PSYB64 Midterm II Latest Exam with
Guaranteed Pass Solutions 2025-2026
Updated.
independent effectors - Answer cells that produce motor responses when directly
stimulated, without neuronal intervention
responses are relatively insensitive, slow, long-lasting, and individualized
myocytes - Answer muscle cells; have contractility, allowing them to do work
they shorten when chemicals (ex., nutrients) come into contact with them
sensorimotor neurons (SM) - Answer neurons that receive sensory information (i.e., detect
stimuli) and projects to effector cells
they afford more sensitivity, speed, amplification, and coordination--as well as highly localized
distribution patterns--than effector neurons alone
how do organisms with simple nervous systems (ex., hydra) initiate feeding? - Answer -
sensorimotor neurons (SM) detect stimuli (ex., nutrients) in the environment
- SM provides input to a set of independent effectors
one-layer nervous system - Answer contains sensorimotor neurons that influence effector
cells
two-layer nervous system - Answer contain sensory neurons that interact with motor
neurons, the latter which influence effector cells
three-layer nervous system - Answer contain sensory neurons and motor neurons, both of
which interact with interneurons; their interactions will influence effector cells
**interneurons lie between sensory and motor neurons. they make NS more flexible and
complex responses more efficient
what is the role of the interneuron in stretch reflexes? - Answer they relax the opposing
muscle
,ex., in an elbow-tap reflex:
- tap = stimulus --> excitation (contraction) of triceps
- inhibitory interneuron will relax the biceps to allow for triceps contraction
how is NS centralization more efficient? - Answer - biological material is used more
efficiently when constructing neural networks
- shorter distances between neural networks and neurons, meaning messages have lesser
distance to travel
- faster conduction times due to efficient organization and shorter distances to travel
the social brain hypothesis (Dunbar, 2003) - Answer as the amount of conspecifics in one's
social group increases, they are more cognitively demanding to maintain
so, the larger the brain, the bigger the social group
the mating mind hypothesis (Miller, 2000) - Answer the demands of attracting and
evaluating sexual mates drove the evolution of higher cognitive abilities
ex., cognitive abilities like humour, creativity, etc. were indicators of strong genetic qualities and
increased mate attractiveness
homology - Answer genetic relatedness between structures (ex., human arms and bird
wings)
analogy - Answer functionally similar body structures that do not share common genetic
inheritance (ex., bird wings and bee wings)
single nucleotide polymorphisms (SNPs) - Answer alleles that differ from other alleles by a
single nucleotide
alleles - Answer different versions of the same gene
apolipoprotein (APOE) alleles and Alzheimer's - Answer - on chromosome 19 necessary for
lipoprotein formation
- E4 has Arg on codon 112 and 158, where E2 has Cys & Cys, and E3 has Cys & Arg
- two copies of APOE E4 --> 91% chance of developing Alzheimer's
, copy-number variations (CNVs) - Answer segments on DNA resulting from insertions,
duplications, and deletions to particular segments
- encompass ~12% of human genome
- can arise de novo (ex., found in ~10% of children with ASD) or be inherited (ex., Huntington's
disease)
epigenetics - Answer changes in phenotypes produced by changes in genetic expression (i.e.,
what genes are turned on/off)
what processes determine gene expression patterns? - Answer - DNA methylation
- histone modification
DNA methylation - Answer presence of methyl groups on DNA bases, associated with gene
silencing; abnormal methylation associated with disease
histone modification - Answer histone interaction with "epigenetic tags" make nearby DNA
more or less likely to be transcribed
DNA methylation and child maltreatment - Answer children with a history of maltreatment
show different methylation patterns than controls:
- typically low- and medium-methylated areas are high-methylated
- typically high-methylated areas are low-methylated
gioblastoma multiforme (GBM) and MGMT gene - Answer MGMT gene: codes for DNA
repair enzyme that can stop effects of certain toxins
- this can reduce effectiveness of chemotherapy drugs (ex., temozolomide)
MGMT methylation is generally associated with better GBM treatments
behavioural genetics - Answer the study of genetic and environmental influences on
behaviour
heritability - Answer the contribution of genetics to the variation of a trait observed in a
population
Guaranteed Pass Solutions 2025-2026
Updated.
