42 Questions
What is the primary site of action for erythropoietin?
Bone marrow
What is the purpose of receptor-mediated endocytosis?
To internalize specific target molecules into the cell
What triggers the process of receptor-mediated endocytosis?
Ligands binding to receptors on the membrane surface
Which type of blood cell is stimulated by erythropoietin?
Red blood cells
What forms as a result of the plasma membrane invaginating and pinching off?
An endosome
What is the primary function of erythropoietin in the bone marrow?
Stimulation of stem cell division and maturation
Where are the receptors located that bind to ligands during receptor-mediated endocytosis?
On the surface of the plasma membrane
Which of the following is NOT a target of erythropoietin?
Thymus
What is the primary function of thymosins?
Stimulation of lymphocyte development
What is the term for the molecule that binds to a receptor during receptor-mediated endocytosis?
Ligand
What is the term for the process by which the plasma membrane invaginates and pinches off to form a vesicle?
Endocytosis
Which type of immune cell is stimulated by thymosins?
Lymphocytes
What is the purpose of the receptors on the plasma membrane during receptor-mediated endocytosis?
To recognize and bind to specific ligands
What is the result of high concentrations of ligands in the extracellular fluid?
The process of receptor-mediated endocytosis is initiated
What is the primary function of M-Phase promoting factor in dividing cells?
Initiating mitosis
Which hormone is responsible for stimulating growth, cell division, and differentiation in various tissues?
Growth hormone
What is the primary target of prolactin in the mammary glands?
Gland and duct cells
What is the role of M-Phase promoting factor in the cell cycle?
Initiating mitosis
Which hormone is responsible for stimulating growth and development of mammary glands and ducts?
Prolactin
What is the primary function of growth hormone in various tissues?
Stimulating growth, cell division, and differentiation
What is the role of M-Phase promoting factor in cellular differentiation?
Regulating cellular differentiation
Which hormone is not responsible for stimulating growth and cell division in various tissues?
M-Phase promoting factor
During which phase of Mitosis do chromosomes become visible under a light microscope?
Early Prophase
What is the term for the protein-bound areas of the centromere that attach to spindle fibers?
Kinetochores
During which phase of Mitosis do daughter chromosomes arrive at opposite ends of the cell?
Anaphase
What is the term for the process of cell division that results in two daughter cells with the same number of chromosomes as the parent cell?
Mitosis
During which phase of Mitosis do nuclear membranes reform and chromosomes uncoil?
Telophase
What is the term for the division of the cytoplasm to form two distinct new cells?
Cytokinesis
What is the term for the rate of cell division?
Mitotic rate
What is the term for cells that maintain the cell populations of high mitotic rate cells?
Stem cells
What is the term for the process of programmed cell death?
Apoptosis
During which phase of Mitosis do chromatids move toward the metaphase plate?
Metaphase
What is the name of the structure formed when pseudopodia surround an object?
Phagosome
Which process is the functional reverse of endocytosis?
Exocytosis
What is the name of the extension of the cell membrane that surrounds an object during phagocytosis?
Pseudopodia
What is the name of the membrane-bound compartment that contains the engulfed object?
Phagosome
What is the term for the release of vesicle contents into the extracellular environment?
Exocytosis
What is the name of the process by which cells engulf solid objects?
Phagocytosis
What is the term for the cellular structure that sorts and modifies proteins and lipids synthesized by the endoplasmic reticulum?
Golgi apparatus
What is the name of the process by which cells take in fluid and dissolved substances?
Pinocytosis
What is the term for the fusion of a vesicle with the plasma membrane?
Exocytosis
What is the name of the compartment where the engulfed object is broken down?
Lysosome
Study Notes
Hormones and Cell Division
- Erythropoietin targets bone marrow, stimulating stem cell division and maturation of red blood cells.
- Thymosins target the thymus and other lymphoid tissues, stimulating division and differentiation of lymphocytes.
Cell Division (Mitosis)
- Early Prophase: Chromosomes become visible under a light microscope, and an array of microtubules called spindle fibers extends between centriole pairs.
- Late Prophase: DNA replication during S phase results in a copy of every one of the 46 chromosomes, and each copy is called a chromatid connected to its duplicate at a single point called the centromere.
- Metaphase: Chromatids move toward the metaphase plate, aligning with the metaphase plate and ending when chromatids are aligned.
- Anaphase: The two daughter chromosomes are pulled apart and drawn toward opposite ends of the cell along chromosomal microtubules.
- Telophase: The nuclear membrane reforms, and the nucleus enlarges; chromosomes gradually uncoil, marking the end of mitosis.
- Cytokinesis: The division of the cytoplasm forms two distinct new cells, beginning in late anaphase and continuing throughout telophase.
Chemical Factors Affecting Cell Division
- M-Phase promoting factor: A regulator mechanism active in all dividing cells, initiating mitosis.
- Growth hormone: Targets all cells, especially in epithelial and connective tissue, stimulating growth, cell division, and differentiation.
- Prolactin: Targets gland and duct cells of mammary glands, stimulating growth, cell division, and development of mammary glands and ducts.
Endocytosis and Exocytosis
- Receptor-mediated endocytosis: Produces vesicles containing a specific target molecule (ligand) in high concentrations, which bind to receptors on the membrane surface, forming pockets that pinch off to form an endosome.
- Phagocytosis: A type of endocytosis involving the engulfment of solid objects, such as bacteria, by pseudopodia, forming a phagosome.
- Exocytosis: The functional reverse of endocytosis, used by the Golgi apparatus to transport its product outside the cell; vesicle contents are released into the extracellular environment.
This quiz covers the role of erythropoietin in stimulating bone marrow and stem cell division, leading to the maturation of red blood cells.
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