MCDB 153: MIDTERM 1 QUESTIONS
AND ANSWERS GRADED A+ 2025/2026
Reductionism - ANS -basis of biology is similar in all organisms
-use more basic organisms as model systems
What are the three main functions of the nervous system? - ANS -detect changes in
environment
-transmit this information
-instruct other cells
What makes up the CNS? - ANS brain and spinal cord
What makes up the PNS? - ANS simply organized nerves that connect the CNS to the rest of
the body
What are the solutions to the fragility of axons? - ANS -run axons together in a pack and
cover them with a sheath
-inside of the axon has a cytoskeleton
What are neurons directly responsible for? - ANS intercellular communication (receive,
conduct, transmit)
1 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
,What type of structure do neurons have? - ANS very elongated structure
What are the 4 regions of a neuron - ANS 1. cell body
2. axon
3. nerve terminal/synapse
4. dendrites
What is the cell body? - ANS -contains nucleus and organelles of neuron
-DNA, RNA and most of protein synthesis
What does the axon do? - ANS -conducts nerve impulse from the cell body to the terminal
-no branching until the end
What is the nerve terminal/synapse? - ANS where the nerve meets the target
Are there more neurons or more glia? - ANS glia
What are glia? - ANS cells of the nervous system
What do glia do? - ANS -surround neurons and hold them in place
-supply nutrients and oxygen to neurons
-insulate one neuron from another
-destroy pathogens and remove dead neurons
2 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
, What is key to the blood:brain barrier? - ANS glial cells
microglia - ANS macrophages of the CNS
What is key to all development? - ANS signal transduction
What are the steps in signal transduction? - ANS 1. extracellular signal molecule binds to
trans-membrane receptor
2. intracellular signaling pathway activated
3. signal reaches target protein
contact-dependent intercellular signaling - ANS -direct cell-cell contact
-involves a transmembrane protein and a membrane-bound signaling molecule
paracrine intercellular signaling - ANS only effects cells nearby
synaptic intercellular signaling - ANS neurons transmit signals and release neurotransmitters
endocrine intercellular signaling - ANS endocrine cells secrete hormones into the
bloodstream, which are then distributed throughout the body
axonal transport - ANS transports products from cell body down axon via cytoskeleton or vice
versa
What are the possible outcomes of signaling? - ANS -survive (interact, move)
-divide
3 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
AND ANSWERS GRADED A+ 2025/2026
Reductionism - ANS -basis of biology is similar in all organisms
-use more basic organisms as model systems
What are the three main functions of the nervous system? - ANS -detect changes in
environment
-transmit this information
-instruct other cells
What makes up the CNS? - ANS brain and spinal cord
What makes up the PNS? - ANS simply organized nerves that connect the CNS to the rest of
the body
What are the solutions to the fragility of axons? - ANS -run axons together in a pack and
cover them with a sheath
-inside of the axon has a cytoskeleton
What are neurons directly responsible for? - ANS intercellular communication (receive,
conduct, transmit)
1 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
,What type of structure do neurons have? - ANS very elongated structure
What are the 4 regions of a neuron - ANS 1. cell body
2. axon
3. nerve terminal/synapse
4. dendrites
What is the cell body? - ANS -contains nucleus and organelles of neuron
-DNA, RNA and most of protein synthesis
What does the axon do? - ANS -conducts nerve impulse from the cell body to the terminal
-no branching until the end
What is the nerve terminal/synapse? - ANS where the nerve meets the target
Are there more neurons or more glia? - ANS glia
What are glia? - ANS cells of the nervous system
What do glia do? - ANS -surround neurons and hold them in place
-supply nutrients and oxygen to neurons
-insulate one neuron from another
-destroy pathogens and remove dead neurons
2 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
, What is key to the blood:brain barrier? - ANS glial cells
microglia - ANS macrophages of the CNS
What is key to all development? - ANS signal transduction
What are the steps in signal transduction? - ANS 1. extracellular signal molecule binds to
trans-membrane receptor
2. intracellular signaling pathway activated
3. signal reaches target protein
contact-dependent intercellular signaling - ANS -direct cell-cell contact
-involves a transmembrane protein and a membrane-bound signaling molecule
paracrine intercellular signaling - ANS only effects cells nearby
synaptic intercellular signaling - ANS neurons transmit signals and release neurotransmitters
endocrine intercellular signaling - ANS endocrine cells secrete hormones into the
bloodstream, which are then distributed throughout the body
axonal transport - ANS transports products from cell body down axon via cytoskeleton or vice
versa
What are the possible outcomes of signaling? - ANS -survive (interact, move)
-divide
3 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
