense mechanisms and antibiotics Signup and view all the answers

Which of the following correctly describes secondary metabolites?

They do not play a main role in growth and development Signup and view all the answers

Which primary metabolite is commonly isolated through the mass production of Corynebacteria glutamicum?

L-glutamate Signup and view all the answers

What is the function of atropine as a secondary metabolite?

It serves as a competitive antagonist for acetylcholine receptors. Signup and view all the answers

Which of the following statements about primary and secondary metabolites is true?

All secondary metabolites are derived from primary metabolites. Signup and view all the answers

What defines an antibiotic as a secondary metabolite?

It is derived from a microorganism. Signup and view all the answers

Which of the following statements about erythromycin is accurate?

It has a wide antimicrobial spectrum. Signup and view all the answers

In photosynthesis, where does the absorption of light primarily occur?

In the thylakoids of chloroplasts. Signup and view all the answers

What is released as a waste product during photosynthesis?

Oxygen Signup and view all the answers

Which pigment is primarily responsible for absorbing light energy in plants?

Chlorophyll a Signup and view all the answers

What role do pigments play in photosynthesis?

They absorb specific wavelengths of light. Signup and view all the answers

During photosynthesis, what process happens to water molecules?

They are split into hydrogen and oxygen. Signup and view all the answers

What is a significant consequence of the process of photosynthesis for life on Earth?

It decreases atmospheric carbon dioxide levels. Signup and view all the answers

What is the primary function of photosystems within thylakoids during the light-dependent reactions?

To gather light energy for photosynthesis Signup and view all the answers

Which statement correctly describes the use of NADPH and ATP in the dark reaction of photosynthesis?

NADPH and ATP are produced during the light reaction and used in the dark reaction. Signup and view all the answers

What is produced as a byproduct during the light-dependent reactions of photosynthesis?

Oxygen Signup and view all the answers

During which phase of photosynthesis is carbon dioxide fixed into organic compounds?

Calvin cycle Signup and view all the answers

Which of the following best represents the function of the Grana within chloroplasts?

To gather light energy and facilitate the light reactions Signup and view all the answers

Which chemical equation accurately represents the processes occurring in the dark reaction of photosynthesis?

3CO2 + 6 NADPH + 5H2O + 9ATP → G3P + 2H+ + 6 NADP+ + 9 ADP + 8 Pi Signup and view all the answers

In what part of the plant cell does the light-dependent reaction of photosynthesis occur?

Thylakoid membranes Signup and view all the answers

What is the end product of the Calvin cycle?

Glyceraldehyde-3-phosphate (G3P) Signup and view all the answers

Study Notes

Metabolism

Metabolism refers to all chemical transformations within living organisms' cells, crucial for life.
Metabolites are the end products or intermediates of metabolic processes.

Primary Metabolites

Directly involved in normal growth, development, and reproduction.
Essential for proper growth, formed during the growth phase.
Examples: ethanol, lactic acid, certain amino acids, L-glutamate, L-lysine, citric acid.
Used in industrial microbiology for large-scale production, like alcohol, amino acids, and citric acid.

Secondary Metabolites

Modified from primary metabolites, typically formed near the stationary phase of growth.
Not directly involved in growth, development, or reproduction.
Often play a role in ecological function, like defense mechanisms (antibiotics, pigments).
Examples: atropine, erythromycin, bacitracin.
Utilized in industrial microbiology for various applications.

Photosynthesis

The process of capturing light energy, converting it, and storing it in glucose.
Occurs in chloroplasts and other green parts of organisms.
Equation: 6CO2 + 12 H2O + light energy -> C6H12O6 + 6O2 + 6H2O

Photosynthesis Steps

Carbon dioxide enters through stomata, water is absorbed by roots and transported through xylem.
Chlorophyll absorbs light energy and splits water molecules into hydrogen and oxygen.
Hydrogen and carbon dioxide are used to produce glucose, oxygen is released as a waste product.
Glucose provides energy for plant growth and development, with excess stored in roots, leaves, and fruits.
Pigments like chlorophyll a, chlorophyll b, and carotenoids are present in thylakoids, responsible for capturing light energy.

Light Reaction of Photosynthesis

Occurs during the day in the presence of sunlight, in the thylakoid membranes of chloroplasts.
Photosystems (Grana) gather light energy within chloroplasts.
Photosystems contain complexes of pigments and proteins involved in light reactions.
Two types of photosystems: photosystem I and photosystem II.
Converts light energy into ATP and NADPH, used in the dark reaction.
Generates ATP and NADPH through electron-transport chains, uses water and produces oxygen.
Chemical equation: 2H2O + 2NADP+ + 3ADP + 3Pi → O2 + 2NADPH + 3ATP

Dark Reaction of Photosynthesis

Also called carbon-fixing reaction, light-independent.
Produces sugar molecules from water and carbon dioxide.
Occurs in the stroma of chloroplasts, utilizing NADPH and ATP from the light reaction.
Plants capture carbon dioxide through stomata and incorporate it into the Calvin cycle.
ATP and NADPH from the light reaction drive the conversion of 6 CO2 molecules to one glucose molecule.
Chemical equation: 3CO2 + 6 NADPH + 5H2O + 9ATP → G3P + 2H+ + 6 NADP+ + 9 ADP + 8 Pi (G3P: glyceraldehyde-3-phosphate)

Calvin Cycle Reactions

Three main stages: carbon fixation, reduction, and regeneration of RuBP.
Carbon fixation: CO2 combines with RuBP, forming a six-carbon compound that splits into two 3-PGA molecules.
Reduction: ATP and NADPH convert 3-PGA into G3P.
Regeneration: Some G3P molecules form glucose, others are recycled to regenerate RuBP.

Glycolysis

Metabolic pathway that converts glucose into pyruvate.
Occurs in the cytosol and is oxygen-independent.
Generates a net gain of two ATP molecules.

Citric Acid Cycle (Krebs Cycle/TCA Cycle)

Occurs in the mitochondrial matrix under aerobic conditions.
Series of enzyme-catalyzed reactions oxidizing acetyl-CoA to form carbon dioxide and reduced coenzymes.
Reduced coenzymes generate ATP in the electron transport chain.
Eight-step process.
Overall reaction of glucose in terms of ADP and ATP: C6H12O6 + 6CO2 + 38 ADP + 38P (inorganic) → 6H2O + 6CO2 + 38 ATP

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Description

This quiz explores key concepts of metabolism including primary and secondary metabolites, their roles in living organisms, and applications in industrial microbiology. Additionally, it addresses the essential process of photosynthesis and its significance in capturing light energy. Test your understanding of these fundamental biological processes.