Metabolism in Cells: Rice Cultivation

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Questions and Answers

What is the role of photosynthesis in plants?

To convert solar energy into chemical energy (correct)

To release carbon dioxide and water

To break down carbohydrates

To synthesize proteins from amino acids

Which process involves breaking down large molecules to release energy?

Metabolism

Photosynthesis

Catabolism (correct)

Anabolism

What percentage of protein is typically found in rice?

15%

10% (correct)

20%

How do rice roots survive in submerged conditions?

By utilizing anaerobic respiration Signup and view all the answers

What is the consequence of modern milling processes on rice?

Removes the bran and germ Signup and view all the answers

In oxidation-reduction reactions, what occurs during oxidation?

Loss of electrons Signup and view all the answers

What is primarily produced during cellular respiration?

Carbon dioxide and water Signup and view all the answers

Which statement correctly defines metabolism?

All chemical processes within a cell, including anabolism and catabolism Signup and view all the answers

What is the primary function of photosynthesis in the biosphere?

It generates energy and oxygen for non-photosynthetic organisms. Signup and view all the answers

Which portion of the electromagnetic spectrum can be detected by the human eye?

Visible spectrum Signup and view all the answers

What happens to photons in the visible light range during photosynthesis?

They excite electrons in chlorophyll molecules. Signup and view all the answers

How does the energy of a photon relate to its wavelength?

Energy is inversely proportional to wavelength. Signup and view all the answers

Which type of radiation has too much energy to be useful in photosynthesis?

Ultraviolet radiation Signup and view all the answers

What is the lowest energy state that an electron can occupy called?

Ground state Signup and view all the answers

What role does visible light play in the process of photosynthesis?

It provides energy to excite electrons. Signup and view all the answers

Which of the following statements about longer wavelengths is true?

They do not carry enough energy for electron excitation. Signup and view all the answers

What happens to an electron when it absorbs a photon?

It is energized and raised to a higher energy level. Signup and view all the answers

Where does photosynthesis primarily take place in plants?

In the chloroplasts Signup and view all the answers

What is the primary function of chlorophyll in photosynthesis?

To absorb light energy Signup and view all the answers

What do carotenoids do in the process of photosynthesis?

They extend the range of light that can be utilized. Signup and view all the answers

Which type of chlorophyll is primarily responsible for initiating photosynthesis?

Chlorophyll a Signup and view all the answers

What is the structure that surrounds the fluid-filled area called the stroma in chloroplasts?

Inner membrane Signup and view all the answers

Which light wavelengths do chlorophyll primarily absorb?

Blue and red Signup and view all the answers

What is the role of stomata in mesophyll cells?

To facilitate gas exchange Signup and view all the answers

What is the primary role of chlorophyll in photosynthesis?

To absorb light energy Signup and view all the answers

Why does the action spectrum not exactly match the absorption spectrum of chlorophyll?

Accessory pigments also absorb light energy Signup and view all the answers

In Engelmann’s experiment, what method was used to measure photosynthesis?

Observing the movement of oxygen-loving bacteria Signup and view all the answers

What are the main raw materials required for photosynthesis?

Carbon dioxide and water Signup and view all the answers

During which stage of photosynthesis does ATP and NADPH get produced?

Light-dependent reactions Signup and view all the answers

What products are formed during the light-dependent reactions of photosynthesis?

ATP and NADPH Signup and view all the answers

What is the general equation for photosynthesis?

6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O Signup and view all the answers

Which of the following is true about accessory pigments?

They help chlorophyll capture additional light energy Signup and view all the answers

Study Notes

Rice as a Staple Food

Rice (Oryza sativa) feeds half the world's population, predominant in Asia, Africa, and Latin America.
It is a cereal crop like wheat and corn, cultivated for its dry seeds (fruits).
Grown submerged in 10-15 cm of water, rice roots thrive in low oxygen environments where most crops fail.
Contains approximately 10% protein; requires supplementation with meat, fish, or protein-rich plants for balanced diets.
White rice, produced through milling that removes bran and germ, is less nutritious than brown rice.

Metabolism Overview

Metabolism encompasses all chemical processes in a cell, divided into anabolic and catabolic reactions.
Anabolic reactions (anabolism) store energy by synthesizing complex molecules from simpler ones (e.g., photosynthesis produces glucose).
Catabolic reactions (catabolism) release energy by breaking down larger molecules into simpler components (e.g., cellular respiration converts glucose to CO₂ and water).

Oxidation-Reduction Reactions

Oxidation-reduction (redox) reactions are vital in metabolism, involving electron transfer between molecules.
Oxidation denotes electron loss, while reduction indicates electron gain; these processes are interlinked.
In cells, hydrogen removal signifies oxidation, and hydrogen gain signifies reduction.

Photosynthesis Process

Photosynthesis transforms solar energy into chemical energy, yielding carbohydrates and oxygen from water and carbon dioxide.
Acts as the foundational energy cycle for the biosphere, essential for life and oxygen supply to non-photosynthetic organisms.

Light and Its Properties

Visible light is part of the electromagnetic spectrum (380-760 nm) and is crucial for photosynthesis.
Light behaves as both a wave (with wavelength) and a particle (photons); its energy inversely correlates with wavelength.
Short wavelengths (e.g., violet) carry more energy, while long wavelengths (e.g., radio waves) lack sufficient energy for photosynthesis.

Electron Excitation Mechanism

Electrons can be energized by absorbing photons, transitioning from a ground state to a higher energy level.
Energized electrons either return to ground state, releasing energy as heat/light, or transfer to another molecule, contributing to photosynthesis.

Chloroplast Structure and Function

Photosynthesis occurs in chloroplasts, predominantly in mesophyll cells, containing multiple chloroplasts for optimal light absorption.
Chloroplasts consist of two membranes with an internal stroma housing enzymes for carbohydrate synthesis and thylakoids for pigment storage.

Chlorophyll and Pigments

Chlorophyll absorbs blue and red light, reflecting green, which leads to the characteristic color of plants.
Chlorophyll a is the primary pigment initiating photosynthesis; chlorophyll b and carotenoids serve as accessory pigments that broaden light absorption.

Action and Absorption Spectrum

The absorption spectrum illustrates pigment light absorption; chlorophyll a and b have distinct absorption profiles.
The action spectrum indicates the effectiveness of light wavelengths for photosynthesis, correlating with but not matching the absorption spectrum.

Engelmann’s Experiment

Engelmann (1883) demonstrated photosynthesis action spectrum using the alga Spirogyra, tracking bacteria movement towards oxygen production in blue and red light, confirming chlorophyll's role.

Photosynthesis Chemical Equation

The general photosynthesis equation: 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O.
Carbon dioxide and water convert into glucose and oxygen using light energy; chlorophyll acts as a catalyst.

Energy Conversion and Stages of Photosynthesis

Light energy absorbed by chlorophyll splits water into oxygen, electrons, and protons, aiding carbohydrate formation.
Photosynthesis occurs in two stages: light-dependent reactions generate ATP and NADPH in thylakoid membranes, utilizing light energy.

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Description

Explore the unique metabolic processes of rice (Oryza sativa), a crucial staple food for millions. This quiz delves into its cultivation in water-logged conditions and the adaptations that allow it to thrive where other crops would struggle. Test your knowledge on the significance of rice in global agriculture.