A cell membrane is semi-permeable. This means that it is size-specific. It allows only a particular maximum size of particles to pass through it. Large molecules such as plasma proteins and lipid molecules cannot therefore penetrate while small moecules such as glucose will easily diffuse across it.
Secondly, a cell membrane is charged. The charge is as a result of a difference in ionization between the intracellular fluid and the extracellular fluid. Substances that have the same charge as the fluid into which they are diffusing will be hard to asorb due to repulsion effect. On the other hand, substances that have opposite charge as the fluid into which they are diffusing will be absorbed easily and faster.
Finally, the cell membrane is made of two layers. Lipid layer and phospholipid layer. Inside these layers, there are embedded particles and substances such as enzymes, receptors, hormones and ion channels. During diffusion of substances across cell membrane, some substances are speeded up by these substances. For instance, Translocase enzyme in the membrane of mitochondria speeds up the transfer of Carnitine transferase into the mitochondrial matrix.
angle of incoming sunlight
Explanation:
The single feature that primarily determines the variation in climate in different parts of the world is the angle of incoming sunlight.
- Climate is simply an extended study of weather over a long period of time.
- The elements of weather like temperature, pressure, rainfall all conditions climate.
- The angle of incoming sunlight is by far the most important factor that determines climatic patterns on the earth.
- Around the equator, the sun is overhead and these regions are usually hot driving a wide range of weather phenomenon.
- The polar and temperate regions receive diffused sunlight because the sun is at an angle there.
learn more:
Sunlight brainly.com/question/1739812
#learnwithBrainly
Answer:
active; prokaryotes
Explanation:
Active transport can be defined as the movement of molecules across cell membranes against a concentration gradient, i.e., from a region of low concentration to a region of high concentration. Group translocation is a specialized type of active transport observed in prokaryotic cells. In group translocation, the transported substance is chemically modified during its movement, thereby the cell membrane becomes impermeable to this substance once it is within the cell. In bacteria, the phosphotransferase system is a type of group translocation that uses phosphoenolpyruvate (PEP) as a source of energy to transport sugar molecules into the cell.
Answer:
Phospholipid bilayer and carbohydrates.
Explanation:
Phospholipids form a double layer that protects the cell from the outside, in this layer the heads of the phospholipids, which are hydrophilic, are orientated towards the inside and the outside of the cell, and the tails of the two layers, which are hydrophobic, are in contact with each other. This bilayer allows the passage of certain substances due to its polarity, the elements that are too big, are ions, or that are hydrophilic have especial channels made of proteins that allow the passage of these kinds of elements
The other component that can affect the permeability is carbohydrates. These, when they attach to lipids and proteins, form a layer around the cell that allows the passage of certain substances, allows the recognition of the cells that are from the body, and the ones that are foreign so that there can be communication between cells.
The graph shows the ages of the women who have breast cancer, which range from ages 40 to 50. So it shows that this type of disease is most commonly diagnosed in women of these ages. Apparently, women are more prone to getting breast cancer the older they are. This is because as you get older, you lose some of your strength to fight these carcinomas so the risk of mutation grows higher as well.
Hope this helps!
