Examples of cell in the following topics:
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- Three basic categories of cells make up the mammalian body: germ cells, somatic cells, and stem cells.
- Pluripotent stem cells undergo further specialization into multipotent progenitor cells that then give rise to functional cells.
- Hematopoietic stem cells (adult stem cells) from the bone marrow that give rise to red blood cells, white blood cells, and platelets
- Mesenchymal stem cells (adult stem cells) from the bone marrow that give rise to stromal cells, fat cells, and types of bone cells;
- Epithelial stem cells (progenitor cells) that give rise to the various types of skin cells
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- In mammals, there are two broad types of stem cells: embryonic stem cells, which are isolated from the inner cell mass of blastocysts, and adult stem cells, which are found in various tissues.
- Stem cells can now be artificially grown and differentiated into specialized cell types with characteristics consistent with muscle or nerve cells through cell culture.
- In one, the daughter cells are initially equivalent but a difference is induced by signaling between the cells, from surrounding cells, or from the precursor cell.
- Stem cells are indicated by (A), progenitor cells by (B), and differentiated cells by (C).
- Pluripotent, embryonic stem cells originate as inner cell mass (ICM) cells within a blastocyst.
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- Cell theory states: living things are composed of one or more cells; the cell is the basic unit of life; cells arise from existing cells.
- The unified cell theory states that: all living things are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells.
- "All cells only arise from pre-existing cells.
- Cells carry genetic material passed to daughter cells during cellular division
- The cell is the basic unit of life and the study of the cell led to the development of the cell theory.
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- In other words, that original single cell is the ancestor of every other cell in the body.
- Single-celled organisms use cell division as their method of reproduction.
- While there are a few cells in the body that do not undergo cell division, most somatic cells divide regularly.
- A somatic cell is a general term for a body cell: all human cells, except for the cells that produce eggs and sperm (which are referred to as germ cells), are somatic cells.
- The cell cycle is an ordered series of events involving cell growth and cell division that produces two new daughter cells.
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- After a pathogen enters the body, infected cells are identified and destroyed by natural killer (NK) cells, which are a type of lymphocyte that can kill cells infected with viruses or tumor cells (abnormal cells that uncontrollably divide and invade other tissue).
- As such, NK cells offer a complementary check for unhealthy cells, relative to T cells.
- NK cells are always active; an interaction with normal, intact MHC I molecules on a healthy cell disables the killing sequence, causing the NK cell to move on.
- After the NK cell detects an infected or tumor cell, its cytoplasm secretes granules comprised of perforin: a destructive protein that creates a pore in the target cell.
- Phagocytic cells then digest the cell debris left behind.
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- External factors can influence the cell cycle by inhibiting or initiating cell division.
- Each cell is produced as part of its parent cell.
- Some cells do live longer than others, but eventually all cells die when their vital functions cease.
- Crowding of cells can also inhibit cell division.
- Another factor that can initiate cell division is the size of the cell; as a cell grows, it becomes inefficient due to its decreasing surface-to-volume ratio.
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- How does a complex organism such as a human develop from a single cell—a fertilized egg—into the vast array of cell types such as nerve cells, muscle cells, and epithelial cells that characterize the adult?
- A multipotent stem cell has the potential to differentiate into different types of cells within a given cell lineage or small number of lineages, such as a red blood cell or white blood cell .
- Finally, multipotent cells can become further specialized oligopotent cells.
- Adult bone marrow has three distinct types of stem cells: hematopoietic stem cells, which give rise to red blood cells, white blood cells, and platelets ; endothelial stem cells, which give rise to the endothelial cell types that line blood and lymph vessels; and mesenchymal stem cells, which give rise to the different types of muscle cells.
- The multipotent hematopoietic stem cells give rise to many different cell types, including the cells of the immune system and red blood cells.
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- A cell is the smallest unit of a living thing.
- A living thing, whether made of one cell (like bacteria) or many cells (like a human), is called an organism.
- For example, both animal and plant cells are classified as eukaryotic cells, whereas bacterial cells are classified as prokaryotic.
- Bone cells help to support and protect the body.
- Cells of the immune system fight invading bacteria.
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- Cell-mediated immunity involves cytotoxic T cells recognizing infected cells and bringing about their destruction.
- Unlike B cells, T lymphocytes (T cells) are unable to recognize pathogens without assistance.
- As with B cells, the clone includes active TC cells and inactive memory TC cells.
- The resulting active TC cells then identify infected host cells.
- B plasma cells and TC cells are collectively called effector cells because they are involved in "effecting" (bringing about) the immune response of killing pathogens and infected host cells.
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- In general, long stretches of the plasma membranes of neighboring plant cells cannot touch one another because they are separated by the cell wall that surrounds each cell.
- Plasmodesmata are numerous channels that pass between cell walls of adjacent plant cells and connect their cytoplasm; thereby, enabling materials to be transported from cell to cell, and thus throughout the plant .
- Also found only in animal cells are desmosomes, the second type of intercellular junctions in these cell types.
- A plasmodesma is a channel between the cell walls of two adjacent plant cells.
- Plasmodesmata allow materials to pass from the cytoplasm of one plant cell to the cytoplasm of an adjacent cell.