How Substances Move in and Out of Cells
Structures and processes involved in the movement of substances into and out of cells.
Epithelial cells – Epithelial cells are also referred to as eukaryotic cells. These types of cells have a unique nucleus and contain membrane-bounded organelles. Epithelial cells absorb and secrete, and the structures of a cells organelles can be viewed from an electron microscope.
The nucleus – the nucleus of a cell contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The nuclear envelope is a double membrane which surrounds the nucleus, with the outer membrane often having ribosomes on its surface. It controls the entry and exit of materials in and out of the nucleus, and contains the reactions taking place within it. Nuclear pores allow the passage of large molecules out of the nucleus, with each nucleus typically containing 3000 pores, each 40-100nm in diameter.
The mitochondrion: The mitochondions double membrane also surrounds the organelle, and controls the entry and exit of materials. The inner membrane of the cell is folded to form Cristae. Cristae provide a large surface area for the attachment of the enzymes involved in respiration.
The rough endoplasmic reticulum manufactures membranes and secretory proteins. In leukocytes the rough ER produces antibodies. In pancreatic cells the rough ER produces insulin. The rough and smooth ER are usually interconnected and the proteins and membranes made by the rough ER move into the smooth ER to be transferred to other locations.
The smooth ER has a wide range of functions including carbohydrate and lipid synthesis. It serves as a transitional area for vesicles that transport ER products to various destinations. In liver cells the smooth ER produces enzymes that help to detoxify certain compounds. In muscles the smooth ER assists in the contraction of muscle cells, and in brain cells it
Epithelial cells – Epithelial cells are also referred to as eukaryotic cells. These types of cells have a unique nucleus and contain membrane-bounded organelles. Epithelial cells absorb and secrete, and the structures of a cells organelles can be viewed from an electron microscope.
The nucleus – the nucleus of a cell contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The nuclear envelope is a double membrane which surrounds the nucleus, with the outer membrane often having ribosomes on its surface. It controls the entry and exit of materials in and out of the nucleus, and contains the reactions taking place within it. Nuclear pores allow the passage of large molecules out of the nucleus, with each nucleus typically containing 3000 pores, each 40-100nm in diameter.
The mitochondrion: The mitochondions double membrane also surrounds the organelle, and controls the entry and exit of materials. The inner membrane of the cell is folded to form Cristae. Cristae provide a large surface area for the attachment of the enzymes involved in respiration.
The rough endoplasmic reticulum manufactures membranes and secretory proteins. In leukocytes the rough ER produces antibodies. In pancreatic cells the rough ER produces insulin. The rough and smooth ER are usually interconnected and the proteins and membranes made by the rough ER move into the smooth ER to be transferred to other locations.
The smooth ER has a wide range of functions including carbohydrate and lipid synthesis. It serves as a transitional area for vesicles that transport ER products to various destinations. In liver cells the smooth ER produces enzymes that help to detoxify certain compounds. In muscles the smooth ER assists in the contraction of muscle cells, and in brain cells it