Some questions about photosynthesis, how does photosynthesis occur?

1. Which structure of the plant can be photosynthesized?

Chloroplasts (organelles), chloroplasts of higher greens are mainly found in the mesophyll cells of the leaves, but other cells may also have chloroplasts.

2. Can it continue to survive and photosynthesize without the plant body?

OK. 3. Is there any way to keep it working after it is separated from the plant?

Extract chloroplasts for in vitro culture, add energy elements, and simulate the photosynthetic system of plants.

In 1954, Alnon [United States] used isolated chloroplasts, ADP and PI to synthesize ATP under illumination and discovered photosynthetic phosphorylation.

Supplement] For the third question, you can do the Hill reaction experiment.

Chloroplast photoreduction reaction (Hill reaction).

1.Purpose of the experiment:

Understand the photoreduction of photosynthesis in chloroplasts.

2.Experimental Principle:

Chloroplasts are the organs that carry out photosynthesis in plants. When the complete chloroplast is prepared in an isotonic solution at low temperature, suspended in an appropriate reaction medium, and in the presence of an oxidant such as 2,6-dichloroindifol (DCIP), O2 is released under light and the dye is reduced at the same time, which is the photoreduction reaction carried out in chloroplasts. When the dye is reduced, the color changes from blue to colorless, so it can be determined according to the change in the OD value of the solution, which is linear over 4-5 minutes.

3.Experiment content:

Equipment & Reagents:

Experimental Instruments Centrifuge, Balance, Model 752 Spectrophotometer.

Experimental Reagents Extraction medium 50 mmoll (buffer (containing sucrose, 10 mmoll NaCl), 1 mmoll l 2,6-dcip solution.

Experimental material: Fresh spinach leaves.

4.Protocol Procedure:

Extraction of in vitro chloroplasts Take fresh spinach leaves, subtract the coarse leaf veins and cut them into pieces, weigh 10g and put them in a mortar, add 10ml of pre-cooled extraction medium and a small amount of quartz sand, quickly grind into a homogenate in an ice bath, add 10ml of extraction medium, filter it in a centrifuge tube with 4 layers of gauze, centrifuge at 700*g at 4 for 3min, discard the precipitate, centrifuge the supernatant at 1500*g at 4 for 8min, discard the supernatant, and the precipitate is complete chloroplast. The chloroplast is suspended with extraction medium, and the OD value of the solution at 660nm is about 10 nm after appropriate dilution, and it is placed in an ice bath for later use.

Determination of chloroplast photoreduction reaction Take 3 clean test tubes, numbered separately, and then add reagents according to the following table:

Pipe number. Extract media ml

Chloroplast suspension ml

When 2,6-DCIP is added, it is immediately shaken and poured into the corresponding cuvette, and the OD value at 620nm is quickly determined, which represents the OD value when the action time is 0. Then the cuvette is placed 60cm away from the 100W light, and the change of OD value is quickly read every 1min, and the reading is carried out continuously for 5-6 times, and the illumination time is strictly controlled.

The results are plotted with the change of OD620 per minute as the ordinate and the time (min) as the abscissa.

Chloroplast. OK.

Provide suitable conditions.

1. Photosynthesis**:

2. Solution of the equation for photosynthesis:

Total reaction formula: CO2+H2O (CH2O)+O2 (fill the top of the arrow with light, and fill the bottom with chloroplasts).

or 6CO2+12H2O C6H12O6+6H2O+6O2 (Fill the top of the arrow with light, and fill the bottom with chloroplasts.)

Each step is a reaction:

H20 H+ O2 (photolysis of water).

Nadp+ +2E- +H+ Nadph (Hydrogen Delivery).

ADP ATP (Energizer).

CO2+C5 compounds C3 compounds (carbon dioxide fixation).

C3 compound (CH2O) + C5 compound (organic matter generation).

3. 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.

2) Dark reaction stage The chemical reaction in the second stage of photosynthesis can be carried out without light energy, and this stage is called the dark reaction stage. 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.

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.

The reduction of C3 is a process of photosynthesis by plants, which converts absorbed CO2 into organic matter, but I don't know why.

C3 is reduced by ATP and NADPH, (CH2O) is just that when scientists first discovered sugar, most of them had (CH20), so sugar was called (CH2O), that is, carbohydrates, but later they found that there were some parts that were not like this, so now it is wrong to say that, but everyone is used to it, and no one is going to pursue it.

A C3 can only become one (CH2O) It takes 6 (CH2O) to become one glucose!

Can you understand that?

The energy released when C3 is hydrolyzed by ATP is reduced by [H].

CH2O) is a shorthand for sugars and does not necessarily refer specifically to glucose.

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

Here CH2O refers to the three-carbon sugar used to synthesize sugar, and the front C3 represents tricarbonic acid.

I've never seen this equation written like this, but if you want to highlight regeneration, I'll see it.

What you get is 6C3=5C3+(CH2O), and six Calvin cycles generate one.

Triose phosphate.

1.The final donor of electrons is water.

