Biol2220 Final Exam QUESTIONS AND CORRECT DETAILED ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED A+
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Course
Biol 2220
Institution
Biol 2220
Biol2220 Final Exam QUESTIONS AND CORRECT DETAILED ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED A+
Homeostasis - Answers - Maintenance of relatively constant conditions in the internal environment
Significance of Homeostasis - Answers - Disruption can lead to disease; Body can adapt to mild str...
Biol2220 Final Exam QUESTIONS AND
CORRECT DETAILED ANSWERS
(VERIFIED ANSWERS) |ALREADY
GRADED A+
Homeostasis - Answers -✔✔ Maintenance of relatively constant conditions in the
internal environment
Significance of Homeostasis - Answers -✔✔ Disruption can lead to disease; Body can
adapt to mild stressors; Variables that need to remain constant: composition,
temperature, volume
Positive Feedback Loops - Answers -✔✔ Positive Feedback: the response of system
goes in the same direction as the change
Cellular Signalling - Answers -✔✔ Specialised cells → tissues → organs;
Communication via transmitters allows functioning; Involves gap junctions and cell-to-
cell interactions
Juxtacrine Signalling - Answers -✔✔ Direct contact between cells; Gap junctions
Paracrine Signalling - Answers -✔✔ Short distance, immediate cellular environment;
Local coordination (proliferation and differentiation)
Autocrine Signalling - Answers -✔✔ Cell signals to self; Self-stimulation (immune
system) or self-identity (development)
Endocrine Signalling - Answers -✔✔ To distant sites, via hormones in the bloodstream;
Development and physiology
Processes in Cell Signalling - Answers -✔✔ Paracrine: signal received from
presynaptic neuron on nearby postsynaptic neuron; Autocrine: signal sent + received by
presynaptic neuron
Receptors - Answers -✔✔ Bind to initiate a physiological response - transmit through
sequences of molecular switches to signalling pathways
Gap Junctions - Answers -✔✔ Formed when 2 connexons adjacently come together to
form a narrow pore between cells - allowing small molecules and ions to move from cell
to cell providing metabolic and electrical coupling
Hormones - Answers -✔✔ Produced in specialised cells/organs, travel via blood
Endocrine Glands - Answers -✔✔ Have specialised cells, produce hormones
Target Organs/Tissues - Answers -✔✔ Must have specific receptors, circulating
hormones will contact, only some respond
Steroid Hormones - Answers -✔✔ Derived from lipid cholesterol
Peptide-Protein Hormones - Answers -✔✔ Long amino chains or short linked chains
Amine Hormones - Answers -✔✔ Modified amino
Hormone Actions - Answers -✔✔ Synthesised and released (stored in
vesicles/released as synthesised); Transported in blood (protein (un)bound); Received
at cell (intra/extra-cellular); Elicit cell actions and responses
(rapid/slow/sustained/cyclical/pulsatile)
Signal Transduction - Answers -✔✔ Classical Genomic Signalling: lipophilic - can
diffuse across membrane + interact with receptors inside cell; Non-Genomic Signalling:
extracellular receptors (GPCRs) have been identified - exact contributions not well
understood
Types of Receptors - Answers -✔✔ G-protein coupled; Ion channel; Enzyme-linked;
[can be ligand-gated channels]
G-Proteins and Signal Transduction - Answers -✔✔ No hormone = GDP is bound to α
subunit of G protein; Hormone attaches to receptor = regulatory components (β & γ)
detach from α and GDP bound to α is exchanged for GPT; Activated α alters function of
another membrane protein usually a channel/enzyme (adenylate cyclase,
phospholipase C)
Secondary Endocrine Organ - Answers -✔✔ Secretes hormone + carries out another
primary function e.g. heart, liver, kidneys
Endocrine Hormones - Answers -✔✔ Tropic hormone: controls secretion of other
hormones e.g. hypothalamus/thyroid; Stimulating hormone: increases hormone
secretion; Inhibiting hormone: decrease hormone secretion
Endocrinology Axes - Answers -✔✔ Hypothalamus releases trophic hormone → effects
release of another → that one effects release of 3rd → 3rd effects target cells
throughout the body
Functional Types of Neurons in CNS - Answers -✔✔ Neurons: made up of cell body,
dendrites and axon; Sensory (afferent): detect/transduce stimuli arising from
outside/inside → CNS; Motor (efferent): carry efferent signals from CNS to effector to
cause a change; Interneurons: connect neurons to one another in CNS, allow CNS to
communicate, form circuits for processing neural information
Functional Types of Glial Cells in CNS and PNS - Answers -✔✔ Neuroglia: Functions:
physical support, supply nutrients and o2, electrical insulation, destroy pathogens,
information processing; Types: astrocytes, oligodendrocytes + schwann cells, microglia,
ependymal cells
Structural Organisation of Neurons - Answers -✔✔ Grey Matter: cell bodies + dendrites
of CNS + location of synaptic connections between neurons; White Matter: axons (CNS)
+ myelin sheath gives appearance
Body Fluid Compartments - Answers -✔✔ ICF = cytosol; ECF
Cell Membrane - Answers -✔✔ 2 layers of phospholipid molecules; selectively
permeable barrier between ICF + ECF
Ion Movement - Answers -✔✔ Concentration gradient → move down conc. gradient,
from high = low conc.; Electrochemical gradient → opposite attract, like repel;
Electrochemical driving force: both factors determine movement into/out of cell
Hydrophilic pore - Answers -✔✔ Allows diffusion of charged ions across membranes.
Passive transport - Answers -✔✔ Movement of ions without energy expenditure.
Ion channels - Answers -✔✔ 100+ types determine ion flow characteristics.
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