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23 Cards in this Set
- Front
- Back
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How many regions does the cell contain?
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3
-plasma membrane -cytoplasm -nucleus |
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What is the plasma membrane?
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the outer thin and flexible membrane of the cell that separates the intracellular from extracellular compartment (fluids). selective permeable membrane
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Describe the structure of the plasma membrane.
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double layer of lipids (phospholipids, cholesterol, and glycolipids) within which proteins are embedded.
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What are phospholipids?
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the most abundant lipids in the plasma membrane. are made up of a hydrophilic head and a hydrophobic tail
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what does the term hydrophobic mean?
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when a substance tends to avoid water. same thing as lipophilic.
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what does the term hydrophilic mean?
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when a substance tends to be attracted to water. same thing a lipophobic.
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What types of proteins are embedded within the plasma membrane's double lipid layer?
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-integral proteins
-peripheral proteins -glycocalyx |
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Describe integral proteins.
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most abundant proteins. most extend entirely through the membrane. can act as receptors.
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Describe peripheral proteins.
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mainly on cytoplasmic side (inside). support the membrane through the use of a network of filaments
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Describe glycocalyx.
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sugar covering on the cell. functions in cell-to-cell binding and recognition.
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what are the functions of the plasma membrane?
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-external cell barrier against substances and forces outside the cell
-receptor for hormones and neurotransmitters -cell recognition -transport of substances in or out of the cell |
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what is diffusion?
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passive movement of substances into and out of the cell. pass freely through the lipid bilayer. move from higher concentration to lower concentration
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what is active transport?
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large molecules transported by pump or carrier and involves integral proteins
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what is vesicular transport?
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large particles and macromolecules passing through the membrane. 2 types: endocytosis and exocytosis
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what is exocytosis?
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when the cell releases its contents to the outside of the cell.
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what is endocytosis?
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when the cell brings large molecules into the itself. 3 types: phagocytosis, pinocytosis, and receptor mediated endcytosis
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what is phagocytosis?
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cell eating. the cell engulfs debris or bacteria and a phagosome is formed. lysosomes then fuse to the phagosome and degrade it. (ex. white blood cells)
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what is pinocytosis?
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cell drinking. fluid is absorbed into the cell. (cells lining the small intestine.)
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what is receptor mediated endocytosis?
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selective mechanism. specific molecules (insulin and other hormones) brought into the cell by attaching to the receptor on the membrane.
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what is familial hypercholesterolemia?
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inherited disease. caused by lack of receptors that bind to cholesterol binding LDLs. result: cholesterol cant enter cell and builds up in the blood stream. leads to atherosclerosis then to stroke or myocardial infarction
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what is the cytoplasm?
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the cellular region between the nucleus and plasma membrane. contains: cytosol.
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describe ribosomes.
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-no membrane
-site of protein production -2 subunits: protein and rRNA |
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Describe the process of translation.
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*free ribosomes make the protein used in the cytosol
ribosomes attached on the surface of rER make the proteins used for cell membrane or exported our of the cell. amino aids on the ribosomes are liked together to form proteins. |
