Ask a question about photosynthesis

Photosynthesis refers to the process in which green plants use light energy to convert carbon dioxide and water into organic matter that stores energy and release oxygen. The process of photosynthesis:1

Photoreaction stage The chemical reaction in the first stage of photosynthesis must have light energy to proceed, and this stage is called the photoreaction stage. The chemical reaction in the photoreaction stage is carried out on the thylakoids within the chloroplast. Dark Reaction Phase The chemical reaction in the second phase of photosynthesis can be carried out without light energy, and this stage is called the dark reaction phase.

The chemical reactions in the dark reaction phase are carried out in the matrix within the chloroplast. The light reaction stage and the dark reaction stage are a whole, and in the process of photosynthesis, the two are closely related and indispensable.

The first thing we see is the macroscopic process of photosynthesis: plants absorb water and carbon dioxide, use light energy, and convert them into sugars and oxygen in the chloroplasts of each leaf. Shown below is the organelle that performs photosynthesis – chloroplasts.

Let's move on to chloroplasts (see the chloroplast zoom in on the screen, which shows the specific process of photosynthesis. We see that the sac-like structure and matrix on the basal strome are working intensively, and we feel "dazzled" when we look at the picture, which shows that the process of photosynthesis is not a simple process.

Point B vs. Point A:

Objective: To study the photosynthesis of rice under different light intensities.

Independent variables: light intensity; Controlled by the distance of the light source;

Dependent variables: photosynthetic intensity; It is reflected by the amount of gas produced by photosynthesis;

3）……If the temperature of the water bath drops at this time, the deflection of the pointer will be affected, and the internal factors are analyzed because the low temperature reduces the activity of respiratory enzymes in rice seedlings, and the respiration is weakened.

1 Light source distance Adjust the lamp distance.

2 b to the left.

Light saturation point. The light intensity decreases to the right.

Light compensation point. 3 Darkness Temperature affects rice respiration.

As can be seen from Figure 2, the photosynthesis intensity at point D is higher than that at point C, so the photosynthesis rate at point C has not reached its peak, that is to say, the external carbon dioxide ** continues to increase, and the intensity of photosynthesis continues to rise, so from point C to point D, the limiting factor of photosynthesis is the concentration of carbon dioxide in the outside world, so the [H] produced by the photoreaction at point C is surplus relative to point D, so the answer is that the content of [H] in chloroplasts is higher at point C and point D

ATP reduces CO2 concentration 5 light intensity.

The growth rate of photosynthesis from point C to point D decreases, the respiration rate remains the same, and the amount of [H] produced remains the same, but because the photosynthetic rate at point D is still higher than that at point C, the consumption of [H] is more than that at point C, and the rest is naturally less than that of C, so the content of [H] at point C is higher.

1.White light is a composite light that contains red light and blue-violet light.

2.The pigments that absorb light energy are chlorophyll a chlorophyll b carotene and lutein, chlorophyll a and b mainly absorb red and blue-violet light, while carotene and lutein mainly absorb blue-violet light.

Therefore, the photosynthesis efficiency of white light on rice will be higher than that of red light.

White light is composed of various colors of light, including violet light, blue light, red light, etc., which can be proved by letting white light form dispersion through a prism, violet light, blue light and other relatively short wavelength light energy is higher, can drive plants to perform photosynthesis of light system one (p700) and light system two (p680), while red light energy is low can only drive light system one, so the efficiency of photosynthesis white light is higher than red light.

White light reflects all color light, does not absorb any color of light, and does not photosynthesize. The albino seedlings of the plant die because they cannot photosynthesize.

White light, as a composite light, includes both red light and blue-violet light, so it is more conducive to photosynthesis, while red light is only conducive to the synthesis of carbohydrates, so the efficiency of photosynthesis is higher than that of red light.