Chapter 5 - Cell Organelles, Membranes, and Transport

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• Chaperonins are proteins that aid in the folding of polypeptides into three-dimensional structures.

  • Eukaryotic cells are found in animals, plants, fungi, and protists.
  • ^^Genetic material, ribosomes, cytosol, and a plasma membrane are found in all cells (both prokaryotic and eukaryotic).^^
  • The genetic material (DNA) in prokaryotes is a circular chromosome situated in the middle of the cell in an area known as the nucleoid region.

• Bacteria may also have additional genetic material outside of the chromosome, which is stored in little circular bits of DNA known as plasmids.

  • DNA is packed into linear chromosomes in eukaryotes, which are housed in a membrane-bound nucleus.

  

• Ribosomes are present in both bacterial and eukaryotic cells and are involved in protein synthesis.

  • Ribosomes are constructed from proteins and ribosomal RNA (rRNA).
  • Both bacterial and eukaryotic ribosomes have a big and a small component, however, their sizes differ somewhat, as illustrated in the attached illustration.
  • %%Ribosomes combine amino acids into polypeptide chains in accordance with the mRNA sequence during translation.%%
  • Both prokaryotes and eukaryotes have free ribosomes in their cytoplasm.
  • Bound ribosomes are present on the rough endoplasmic reticulum membrane in eukaryotes.
  • The endoplasmic reticulum is a network of membrane channels in eukaryotic cells.
  • Ribosomes are attached to the membranes of the rough endoplasmic reticulum, which performs protein synthesis.
  • The smooth endoplasmic reticulum lacks ribosomes and is involved in the production of lipids as well as the detoxification of toxic compounds in the cell.

• The Golgi complex (also known as the Golgi body) is a stack of flattened membrane sacs (called cisternae).

  • The lumen is the inside of each cisterna and includes the enzymes required for the Golgi complex to operate.
  • The Golgi complex regulates protein modification and packaging for transport.
  • Proteins synthesized on the rough endoplasmic reticulum's free ribosomes are transported to the Golgi, where they are modified into their final shape and packaged into vesicles for transit throughout the cell.
  • The Golgi complex is frequently discovered near the rough endoplasmic reticulum.

• Lysosomes are membrane-bound sacs that contain hydrolytic enzymes and are involved in a number of cell functions.

  • @@Lysosomes can aid in the digestion of macromolecules, the breakdown of worn-out cell components, the function of apoptosis, and the destruction of bacteria and viruses that have infiltrated the cell.@@
  • Vacuoles offer turgor pressure and support to the plant cell by taking up space within the cell.

• Mitochondria are organelles that generate energy for the cell.

  • The mitochondria have two membranes, one smooth on the outside and one folded on the inside.
  • The surface area accessible for energy generation during cellular respiration is increased by these folds on the inner membrane.

• The mitochondria's double-membrane shape also allows them to generate the proton gradients required for ATP generation.

  • The matrix, an enzyme-containing fluid, is located in the middle of the mitochondria.
  • The Krebs cycle (the citric acid cycle) processes take place in the mitochondrial matrix. Mitochondria have their own mitochondrial DNA (mtDNA). Chloroplasts are photosynthesizing cells found in plants and algae.

• Chloroplasts, like mitochondria, have a double-membrane structure.

  • Chloroplasts feature a smooth outer membrane and pancake-shaped membranous sacs called thylakoids, which are stacked to form grana (singular: granum).
  • Stroma is the liquid that surrounds the grana inside the chloroplast.

• The thylakoids membranes participate in photosynthesis's light-dependent activities, whereas the stroma's enzymes participate in photosynthesis's light-independent reactions.

  • Other structures can be seen in both plant and animal cells.
  • ^^The peroxisome aids in the oxidation of molecules and the breakdown of poisons in the body.^^

• The Krebs cycle (the citric acid cycle) processes take place in the mitochondrial matrix. Mitochondria have their own mitochondrial DNA (mtDNA).

  • Chloroplasts are photosynthesizing cells found in plants and algae.
  • Chloroplasts, like mitochondria, have a double-membrane structure.
  • Chloroplasts feature a smooth outer membrane and pancake-shaped membranous sacs called thylakoids, which are stacked to form grana (singular: granum).

• %%Stroma is the liquid that surrounds the grana inside the chloroplast.%%

  • The thylakoids membranes participate in photosynthesis's light-dependent activities, whereas the stroma's enzymes participate in photosynthesis's light-independent reactions.
  • Other structures can be seen in both plant and animal cells.
  • The peroxisome aids in the oxidation of molecules and the breakdown of poisons in the body.

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