{"id":329,"date":"2016-09-20T18:03:30","date_gmt":"2016-09-20T18:03:30","guid":{"rendered":"https:\/\/pressbooks.hcfl.edu\/bio1\/chapter\/vesicles-vacuoles-lysosomes-peroxisomes-2\/"},"modified":"2025-08-29T17:45:21","modified_gmt":"2025-08-29T17:45:21","slug":"vesicles-vacuoles-lysosomes-peroxisomes-2","status":"publish","type":"chapter","link":"https:\/\/pressbooks.hcfl.edu\/bio1\/chapter\/vesicles-vacuoles-lysosomes-peroxisomes-2\/","title":{"raw":"Vesicles and Vacuoles, Lysosomes, and Peroxisomes","rendered":"Vesicles and Vacuoles, Lysosomes, and Peroxisomes"},"content":{"raw":"

Vesicles and Vacuoles<\/h1>\nVesicles <\/strong>and vacuoles <\/strong>are membrane-bound sacs that function in storage and transport. Vacuoles are somewhat larger than vesicles, and the membrane of a vacuole does not fuse with the membranes of other cellular components. Vesicles can fuse with other membranes within the cell system. Additionally, enzymes within plant vacuoles can break down macromolecules.\n\n[caption id=\"attachment_65\" align=\"alignnone\" width=\"248\"]\"figure_03_13\" Figure 13 The endomembrane system works to modify, package, and transport lipids and proteins. (credit: modification of work by Magnus Manske)[\/caption]\n

\u00a0The Central Vacuole (plants)<\/h1>\nPreviously, we mentioned vacuoles as essential components of plant cells. If you look at\u00a0Figure 1<\/strong>, you will see that plant cells each have a large, central vacuole that occupies most of the cell.\n\n[caption id=\"attachment_59\" align=\"alignnone\" width=\"300\"]\"square Figure 1 A generalized plant cell. Note the large grey central vacuole.[\/caption]\n\nThe\u00a0central vacuole\u00a0<\/strong>plays a key role in regulating the cell\u2019s concentration of water in changing environmental conditions. In plant cells, the liquid inside the central vacuole provides turgor pressure, which is the outward pressure caused by the fluid inside the cell. Have you ever noticed that if you forget to water a plant for a few days, it wilts? That is because as the water concentration in the soil becomes lower than the water concentration in the plant, water moves out of the central vacuoles and cytoplasm and into the soil. As the central vacuole shrinks, it leaves the cell wall unsupported. This loss of support to the cell walls of a plant results in the wilted appearance. Additionally, this fluid has a very bitter taste, which discourages consumption by insects and animals. The central vacuole also functions to store proteins in developing seed cells.\n

Lysosome<\/h1>\nIn animal cells, the lysosomes <\/strong>are the cell\u2019s \u201cgarbage disposal.\u201d Digestive enzymes within the lysosomes aid the breakdown of proteins, polysaccharides, lipids, nucleic acids, and even worn-out organelles. In single-celled eukaryotes, lysosomes are important for digestion of the food they ingest and the recycling of organelles. These enzymes are active at a much lower pH (more acidic) than those located in the cytoplasm. Many reactions that take place in the cytoplasm could not occur at a low pH, thus the advantage of compartmentalizing the eukaryotic cell into organelles is apparent.\n\nLysosomes also use their hydrolytic enzymes to destroy disease-causing organisms that might enter the cell. A good example of this occurs in a group of white blood cells called macrophages, which are part of your body\u2019s immune system. In a process known as phagocytosis, a section of the plasma membrane of the macrophage invaginates (folds in) and engulfs a pathogen. The invaginated section, with the pathogen inside, then pinches itself off from the plasma membrane and becomes a vesicle. The vesicle fuses with a lysosome. The lysosome\u2019s hydrolytic enzymes then destroy the pathogen (Figure 2<\/strong>).\n\n[caption id=\"attachment_64\" align=\"alignnone\" width=\"300\"]\"figure_03_12 Figure 2 A macrophage has phagocytized a potentially pathogenic bacterium into a vesicle, which then fuses with a lysosome within the cell so that the pathogen can be destroyed. Other organelles are present in the cell, but for simplicity, are not shown.[\/caption]\n

Peroxisomes<\/h1>\nPeroxisomes\u00a0<\/strong>are small, round organelles enclosed by single membranes. They carry out oxidation reactions that break down fatty acids and amino acids. They also detoxify many poisons that may enter the body. Alcohol is detoxified by peroxisomes in liver cells. A byproduct of these oxidation reactions is hydrogen peroxide, H2O2, which is contained within the peroxisomes to prevent the chemical from causing damage to cellular components outside of the organelle. Hydrogen peroxide is safely broken down by peroxisomal enzymes into water and oxygen.\n\n \n

References<\/h1>\nUnless otherwise noted, images on this page are licensed under CC-BY 4.0<\/a>\u00a0by\u00a0OpenStax<\/a>.\n\nText adapted from: OpenStax<\/span>, Concepts of Biology. OpenStax CNX. May 18, 2016 http:\/\/cnx.org\/contents\/b3c1e1d2-839c-42b0-a314-e119a8aafbdd@9.10","rendered":"

