the cell

• Cells are the basic unit of life.
• Organelles are small structures inside a cell with specific functions.
• The best-known type of blood cell is the red blood cell, which carries oxygen from the lungs to the body’s tissues.
• The cell membrane/plasma membrane regulates materials entering and exiting the cell and is made of two layers of phospholipids and proteins.
• The cytoplasm is located inside the cell membrane but outside the nucleus and contains all cell contents that live between the cell membrane and the nucleus, including organelles and cytosol.
• Nuclei exhibit variation in shape, size and location, but certain common features include being a large, spherical organelle near the centre of the cell, about 6um in diameter, about 10% of the cell volume, and can be oval, flattened, tiny, huge, single, many, lobed or position variable.
• The nucleus acts as a control centre and regulates DNA & RNA actions.
• The nuclear envelope regulates what enters or exits the nucleus and is made of a double layer of lipids with selective permeability.
• The nucleolus produces RNA, which are used to make all proteins and is located inside the nucleus, separate from DNA.
• DNA, or Deoxyribonucleic acid, is the information on how to make proteins and is made up of nucleotides locked in the nucleus.
• DNA is wound around proteins called histones to form nucleosomes.
• Nucleoplasm is an amorphous fluid containing soluble components such as proteins, RNA, ribonucleoproteins and small molecules, plus the fibrous chromatin which occupies about 80-90% of the nuclear volume.
• The main functions of the Golgi body are protein modifications, protein processing, and protein sorting and localisation.
• About 1 in 4000 children will develop mitochondrial disease by the age of 10.
• Flagella are one long fibre that provides taxis movement and requires ATP.
• Mitochondrial disorders occur spontaneously and relatively often.
• The cytoskeleton provides support and structure for the cell and organises and moves the cytoplasmic contents.
• The cytoskeleton consists of microfilaments, microtubules, and intermediate filaments.
• The protons flow back down the gradient through ATP synthase and this energy drives coupled ATP synthesis.
• When a mitochondrion divides, the 5-10 copies of DNA are divided randomly between the two new mitochondria.
• The Golgi apparatus packages molecules in cis face and out the trans face, forming vesicles to be transported.
• The Golgi apparatus is a pancake-shaped layered organelle with variability in size and number of compartments.
• Mutations to mitochondrial DNA occur frequently, due to error-prone DNA replication.
• Cilia are many short fibres that go around the edge of eukaryotic cells.
• The Golgi apparatus has a slightly concave, polarised structure.
• The Golgi apparatus functions to package, label and ship proteins out of the cell.
• Mitochondrial inheritance behaves differently to nuclear inheritance.
• Every electron from the high energy electrons is used to pump H+ ions across the inner mitochondrial membrane from the matrix and into the inter-membrane space.
• The endoplasmic reticulum, or ER, is a transportation route for proteins and is often associated with vesicles that bud off the ER to transport proteins to the Golgi body.
• Rough ER is covered with ribosomes and is sheet-like in appearance, prominent in cells carrying out extensive protein synthesis.
• Smooth ER is prominent in cells with lipid and drug metabolism and is more tubular.
• The main functions of the ER include detoxification of drugs, translocation of proteins, glycosylation of proteins, and assembly of lipid bilayers.
• Ribosomes make proteins and have a binding site in the middle, they are small circular organelles made of 2 subunits - a larger and smaller one.
• Vacuoles and vesicles are types of organelles.
• Mitochondria are present in all eukaryotic cells and their major function is energy conversion and ATP generation.
• Mitochondrial function involves oxidative metabolism, with stages including the conversion of food energy into ATP, the conversion of large molecules into smaller subunits, the conversion of numerous small molecules into a few key molecules which play a central role in metabolism, and the oxidation to produce ATP.
• Lysosomes are small membrane-bound organelles.
• Lysosomes are involved in phagocytosis, a process where WBC attack and destroy invaders, then digest them in lysosomes.
• Lysosomal enzymes work best at pH 5 and so organelles can create custom pH by proteins in the lysosomal membrane pumping H+ ions from the cytosol into lysosome.
• Mitochondria convert food energy to ATP through oxidative phosphorylation, a mechanism that involves ETCs, proton gradients and coupled ATP synthesis.