BIO 152 Exam #2 Practice

Concentration of urine (loss of water) in human kidneys occurs as urine flows down collecting ducts from the cortex to the bottom of the medulla. Why does water diffuse across the collecting duct cells to the space outside the duct, the interstitial fluid?

4. There are water channels (aquaporins) in the duct cell membranes that allow water to pass from cytoplasm to interstitial fluid.

What is NOT a consequence of hemoglobin binding to a molecule of oxygen?

A molecule of carbon dioxide is released from the hemoglobin molecule

If you become extremely allergic to insect bites, where should you move to most reduce the chances of suffering a severe reaction to a bite?

Barrow, Alaska

Insects can be treated with a drug that causes the small muscles surrounding spiracles to relax and stay relaxed, making it impossible for the insect to close spiracles. Alternatively, one can plug up all the spiracles with glue. In each case the insect dies. Why does it die after the first treatment? Why does it die after the second treatment?

First: desiccation (drying out). Second: inability to make ATP

Which principle of heat exchange is the most important explanation for why birds look larger in colder weather because they fluff their feathers?

Fluffing creates a pocket of air near the bird that acts as insulation

How has the avian lung adapted to the metabolic demands of flight?

Gas exchange occurs during both inhalation and exhalation

Carbon dioxide is found in the circulatory system primarily in the form of:

HCO3 (bicarbonate ion)

The hagfish (Eptatretus cirrhauts) is a jawless marine vertebrate that is isotonic with its environment and is considered to be an osmoconformer. How might this interesting adaptation limit the habitat that hagfish can tolerate.

Hagfish Habitat is limited by the salinity of the environment

Why does the oxygen content of water increases linearly with increase in oxygen partial pressure while the oxygen content of blood increases in a sigmoidal (S-shaped) fashion.

Hemoglobin shows cooperative oxygen binding

Blood returning to the mammalian heart in a pulmonary vein drains first into the:

Left atrium

From an evolutionary perspective, which of the following adaptations makes the most sense? That is, which one contributes most to survival of the particular species in a particular environment?

Long loops of Henle in a desert fox

Following glycolysis and the Krebs cycle, but before the electron transport chain and oxidative phosphorylation, the carbon skeleton of glucose has been broken down to CO2 with some net gain of ATP. Most of the energy from the original glucose molecule at that point in the process, however, is in the form of...

NADH

In which sort of environment are homeostatic control systems most advantageous to animal species?

One that is highly changeable

Why does blood pressure decrease as blood travels through a capillary?

The capillary branches

What prevents the atria and ventricles of a 4-chambered heart from contracting at the same time?

The electrical signal generated in the right atrium is delayed at the atrioventricular node before passing to the ventricles.

In photosynthesis, electrons are 'excited' by photons and some of the energy is used to produce ATP. In mitochondria, electrons are also used to produce ATP but these electrons do not become 'excited'. How can ATP be produced in mitochondria without exciting electrons?

The electrons that take part in mitochondrial ATP sythesis started as high-energy electrons not needing to become more energetic

Why does the PO2 of air inspired by humans decrease from about 140mm Hg to about 105mm as soon as it enters the lungs and before it even gets to the alveoli?

The entire airway contains air with a low PO2 before inhalation

As blood flows through a capillary it first loses water and then regains water before entering a venule. What causes this movement of water?

The fluid outside the arterial end has a higher osmotic concentration than the fluid outside the venous end

A molecule of oxygen binds to a human hemoglobin protein. What happens next to the hemoglobin?

The hemoglobin molecule undergoes two shape changes, one to bind the oxygen molecule more tightly and the other to influence the shape of other hemoglobin molecules.

Which feature of endotherm respiratory systems is responsible for removal of water from exhaled air?

The lower temperature of airway surfaces following inhalation

Why are the renal artery and renal vein critical to the process of osmoregulation in vertebrates?

The renal artery delivers blood with nitrogenous waste to the kidney and the renal vein brings blood with less nitrogenous wastes away from the kidneys.

When you are running, your muscles are using more oxygen and releasing more carbon dioxide into the blood than when you are at home on the couch. Which of the following would occur during your run?

The respiratory center in brain wold increase the rate of breathing

Blood is pumped at high pressures in arteries from the heart to ensure that all parts of the body receive adequate blood flow. Capillary beds, however, would hemorrhage under direct arterial pressures. How does the design of the circulatory network contribute to reducing blood pressure to avoid this scenario?