The final receptor is NADPH

2.Active chemical energy refers to ATP

Nadph is more reductive.

3.The dark reaction absorbs CO2

Consume atpnadph

Produces organic matter and C5

ADP and water.

As can be seen from the figure, under 4klx illumination: 15° 25°

Net photosynthetic rate: 40 50

Respiration rate: 10 to 20

So, (1) Answer: 0 mg.

Analysis: 25° all-day oxygen release 50 12-20 12=360, 15° all-day oxygen release 40 12-10 12=360, because the all-day oxygen release is equal, so the all-day glucose accumulation is equal, the difference is 0

2) Answer: milligrams.

Analysis: The "production volume" of glucose throughout the day is found, that is, the sum of the total light throughout the day. Oxygen production throughout the day (50 + 20) 12 = 840 mg, unit conversion by photosynthetic reaction formula, glucose production throughout day is 180 840 (32 6) = mg.

3) Answer: 72ml

Analysis: If the respiratory quotient is given in the question, then the respiratory function not only consumes glucose, but the respiratory intensity must be calculated according to the respiratory quotient first, and then the (gronet) photosynthetic intensity must be calculated. 25° net photosynthesis throughout the day:

50+20）×12-20× ；15° net photosynthesis: (40+10) 12-10 ; Full-day difference: 504-432=72

The problem is difficult and the calculation is very cumbersome, so it's not appropriate for you to send out such a question without a reward, so please add it

Hope it helps

According to the figure, at 25 hours with a light intensity of 0 (dark), 20 mg of oxygen per hour (for respiration) is required

At 15 hours, at 0 light intensity (darkness), 10 mg of oxygen per hour (for respiration) is required

1) 4klx light, 25 under the release of oxygen per hour 50mg, then the amount of oxygen released per hour by photosynthesis is 50mg + 20mg = 70mg, 15 release of oxygen 40mg, then the amount of oxygen released by photosynthesis is 40mg + 10mg = 50mg

At 25, the oxygen produced by the plant throughout the day was 70 mg h 12 h 20 mg h 24h = 360 mg, and the accumulated glucose was 360 mg 192 180 = 450 mg (photosynthesis reaction formula: O2 + 6H2O = C6H12O6 + 6O2, respiration is reversed).

At 15, the oxygen produced throughout the day was 50 mg h 12 h 10mg h 24h = 360 mg, and the accumulated glucose was the same as above.

So: the amount of accumulation is equal.

2) Light 25, darkness 15, plants throughout the day to produce oxygen.

70mg/h×12 h－20mg/h×12h－10mg/h×12h = 480mg

The accumulated glucose is: 480 mg 192 180 = 600 mg

3) The respiration quotient is, then the plant respirates CO2 O2= , CO2 production is a multiple of the oxygen consumption, CO2 = O2.

In 25 days of photosynthesis 840 mg of oxygen is produced, the consumption of CO2 is 840 32 44 = 1155 mg, and the respiration consumes 480 mg of oxygen, then the production of CO2 is = 462 mg

The CO2 in the environment is reduced by 1155mg - 462mg = 690mg.

At 15, photosynthesis produces 600 mg of oxygen throughout the day, consuming CO2 of 600 32 44 = 825 mg, and respiration consuming 240 mg of oxygen, then producing CO2 = 231 mg

The CO2 in the environment was reduced by 825mg -231mg = 594mg

25 environment compared to 15 environment, environmental CO2 690 mg 594 mg = 96 mg

6co2+6h2o=c6h12o6+6o2

6o2:c6h12o6=6*32:180=16:15

Under 4klx, 25 degrees produces (50-40)*12 more oxygen than 15 degrees, which produces 120 16*15 more glucose, that is, milligrams, and plants consume 20 milligrams of oxygen per hour at 15 degrees in dark conditions, and do not consume at 25 degrees, and the glucose decomposition formula is the same as above, a total of 20 * 12 oxygen is consumed within 12 hours, and 240 16*15 glucose is consumed, that is, 225 milligrams, and the difference between production and consumption is milligrams.

Light 25 degrees for 12 hours produces a total of 50 * 12 oxygen, produces glucose 600 16 * 15 that is, milligrams, dark 15 degrees consumes a total of 20 * 12 mg of oxygen, consumes 225 mg of glucose, and the total amount of glucose produced is milligrams.

At 25 degrees, 12 hours of light produces 50*12=600 mg of oxygen, which is not consumed when dark, and the respiratory quotient is, and the CO2 mass is 420 mg.

12 hours of light at 15 degrees Celsius produces 40 * 12 = 480 mg of oxygen, and when it is dark, it consumes 20 * 12 = 240 mg of oxygen, the difference is 240, and the respiratory quotient is, the amount of CO2 is 168 mg.

This question may be written incorrectly in the unit of CO2 later, if you want to calculate the volume and consider the density of the gas in the ideal state, it should be the mass, that is, 420-168 = 252 mg.

The above is all the steps to solve the problem, and it is necessary to understand the reaction formula of photosynthesis, as well as the molecular formula of glucose, relative molecular mass. Hope it helps.