independent effectors - Answer cells that produce motor responses when directly
stimulated, without neuronal intervention
responses are relatively insensitive, slow, long-lasting, and individualized
myocytes - Answer muscle cells; have contractility, allowing them to do work
they shorten when chemicals (ex., nutrients) come into contact with them
sensorimotor neurons (SM) - Answer neurons that receive sensory information (i.e., detect
stimuli) and projects to effector cells
they afford more sensitivity, speed, amplification, and coordination--as well as highly localized
distribution patterns--than effector neurons alone
how do organisms with simple nervous systems (ex., hydra) initiate feeding? - Answer -
sensorimotor neurons (SM) detect stimuli (ex., nutrients) in the environment
- SM provides input to a set of independent effectors
one-layer nervous system - Answer contains sensorimotor neurons that influence effector
cells
two-layer nervous system - Answer contain sensory neurons that interact with motor
neurons, the latter which influence effector cells
three-layer nervous system - Answer contain sensory neurons and motor neurons, both of
which interact with interneurons; their interactions will influence effector cells
**interneurons lie between sensory and motor neurons. they make NS more flexible and
complex responses more efficient
what is the role of the interneuron in stretch reflexes? - Answer they relax the opposing
muscle
,ex., in an elbow-tap reflex:
- tap = stimulus --> excitation (contraction) of triceps
- inhibitory interneuron will relax the biceps to allow for triceps contraction
how is NS centralization more efficient? - Answer - biological material is used more
efficiently when constructing neural networks
- shorter distances between neural networks and neurons, meaning messages have lesser
distance to travel
- faster conduction times due to efficient organization and shorter distances to travel
the social brain hypothesis (Dunbar, 2003) - Answer as the amount of conspecifics in one's
social group increases, they are more cognitively demanding to maintain
so, the larger the brain, the bigger the social group
the mating mind hypothesis (Miller, 2000) - Answer the demands of attracting and
evaluating sexual mates drove the evolution of higher cognitive abilities
ex., cognitive abilities like humour, creativity, etc. were indicators of strong genetic qualities and
increased mate attractiveness
homology - Answer genetic relatedness between structures (ex., human arms and bird
wings)
analogy - Answer functionally similar body structures that do not share common genetic
inheritance (ex., bird wings and bee wings)
single nucleotide polymorphisms (SNPs) - Answer alleles that differ from other alleles by a
single nucleotide
alleles - Answer different versions of the same gene
apolipoprotein (APOE) alleles and Alzheimer's - Answer - on chromosome 19 necessary for
lipoprotein formation
- E4 has Arg on codon 112 and 158, where E2 has Cys & Cys, and E3 has Cys & Arg
- two copies of APOE E4 --> 91% chance of developing Alzheimer's
, copy-number variations (CNVs) - Answer segments on DNA resulting from insertions,
duplications, and deletions to particular segments
- encompass ~12% of human genome
- can arise de novo (ex., found in ~10% of children with ASD) or be inherited (ex., Huntington's
disease)
epigenetics - Answer changes in phenotypes produced by changes in genetic expression (i.e.,
what genes are turned on/off)
what processes determine gene expression patterns? - Answer - DNA methylation
- histone modification
DNA methylation - Answer presence of methyl groups on DNA bases, associated with gene
silencing; abnormal methylation associated with disease
histone modification - Answer histone interaction with "epigenetic tags" make nearby DNA
more or less likely to be transcribed
DNA methylation and child maltreatment - Answer children with a history of maltreatment
show different methylation patterns than controls:
- typically low- and medium-methylated areas are high-methylated
- typically high-methylated areas are low-methylated
gioblastoma multiforme (GBM) and MGMT gene - Answer MGMT gene: codes for DNA
repair enzyme that can stop effects of certain toxins
- this can reduce effectiveness of chemotherapy drugs (ex., temozolomide)
MGMT methylation is generally associated with better GBM treatments
behavioural genetics - Answer the study of genetic and environmental influences on
behaviour
heritability - Answer the contribution of genetics to the variation of a trait observed in a
population
