The cell membrane is a selectively permeable barrier that separates the internal environment of a cell from the external environment. Small, uncharged molecules such as oxygen, carbon dioxide, and nitrogen can diffuse directly through the cell membrane.
It is made up of a phospholipid bilayer that consists of hydrophilic heads and hydrophobic tails. The hydrophobic tails face each other, creating a nonpolar region in the middle of the membrane that prevents the diffusion of most molecules. However, there are certain types of molecules that can diffuse the cell membrane directly.
Small, nonpolar molecules such as oxygen, carbon dioxide, and nitrogen are able to pass through the cell membrane by simple diffusion. They can dissolve in the nonpolar region of the membrane and cross from one side to the other without the need for a transport protein. Other small molecules like water can diffuse through the cell membrane, but at a much slower rate due to its polar nature.
On the other hand, larger molecules such as glucose, amino acids, and ions require transport proteins to cross the cell membrane. These proteins help to facilitate the movement of these molecules across the membrane, either through channels or carriers.
In conclusion, only small, nonpolar molecules can diffuse the cell membrane directly. Larger molecules require transport proteins to assist their movement across the membrane.
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Small, uncharged substances like oxygen, and carbon dioxide, and hydrophobic molecules like lipids can directly diffuse through the cell membrane in a process known as simple diffusion. Larger molecules like glucose, amino acids, and polar substances, as well as ions, cannot; they need special means to pass through, often utilizing specific protein channels via facilitated transport.
The molecules that can directly diffuse through the cell membrane are mainly small, uncharged substances such as oxygen and carbon dioxide, and hydrophobic molecules like lipids. This process is known as simple diffusion, where molecules move down their concentration gradient, from an area of high concentration to an area of lower concentration. The cell's lipid bilayer structure allows these types of substances to pass.
However, larger molecules like glucose, amino acids, and polar substances can't readily pass through the membrane due to their size or charge. They require special means of penetrating plasma membranes, often through specific protein channels in a process known as facilitated transport. Moreover, ions such as sodium, potassium, calcium, and chloride also need these special means because their charge prevents them from diffusing directly through the membrane's mosaic.
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Answer:
The answer is physically fit
Explanation:
A physically fit person is able to carry out activities without unwarranted fatigue. Physical fitness include muscle strength and endurance, flexibility, body composition etc. A physically fit person normally gets proper nutrition, enough physical exercise and rest. A physically fit person is generally healthy .
Answer:
Your correct answer is physically fit
Explanation:
B. Line graph
C. Pie graph
D. Bar graph
The answer is:
D. Bar graph
In a bar graph you can put in the Y axis the percentage from 0 to 100 and you just put the states in the X axis, this way you can make a visual representation of the differences on the populations ages in the different states of the United States.
The correct answer is: Option D. Bar graph.
By presenting the age intervals (based on percentages) in the shape of bars, anyone could easily compare these elements jusy by analyzing the altitude of the bars. With this method, highlighting both the most prominent age set (highest value) and the most lacking one (lowest value) is a simple task.
B.Georg and Ulrich find peace and forgiveness.
C.In times of crisis, people reconsider their values.
D.In literature, the forest is often a dark and dangerous place.
Answer:
C. In times of crisis, people reconsider their values.
Explanation:
The story 'Interlopers' is about a feud between two families over a forest land. The two families refused to compromise the ownership of the land until their actions put Georg and Ulrich in a difficult situation. The story itself is symbolic. Human conflict, greed, anger, jealousy are been analyzed in this story. The story also explains that we should reconsider our values especially in times of crises. Georg and Ulrich lived their lives in hatred for each other because none of them wanted to give up on the issue until they met their waterloo. When they are trapped by the trees, they were left with no option other than to reconcile. After the reconciliation, the wolves appear and this is an indication of the consequences of their behaviour.
They nearly lost the portrait which was a family heirloom during the move.
B.
They nearly lost the portrait which was a family heirloom, during the move.
C.
They nearly lost the portrait, which was a family heirloom, during the move.
D.
They nearly lost the portrait, which was a family heirloom during the move.
Answer:
The correct answer is :Odysseus is a great warrior, a hero, and a killer of monsters; such characteristics were valued.
Explanation:
I went from one class to the next all day.
I was like a bee buzzing from flower to flower.
My day at school was a marathon.
The answer is I went from one class to the next all day.