Lecture 15 Flashcards
How is thermoregulation behaviourally controlled?
Repositioning the body in the environment to control body temperature.
How is thermoregulation physiologically controlled?
Immediate neural responses E.g. sweating, panting.
Long term adaptation/acclimatisation E.g. changes in insulation/capacity to alter metabollic heat.
Define tolerance.
Capacity to endure continued environmental conditions without an adverse reaction. Factors like temperature, salinity etc.
How does tolerance differ?
Differs between species, within and between populations, change between season, life stages condition, age etc.
What is the zone of tolerance?
Central range where an animal is most comfortable. Bounded by upper and lower zone of physiological stress within which organisms can survive for an indefinite period of time.
What effects heat tolerance?
Thermal history E.g. exposure to warm temperatures increases heat tolerance but decreases cold tolerance.
Seasonal changes in temperature.
What are heat shock proteins?
Proteins present in all cells that limit the consequence of adverse conditions (stress). Limit consequences of damage from stress and facilitate cellular recovery.
What are the primary functions of HSPs?
Promote proper folding/refolding of proteins.
Prevent potentially damaging interactions between proteins.
Aid in disassembly of protein aggregates.
How do HSPs act as molecular chaperones?
They stabilise other proteins and minimise probability of inappropriate reactions. Involved in folding, assembly, regulation and degradation of other proteins.
How are HSPs highly conserved?
They are present in all major components of all cells of all animals, plants and prokaryotes.
What are some examples of stress that cause HSP expression?
High/low temperatures, pH shift (affects ionic bonds), toxic substances/pollution, physical stress, hypoxia.
In what ways can HSPs be expressed?
Constituatively (all of the time),
increased during/after stress,
Exclusively induced by stress.
Describe the HSP response.
- Stress causes proteins to denature.
- Denatured proteins are detected.
- HSP proteins are produced which don’t denature as they have better hydrogen bonds and secondary structure.
- HSPs act as molecular chaperones and help proteins fold back to their original conformation.
What are the secondary functions of HSPs?
Aid immune response as they are normally found inside cells so if detected outside this signals cell damage. They help present antigens from diseased cells to T-cells.
What are the costs of HSPs?
They are energetically costly to produce
E.g. Drosophila engineered to have more HSP genes developed slower and had higher mortality.
