Inside a Eukaryote: Plants and Chloroplasts
A typical plant cell might contain as many as 50 chloroplasts.
The chloroplast is made up of 3 types of membrane:- A smooth outer membrane which is freely permeable to molecules.
- A smooth inner membrane which contains many transporters: integral membrane proteins that regulate the passage in an out of the chloroplast of
- small molecules like sugars
- proteins synthesized in the cytoplasm of the cell but used within the chloroplast
- A system of thylakoid membranes
Thylakoids- The thylakoid membranes enclose a lumen: a system of vesicles (that may all be interconnected).
- At various places within the chloroplast these are stacked in arrays called grana (resembling a stack of coins).
- Photosynthesis in Higher Plants
- small molecules like sugars
- proteins synthesized in the cytoplasm of the cell but used within the chloroplast
- Photosynthesis in Higher Plants
Most photosynthesis occurs in the leaves of plants, although there may be photosynthetic stems, flowers, and fruits. At the cellular level, photosynthesis occurs inside organelles known as chloroplasts. Plants use photosynthetic pigments (e.g., chlorophyll) to capture the light energy which is ultimately converted into chemical energy in the form of sugars. Photosynthesis involves two stages, the light reactions and calvin cycle reactions.
Questions:
1. In what organelles does the process of photosynthesis occur?
2. How many stages are involved in photosynthesis
3. What is chlorophyll and what is its role in higher plants?
Questions:
1. In what organelles does the process of photosynthesis occur?
2. How many stages are involved in photosynthesis
3. What is chlorophyll and what is its role in higher plants?
The Importance of Photosynthesis
Photosynthesis harnesses the sun's energy into utilizable forms of energy on earth. Most biological organisms such as animals and fungi are unable to directly use light energy to power biological processes such as active transport, cell division and muscle movement.
ATP is used to power these processes. Photosynthesis converts light energy into chemical energy in the form of glucose and then the process of cellular respiration converts energy in glucose to energy in the form of ATP which is ultimately used to power biological processes.
The energy produced by photosynthesis forms the basis of virtually all terrestrial and aquatic food chains. As a result, photosynthesis is the ultimate source of carbon in the organic molecules found in most organisms. The high oxygen concentration in the atmosphere is derived directly from the light reactions of photosynthesis. Prior to the evolution of photosynthesis on earth, the atmosphere was anoxic.
Critical Thinking
1. Since plants can not use the sun's light energy, to what form must it be converted in order to make food?
2. What is the end product of photosynthesis?
3. How do molecules provide energy for cell function, development, and activities?
ATP is used to power these processes. Photosynthesis converts light energy into chemical energy in the form of glucose and then the process of cellular respiration converts energy in glucose to energy in the form of ATP which is ultimately used to power biological processes.
The energy produced by photosynthesis forms the basis of virtually all terrestrial and aquatic food chains. As a result, photosynthesis is the ultimate source of carbon in the organic molecules found in most organisms. The high oxygen concentration in the atmosphere is derived directly from the light reactions of photosynthesis. Prior to the evolution of photosynthesis on earth, the atmosphere was anoxic.
Critical Thinking
1. Since plants can not use the sun's light energy, to what form must it be converted in order to make food?
2. What is the end product of photosynthesis?
3. How do molecules provide energy for cell function, development, and activities?
The Greenhouse Effect and Global Warming: How Photosynthesis Can Help
Carbon dioxide (CO2) is an atmospheric constituent that plays several vital roles in the environment. It absorbs infrared radiation in the atmosphere. It plays a crucial role in the weathering of rocks. It is the raw material for photosynthesis and its carbon is incorporated into organic matter in the biosphere and may eventually be stored in the Earth as fossil fuels.
Most of the sun's energy that falls on the Earth's surface is in the visible light portion of the electromagnetic spectrum. This is in large part because the Earth's atmosphere is transparent to these wavelengths (we all know that with a functioning ozone layer, the higher frequencies like ultraviolet are mostly screened out). Part of the sunlight is reflected back into space, depending on the albedo or reflectivity of the surface. Part of the sunlight is absorbed by the Earth and held as thermal energy. This heat is then re-radiated in the form of longer wavelength infrared radiation. While the dominant gases of the atmosphere (nitrogen and oxygen) are transparent to infrared, the so-called greenhouse gasses, primarily water vapor (H2O), CO2, and methane (CH4), absorb some of the infrared radiation. They collect this heat energy and hold it in the atmosphere, delaying its passage back out of the atmosphere.
Analysis Questions:
1. We can not realistically stop the rise of CO2, however, we can slow it down. Provide ways in which we can stop global warming from occuring.
2. What are the consequences of global warming?
3. How can the process of photosynthesis contribute to the decreased amount of carbon dioxide, and the rise of oxygen levels n the atmosphere?
Most of the sun's energy that falls on the Earth's surface is in the visible light portion of the electromagnetic spectrum. This is in large part because the Earth's atmosphere is transparent to these wavelengths (we all know that with a functioning ozone layer, the higher frequencies like ultraviolet are mostly screened out). Part of the sunlight is reflected back into space, depending on the albedo or reflectivity of the surface. Part of the sunlight is absorbed by the Earth and held as thermal energy. This heat is then re-radiated in the form of longer wavelength infrared radiation. While the dominant gases of the atmosphere (nitrogen and oxygen) are transparent to infrared, the so-called greenhouse gasses, primarily water vapor (H2O), CO2, and methane (CH4), absorb some of the infrared radiation. They collect this heat energy and hold it in the atmosphere, delaying its passage back out of the atmosphere.
Analysis Questions:
1. We can not realistically stop the rise of CO2, however, we can slow it down. Provide ways in which we can stop global warming from occuring.
2. What are the consequences of global warming?
3. How can the process of photosynthesis contribute to the decreased amount of carbon dioxide, and the rise of oxygen levels n the atmosphere?