Which step in photosynthesis does not need light?(1 point)
Responses
Chlorophyll absorbs energy.
Chlorophyll absorbs energy.
Water splits into hydrogen and oxygen.
Water splits into hydrogen and oxygen.
Carbon dioxide and hydrogen combine to make glucose.
Carbon dioxide and hydrogen combine to make glucose.
Oxygen is released.
Oxygen is released.
The step in photosynthesis that does not need light is: Water splits into hydrogen and oxygen.
Question
A scientist performs an experiment by placing petroleum jelly on under side of plant leaves. This blocks the leaves’ stomata. The plant continues to be watered and is located in a sunny spot. What will the scientist observe?(1 point)
Responses
The plant grows and thrives.
The plant grows and thrives.
The plant grows, flowers, and seeds.
The plant grows, flowers, and seeds.
The plant goes into hibernation.
The plant goes into hibernation.
The plant withers and dies.
The plant withers and dies.
How many carbon atoms combine in the photosynthesis reaction?(1 point)
Responses
6 carbon atoms combine in the photosynthesis reaction.
The step in photosynthesis that does not need light is the splitting of water into hydrogen and oxygen. This step is known as photolysis or the light-independent reaction. To understand why this step does not require light, let's break it down.
Photosynthesis is the process by which plants and some other organisms convert sunlight, carbon dioxide, and water into oxygen and glucose (a sugar used for energy). It occurs in two main stages: the light-dependent reactions and the light-independent reactions (also called the Calvin cycle).
During the light-dependent reactions, light energy is used to excite electrons in chlorophyll molecules, which creates energy-rich compounds like ATP and NADPH. These reactions occur in the thylakoid membranes of the chloroplasts, where pigments like chlorophyll are located. So, light is essential for this stage.
However, in the light-independent reactions (Calvin cycle), the energy acquired from the light-dependent reactions is used to convert carbon dioxide (CO2) into glucose. This cycle takes place in the stroma (the fluid-filled space of the chloroplasts), where the enzymes and molecules responsible for this process are located.
The splitting of water into hydrogen and oxygen molecules is the initial step of the light-independent reactions. This process is driven by the energy derived from the light-dependent reactions, which is temporarily stored in ATP and NADPH. Therefore, while indirectly influenced by light, the splitting of water itself does not require light.
So, the answer is: Water splits into hydrogen and oxygen.