FBBC Exam 2 With Complete Solution
Where does communication between neurons occur? - Answer synapse
How do neurons communicate - Answer Through the release of neurochemicals;
neurotransmitters
Components of a synapse - Answer presynaptic neuron, synaptic cleft, postsynaptic
neuron
Synaptic cleft space - Answer 10-50nm
What are neurotransmitters? - Answer Chemicals released at the presynaptic site into
the synaptic cleft
How do neurotransmitters function? - Answer They bind to receptors on the
postsynaptic site
How do receptors interact with neurotransmitters? - Answer Receptors may only bind
specific neurotransmitters or specific sets of transmitters
Types of Synapses - Answer Axodendritic-axoaspinous, Axosomatic, Axoaxonic,
Dendrodenritic
Axodendritic-Axoaspinous - Answer Chemical synapse between axons and dendrites;
usually excitatory (depolarizing); unidirectional
Axosomatic - Answer Chemical synapse between axons and cell body; Inhibitory
Axoaxonic - Answer chemical synapse from axon to axon; modulatory
Dendrodendritic - Answer chemical synapse from dendrite to dendrite; modulatory;
bidirectional
Gap junction - Answer A way in which cells can communicate without a synapse;
electrical
Components of a gap junction - Answer A gap junction consists of a presynaptic
terminal and a postsynaptic site without a synaptic cleft.
How wide is the space between the pre and postsynaptic sites in a gap junction? -
Answer The space between the pre and postsynaptic sites in a gap junction is only 2-4
nm, compared to 10-50 nm in regular synapses.
How does information flow through gap junctions? - Answer Information flows through
gap junctions via proteins lined up (connexons) allowing ions from neuron #1 to flow
through to neuron #2.
Why is communication through gap junctions considered fast? - Answer Communication
through gap junctions is fast because ions can move directly from one side to the other
,without the need for neurotransmitter release.
Where are gap junctions commonly found in the nervous system? - Answer Gap
junctions are abundant in the developing nervous system and in the brainstem reticular
formation.
Functions of a gap junction - Answer -behaviors that require a rapid response: escape
behaviors particularly in invertebrates, retina's response to visual stimuli in vertebrates,
-embryonic development (may help neighboring cells communicate with each other
quickly to direct cells to the right place at the right time.) Studies show blocked gap
junctions lead to improper embryonic development.
-expressed in glial cell types (astrocytes, microglia, oligodendrocytes)connect glia and
neurons
neuronal membrane - Answer Membrane of all neurons that covers the cell body
dendrites and axons; 8-10 nm thick
2 components of neuronal membrane - Answer Lipids and proteins
Lipid membrane - Answer fat molecules, make up 40% of the membrane and provide the
main structural characteristics; 2 parts to a lipid molecule, the polar head and 2
nonpolar fatty acids.
Polar Head - Answer contains phosphate therefore the lipids are called phospholipids.
long-chain hydrocarbons make up the fatty acid tails.
Lipid bilayer components - Answer Contains 2 hydrophilic polar heads facing the
aqueous solutions on the inside of the cell - intracellular fluid - and the outside of the cell
- extracellular fluid.
The hydrophobic nonpolar tails - Answer Fatty acid chains - facing inward towards each
other.
2 types of proteins in the membrane. - Answer extrinsic and intrinsic proteins
Extrinsic proteins - Answer located on either the inner or outer surface of the
membrane. These are mainly hydrophilic; may serve as enzymes, to activate or
inactivate the action of neurotransmitters
Intrinsic proteins - Answer -located either partially or completely within the lipid bilayer;
can span the membrane and protrude at both ends.
-intrinsic proteins have a large amount of hydrophobic amino acids
-they the transfer of molecules from either side of the membrane; channel.
Passive transport across the membrane - Answer Some things NEED to get past the
semipermeable membrane. -occurs when substances flow across the membrane and
, down a concentration gradient.
-Ions move along a concentration gradient, from HIGH TO LOW, until there is an equal
concentration on both sides.
-no expenditure of energy.
Semi-permeable membrane - Answer -only some substances can pass through (like
water and oxygen) while others cannot
-membrane's selective permeability is usually based on size, charge, or solubility of the
molecules
Passive diffusion - Answer If substances are soluble in the lipid membrane, they cross
the membrane easily through concentration gradient.
No channels/pores needed
No energy
The time to reach equilibrium depends on molecule size, shape, chemical properties
and electrical charge
Due to the non-polar hydrophobic portion of the lipid bilayer, most substances need to
be transported across the neuronal membrane
Filtration - Answer -another type of passive transport
-small molecules that are water soluble penetrate the membrane through pores (0.7-0.8
nmin diameter) some neurotransmitters
ex. ion channel (some are gated)
Facilitated diffusion - Answer -another type of passive transport
-allows for substances which are water-soluble and lipid soluble to pass through the
membrane
Carrier molecule - Answer binds the substrate and translocates to carry the substrate
into the cell down the concentration gradient.
-No energy is required.
Active transport across the membrane - Answer -hen molecules are moved up a
concentration gradient, from an area of low concentration to high concentration.