Vesicles and Vacuoles<\/h1>\n

Vesicles <\/strong>and vacuoles <\/strong>are membrane-bound sacs that function in storage and transport. Vacuoles are somewhat larger than vesicles, and the membrane of a vacuole does not fuse with the membranes of other cellular components. Vesicles can fuse with other membranes within the cell system. Additionally, enzymes within plant vacuoles can break down macromolecules.<\/p>\n

\"figure_03_13\"
Figure 13 The endomembrane system works to modify, package, and transport lipids and proteins. (credit: modification of work by Magnus Manske)<\/figcaption><\/figure>\n

\u00a0The Central Vacuole (plants)<\/h1>\n

Previously, we mentioned vacuoles as essential components of plant cells. If you look at\u00a0Figure 1<\/strong>, you will see that plant cells each have a large, central vacuole that occupies most of the cell.<\/p>\n

\"square
Figure 1 A generalized plant cell. Note the large grey central vacuole.<\/figcaption><\/figure>\n

The\u00a0central vacuole\u00a0<\/strong>plays a key role in regulating the cell\u2019s concentration of water in changing environmental conditions. In plant cells, the liquid inside the central vacuole provides turgor pressure, which is the outward pressure caused by the fluid inside the cell. Have you ever noticed that if you forget to water a plant for a few days, it wilts? That is because as the water concentration in the soil becomes lower than the water concentration in the plant, water moves out of the central vacuoles and cytoplasm and into the soil. As the central vacuole shrinks, it leaves the cell wall unsupported. This loss of support to the cell walls of a plant results in the wilted appearance. Additionally, this fluid has a very bitter taste, which discourages consumption by insects and animals. The central vacuole also functions to store proteins in developing seed cells.<\/p>\n

Lysosome<\/h1>\n

In animal cells, the lysosomes <\/strong>are the cell\u2019s \u201cgarbage disposal.\u201d Digestive enzymes within the lysosomes aid the breakdown of proteins, polysaccharides, lipids, nucleic acids, and even worn-out organelles. In single-celled eukaryotes, lysosomes are important for digestion of the food they ingest and the recycling of organelles. These enzymes are active at a much lower pH (more acidic) than those located in the cytoplasm. Many reactions that take place in the cytoplasm could not occur at a low pH, thus the advantage of compartmentalizing the eukaryotic cell into organelles is apparent.<\/p>\n

Lysosomes also use their hydrolytic enzymes to destroy disease-causing organisms that might enter the cell. A good example of this occurs in a group of white blood cells called macrophages, which are part of your body\u2019s immune system. In a process known as phagocytosis, a section of the plasma membrane of the macrophage invaginates (folds in) and engulfs a pathogen. The invaginated section, with the pathogen inside, then pinches itself off from the plasma membrane and becomes a vesicle. The vesicle fuses with a lysosome. The lysosome\u2019s hydrolytic enzymes then destroy the pathogen (Figure 2<\/strong>).<\/p>\n

\"figure_03_12
Figure 2 A macrophage has phagocytized a potentially pathogenic bacterium into a vesicle, which then fuses with a lysosome within the cell so that the pathogen can be destroyed. Other organelles are present in the cell, but for simplicity, are not shown.<\/figcaption><\/figure>\n

Peroxisomes<\/h1>\n

Peroxisomes\u00a0<\/strong>are small, round organelles enclosed by single membranes. They carry out oxidation reactions that break down fatty acids and amino acids. They also detoxify many poisons that may enter the body. Alcohol is detoxified by peroxisomes in liver cells. A byproduct of these oxidation reactions is hydrogen peroxide, H2O2, which is contained within the peroxisomes to prevent the chemical from causing damage to cellular components outside of the organelle. Hydrogen peroxide is safely broken down by peroxisomal enzymes into water and oxygen.<\/p>\n

 <\/p>\n

References<\/h1>\n

Unless otherwise noted, images on this page are licensed under CC-BY 4.0<\/a>\u00a0by\u00a0OpenStax<\/a>.<\/p>\n

Text adapted from: OpenStax<\/span>, Concepts of Biology. OpenStax CNX. May 18, 2016 http:\/\/cnx.org\/contents\/b3c1e1d2-839c-42b0-a314-e119a8aafbdd@9.10<\/p>\n","protected":false},"author":130,"menu_order":11,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":["lisa-bartee-do7vbnbexe","christine-anderson-t15c7lrfew"],"pb_section_license":"cc-by"},"chapter-type":[],"contributor":[67,66],"license":[53],"class_list":["post-329","chapter","type-chapter","status-publish","hentry","contributor-christine-anderson-t15c7lrfew","contributor-lisa-bartee-do7vbnbexe","license-cc-by"],"part":223,"_links":{"self":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters\/329","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/users\/130"}],"version-history":[{"count":1,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters\/329\/revisions"}],"predecessor-version":[{"id":330,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters\/329\/revisions\/330"}],"part":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/parts\/223"}],"metadata":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters\/329\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/media?parent=329"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapter-type?post=329"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/contributor?post=329"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/license?post=329"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}