Thành viên:Naazulene/Sinh lý tế bào

Sinh lý tế bào là ngành nghiên cứu về các ào để nó hoạt động diễn ra trong tế bào để nó sống. Tế bào động vật, thực vật và vi sinh vật có nhiều điểm giống nhau về sinh lý, mặt dù về giải phẫu thì chúng khác nhau. ^[1]^{[cần số trang]}

Các đặc điểm chung

Có hai phân loại tế bào chính: nhân sơ và nhân thực. Tế bào nhân sơ là những tế bào đầu tiên; chúng không có nhân, và cơ chế cữa chung đơn giản hơn tế bào nhân thực. Tế bào nhân thực thì có nhân chứa DNA, cũng như một số bào quan.^[2]

Tế bào nhân sơ

Typical prokaryotic cell structure

Tế bào nhân sơ có DNA trong một vùng gọi là vùng nhân (nucleoid). Vùng này không có màng ngăn cách giữa các phần khác của tế bào. Sinh vật nhân sơ có hai nhóm chính: vi khuẩn (bacteria) và cổ khuẩn (archea). Tế bào nhân sơ có ít bào quan hơn các tế bào nhân thực. Cả hai đều có màng sinh vất và ribosome (tùy theo tài liệu mà ribosome có được xem là bào quan hay không). Hai đặc điểm độc đáo của tế bào nhân sơ là lông và roi.^[1]

Tế bào nhân thực

Typical eukaryotic animal cell structure

Eukaryotes have a nucleus where DNA is contained. They are usually larger than prokaryotes and contain many more organelles. The nucleus, the feature of a eukaryote that distinguishes it from a prokaryote, contains a nuclear envelope, nucleolus and chromatin. In cytoplasm, endoplasmic reticulum (ER) synthesizes^{[cần giải thích]} membranes and performs other metabolic activities. There are two types, rough ER (containing ribosomes) and smooth ER (lacking ribosomes). The Golgi apparatus consists of multiple membranous sacs, responsible for manufacturing and shipping out materials such as proteins. Lysosomes are structures that use enzymes to break down substances through phagocytosis, a process that comprises endocytosis and exocytosis. In the mitochondria, metabolic processes such as cellular respiration occur. The cytoskeleton is made of fibers that support the structure of the cell and help the cell move.^[1]

Physiological processes

There are different ways through which cells can transport substances across the cell membrane. The two main pathways are passive transport and active transport. Passive transport is more direct and does not require the use of the cell's energy. It relies on an area that maintains a high-to-low concentration gradient. Active transport uses adenosine triphosphate (ATP) to transport a substance that moves against its concentration gradient.^[3]^{[cần số trang]}

Movement of proteins

The pathway for proteins to move in cells starts at the ER. Lipids and proteins are synthesized^{[cần giải thích]} in the ER, and carbohydrates are added to make glycoproteins. Glycoproteins undergo further synthesis^{[cần giải thích]} in the Golgi apparatus, becoming glycolipids. Both glycoproteins and glycolipids are transported into vesicles to the plasma membrane. The cell releases secretory proteins known as exocytosis.^[1]

Transport of ions

Ion Transport: Direction of Na/K flow

Ions travel across cell membranes through channels, pumps or transporters. In channels, they move down an electrochemical gradient to produce electrical signals. Pumps maintain electrochemical gradients. The main type of pump is the Na/K pump. It moves 3 sodium ions out of a cell and 2 potassium ions into a cell. The process converts one ATP molecule to adenosine diphosphate (ADP) and ^{[cần giải thích]} In a transporter, ions use more than one gradient to produce electrical signals.^[2]

Endocytosis in Animal Cells

Endocytosis in animal cells

Endocytosis is a form of active transport where a cell takes in molecules, using the plasma membrane, and packages them into vesicles.^[1]^:139–140

Phagocytosis

In phagocytosis, a cell surrounds particles including food particles through an extension of the pseudopods, which are located on the plasma membrane. The pseudopods then package the particles in a food vacuole. The lysosome, which contains hydrolytic enzymes, then fuses with the food vacuole. Hydrolytic enzymes, also known as digestive enzymes, then digest the particles within the food vacuole.^[1]^:139–140

Pinocytosis

In pinocytosis, a cell takes in ("gulps") extracellular fluid into vesicles, which are formed when plasma membrane surrounds the fluid. The cell can take in any molecule or solute through this process.^[1]^:139–140

Receptor-mediated endocytosis

Receptor-mediated endocytosis is a form of pinocytosis where a cell takes in specific molecules or solutes. Proteins with receptor sites are located on the plasma membrane, binding to specific solutes. The receptor proteins that are attached to the specific solutes go inside coated pits, forming a vesicle. The vesicles then surround the receptors that are attached to the specific solutes, releasing their molecules. Receptor proteins are recycled back to the plasma membrane by the same vesicle.^[1]^:139–140

References

^ ^a ^b ^c ^d ^e ^f ^g ^h Urry, Lisa A.; Cain, Michael L.; Wasserman, Steven A.; Minorsky, Peter V.; Reece, Jane B. (2017). Campbell Biology . New York: Pearson. ISBN 978-0134093413. LCCN 2017448967. OCLC 956379308.
^ ^a ^b Landowne, David (2006). Cell Physiology. Lange Physiology Series. New York: McGraw-Hill. ISBN 978-0071464741. LCCN 2006282125. OCLC 70047489.
^ Clark, Mary Ann; Choi, Jung; Douglas, Matthew (28 tháng 3 năm 2018). Biology . OpenStax. ISBN 978-1-947172-51-7.

External links

Overview at Medical College of Georgia (archived)
MeSH Physiological Phenomena Cell Physiological Phenomena
MeSH Electrophysiology

Bản mẫu:Signal transduction Bản mẫu:Physiology types

[CampbellBiology-1] ^ ^a ^b ^c ^d ^e ^f ^g ^h Urry, Lisa A.; Cain, Michael L.; Wasserman, Steven A.; Minorsky, Peter V.; Reece, Jane B. (2017). Campbell Biology . New York: Pearson. ISBN 978-0134093413. LCCN 2017448967. OCLC 956379308.

[Landowne2006-2] Landowne, David (2006). Cell Physiology. Lange Physiology Series. New York: McGraw-Hill. ISBN 978-0071464741. LCCN 2006282125. OCLC 70047489.

[3] Clark, Mary Ann; Choi, Jung; Douglas, Matthew (28 tháng 3 năm 2018). Biology . OpenStax. ISBN 978-1-947172-51-7.

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