-Requires energy
Pumps - Answer -Require energy to rotate the carrier molecule from oneposition to
another and back pumps
Where does communication between neurons occur? - Answer synapse
How do neurons communicate - Answer Through the release of neurochemicals;
neurotransmitters
Components of a synapse - Answer presynaptic neuron, synaptic cleft, postsynaptic
neuron
Synaptic cleft space - Answer 10-50nm
What are neurotransmitters? - Answer Chemicals released at the presynaptic site into
the synaptic cleft
How do neurotransmitters function? - Answer They bind to receptors on the
postsynaptic site
How do receptors interact with neurotransmitters? - Answer Receptors may only bind
specific neurotransmitters or specific sets of transmitters
Types of Synapses - Answer Axodendritic-axoaspinous, Axosomatic, Axoaxonic,
Dendrodenritic
Axodendritic-Axoaspinous - Answer Chemical synapse between axons and dendrites;
usually excitatory (depolarizing); unidirectional
Axosomatic - Answer Chemical synapse between axons and cell body; Inhibitory
Axoaxonic - Answer chemical synapse from axon to axon; modulatory
Dendrodendritic - Answer chemical synapse from dendrite to dendrite; modulatory;
bidirectional
Gap junction - Answer A way in which cells can communicate without a synapse;
electrical
Components of a gap junction - Answer A gap junction consists of a presynaptic
terminal and a postsynaptic site without a synaptic cleft.
How wide is the space between the pre and postsynaptic sites in a gap junction? -
Answer The space between the pre and postsynaptic sites in a gap junction is only 2-4
nm, compared to 10-50 nm in regular synapses.
How does information flow through gap junctions? - Answer Information flows through
gap junctions via proteins lined up (connexons) allowing ions from neuron #1 to flow
through to neuron #2.
Why is communication through gap junctions considered fast? - Answer Communication
through gap junctions is fast because ions can move directly from one side to the other
,without the need for neurotransmitter release.
Where are gap junctions commonly found in the nervous system? - Answer Gap
junctions are abundant in the developing nervous system and in the brainstem reticular
formation.
Functions of a gap junction - Answer -behaviors that require a rapid response: escape
behaviors particularly in invertebrates, retina's response to visual stimuli in vertebrates,
-embryonic development (may help neighboring cells communicate with each other
quickly to direct cells to the right place at the right time.) Studies show blocked gap
junctions lead to improper embryonic development.
-expressed in glial cell types (astrocytes, microglia, oligodendrocytes)connect glia and
neurons
neuronal membrane - Answer Membrane of all neurons that covers the cell body
dendrites and axons; 8-10 nm thick
2 components of neuronal membrane - Answer Lipids and proteins
Lipid membrane - Answer fat molecules, make up 40% of the membrane and provide the
main structural characteristics; 2 parts to a lipid molecule, the polar head and 2
nonpolar fatty acids.
Polar Head - Answer contains phosphate therefore the lipids are called phospholipids.
long-chain hydrocarbons make up the fatty acid tails.
Lipid bilayer components - Answer Contains 2 hydrophilic polar heads facing the
aqueous solutions on the inside of the cell - intracellular fluid - and the outside of the cell
- extracellular fluid.
The hydrophobic nonpolar tails - Answer Fatty acid chains - facing inward towards each
other.
2 types of proteins in the membrane. - Answer extrinsic and intrinsic proteins
Extrinsic proteins - Answer located on either the inner or outer surface of the
membrane. These are mainly hydrophilic; may serve as enzymes, to activate or
inactivate the action of neurotransmitters
Intrinsic proteins - Answer -located either partially or completely within the lipid bilayer;
can span the membrane and protrude at both ends.
-intrinsic proteins have a large amount of hydrophobic amino acids
-they the transfer of molecules from either side of the membrane; channel.
Passive transport across the membrane - Answer Some things NEED to get past the
semipermeable membrane. -occurs when substances flow across the membrane and
, down a concentration gradient.
-Ions move along a concentration gradient, from HIGH TO LOW, until there is an equal
concentration on both sides.
-no expenditure of energy.
Semi-permeable membrane - Answer -only some substances can pass through (like
water and oxygen) while others cannot
-membrane's selective permeability is usually based on size, charge, or solubility of the
molecules
Passive diffusion - Answer If substances are soluble in the lipid membrane, they cross
the membrane easily through concentration gradient.
No channels/pores needed
No energy
The time to reach equilibrium depends on molecule size, shape, chemical properties
and electrical charge
Due to the non-polar hydrophobic portion of the lipid bilayer, most substances need to
be transported across the neuronal membrane
Filtration - Answer -another type of passive transport
-small molecules that are water soluble penetrate the membrane through pores (0.7-0.8
nmin diameter) some neurotransmitters
ex. ion channel (some are gated)
Facilitated diffusion - Answer -another type of passive transport
-allows for substances which are water-soluble and lipid soluble to pass through the
membrane
Carrier molecule - Answer binds the substrate and translocates to carry the substrate
into the cell down the concentration gradient.
-No energy is required.
Active transport across the membrane - Answer -hen molecules are moved up a
concentration gradient, from an area of low concentration to high concentration.
-Requires energy
Pumps - Answer -Require energy to rotate the carrier molecule from oneposition to
another and back pumps
