revision

• What is the modern cell theory?

  -cell contains hereditary info that can be passed on

  -all cells are comprised of some chemical mix

  -cells carry out all basic chemical and physiological processes within themselves

  -cellular activity depends on subcellular structures
• What is the basic cell theory?

  -all organisms are composed of cells

  -cell is the basic unit of life

  -cells are produced by division of preexisting cells
• why are we made up individual cells?

  -efficiency: SA to Volume ratio

  -specialisation: numerous small cells allow for different cells to have different functions
• What is the function of the cell (plasma) membrane?


  separates living cells from non-living surroundings

  selective permeability

  critical for cell-cell communication

  incorporates receptors, where a single signal can lead to many downstream alterations in behavior
• What are cilia?


  protrusions from the cell surface

  two forms: motile and non-motile
• What are flagella?


  longer and fewer than cilia

  involved in cell movement

  used for movement of materials along the outside of the cell
• What cellular reactions occur in the cytoplasm?

  glycolysis

  gluconeogenesis

  biosynthesis of sugars, fatty acids and amino acids

  RNA modification

  Protein synthesis
• What are the functions of the mitocondria?

  site of cellular respiration: Krebs cycle for production of ATP (cellular metabolism)

  cell differentiation

  cell death

  controls cell cycle and growth
• Where did mitochondria originate from?

  free living organism living inside another cells due to endosymbiosis
• Where is DNA located?

  the nucleus

  the mitocondria
• What occurs if you have a defect in mitochondria?

  minor: exercise intolerance

  serious: retinal ganglion cell degeneration
• What are the two types of endolasmic reticulum?

  Rough and smooth
• What is the function of the rough ER?

  -translation of mRNA into proteins by ribosomal complexes

  -production and processing of specific proteins
• What is the function of the smooth ER?


  -no ribosomes

  -site of carbohydrate metabolism: ion regulation,synthesis and metabolism of steroids and lipids,some drug detoxification
• Name some disorders of the endoplasmic reticulum?


  cerebral ischaemia

  sleep apnea

  Alzheimer's

  multiple sclerosis

  ayotrophic lateral sclerosis

  prion disease
• What is the function of the Golgi?


  cell products are sentto Golgi after RER and SER

  sorts, modifies and packages products and sends them in and out of the cell
• What is the function of a vacuole?

  cellular space for water and storage
• What is the function of a lysosome?

  vesicle produced by the Golgi, contains digestive enzymes
• What is the function of a peroxisome?

  bud off from the ER including a host of toxins

  break down long chain fatty acids
• What is found within the nucleus?

  the majority of cellular DNA

  DNA wrapped around histones= chromatin

  in nondividing cells chromatinis not formed
• What is heterochromatin?


  tightly packed DNA

  transcriptionally inactive
• What is euchromatin?


  loose open chromatin

  active transcription (gene expression)
• where does transcription occur?

  in the nucleus
• where does translation occur?

  at the ribososome
• What is totipotency?


  embryonic cells within the first few divisions

  zygote
• What is pluripotency?


  capable of giving rise to different cell types

  blastocyst
• What is multipotency?


  can develop into more than 1 type of cell but are more limited than pluripotent

  gastrula
• What is nullipotency?


  can no longer differentiate

  ectoderm
• What are transcription factors?


  proteins that directly regulateand drive gene expression by interacting with regulatory region of a gene- a promoter
• What are master regulators?

  switches on a cascade of genes encoding other transcription factors

  examples: SRY and eyeless (ey)
• What are the three regions of spermatozoa?

  head- acrosome and nucleus

  midpiece- mitochondria

  tail- flagellum
• What are some forms of macroscale imaging?

  ultrasound

  optical projection tomography (OPT)
• What is resolution


  the ability to distinguish 2 small and closely spaced objects as separate entities
• what is the diffraction limit?

  200nm
• Why is confocal microscopy better than light microscopy?

  higher contrast

  resolution in X, Y and Z planes

  takes image within a single plain

  far sharper

  use different fluorescent stains

  Can make 3D wholemount images
• What is electron microscopy?

  suborganelle structures

  resolution is greater than light microscopes

  electrons have a shorter wavelength than light

  resolution of up to 50pm
• What are the main steps of preparing a specimen for analysis?

  1. Fixation: cross link proteins and stabilise cell structure

  2. Embedding : wax/resin support for tissue before sectioning

  3. sectioning: production of thin slices (5-10 microns)

  4. Mounting:mounted on a glass slide

  5. Clearing and rehydration: cleared with xylene and rehydrated with decreasing levels of alcohols

  6. Staining: immunobased

  7. Dehydration and clearing: for better resolution

  8. Final mounting: covered with coverslip for protection
• What are the different stains used to visualise cells?

  haemotoxylin- nucleus

  eosin- cytoplasm

  alcian blue- connective tissues
• What is immunofluorescence?


  uses properties of antibody-antigen recognition

  detect location of proteins and other cell molecules

  direct and indirect detection

  antibodies are raised against molecule of interest and can be polyclonal (easy to produce and less specific) or monoclonal (difficult to produce and more specific)
• What is direct detection?

  -antibody is tagged with an enzyme (light microscopy)

  -is detected by adding substrate with a fluorescent marker (fluoro microscopy)

  -