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BIOL381 Animal Physiology Exam 1


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What advantage does homeostasis confer on animals that practice it?
Homeostasis allows animals to survive in stressful and varying environments.
Return of sensory information to a controller that controls a bodily variable
An externally induced change to a variable in a controlled system
Receives output from a controlled system and funnels it to an amplifier
Receives output data from a sensor and inverts the signal, then sends it to the controller (ex. amplifier receives a + (positive) signal, reverses it to a - (negative) signal, then sends it to the controller
The output signal sent by a sensor to an amplifier that indicates the severity of a change to a controlled system (compared to a desired set point) via increases/decreases in the signal strength
Feedback involving the inversion of a sensor output signal by an amplifier; critical to maintaining homeostasis
Feedback in which the sensor output signal is not inverted by an amplifier, resulting in the controlled system change being reinforced and strengthened over time
What is a non-pathological example of positive feedback?
The rising phases of cycling events: vomiting, expulsion of a fetus from the uterus, swallowing
The humane treatment of animals that looks after their comfort and well-being
Concept that animals have intrinsic rights to "life, liberty and the pursuit of happiness"
Maintains internal ion concentrations at a set point despite external concentrations
Maintains internal oxygen concentration as oxygen availability falls
What is an example of an oxyregulator?
Crayfish, mollusks
Organism that does not maintain homeostasis with respect to one or more internal variables that are influenced by the environment
What is an example of an osmoconformer?
What is an example of an oxyconformer?
Annelid worms
Animal responses to environmental condition change with season and stage of life
Animal response to environmental condition change induced by a researcher
What are some examples of bodily variables that can be regulated?
Temperature, H2O percent, dissolved solute concentrations, O2 concentrations
Range of environmental values for a given variable that are most complimentary to homeostatic efforts to maintain that variable at its set point
England, 1500s:

- Blood flows unidirectionally out of the heart under pressure exerted by the heart.
- Blood then circulates through blood vessels and returns to the heart, completing a round trip.
- Prior belief: blood sloshes back and forth between vessels.

1800s, France:

- Measured body fluids in mammals to determine: temperature, volume, composition, concentrations of constituents

C = constituent amount/volume of fluid when dissolved
Capacity to do work
What 4 things do cells require from their environment?
1. C, N and H from nutrient molecules
2. O2 from air/water
3. Energy from nutrient molecules (energy in a form cells can use to perform work)
4. Heat

What is a triglyceride without its 18-Carbon chains?
Fatty acid
What is the central molecule of triglyceride?
Glycerol (C3O3)
What makes up a triglyceride?
Glycerol and one or more 18-Carbon chains
Deriving heat from surrounding fluid
Deriving heat directly from the source
What is the classic experiment demonstrating how the molecular building blocks of life arose spontaneously on the primordial Earth?
Miller, Stanley (1953) - Peptides, amino acids and nucleic acids (molecules essential to primitive life) appear when lightning-like electric discharges are performed on an experimental atmosphere of methane, ammonia and water.
How is the reactivity of a given atom determined?
By the number of electrons in the outermost shell
Why are Carbon, Hydrogen and Oxygen the most common elements in organic molecules?
They are the only one- and two-shell elements that form strong covalent bonds (sharing 3, 1 and 2 electrons respectively).
The "dipole" nature of H2O causes it to have what physical/chemical properties?
- Aligns with electrostatic fields.
- High dipole movement: 4.8 debyes
- Most important chemical feature: capable of making Hydrogen bonds between H+ of one H2O and the O of neighboring H2O
- Angle between 2 covalently bonded water molecules is 105 degrees, creating a tetrahedral lattice

Why are weak acids used in buffering systems?
Weak acids dissociate only slightly, ensuring a large reserve of A-. New H+ ions combine with A- to reform HA, while OH- can combine with H+ to form H2O.
Number of moles of solute in 1000g of solvent
Number of moles of solute dissolved in 1 L of solution
What is the weight of 1 mole CO2 in grams?
Why do only some liquids conduct electricity?
Conduction in liquids is only supported by the presence of cations (+) and anions (-).
How many ions flow past a point (amps) in a current of 1 mA?
0.001 amps (ions/sec)
How does attraction vary between a monopole binding site and a multipolar binding site with respect to a cation?
When a binding site is multipolar, attraction falls more rapidly with distance. When a monopole cation carrying a full charge is presented with a binding site, the a exponent of d^a is equal to 1.
Can function as an acid or a base (ex. H2O)
Describe the 4 levels of structure in a protein.
PRIMARY - Specific linear sequence of amino acid residues in the polypeptide.
SECONDARY - Local organization of polypeptide chain parts
TERTIARY - Foldings of the polypeptide chain to form globular or rod-like molecules
QUARTERNARY - Joinings of 2+ polypeptide chains to from dimers