The total cross-sectional diameter of the arterial circulation increases with progression from artery to arteriole to capillary, leading to a reduced blood pressure.

The energy of electron transport serves to move (translocate) protons to the outer mitochondrial compartment. How does this help the mitochondrion to produce energy in a useful form?

The translocation of protons sets up the electrochemical gradient that drives ATP synthesis in the mitochodria

In a cross section (end-on view) through an artery and a vein running parallel in your leg, which would be the artery?

The vessels with more muscle tissue in the wall

What role do chloride cells play in osmoregulation of marine fish with bony skeletons?

They are involved in excretion of excess salt

How do the small molecules in blood get out of a blood vessel and into nearby tissue?

They diffuse in the space between the edges of neighboring endothelial cells

On very cold days your nose tends to 'run' with a thin, watery secretion. This does not seem to be a very 'smart' response because you lose water from your body. Why does your nose do this?

To guard against the possibility that your airway would become too dry

Which system plays the greatest role in the homeostatic function of helping to regulate volume and composition of blood and interstitial fluid?

Urinary system

What is the main reason that a person sitting on the beach with an air temperature of 15°C loses heat less rapidly than when immersed in lake water at 15°C?

Water conducts heat more efficiently than air does

Which of the following would result in a human's production of hypotonic urine? (Hypotonic = too much water).

a decrease in release of ADH by the brain

Your brain 'knows' when your body temperature changes because:

a protein in nerve cells changes shape

In which animal does blood not always go to the gas exchange surface after leaving the heart?

alligator

Which of the following affects the osmolarity of a solution?

concentration of cations, anions, and water

The loop of Henle dips into the renal cortex. This is an important feature of osmoregulation in terrestrial vertebrates because _____.

differential permeability of ascending and descending limbs of the loop of Henle are important in establishing an osmotic gradient

There are advantages and disadvantages to adaptations. Animals that are endothermic are likely to be at a disadvantage in which of the following environments?

environments with variable and limited food sources

Freshwater fish are hypertonic compared to their environment. To maintain homeostasis in this environment, they must _____.

excrete large quantities of water

An animal exhibits behavioral thermoregulation, has bones, and the major gas exchange organ (respiratory surface) is the skin. This animal is most likely a:

frog

During the production of urine, animals using hydrostatic pressure to filter blood must also

have a closed circulatory system

Which term best describes an animal that, although generating a significant amount of heat through metabolism, nonetheless does not maintain a constant body temperature?

heterothermic endotherm

Malpighian tubules form 'pre-urine', which is further processed by which of the following anatomical structures of insects?

hindgut

The main difference between respiration in terrestrial insects and in terrestrial vertebrates is that

insects rely on their tracheal system to deliver oxygen in air to their tissues, whereas terrestrial vertebrates rely on their lungs to deliver oxygen to their tissues through the blood in their circulatory system

You prop open the gill covers of a fish, tie a string around its tail, and tow it backward through the water. This action forces water to flow in the back of the gill covers, from back to front over the gills, and out through the fish's mouth. What effect would this backward movement have on gas exchange?

it would reduce efficiency of gas exchange

African lungfish, which are often found in small stagnant pools of fresh water, produce urea as a nitrogenous waste. What is the advantage of this adaptation?

small stagnant pools do not provide enough water to dilute toxic ammonia

Which of the following statements concerning the composition of the filtrate formed by the renal corpuscle of the human kidney is correct?

the filtrate is similar to blood but is without large proteins and cells

All of the following represent examples of how the structure of respiratory organs conforms to Fick's Law of Diffusion except

the flow of blood through fish gills is in the same direction as the flow of water over the gill surface

What is the purpose in having several steps in glycolysis and the TCA cycle (Kreb's cycle) instead of a single step from glucose and oxygen to carbon dioxide and water?

the multi-step process allows energy to be recovered from the reactions in many small amounts. In single step process the energy would be released all at once.

Some animals exchange oxygen and carbon dioxide directly across the skin. Amphibians and a few other small animals do this but there are no large animals that exchange gasses this way. Why don't large animals utilize this strategy?

the volume of large animals is greater than the volume of small animals

If you were convinced that endothermic fish exist in the world, what characteristic of such a fish would you consider the best indicator that you're correct?

unusually large gills

An animal that lives in a very dry environment needs to minimize water loss and will thus most likely secrete nitrogenous waste in the form of

uric acid