Temperature Flashcards
What are the effects of temperature on biological processes?
Temperature affects metabolic activity, behavior, and geographical distribution of animals.
What range of temperatures do most vital activities in animals occur?
Vital activities occur between -2 and +50 °C, with most animals living in a narrower range.
How does temperature affect molecular and organism levels in animals?
At the molecular level, temperature affects the structure and function of biological membranes and the speed of enzymatic processes. At the organism level, it influences body temperature regulation and metabolic heat production.
What is the relationship between protein activity and temperature?
Temperature affects the three-dimensional structure of proteins, modifying their functional properties. Protein activity increases with temperature to a point, after which proteins denature and activity decreases.
How do animals adapt their enzymatic activity to different temperatures?
Animals adapt by modifying gene expression, expressing alternative isoforms, and adjusting enzyme activity to maintain catalytic efficiency at different temperatures.
How do short-term temperature changes affect enzymatic activity in animals?
Short-term changes can modify gene expression, enzyme activity, substrate concentration, and energy intake through the intervention of hormones or neurotransmitters.
What are medium-term responses to temperature changes in animals?
Medium-term changes involve modifying gene expression and expressing alternative isoforms to adapt enzymatic activity over days or weeks.
What are long-term adaptations to temperature changes in animals?
Long-term adaptations occur during molecular evolution, selecting enzymes suitable for particular thermal environments, focusing on enzyme flexibility and gene expression regulation.
How do enzymes in poikilotherm animals differ in various temperatures?
Enzymes in poikilotherm animals differ in structural and functional characteristics, making them more suitable for their usual body temperatures.
What is the relationship between specific activity and enzyme-substrate affinity?
The specific activity of enzymes is often related to the enzyme-substrate affinity, which is optimal at a temperature-dependent value.
How does global warming affect poikilotherm species?
Global warming may cause poikilotherms to function with non-optimized molecular systems, as natural selection might not keep up with rapid temperature changes.
Give an example of a fish adapted to cold temperatures.
The Antarctic fish Pagothenia borchgrevinki has extremely temperature-sensitive acetylcholinesterase activity, while the mullet Mugil cephalus maintains enzyme activity over a wide temperature range
What role do chaperonins or heat shock proteins (HSPs) play in thermal adaptation?
HSPs assist in the correct folding of proteins and increase significantly in response to environmental stresses such as thermal shock, preventing protein aggregation and assisting in refolding.
How do HSPs vary among species exposed to different environmental temperatures?
Species like Antarctic fish produce only basal levels of HSPs, while species in environments with large temperature variations, such as intertidal molluscs, produce higher levels of HSPs.
What are the primary modes of heat exchange in animals?
The primary modes of heat exchange are conduction, convection, evaporation, and irradiation.
How does body size affect thermal inertia in animals?
Larger body size increases thermal inertia, making it an advantage in environments with rapid temperature fluctuations.
What is the role of thermoreceptors in animals?
Thermoreceptors perceive and respond to changes in environmental temperature, activating homeostatic adjustments.
Where are thermoreceptors located in mammals?
Thermoreceptors are located in the skin (peripheral) and within the nervous system (central, in the hypothalamus).
What types of TRP channels are involved in thermosensation?
TRPV1 and TRPV2 for intense heat, TRPV3 and TRPV4 for moderate heat, TRPM8 for cold, and TRPA1 for intense cold.
What is the main difference between ectothermy in aquatic and terrestrial environments?
Aquatic ectotherms tend to have body temperatures equal to the environmental temperature due to water’s high heat capacity, while terrestrial ectotherms can have body temperatures different from the air temperature due to radiation and evaporation.
How do animals react to rapid changes in environmental temperature?
Animals react with acute responses (acclimatization and acclimation) and more complex responses like chronic responses or evolutionary adaptations over time.
What is the Q10 temperature coefficient?
Q10 is the multiplicative factor by which the metabolic rate increases for each 10 °C temperature increase, generally between 2 and 3 in ectotherms.
How do ectotherms react to a rapid change in environmental temperature?
Ectotherms react with acute responses (acclimatization and acclimation), chronic responses at the organism level, and evolutionary responses involving entire populations and gene frequency variations.
How do global temperature changes since 1980 affect ectotherms in different regions?
Temperature changes rose fastest in the Arctic and north temperate zones, more slowly in the tropics, and remained unchanged in the south temperate zone, impacting ectotherms’ basal metabolic rates accordingly.
What is the relationship between metabolic rate and temperature in ectotherms?
The relationship is exponential, defined by the temperature coefficient (Q10), indicating how metabolic rate increases with temperature.
What happens to fish on the Great Barrier Reef as water temperatures rise?
Fish like the cardinalfish lose much of their aerobic capability, limiting their ability to increase O2 consumption and engage in aerobic exercise.
- decrease in aerobic scope
What role do anti-freeze proteins (AFPs) play in fish?
- AFPs lower the freezing point of body fluids by binding to ice crystals, preventing their growth and formation
- Producing AFPs on a basal level means that Antarctic fish continuously produce a low, constant amount of AFPs regardless of environmental conditions.
- Basal production ensures that there is always a sufficient amount of AFPs to inhibit ice crystal growth and prevent freezing without the need for additional regulatory mechanisms.
How do they work?
- lower the freezing point of the fish’s internal fluids (not the surrounding water)
- interacting directly with the surface of ice crystals that may form within the fish’s body fluids.
- This interaction inhibits the growth of the ice crystals, preventing them from expanding and causing damage to the fish’s cells and tissues
- AFPs do not affect the freezing point of the water outside the fish, only the internal fluids where they are present.