Why does cysteine commonly inhibit enzyme reactions?
Two cysteine residues can perform a sulfhydryl group through a disulfide (S-S bond). This highly reactive group often renders enzyme binding sites catalytically inoperative.
Why do proteins denature at high temperatures?
QUATERNARY: Protein sub-units dissociate
TERTIARY: Covalent interactions, noncovalent dipole-dipole interactions, and van der Waals interactions are disrupted
SECONDARY: Proteins lose repeating patterns and adopt random coil patterns
PRIMARY: No change

Do living organisms violate the 2nd Law of Thermodynamics with their consistently low entropy?
No. Living organisms do not represent closed systems-- they maintain low entropy (disorder) at the expense of their surrounding environment, which gains disorder.
At a particular temperature, will delta-S > delta-H be endergonic or exergonic?
delta-S = change in entropy
delta-H = change in heat

change in entropy > change in heat

Endergonic (exergonic reactions give off heat)

When does an endergonic reaction proceed?
When enough energy has been absorbed from the environment
What is delta-G for a system at equilibrium?
delta-G = change in Gibbs Free Energy

System at equilibrium delta-G = 0 (there is no change in GFE)

How does ATP supply energy to endergonic reactions?
ATP decomposes into ADP + P, releasing energy for use in the reaction.
Endergonic reactions or transport processes are linked to exergonic reactions that provide a surplus of energy
Why does an increase in temperature increase the rate of reaction?
Heat causes the molecules involved in the reaction to move faster (remember 0 Kelvin temperature = no molecule movement)
How are enzymatic reactions influenced by temperature?
Generally, enzymatic reactions have a rate increase with temperature. However, different enzymes also denature at higher temperatures, and at that point will become less effective, then inoperative.
Product of breaking down carbohydrates such as sugar (by glycolysis) or triglycerides; located in special molecules made in cells by concentrating energy derived from breaking covalent bonds in nutrient molecules
What 3 substances are broken down by glycolysis?
Glucose 1-phosphate

When carbohydrates are broken down by glycolysis, are the products the end products or intermediates?
Intermediates - the products must directly/indirectly transfer phosphate bond energy to the covalent bonds of ATP
Adenosine triphosphate; provides energy for all cell processes
How does ATP break itself down for energy?
It typically only breaks one Phosphate bond, making ADP + P
Energy required to raise 1g water by 1 degree Celsius
Amount of substance containing 6.02 x 10^23 molecules
ATP is not the greatest energy in a living system, but it is the most _______.
ATP synthesis during cellular respiration (equation)
ADP + P --> respiration + O2 + fuel ---> ATP OR CO2 + H2O (byproducts)
What are 3 types of work ATP can be used for?
Mechanical work
Transport work

Breakdown of large molecules into small ones, releasing covalent bond energy
Synthesis of large molecules from small ones
What are the products of the catabolism of nutrient molecules used for?
Sources of high-energy phosphate bonds for ADP, creating ATP
Catabolism always requires ___ and always has ___ as a byproduct.
O2, CO2
What happens to nonpolar molecules like O2 and CO2 when they come in contact with the cell membrane?
Dissolve readily in cell membrane lipids
Cellular respiration can be measured as an exchange between O2 and ____.

In cellular respiration, O2 intake and CO2 output are always equal.

