Cells

• Cancer - disease resulting from cells that break away from an original tumor to form secondary tumors elsewhere in the body
• Differentiation - the process by which cells become specialised for different functions
• Eukaryotic cell - a cell that has a membrane-bound nucleus and chromosomes it has a variety of other membrane bound organelles
• Mitosis - the type of nuclear division in which the 2 daughter cells have the same number of chromosomes as the parent cell
• Plasmid - a small circular pipe of DNA found in bacterial cells
• Prokaryotic cell - cell of an organism to the kingdom Prokaryota that is characterised by lacking a nucleus and membrane bound organelles
• Tumour - swelling in an organism that is made up of cells that continue to divide in an abnormal way
• Golgi apparatus - post office - processes and packages new lipids and proteins as well as making lysosomes
• Golgi vesticle - stores lipids and proteins made by the Golgi apparatus and transports them out of the cell via the cell surface membrane
• Cell vacuole - found in cytoplasm contains cell sap ( weak solution of sugar / salts) it helps to maintain pressure inside the cell and keeps it rigid it also is involved in the isolation of unwanted chemicals inside the cell
• Tonoplast - surrounding membrane of the cell vacuole
• Plasma membrane - found on the surface of animal cells and just inside the cell wall of other cells it's mainly made up of lipids and proteins and helps to regulate the movement of substances into and out of the cells as well as responding to chemical changes
• Chloroplasts (site of photosynthesis)- small flat structure found in plant / algal cells it's surrounded by a double membrane - chloroplast envelope, has internal thylakoid membranes that stack up to form grana which are linked together by lamella, it's surrounded by a thick fluid called the stroma
• Mitochondria - site of respiration and produces ATP it has an outer membrane and a inner membrane - which is folded into cristae it also has matrix which is a gel like material that is the site of respiration (contains ribosomes/DNA)
• Lysosomes - type of Golgi vesticle that contains lysosomes (digestives enzymes) inside it's surrounding membrane, which can be used to digest foreign substances or worn out components of the cell
• Nucleus - controls the transcription of DNA which means it can control the cells activity, its internal nucleolus contains chromosomes and is surrounded by the nucleoplasm which also contains chromatin. This is surrounded by the nuclear envelope which has nuclear pores which allows the movement of mRNA
• Smooth endoplasmic reticulum - tubular structure with space and is the cite of the synthesis and processing of lipids and carbohydrates
• Rough endoplasmic reticulum - system of membranes enclosing a fluid filled space with the surface covered in ribosomes. It folds and processes proteins that have been made in the ribosomes
• Cell wall - rigid structure that supports the cell and prevents it changing shape. In plants and algae it's made of cellulose and in fungi it chitin
• Ribosomes- 80s in eukaryotic cells and 70s in prokaryotic cells, mitochondria and chloroplasts. It's attached to the RER and its made up of proteins and RNA with no membrane and it's the site where membranes are made where mRNA are translated into proteins
• Transmission electron microscope (TEM) - electrons for a beam through the specimen which requires it to be thin the denser parts of the specimen absorb more electrons making them look darker
• TEM 2 - the specimen isn't living due to it being in a vacuum a high resolution image is given
• Scanning electron microscope (SEM) - electrons beam across the specimen knocking off electrons from it
• SEM 2 - it produces a 3D image of the specimen that shows its surface but it has a lower resolution
• Homogenisation - process in cell fraction where cells are broken up through vibration or blending which breaks up the plasma membrane releasing the organelles into a isotonic, cold and buffered (pH) solution
• Ultracentrifugation - (2nd step in cell fraction) separating of the organelles by spinning in a centrifuge in a low speed where the heaviest organelles become a pellet and the rest are suspended above in a supernatant which is then continually removed and centrifuged at higher and higher speeds so that the pellet is made of lighter and lighter organelles
• Resolution - ability to distinguish between two separate points on an image or how detailed it is
• Magnification - how many times larger an image is than the object
• Viruses - acellular, they're nucleic acids surrounded by proteins. Structure - have a protein coat (capsid) with attachment proteins surrounding it and inside is a core of genetic material
• Viral replication - 1- viruses attached to host cell receptor proteins 2- genetic material is released into the host cell 3- genetic material and proteins are replicated by host cell 'machinery' 4- viral components assemble 5- replicated viruses released from host cell