final exam prep Flashcards
Some benefits of oxygen use in the evolution of organisms
Increases in animal size, complexity, size, and movement
what is the primry role of O2 in physiolgy
electron acceptor in aerobic respiration; increased efficiency of energy production
What are the requirements for obtaining oxygen?
Interface with the environment and respiratory pigments; also require a trnsport mechanism (such as a circulatory system)
Characteristics of respiratory pigments
metal-protein complexes, colored
4 Functions of respiratory pigments
O2 transport and storage
Facilitate diffusion
O2 sensor
O2 protection ???
4 major groups of respiratory pigments differ based on
binding characteristics
color
metal used
4 major types of respiratory pigment
Hemoglobin
Chlorocruorin
Hemerythrin
Hemocyanin (Cu)
How does O2 binding affect Hemoglobin molecules
Hemoglobin made of four heme groups
O2 binding causes conformational changes such that O2 affinity is increased with each molecule bound
Allows for rapid uptake and release of O2
4 factors that affect O2 dissociation
Temperature
pH
CO2
Inorganic ions
P50
the PO2 at which respiratory pigments are 50% saturated
Increased P50 means decreased affinity for O2
How does salt affect o2 dissociation?
increased salt means decreased affinity (increased P50)
How do CO2 and pH affect O2 binding and carrying capacity
Co2 (which decreases pH) and a decrease in pH in general cause a decreased affinity for O2 to respiratory pigments.
Root effect
Decrease in overall carrying capacity of O2 in a respiratory pigment due to a decrease in pH
Bohr effect
A decrease in the binding affinity (or increase in P50) due to decreased pH.
Why is the Bohr effect a GOOD thing?
because, as you get to tissuesthat are O2 poor, that have ncreased Co2, it facilitates release of O2 into those tissues.
three aspects of gill form that are highly conserved among taxa
Structure (high surface area)
position (area of increased water flow/exposure)
Function (O2 uptake, transport)
3 mechanisms to remove CO2 from tissues
- Diffusion into blood
- binding to hemoglobin
- Bicarbonate buffer system
3 main functions of blood
- Transport of solutes and cells
- transport of heat
- Transmission of force
3 parts of a circulatory system
- Pump (heart)
- Conduit (blood vessels)
- exchange stations (sinuses. capillary beds, lung, kidneys.)
which respiratory pigment lacks cooperative binding kinetcs?
Hemocyanin; only has one subunit. 1/4 as efficient as hemoglobin.
two important properties of temperature
- primary determinant of metabolic rate (and therefore food and energy conumption.)
- Primary determinant of protein/tissue function
what are 3 ways that temperature has an impact on protein/tissue function?
- Protein conformation and enzymatic rates
- Rates of diffusion and osmosis
- Physical state of cells (membrane viscosity)
Types of thermal relations (4)
- Endotherms
- Ectotherms or poikilotherms (poikilo means variable)
- thermoregulating (behavioral or homeothermic via physiology)
- Nonthermalregulating
Why are there very few homeothermic aquatic organisms?
Heat convection in the water makes it difficult and neergetically costly
Convection
heat transfer via the flow of a material substance, much faster than conduction
Most common type of thermal relation (aquatic or otherwise)
ectothermic
Eury vs steno thermal
May function over a broad or narrow temperature range.
Critical thermal maximum (Ct max)
thermal limit
may be defined by mortality or loss of coordination
Ultimate Ct max-boiling point of water
Duration of thermal exposure important
3 ways organisms might respond to high temps
- Regulate via evaporative cooling (not available to aquatic orgs!)
- Behavioral responses
- Biochemical or physical adaptations
Two easy behavioral repsonses
- Leave area (for highly mobile species)
2. Sessile/less mobile may alter burrow depth to buffer against thermal changes
two examples of physical adaptiations to temperature
- Alterations in pigment
2. Blubber or other insulation
Q10
the rate by which a reaction increases with a 10 degree increase in temperature
Q10 is usually beteen 2 and 3 for poikilothermic species
pejus temperature
the temperature of turning worse
Membrane fluidity depends in large part to the degree of
hydrocarbon saturation
Saturated hydrocarbons means
no double bonds!
the degree of chemical unsaturation of the hydrocarbon tails of brain phospholipids varies with
habitat temperatre
Organisms that are warm adapted will have membrane phospholipids that are primarily
saturated
organsims that are primarily cold adapted will have membranes that are more
unsaturated.
How does degree of saturation of phospholipids alter membrane viscosity
Saturated phospholipds tend to have straight fatty acid tails, which encourages tigheter packing of molecules, creating a more “solid” lipid structure.
Unsaturated phospholipds had kinked fatty acid tails due to the introduction of double bonds between carbons of the fatty acid chains. This contributes to increased viscosity of the lipid, as molecules cannot pack as tightly.
4 problems associated with the cold
- Decreased membrane fluidity
- Freezing
- intracellular ice crystal formation is lethal to cells
- Extracellular ice formation my be tolerated but dehydrates cells due to changes in osmotic gradients
How do antifreeze proteins work
They bind to ice crystals to prevent further growth
