Cell Structure

• What is the eyepiece graticule on a microscope?

  A fine scale that fits inside the eyepiece lense. Its units are arbitary.
• What is the stage micrometer on a microscope?

  • A scale fitted on the coverslip
  • The size of the divisions are known
• What is the double membrane surrounding the nucleus called? - Nuclear membrane
• What do the nuclear pores do?

  They control the passage of material between the cytoplasm and nucleus
• Are ribosomal subunits synthesised or assembled in the nucleus?

  Synthesised
• What is chromatin made of?

  Linear coils (more than one) of DNA bound to proteins
• What's the deeply folded layer within mitochondria called and what's their function?

  The folds are called cristae and are there to increase surface area for attachment of enzymes during aerobic respiration
• How are epithelical cells adapted for their function?

  The cell membrane of the small intestines is folded into structures called microvilli to increase surface area for diffusion
• What is the role of the smooth ER and rough ER?

  Smooth endoplasmic reticulum:

  • The synthesis, storage and transport of lipids and carbohydrates

  Rough Endoplasmic reticulum:

  • The synthesis of proteins by ribosomes with the rough ER's large surface area.
• • How are images produced on a scanning electron microscope?Electrons are reflected off the surface of the specimin
• Why are some structures darker than others through the transmission microscope?

  They're a denser material so appear darker
• To convert from cm to m you times by 1000

  To convert from g to kg you times by 1000

  To convert from µmt o m you times by 1000000

  To convert from mm to m you times by 100

  To convert from mm o mol you times by 1000

  To convert from µmol to mol you times by 1000000
• What are the folds in mitochondria called and what's the fluid called that's inside the mitochondria?

  Folds = cristae

  fluid = matrix
• What do lysosomes do?

  Kill unwanted organelles (viruses, etc) within the cell
• What does the golgi apparatus do?

  Modifies and packages molecules and releases lysosomes
• What does eukaryotic mean?

  An organelle with membrane bound DNA (nucleus)
• What is the structure of a prokaryotic's DNA called?

  Nucleoid
• How are bacteria energy reserves stored?

  Glycogen granules
• Why is the solution ice cold during microscope prep?

  It decreases enzyme activity Or It stops organelle digestion and autolysis
• How does a virus replicate using a host cell? [5]

  Attachment proteins attach to receptors

  Viral nucleic acid enters the cell

  Nucleic acid replicates in the cell

  Or reverse transcriptase makes DNA from RNA

  Cell will now produce viral capsid proteins and enzymes

  The virus will be assembled and released from the cell
• What is an isotonic system? [3]

  Even number of water and solute molecules on each side

  No net movement of water

  No osmosis
• What additional structures can prokaryotes have? [2]

  Plasmids

  Capsules
• What kind of organelles do prokaryotes not have?

  Membrane bound organelles like mitochondria and the golgi apparatus
• What's the difference between ribosomes in eukaryotes and prokaryotes?

  In prokaryotes there are 70s ribosomes which are smaller than the 80s ribosomes that are in eukaryotes
• What's the cell wall in prokaryotes made of?

  Murein
• What's the purpose of a flagella?

  To move through liquids
• Where are cell organelles in a prokaryotes found?

  Freely dispersed in the cytoplasm
• What do attatchment proteins on viruses do?

  They allow the virus to attatch to host cells
• What conditions are solutions under when being prepped to be viewed under a microscope?

  Tissue is chopped into an ice-cold, isotonic, buffered solution
• Why is the solution buffered during microscope preperation?

  Provides a constant pH to prevent enzymes/proteins from denaturing
• What are plasmids? [3]

  Plasmids are small rings of DNA possessing important genes for survival like antibiotic resistance
• Why do we use log to reprosent the number of cells in a prokaryote population growth curve?

  To allow us to work with a large range / increase in numbers
• What is a capsule's function?

  A slimy layer for further protection against other bacterial cells
• What is murein composed of and what is its function?

  It's composed of a mixture of sugars and peptides

  Its function is as a physical barrier to protect the bacterial cells from mechanical damage
• Why is the solution isotonic during microscope prep? [2]

  Solution and organelles will have the same water potential to prevent osmosis and the lysis (bursting) of organelles
• How is eukaryotic DNA packaged? [3]

  DNA double helix is coiled around histones to form nucleotides

  These are wrapped around further proteins to form chromosome structures
• What stain can be used to see chromosomes in cells?

  Acetic Orcein
• Describe metaphase including visuals

  Chromosomes line up on the equator of the spindle

  Spindle fibres attach to chromosomes at the centromere

  
• Describe anaphase including visuals

  Spindle fibres contract and pull sister chromatids towards opposite poles

  
• Fill in the blank:

  1. Attachment protein - A
  2. Lipid membrane - B
  3. Capsid - C
  4. RNA - D
  5. Reverse transcriptase - E
  6. Matrix - F