/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 12 What is the biochemical function... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 12: Problem 12

What is the biochemical function of the glyoxylate cycle in plants?

Short Answer

Expert verified
Answer: The main function of the glyoxylate cycle in plants is to enable the synthesis of glucose from two-carbon compounds, such as acetate or fatty acids, through gluconeogenesis. It achieves this function by bypassing decarboxylation steps of the citric acid cycle through the action of two key enzymes, isocitrate lyase and malate synthase. Isocitrate lyase cleaves isocitrate into glyoxylate and succinate, conserving carbon atoms. Malate synthase catalyzes the condensation of glyoxylate with an acetyl-CoA molecule, forming malate, and regenerating the intermediate oxaloacetate for the citric acid cycle, ultimately leading to the synthesis of glucose.

Step by step solution

01

Overview of the glyoxylate cycle

The glyoxylate cycle is a metabolic pathway found in plants, bacteria, and fungi. It is a modification of the citric acid cycle (also known as the Krebs cycle or tricarboxylic acid cycle) and allows for the conversion of simple compounds like acetate or fatty acids into more complex molecules, such as glucose, which can be used as an energy source.
02

Main function of the glyoxylate cycle

The main function of the glyoxylate cycle in plants is to enable the synthesis of glucose from two-carbon compounds, such as acetate or fatty acids, through a process called gluconeogenesis. This is particularly important for plants during germination, when the new plant relies on stored lipids as its primary energy source.
03

Bypassing steps from the citric acid cycle

The glyoxylate cycle bypasses the decarboxylation steps of the citric acid cycle, conserving the carbon atoms and allowing the net synthesis of glucose. It does this through the action of two key enzymes, isocitrate lyase and malate synthase, that are not present in animals.
04

Isocitrate lyase

Isocitrate lyase is an enzyme that cleaves isocitrate into glyoxylate and succinate. This step bypasses the two decarboxylation steps in the citric acid cycle (the conversion of isocitrate to 伪-ketoglutarate and then to succinyl-CoA), preventing the loss of carbon atoms as CO2.
05

Malate synthase

Malate synthase is an enzyme that catalyzes the condensation of glyoxylate with an acetyl-CoA molecule, forming malate. This allows the cycle to continue by regenerating one of the intermediates needed for the citric acid cycle (oxaloacetate), ultimately leading to the synthesis of glucose.
06

Additional roles of the glyoxylate cycle in plants

Apart from its primary function of gluconeogenesis, the glyoxylate cycle also plays important roles in nitrogen metabolism and the detoxification of glyoxylate. By converting glyoxylate to malate, which can be incorporated into the citric acid cycle, plants can prevent the build-up of harmful levels of glyoxylate and help maintain a balance in cellular metabolism.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

How does differential localization of PSII and PSI complexes within the thylakoid membrane control rates of cyclic photophosphorylation?

Why is it incorrect to refer to the Calvin cycle as the dark reactions of photosynthesis?

Describe the structure and function of chloroplasts, and compare the role of chloroplast membranes to that of mitochondrial membranes.

Write the net equation for the photosynthetic electron transport system, following the absorption of 8 photons and oxidation of \(2 \mathrm{H}_{2} \mathrm{O}\). Briefly describe the structure and function of the six key proteins required for this process.

What is the functional relationship between photosynthesis and aerobic respiration, and how does this relate to the metabolic needs of autotrophs and heterotrophs?
See all solutions

Recommended explanations on Biology Textbooks

Biological Organisms

Read Explanation

Astrobiological Science

Read Explanation

Plant Biology

Read Explanation

Cellular Energetics

Read Explanation

Bioenergetics

Read Explanation

Biological Molecules

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.