Where are 2 places ATP is created in mitochondria?
Cytosol, mitochondrial center (at the site of respiration)
Inner mitochondrial membrane near the site of respiration
ATP Production in cell cytosol (equation)
Polysaccharides ---> 5- and 6-Carbon sugars ---> 3-Carbon sugars ---> ATP OR pyruvate ---> goes inside mitochondria OR lactate
Chain of individual glucose molecules bound covalently -- broken down by digestion
Breakdown of starches that releases individual glucose molecules into the blood
What happens to the energy of starch bonds (glucose-glucose) during digestion?
Released as heat
No O2 used
Breakdown of 5- and 6-Carbon sugars into 3-Carbon sugars
Electron-accepting coenzyme that captures energy from glycolytic substrates
5- and 6-Carbon sugars that are transformed into 3-Carbon sugars by glycolysis
Adding an electron to a molecule (ex. NAD is reduced to NADH)
Removing an electron from a molecule (ex. glycolytic substrates are oxidized)
Paired oxidation and reduction reactions
Phosphorylation of ADP to produce ATP while the glycolytic substrate is being transformed
What is the name of the process that creates ATP inside the mitochondria?
Kreb Cycle
KREB CYCLE: Pyruvate
1. Pyruvate becomes lactate OR CO2 OR has a Carbon removed and Coenzyme A added to form acetyl CoA (2C remaining)
2. Combines with OAA to form CA (citric acid citrate) with 6C
KREB CYCLE: CA (citric acid citrate)
3. 2C removed, breaking down CA into 2CO2s, and recycling CA itself to OAA (producing one more CO2, for 3 total CO2)
KREB CYCLE: Recycling of citric acid
4. Citric acid is transformed to yield new electrons captured by NAD and the secondary electron acceptor FAD
KREB CYCLE: Recycled citric acid meets H+
5. H+ addition leads to transport of energy to the electron transport chain
KREB CYCLE: Electron Transport Chain (3 products)
6. NADH from cytosol glycolysis and NADH/FADH from Kreb Cycle are oxidized, recycling NAD and FAD, ATP is produced, and H2O is produced where O2 is added
In the Kreb Cycle, H2O acts as what?
Terminal electron acceptor; H2O gathers e/p removed from NADH and FADH that combine with O2, as O2 takes up energy-poor e
When electrons are removed from NADH and FADH (yielding NAD and FAD), where does the energy go?
Some goes to ATP, most released as heat
How many moles of ATP are produced per 1 mole of NADH?
3 moles ATP per 1 mole NADH
How many moles of ATP are produced per 1 mole of FADH?
2 moles ATP per 1 mole FADH (there is only 1 FADH per cycle, so only 2 moles ATP per pyruvate)
How many moles of ATP are produced from 1 mole of pyruvate?
2 moles ATP per 1 mole pyruvate
How many moles of H2O are produced per Kreb cycle?
3 H2O per cycle
Water produced during the Kreb cycle; relied upon by desert animals
No O2 in cell, cell cannot produce ATP and eventually dies; drowning, CO poisoning cause this
Why does CO poisoning cause anoxia?
CO bonds with O2-carrying molecule in the blood
1 mole glucose catabolized (6C)
2 moles pyruvate produces (3C each)
3 moles O2 required
1 mole pyruvate catabolized
3 moles CO2 produced
3 moles H2O produced

STOICHIOMETRY: Metabolism of 1 Mole Glucose
Requires: 6 moles O2
Requires: 2 turns of Kreb cycle
Products: 6 CO2 and 6 H2O

Metabolism of 1 mole of glucose (equation)
C6H12O6 + 6O2 --> 6CO2 + 6H2O
How much energy is released by the complete catabolism of 1 mol glucose?
686 kcal, only 288 kcal captured (38.7%) and remainder released as heat
What is an example of anaerobic metabolism?
Pyruvate + NADH ---> Lactate + NAD (no oxygen used)
Some animals do not use mitochondria and do not require O2.

But only 2 moles of ATP are earned per 1 mole glucose (1/19 as efficient as aerobic metabolism)

Some organisms use this as an anoxia failsafe.

Lactic Acid Dehydrogenase; catalyst to the pyruvate --> lactate reaction that applies in both directions
What happens regardless of whether glucose is transformed for mitochondrial use OR glucose is transformed into lactate?
NADH recycles into NAD
What process causes oxygen debt?
Lactate production by cells producing pyruvate from sugar
How is oxygen debt repaid?
Lactate is broken down in the blood by the liver, returning O2
Why does the liver remove lactate?
Prevents blood/tissues from becoming too acidic
Permits lactate conversion to pyruvate (and then to sugar)
Sugar from pyruvate that is stored by the liver
Conversion of lactate to pyruvate to glycogen (sugar)
How can the liver maintain blood sugar homeostasis?
Breaks glucose off of glycogen molecules
Besides the liver, what other tissue removes lactate from the blood? Why?
Muscle removes lactate and uses the resulting glycogen to fuel contraction
Rate of energy use at rest (no digestion) in nonstressful temps in kcal/hour
When does O2 debt occur between rest and exercise?
Exercise creates energy need; O2 debt occurs as anaerobic respiration supplies energy while aerobic respiration lags
What are some reasons for the lag in energy produced by aerobic respiration?
O2 cannot be abosrbed into the blood quickly enough and lags the electron transport chain
Blood flow is not fast enough when the animal starts at rest
Heart/Respiratory activity takes time to increase

What are 2 lactate steps of anaerobic metabolism?

