Cell Structure

• Object


  material put under the microscope
• Image


  the appearance of material when viewed, always bigger than the object
• magnification


  how many times bigger the image is to the object
• Eukaryotic cell


  larger cell with a distinct nucleus and membrane-bound organelles
• Prokaryotic cell


  smaller cells with no nucleus or nuclear envelope and no membrane-bound organelles
• Nuclear Envelope


  a double membrane that surrounds the nucleus
• Nuclear Pores


  allows passage of large molecules, like mRNA, out of the nucleus
• Nucleoplasm


  jelly-like material that makes up the bulk of the nucleus
• Nucleolus


  small, spherical region that manufactures ribosomal RNA and assembles the ribosomes
• Chromosome


  a thread-like structure made of protein (histones) and DNA by which hereditary information is physically passed from one generation to the next
• Chromatin


  the diffuse material that makes up chromosomes, consists of DNA and the protein histone
• Double membrane


  control the entering and exiting of materials, the inner membrane is folded to form extensions (cristae)
• Cristae


  extensions of inner membrane, provide large surface area for the attachment of substances used in respiration
• Matrix


  contains the proteins, lipids, ribosomes and DNA that allows the mitochondria to control the production of some of their own proteins
• Chloroplast envelope


  double plasma membrane that surrounds organelle, highly selective in what enters and leaves chloroplast
• Stroma


  fluid-filled matrix where the light-independent reaction of photosynthesis (2nd stage - synthesis of sugars) takes place
• Thylakoid


  series of flattened membranous sacs in a chloroplast that contain chlorophyll and the associated molecules needed for the light-dependent reaction of photosynthesis
• Granum 


  a stack of thylakoids in a chloroplast that is the site of light-dependent reaction of photosynthesis
• Capsule


  Mucilaginous slime, protects bacteria from other cells, help to group bacteria together
• Cell wall (prokaryotic)


  made of murein, physical barrier, protecting against mechanical damage and osmotic lysis (bursting if cell absorbs too much water via osmosis)
• DNA (Prokaryotic)


  Circular DNA
• Ribosomes (Prokaryotic)


  protein synthesis, 70s, ribosomes (have the same function as the larger 80s ribosomes in eukaryotic cells)
• Flagellum (Prokaryotic)


  most have it, whip-like movement through fluids
• Pilus (Prokaryotic)


  enable bacteria to connect and share genetic information
• Plasmid (Prokaryotic)


  Additional same pieces of DNA, enable bacteria to survive in adverse conditions, e.g. produce enzymes to break down antibodies
• Attachment Protein (virus)


  allows virus to identify and attach to host cell
• Nucleic acids (Virus)


  DNA or RNA
• Capsid (virus)


  protein coat
• Enzymes (virus)


  some viruses have them e.g. reverse transcriptase
• Liquid envelope (virus)


  some viruses have them
• Homegenation


  process of chopping up/blending/ liquefying
• Sediment


  the heavier part of the homogenate
• Ultracentrifugation


  spinning the homogenate at increasing speeds in a centrifuge
• Supernatant


  the liquid portion of a mixture left at the top of the tube when suspended particles have been separated out at the bottom during centrifugation
• Isotonic solution


  solution which has the same water potential as the tissue, to prevent organelles bursting or shrinking due to gain or loss of water via osmosis
• Buffered solution


  solution to maintain pH and prevent proteins denaturing and reduce enzymes denaturing
• Resolution


  the level of detail or how clear the image is
• Mitosis


  the type of nuclear division in which the daughter cells have the same number of chromosomes as the parent cell
• Chromatid


  one of the two strands of a chromosome that are joined together by a single centromere prior to cell division
• Benign tumour


  non-cancerous, don't spread from site of origin but develop blood vessels, contained within a membrane, can compress and damage adjacent tissues