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If by why you mean how, then the answer lies in the fact that cell membranes have special transport channels for different materials. Essentially, the phospholipid bilayer means that the outside of the cell membrane is charged (polar) and the inside is uncharged (non-polar). Whilst uncharged molecules can easily squeeze in between the phospholipids, the charged molecules have a problem. Because they carry a charge it means that they cannot enter the area in the middle where there is no charge, so there are special protein channels. These channels are lined with charge and allow the passage of polar (charged) molecules through the cell membrane.
Wiki User
∙ 12y ago
Polar molecules can pass through a cell's plasma membrane via facilitated diffusion by using protein channels or carriers. These proteins create a pathway for the polar molecules to move across the membrane. Additionally, some polar molecules can also be transported through the membrane by active transport mechanisms.
Wiki User
∙ 14y agoNon polar molecules can pass through easily since the middle part of cell is hydrophobic as well. However, the size of this non polar molecule has to be relatively small to fit in between the pores (between the phospholips). If bigger, they must use other methods like protein channels.
It is much harder for polar molecules to pass through since the middle part is hydrophobic. However, polar molecules like water can pass through since they go through extremely fast and because they are extremely SMALL molecules. Bigger ones have no chance of going through phospholipds.
Wiki User
∙ 13y agoBecause the plasma membrane has a hydrophobic inner layer.
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Plasma membrane in eukaryotic cells is made up of?
The plasma membrane in eukaryotic cells is primarily composed of a phospholipid bilayer. This bilayer contains embedded proteins that help regulate the movement of molecules in and out of the cell. Additionally, cholesterol molecules are also present in the plasma membrane to provide stability and fluidity.
Why an animal plasma membrane is not responsible for the synthesis of ATP?
The synthesis of ATP occurs in the mitochondria through a process called oxidative phosphorylation, not in the plasma membrane. The plasma membrane is responsible for regulating the passage of molecules into and out of the cell, maintaining cell structure, and cell communication through signaling molecules.
The cell membrane also is called the?
The cell membrane is also known as the plasma membrane or the cytoplasmic membrane. It is a biological membrane that separates all cells' interior from the outside, though can be permeated by selection ions and molecules. Its basic function is to protect the cell from its surroundings.
Why do most substances have to be assisted through the plasma membrane?
Most substances have to be assisted through the plasma membrane because the membrane acts as a selective barrier to control the movement of molecules in and out of the cell. Specialized transport proteins help facilitate the movement of specific substances through the membrane via processes like passive diffusion, active transport, and facilitated diffusion.
What are caveoli?
Caveoli are small invaginations or pockets in the plasma membrane of cells. They play a role in endocytosis, a process by which cells take in molecules (such as nutrients) from the external environment. Caveoli are particularly abundant in endothelial cells, where they contribute to regulating the transport of molecules across the cell membrane.
Which structure regulates passage of molecules into and out of cells?
The cell membrane, also known as the plasma membrane, regulates the passage of molecules into and out of cells. It acts as a selectively permeable barrier, allowing some substances to pass through while blocking others to maintain the cell's internal environment.
Plasma membrane in eukaryotic cells is made up of?
The plasma membrane in eukaryotic cells is primarily composed of a phospholipid bilayer. This bilayer contains embedded proteins that help regulate the movement of molecules in and out of the cell. Additionally, cholesterol molecules are also present in the plasma membrane to provide stability and fluidity.
Which cell or cells have a plasma membrane?
ALL CELLS HAVE a plasma membrane
How do glucose molecules cross a plasma membrane on the apical side of epithelial cells?
Glucose molecules cross the plasma membrane on the apical side of epithelial cells through facilitated diffusion using glucose transporters such as GLUT1 and GLUT2. These transporter proteins help the glucose molecules move down their concentration gradient into the cell.
Do plant cell's animal cell's and bacterial cell's all have a plasma membrane?
Yes, all plant cells, animal cells, and bacterial cells have a plasma membrane. The plasma membrane is a semi-permeable membrane that surrounds the cell and regulates the passage of molecules in and out of the cell.
How do some molecules get into cells?
Some molecules get into cells by going through their permeable membrane.
Why an animal plasma membrane is not responsible for the synthesis of ATP?
The synthesis of ATP occurs in the mitochondria through a process called oxidative phosphorylation, not in the plasma membrane. The plasma membrane is responsible for regulating the passage of molecules into and out of the cell, maintaining cell structure, and cell communication through signaling molecules.
Why do most substances have to be assisted through the plasma membrane?
Most substances have to be assisted through the plasma membrane because the membrane acts as a selective barrier to control the movement of molecules in and out of the cell. Specialized transport proteins help facilitate the movement of specific substances through the membrane via processes like passive diffusion, active transport, and facilitated diffusion.
The cell membrane also is called the?
The cell membrane is also known as the plasma membrane or the cytoplasmic membrane. It is a biological membrane that separates all cells' interior from the outside, though can be permeated by selection ions and molecules. Its basic function is to protect the cell from its surroundings.
What are caveoli?
Caveoli are small invaginations or pockets in the plasma membrane of cells. They play a role in endocytosis, a process by which cells take in molecules (such as nutrients) from the external environment. Caveoli are particularly abundant in endothelial cells, where they contribute to regulating the transport of molecules across the cell membrane.
What are chemical messengers that pass through the plasma membrane of cells and have receptor molecules in the cytoplasm?
Steroid hormones are chemical messengers that can pass through the plasma membrane of cells due to their lipid-based structure. Once inside the cell, they bind to receptor molecules located in the cytoplasm or nucleus, leading to changes in gene expression and cellular functions.
What are the molecules in a plasma membrane that provide basic membrane structure cell identity and membrane fluidity?
Phospholipids are the main molecules in the plasma membrane that provide basic membrane structure. Glycolipids and glycoproteins contribute to cell identity through their unique carbohydrate chains. Cholesterol helps to maintain membrane fluidity by modulating the packing of phospholipids.
