Summary: Cell Biology Cpr's

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• CPRs

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• What lens is controlled by the spotsize function in the TEM?

  Condenser lens.

• What is the function of the apertures in the TEM?

  Filter out scattered electrons.

• In the figure, a piece of striped muscle tissue is visualized using different microscopy methods. Identify the different microscopy methods (LM/EM):A:B:C:D:

  A: LM
  B: LM
  C: LM
  D: EM

• Six sarcomeres are shown by electron microscopy.A: How many cells are visualized in this image? B: What filament is forming the dark-coloured A-band? C: What filament is forming the lightly coloured I-band?

  A: 1.
  B: Myosin.
  C: Actin.

• In contrast to the skeletal and heart muscle tissue, the smooth muscle tissue does not show the stripy pattern of A- and I-bands. What filaments control the contraction of smooth muscle cells? 

  Myosin and actin.

• Some axons are coated by myelin. From EM images, it can be observed that myelin consists of multiple membranes wrapped around the axon. What the role of the multiple membrane layers and myelin in axon function?

  - Speed up the action potential velocity traveling over the axon;
  - Insulates against charge-leakage of the axon.

• The synapse is an autonomous structure where signals from one neuron are transferred to the next neuron using neurotransmitters.A. Which structure contains these neurotransmitters? Choose one of the numbers indicated in the image.B. The synapse can be divided in a pre-synapse, a post-synapse, a synaptic cleft and the extracellular space. Indicate which numbers in the figure above correspond to each of these parts.

  A: 1
  B: 1) Pre-synapse;2) Extracellular space;
  3) Post-synapse;
  4) Synaptic cleft.

• The post-synapse shows a dark coloured, protein-rich area on the plasma membrane. What is the name of this area, and what does it do for synapse function?

  Post-synaptic density, this contains the neurotransmitter receptors.

• There is a contactpoint between a neuron and a skeletal muscle.A1. How is this contact point called?A2. What is the main neurotransmitter regulating the neurotransmission between nerve and muscle?

  A1. Neuromuscular junction.
  A2. Acetylcholine.

• There is an important difference between the postsynaptic structure of neuron/neuron synapses in the brain and neuron/muscle synapses. What is this difference and why is this important? The postsynaptic structure of the neuromuscular junction is ...a... compared to central synapse so that this synapse ...b....

  a: folded
  b: can harbor more postsynaptic receptors.