BRAINCAKECell Structure
Revision notes for Cell Structure in OCR Biology A (H020). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- Eukaryotic Cell StructureThe cell is the basic unit of all living things.
- CompartmentalisationIn Eukaryotic cells there are membrane-bound compartments called organelles that provide different environments for different processes.
- NucleusThe nucleus is the largest organelle in the cell.
- NucleolusThe nucleolus is a spherical structure within the nucleus where ribosomal RNA (rRNA) is manufactured.
- MitochondriaMitochondria are the site of aerobic respiration.
- VesiclesVesicles are fluid filled sacs formed from single membranes.
- LysosomesLysosomes are vesicles containing a hydrolytic enzyme called lysozyme.
- The CytoskeletonThe cytoskeleton is an extensive network of long fibres and elements that provide shape, movement and anchorage for cells.
- Cell MovementMovement of cells is through actin fibres in the cytoskeleton.
- CentriolesThe centrioles are a pair of microtubules at right angles to each other next to the nucleus of all animal and some protoctist cells.
- Cilia and FlagellaCilia have both motility and sensory functions.
- Smooth Endoplasmic ReticulumThe endoplasmic reticulum is a network of membranes surrounding tubules and flattened membranous sacs called cisternae.
- RibosomesRibosomes are the site of protein synthesis.
- Rough Endoplasmic ReticulumThe endoplasmic reticulum is a network of membranes surrounding flattened membranous sacs called cisternae.
- Golgi ApparatusThe Golgi Apparatus is a stack of flattened sacs called cisternae.
- Plant CellsThe cell wall encloses all plant cells.
- Cellulose Cell WallThe cell wall encloses all plant cells.
- VacuolePlant cells have large permanent vacuoles.
- ChloroplastsChloroplasts are found in the leaves and stems of plants and are the site of photosynthesis.
- Prokaryotic CellsProkaryotes are bacteria and cyanobacteria (formerly called blue-green algae).
- DNAProkaryotic DNA and Eukaryotic DNA are essentially the same - a double-helix - but packaged differently.
- RibosomesThe ribosomes of prokaryotic cells are smaller than the ribosomes of eukaryotic cells.
- Cell WallAnimal cells do not have a cell wall.
- FlagellaThe flagella of eukaryotes is made of microtubules with a 9+2 arrangement.
- The Theory of EndosymbiosisThe theory of endosymbiosis states that mitochondria and chloroplasts were once free-living prokaryotes. which were taken into other cells by…
- Comparison with Eukaryotic CellsIn Eukaryotes, linear DNA exists as many chromosomes associated with histone proteins (chromatin) in the nucleus which is enclosed by the nuclear…