A question in the textbook of the compulsory one of high school biology courses

Ratio of cell surface area to volume. The expansion bubble in protozoan cells is the ratio of membrane surface area to volume.

The nucleocytoplasm ratio of the cell, the cell size controlled by the nucleus is proportional to the size of the nucleus. So a larger cell like paramecium has two nuclei, ensuring a normal nucleocytoplasmic ratio.

Then, there are generally 2 nuclei that can reduce the burden on the cell itself.

Our teacher explained every question really well: it is related to the factors that limit the growth of cells: 1. The surface body ratio of cells, protozoan expansion bubbles increase the cell surface body ratio;

2 nucleocytoplasmic ratio: the cell size controlled by the nucleus is directly proportional to the size of the healing, like paramecium, the individual large cell has 2 nuclei, to ensure a normal nucleocytoplasmic ratio.

Finished Add: Why did you look at the upstairs and it was the same, and the teacher copied the whole explanation?!

The nucleus is the control center of all life activities.

You can check the general information books yourself or ask the teacher.

1 c If it's bound water, free water, then the ratio goes down, and if it's free water, combined with Songshou water, then the ratio goes up.

Bound water is one of the states of water in the presence of organisms and cells, and is water that adsorbs and binds to organic solid matter.

Free water, water that is not adsorbed by colloidal particles or macromolecules in plant cells, can move freely, and acts as a solvent.

Sun-dried wheat seeds: starch.

Sun-dried embryos: proteins.

Sudan III is also orange, in order to avoid the residual Sudan III affecting the experimental effect, so wash off the surface of the test solution to make it more visible under the microscope.

I don't understand hi me.

Choose A to replicate twice for a total of 4 8 strands Only the next two strands are 32p, which can be regarded as 1 DNA molecule, the relative molecular weight has not increased or decreased from the original, and the other 3 DNA molecules are all 31p, and the relative molecular weight is reduced by 2000x3=6000. There are a total of 4 progeny DNA molecules, and the relative molecular weight is reduced by 6000 on average 4=1500

A After two replicates, we get 4 DNA molecules, two of which are 32p, and the average of the 8 strands is (32*2+31*6) 8= Because it's 1000 pairs of bases, each piece of DNA has 2000 bases.

Pick a to reduce 1500

After 2 replicates, the number of single strands of DNA obtained by selecting B is 8, and 6 of them are newly replicated, that is, the strand containing 32p contains a total of 6000 bases, and the mass of each base is relatively increased by 1, so the mass is increased by 6000, and because there are 4 double-stranded DNA molecules, each DNA molecule is increased by an average of 1500Hope it helps, thank you!

I choose AThere are four DNA molecules and eight strands that are replicated twice, and two of the strands are from the parent strand, and the remaining six are p31-containing ones, and one strand is reduced by 1000, so a total of 6000 is reduced, and divided by 4 gives 1500, so there is an average reduction of 1500

Select C The oxygen in the blood is transported to the myocardium through the blood in the red blood cells, and then enters the plasma through free diffusion (out of the cell, through a layer of cell membrane), then through the capillary wall cells into the interstitial fluid (in and out of the cell, through two layers of cell membrane), and then into the cardiomyocyte (into the cell, through a layer of cell membrane), and finally into the mitochondria to be utilized (into the mitochondrial double membrane).

So a total of 6 layers of cell membranes.

It enters the interstitial fluid through capillaries, which have two membranes in their walls.

into the histiocytes, i.e., cardiomyocytes, a layer of membrane.

To be utilized, so also to enter the mitochondria, two layers of membranes.

So at least five floors.

Just choose B.

4 layers, as soon as you can forget about graduation, the capillaries will be 2 layers.