About chloroplasts and totipotency of cells

The biology competition has just tested the relevant knowledge of this question.

The crux of the matter is that chloroplasts and mitochondria are semi-autonomous organelles.

It has its own genetic material and is also controlled by the genetic material in the nucleus.

The nucleus is the most important organelle and all the other organelles are controlled by it.

Totipotency refers to the fact that each cell has genes in its nucleus that produce all kinds of cells, but are selectively expressed because of differentiation.

Refers to the nucleus of a cell that has all the genetic material.

Rather than saying that plant cells are totipotent, in fact, the nucleus of each cell has genes that produce all kinds of cells, but they are selectively expressed because of differentiation. You can see on TV about human stem cells, what happens when you put it, it's very similar to plants.

Mitochondria and chloroplasts have a saying from the origin of species, that is, all the double-membrane structure organelles in the cell are exogenous - that is, they are not original, mitochondria and chloroplasts have their own DNA inside, which can replicate themselves independently and are not affected by the nucleus, but I think this is a bit like the relationship between autonomy and the state, small things don't matter, but the general direction must be the same, and it can't be messed with.

The selective expression of genes in different time and space enables the differentiation of plant cells into various organs with different functions.

That's right, it's cytoplasmic inheritance.

Chloroplasts and mitochondria are controlled by and are primarily influenced by genes in the nucleus.

The DNA of the nucleus has the whole set of genetic information about the organism, but its expression is selective, and it is expressed through RNA.

Even the explanation is not comprehensive, even this aspect is only at the level of high school!

1. The separation of chloroplasts should be done in isotonic solution (sodium chloride.

or sucrose. solution) to avoid osmotic pressure.

chloroplasts are damaged. The homogenate was centrifuged at 1000 r min for 2 min to remove tissue debris and some of the broken intact cells.

2. Then centrifuge at 3000 r min for 5min to obtain precipitated chloroplasts (mixed with part of the nucleus). The separation process is best carried out under the condition of 0 4; If at room temperature, quickly separate and observe.

The chloroplast is composed of three parts: chloroplast outer cover, thylakoid and matrix, and it is an organelle that contains chlorophyll for photosynthesis. The function of chloroplasts is to carry out photosynthesis, and they are the "nutrient manufacturing workshop" and "energy conversion station" of plants.

Outer coat: The chloroplast is surrounded by two smooth unit membranes. The two membranes are separated by a brighter space with low electron density. These two layers of unit membrane are called chloroplast membranes or outer coats. The chloroplast membrane is filled with a matrix in a fluid state with many lamellar structures in the matrix.

Thlakoids: Each lamellae is made up of two layers of membranes that are closed around and are in the shape of a flat sac, called thylakoids. Within the thylakoids is an aqueous solution.

Small thylakoids are stacked on top of each other to form a strigotryp, and such thylakoids are called sclerotoid thylakoids. The sheets that make up the basal grains are called basal lamellae. Large thylakoids traverse the stroma and run between two or more basal granules.

Such a lamella is called a stromal lamellae, and such a thylakoid is called a stromal thylakoid.

Matrix: It is the liquid in the space between the inner membrane and the thylakoid, and the main components include enzymes related to carbon assimilation, in addition, chloroplast DNA, protein synthesis system, and some particle components, such as various RNA, ribosomes and other proteins.

The function of chloroplasts is to carry out photosynthesis. Photosynthesis is the process by which chlorophyll absorbs light energy and converts it into chemical energy while using carbon dioxide and water to make organic matter and release oxygen. It consists of many complex steps, which are generally divided into two stages: light reaction and dark reaction.

Light reaction: This is the process by which pigment molecules such as chlorophyll absorb and transfer light energy, convert light energy into chemical energy, and form ATP and Nadph. In this process, the water molecules are broken down and oxygen is released.

The process of reducing CO2, fixing the formed intermediate products, and making carbohydrates such as glucose. Through this process, the active chemical energy in ATP and Nadph2 is converted into stable chemical energy stored in carbohydrates. It is also known as carbon dioxide assimilation or carbon assimilation process.

It is a process in which many enzymes are involved in the reaction.

The function of chloroplasts is to carry out photosynthesis. Chloroplasts are sites of photosynthesis, where photosynthesis takes place, converting light energy into chemical energy and storing it in the organic matter it makes. It can be said that the energy required for almost all life activities is solar energy (light energy).

Green plants are the main energy converters because they contain chloroplasts, which are organelles that complete energy conversion, which can use light energy to assimilate carbon dioxide and water, synthesize energy-storing organic matter, and produce oxygen in the same way. The photosynthesis of green plants is the fundamental source of the survival, reproduction and development of organisms on the earth, and chloroplasts have made great contributions.

Photosynthesis Plant cells are surrounded by a double membrane and contain organelles that allow chlorophyll to carry out photosynthesis. The interstitium is suspended by thylakoids made up of membranous sacs, which contain chloroplast DNA

Chloroplasts are structures that carry out photosynthesis inside the cells of green plants and are a type of plastid. There are three types of plastids: round, oval or disc-shaped. Chloroplasts contain chlorophyll a and b and are green in color, which is easy to distinguish from the other two types of plastides: colorless white bodies and yellow to red colored bodies.

The function of chlorophyll a and b is to absorb light energy and convert it into chemical energy through photosynthesis. The chloroplast is oblate spherical, about microns thick and about 5 microns in diameter. It has a double-layer membrane with interstitium, which contains enzymes and sheets that are in a dissolved state.

The lamellae are stacked from closed, hollow disc-shaped thylakoids, which are required for the formation of the high-energy compound adenosine triphosphate (ATP).

Not all plant cells contain chloroplasts. Chloroplasts are only found in some higher plants and some algae, and large single-celled prokaryotes like cyanobacteria do not have chloroplasts. Chloroplasts are a type of plastid and are energy converters unique to higher plants and some algae.

Its double-layer membrane structure separates it from the cytoplasm and has a lamellar membrane containing chlorophyll, hence the name chloroplast.

In higher plants, chloroplasts are like biconvex or planoconvex lenses, with a long diameter of 5-10um, a short diameter of 2-4um, and a thickness of 2-3um. The mesophyll cells of higher plants generally contain 50 200 chloroplasts, which can account for 40% of the cytoplasm, and the number of chloroplasts varies according to the cell type, ecological environment, and physiological state of the species. In algae, chloroplasts have various shapes, such as reticulated, banded, lobed and star-shaped, etc., and the volume is huge, up to 100um.

Chloroplasts are composed of three parts: chloroplast outer cover, thylakoids, and matrix, and it is an organelle that contains chlorophyll for photosynthesis. Chloroplasts contain 3 different membranes: the outer membrane, the inner membrane, the thylakoid membrane, and 3 types of cavities that are separated from each other: the intermembranous space, the matrix, and the thylakoid lumen.