Answer:
The process of passage of different molecules, solutes, and liquids, through the phospholipid bilayer in human cells, and really in all animal cells, is highly dependent on a tight coordination between chemical, and thermodynamic balances, that will collaborate in these elements being able to pass, or not pass, through a cell´s membrane, and activate other mechanisms within the cell when their passage is not possible. Unlike what was once believed, that transport proteins were like buses parked at the membrane and waiting to be loaded with molecules to later remove themselves from the membrane and carry their load into the cytoplasm, scientific research has found that this is definitely so, and that transport proteins do not come off the layer to transport molecules. They are permanently anchored to the membrane and through a series of second messenger systems, energy produced by the passage of certain ions like potassium and sodium, and other such processes, these transport proteins become activated, allow the passage of molecules and change them in such a way that they can be taken into the cell in vesicles, or, they will anchor them to second messengers, who will be responsible for carrying the molecule inside.
From the list of words given and the two sentences down below, which are two reasons why the earlier believed models for transport proteins are not correct would be:
1. Integral membrane proteins are embedded stably in the membrane and protrude from one or both side based on their hydrophobic, or hydrophilic, regions. These sides will not switch because of the disbalance that would be created if the two sides had to be switched chemically to allow them to pass to the opposie sides.
2. For protein to traverse a membrane, movement of its hydrophilic regions through the interior of the membrane would be required, which would be highly endergonic and hence thermodynamically improbable.
The 3 checkpoints include G1 where the cell growth is checked, G2 where the integrity of the DNA/chromosome is checked, and M where the integrity of the metaphase plate is checked.
<h3>Cell cycle checkpoints</h3>
There are 3 regulatory checkpoints in the life cycle of cells:
- G1: the size of the cell, the presence of growth factors, and the integrity of the DNA are checked before the cell irreversibly commits to division.
- G2: the integrity of the DNA and the correctness of the replication process at the S-phase are checked.
- M: correct attachment of the spindle fibers to the chromosomes at the metaphase plate is checked.
More on cell cycle checkpoints can be found here: brainly.com/question/2128300
Answer:
SEM ANSWER
Explanation:
Electron microscopy is a powerful tool in the field of microbiology. It has played a key role in the rapid diagnosis of viruses in patient samples and has contributed significantly to the clarification of virus structure and function, helping to guide the public health response to emerging viral infections. In the present study, we used scanning electron microscopy (SEM) to study the infectious cycle of SARS-CoV-2 in Vero E6 cells and we controlled some key findings by classical transmission electronic microscopy (TEM). The replication cycle of the virus was followed from 1 to 36 h post-infection. Our results revealed that SARS-CoV-2 infected the cells through membrane fusion. Particles are formed in the peri-nuclear region from a budding of the endoplasmic reticulum-Golgi apparatus complex into morphogenesis matrix vesicae. New SARS-CoV-2 particles were expelled from the cells, through cell lysis or by fusion of virus containing vacuoles with the cell plasma membrane. Overall, this cycle is highly comparable to that of SARS-CoV. By providing a detailed and complete SARS-CoV-2 infectious cycle, SEM proves to be a very rapid and efficient tool compared to classical TEM.
Answer:
Asexual reproduction is a type of reproduction that doesn’t involve gametes fusing or the change in the number of chromosomes. A spider plant is the perfect example of asexual reproduction, but when it comes to plants like that, it’s referred to a type of asexual reproduction called vegetative propagation.
Answer:
Smooth Muscle
Explanation:
In the digestive tract it's called the muscularis mucosa.
