Question

Структуры мембраны через которые проникают крупные молекулы

Answer 1

Ответ:

мембра́на (также цитолемма, плазмалемма, или плазматическая мембрана) — эластическая молекулярная структура, состоящая из белков и липидов. Отделяет содержимое любой клетки от внешней среды, обеспечивая её целостность; регулирует обмен между клеткой и средой; внутриклеточные мембраны разделяют клетку на специализированные замкнутые отсеки — компартменты или органеллы, в которых поддерживаются определённые условия среды.

Модель клеточной мембраны. Маленькие голубые и белые шарики — гидрофильные «головки» фосфолипидов, а присоединённые к ним линии — гидрофобные «хвосты». На рисунке показаны только интегральные мембранные белки (красные глобулы и жёлтые спирали). Жёлтые овальные точки внутри мембраны — молекулы холестерина. Жёлто-зелёные цепочки бусинок на наружной стороне мембраны — цепочки олигосахаридов, формирующие гликокаликс

Объяснение:

Ну вот так

Answer 2

Structures of Membranes that Allow the Passage of Large Molecules

The cell membrane is a selectively permeable barrier that controls the movement of substances into and out of the cell. While small molecules can pass through the membrane via simple diffusion or facilitated diffusion, larger molecules require specialized structures to cross the membrane. Here are some structures of membranes that allow the passage of large molecules:

1. Protein Channels and Pores: Membranes contain protein channels and pores that allow the passage of specific molecules based on size, charge, and other properties. These channels and pores are often selective, meaning they only allow certain molecules to pass through. Examples include ion channels, aquaporins for water transport, and nuclear pores for the transport of macromolecules in and out of the nucleus.

2. Transporters and Carriers: Membranes also have transporters and carriers that facilitate the movement of large molecules across the membrane. These proteins bind to the molecule they are transporting and undergo conformational changes to transport the molecule across the membrane. Examples include glucose transporters and amino acid transporters.

3. Endocytosis and Exocytosis: Endocytosis and exocytosis are processes by which large molecules are transported across the cell membrane via vesicles. In endocytosis, the cell membrane invaginates to form a vesicle that engulfs the molecule, allowing it to enter the cell. In exocytosis, vesicles containing the molecule fuse with the cell membrane, releasing the molecule outside the cell.

4. Phagocytosis and Pinocytosis: Phagocytosis and pinocytosis are specialized forms of endocytosis. Phagocytosis is the process by which cells engulf large particles, such as bacteria or cellular debris, while pinocytosis is the process by which cells take in fluid and dissolved solutes. These processes allow the cell to internalize large molecules and particles.

It's important to note that the specific structures involved in the transport of large molecules across the membrane can vary depending on the type of cell and the molecule being transported. The cell membrane is a complex and dynamic structure that plays a crucial role in maintaining cellular homeostasis and allowing the passage of essential molecules.

I hope this information helps! Let me know if you have any further questions.

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