光合呼吸实验设计

Front

In the experiment "using methylene blue to measure yeast anaerobic respiration", what is the complete purpose of adding "liquid paraffin" to the surface of the test tube?

Back

To isolate air (oxygen), ensure an anaerobic environment

Front

In the chloroplast suspension experiment, what are the two core functions of adding "pH 7.2 phosphate buffer"?

Back

① Maintain stable solution pH to prevent pH changes from affecting the activity of enzymes involved in the light-dependent reaction;

② Maintain the osmotic pressure of chloroplasts to prevent chloroplasts from absorbing water and bursting (lysis).

Front

Before measuring larval respiration with a simple respirometer, what key operation must be completed? (Purpose: Eliminate initial errors)

Back

Open the valve of the respirometer to equalize the air pressure inside the apparatus with the outside before closing it

Front

DCPIP changes from blue to colorless in an environment of "chloroplasts + light". What is the fundamental reason? (Need to link to the light-dependent reaction process)

Back

During the light-dependent reaction, photolysis of water produces NADPH (or [H]), and DCPIP, as a hydrogen acceptor, is reduced by NADPH, causing the color to fade.

Front

In the experiment "the effect of light wavelength on chloroplast photosynthetic rate", when using "red/blue/green filters", what other variable must be controlled simultaneously? How to control it?

Back

Light intensity must be controlled to be constant; Control method: Fix the light source at the same distance (e.g., 15cm) to ensure consistent light intensity received by different filters.

Front

In a simple respirometer, what is the direct reason for the droplet moving "left" during larval respiration?

Back

Larvae consume O₂ during respiration, and the produced CO₂ is absorbed by KOH solution. This reduces the total gas volume inside the apparatus and lowers the air pressure, so atmospheric pressure pushes the droplet to the left.