What are 2 ways the body reacts to anaerobic metabolism and oxygen debt?

1. Cells produce lactic acid from pyruvic acid (catalyzed by LDH).
2. Lactate leaves cells and dissolves in blood.


1. Some cells absorb blood lactate and convert it back to pyruvic acid
2. Gluconeogenesis leads to glycogen storage

Removal of lactate from the blood requires ____ _____ because ____ is required to produce glucose and glycogen.
aerobic metabolism, ATP
What happens related to O2 debt at the end of exercise?
O2 use remains elevated until all blood lactate is removed

The Rate of O2 Uptake is equivalent to the Rate of Energy Use.

SACCHARIDES (general formula)

If n = 6, C6H12O6 (glucose)

All compounds with the formula C6H12O6
What is the primary fuel molecule?
What are sugar names based on?
How many C they have.

3 = triose
5 = pentose
6 = hexose

What are saccharide names based on?
How many sugars they have linked together

0 = mono
2 = di
3+ = poly

What are 2 characteristics of lipids (triglycerides)?
1. Nonpolar
2. Insoluble in H2O
Fatty Acids have 3 "R"s connected to them. What does an "R" represent?
16-18 Carbon molecule chain
When H atoms are attached to all available C
When H are removed and Cs double-bond

More double bonds = polysaturated fatty acid

DIGESTION (general formula)
Glucose + 3H2O ---> glycerol + fatty acids
ALPHA-AMINO ACIDS (general structure)
COOH (carboxyl group)
(amino group)NH2--C--H
(one of 20 residues)

In an alpha-amino acid, what is "R"?
One of 20 different amino acid residues
Connects amino group (NH2) of one amino acid to the carboxyl group (COOH) of another amino acid

A tetrapeptide can have a different "R" on each of its individual amino acid groups.

What is the least accurate method of measuring metabolism?

Direct: Measure heat production
Indirect: Difference between calories in food eaten + calories in waste excreted

Exploits stoichiometry of metabolic summary reactions (amount of O2 used per gram metabolized) to measure metabolism
What are the respiratory quotients (RQs) for carbohydrates, proteins and fats?
Carbohydrates = 6/6 = 1
Proteins = 0.80
Fats = 102/145 = 0.71

How much energy is gained from metabolizing 1 gram of carbohydrates, proteins and fats?
Carbohydrates = 17 kJ/gram
Proteins = 17 kJ/gram
Fats = 39 kJ/gram

Convert 1 kJ into joules and calories.
1 kJ = 1000 joules = 239 calories
Convert 1 calorie into Joules.
1 calorie = 4.18 J
1 J = 0.239 calories
Convert 1000 mL H2O into kg and liters.
1000 mL H2O = 1 kg = 1 L
Why is it difficult to write a summary reaction for proteins?
Because proteins contain N, which animals also make as a metabolic byproduct and excrete as urea and other compounds
When proteins are digested, where does the energy come from?
Proteins are broken down into amino acids which are broken down into energy
How much O2 is used to metabolize 1 mole of carboyhdrates, proteins and fats?
Carbohydrates = 6 moles O2 per 1 mole carbohydrate
Proteins = N/A
Fats = 72.5 moles O2 per 1 mole fats

Rate of O2 uptake can only be counted as energy for which type of respiration?
What is the heat production per gram of carbohydrates, proteins and fats?
Carb = 17.1 kJ/gram
Prot = 17.6 kJ/gram
Fat = 38.9 kJ/gram

Why is heat production a useful measurement in determining metabolism?
Eventually all energy (even that used to create glucose) is released from the body as heat
What are 4 occasions when heat is released?
1. Breakdown of molecules that used energy for their synthesis
2. Breakdown of fuel molecules (40% captured for ATP)
3. ATP use by cells
4. ATP use for work

If you have glucose fuel, and the energy used is 21 kJ/Liter O2 consumed, and 5L O2 is consumed in 1 minute, what is the energy use rate?
21 kJ/L O2 X 5L O2/1 min

21 kJ X 5/1 min

105 kJ/min

If RQ = 0.85 (halfway between 1.0-carbs and 0.71-fats), how can the fuel type be calculated?
Collect urine sample to find out # of amino acids and subtract from 50/50 carb/fat ratio, but general animals do not spend protein making ATP

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