 |
Главная Случайная страница Контакты | Мы поможем в написании вашей работы! | |
A. Boundary functions
|
|
1. The cell membrane keeps nutrients in the cell.
a. Animal cells accumulate organic molecules from their environment and retain them for the metabolic purposes of providing energy for life and building blocks for cytoplasm.
b. Without a selective barrier, cells could not accumulate the materials necessary to sustain life.
2. Many important constituents are accumulated by the expenditure of metabolic energy. Membranes help retain transported substrates.
3. Useful substrates are gathered from the environment or synthesized by the cell and kept within the cell for the cell's own uses.
4. Cell waste products are expelled across the plasma membrane.
14 Histology and Cell Biology
| Receptors for hormones and viruses Cytoplasm Bulk transport Cell-cell adhesion and recognition matrix adhesion SI and recognition Anchor for cytoplasmic filaments Collagen fibril Cell-extracellular matrix adhesion and recognition | Рецепторы гормонов и вирусов цитоплазма Массовый транспорт Межклеточной адгезии и признание матрица адгезии SI и признание Якорь для цитоплазматических нитей Коллаген фибрилл Cell-внеклеточной матрицы адгезии и признание |
Figure 2-1. Diagram of the major plasma membrane functions. The plasma membrane perlorms barrier functions; anchors cytoplasmic filaments; transports small molecules; provides for bulk transports of water, ions, and macromolecules; contains receptors; and is involved in cell-to-cell interaction and cell-matrix interaction.
Дата публикования: 2014-12-28; Прочитано: 137 | Нарушение авторского права страницы | Мы поможем в написании вашей работы!
