Biology 2601A/B Midterm: Midterm 2 Notes

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ivorymarten910

5 Dec 2016

School

Western University

Department

Biology

Course

Biology 2601A/B

Professor

Christopher G Guglielmo

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Document Summary

Aerobic metabolism is dependent on the exchange of oxygen (o2) and carbon dioxide (co2) from the environment. Plants take up co2 and release o2. Mitochondria take up o2 and release co2. Diffusion alone is too slow to maintain the rates of gas exchange needed to support the metabolism of larger organisms. Small surface area + large volume = not. Large surface area + small volume = good for diffusion. Diffusion of gasses or solute works for about a mm or less, bigger is too slow to meet the demands of the organisms. Oxygen flows in through the ostium, and deoxygenated oxygen flows out the osculum a the top. Mechanism allows oxygen to reach all the tissues. Getting o2 out of the external medium and into the cells: often via the circulatory system, air: ~ 21% o2 as a gas, water: ~0. 8% o2 in solution. Getting co2 out of the cells and into the external medium.

Related Questions

True of False: Freshwater environments have a higher concentration of oxygen than saltwater environments.

QUESTION 2 If the difference in partial pressure of gas on either side of the barrier to diffusion is 0, which of these events will occur?

The area for gas exchange will increase to accommodate this similarity.

The constant for diffusion will decrease.

The rate of diffusion will be 0.

The distance thickness of the barrier to diffusion will also be 0.

QUESTION 3 On the x-axis of the oxygenâhemoglobin equilibrium curve is the partial pressure of oxygen in tissues. Which type of blood is most likely to be represented by the right-hand side of the axis? (Hint: the oxygen-hemoglobin equilibrium curve is figure 45.14 in your book on pg 913)

blood found in the left ventricle

blood found in the right atrium

blood found in the superior vena cava

blood found in the inferior vena cava

QUESTION 4 Which of these is an example of pulmonary circulation?

Blood is pumped from the right ventricle to the lungs.

Blood is pumped from the left ventricle to the aorta.

Blood is pumped from the aorta to the cardiac vein.

Blood is pumped from the inferior vena cava to the right atrium.

QUESTION 5 O2 will diffuse from blood to tissue faster in response to which of the following conditions?

an increase in the PO2 of the tissue

a decrease in the PO2 of the tissue

an increase in the thickness of the capillary wall

a decrease in the surface area of the capillary

QUESTION 6 Which of the following promotes oxygen release from hemoglobin?

a decrease in temperature

a decrease in carbon dioxide levels

a decrease in pH

a decrease in carbonic anhydrase

QUESTION 7 How does the medulla oblongata sense the amount of carbon dioxide in the blood?

A. Carbonic anhydrase produced by cells performing cellular respiration is exported and travels though the blood, and binds to a receptor on the medullary respiratory center, which causes a signal amplification resulting in a change in gene expression which results in the production of proteins that will cause the diaphragm to contract

B. CO2 produced by cells performing cellular respiration reacts with blood plasma for form an acid, which increases the pH of the blood, which causes the medullary respiratory center to contract the diaphragm

C. CO2 produced by cells performing cellular respiration reacts with blood plasma for form an acid, which decreases the pH of the blood, which causes the medullary respiratory center to contract the diaphragm

D. A and B

E. A and C

QUESTION 8 Which of the following parts of the lung are considered "dead space"? A. The alveoli B. The trachea C. The bronchi D. B and C E. All of the above

QUESTION 9 Which of the following blood vessels have the thinnest walls?

arteries

arterioles

capillaries

venules

veins

QUESTION 10 How does the interstitial fluid return to the bloodstream?

A. Interstitial fluid flows into the capillary where the osmotic pressure driving fluid into the bloodstream is greater than the blood pressure driving fluid out of the blood

B. Interstitial fluid flows into the capillary where the blood pressure driving fluid into the bloodstream is greater than the osmotic pressure driving fluid out of the blood

C. Interstitial fluid leaves the tissue via lymphatic ducts and travels through the lymphatic system, which returns the fluid to the veins. D. A and C

E. B and C

QUESTION 11 True or False: When an electrocardiogram (EKG or ECG) shows a flat line (aka asystole), medical personnel will restart the heart using a defibrillator.

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Background

Almost all animal and plant cells require oxygen and give off carbon dioxide. This is called gas exchange and it occurs by passive diffusion. Some animals do all or most of their gas exchange across their skin (for example amphibians) but they have very low metabolisms and use very little oxygen and get rid of very little carbon dioxide.

On the other hand humans (and other mammals) have very high metabolic requirements and we canât rely on gas exchange over the limited 1.5 to 2.0 square meters of our skin to get enough oxygen in and carbon dioxide out fast enough. Our gas exchange takes place across a very thin membrane in the Alveoli of the lung and the gas exchange surface in humans is estimated to be between 50 and 100 square meters, or between 25 and 67 times our skin surface area.

Our lungs provide a huge surface for gas exchange but they are a dead-end system. Once the oxygen in the lungs is used up it needs to be replenished and carbon dioxide builds up in the air spaces in the lungs and needs to get out. This is where the diaphragm and a few of the skeletal muscles become important. In its relaxed state the diaphragm is at its longest and the space in the thoracic cavity (and the lungs) is small. When the diaphragm contracts it shortens, which increases the volume of the thoracic cavity (and the lungs). The increase in size means the pressure is lower in the lungs than outside so air comes into the lungs (inhalation). As the diaphragm relaxes, the lungs decrease in size enough that the pressure inside the lungs is higher than the external air pressure so air comes out (exhalation).

Introduction

In this lab you will be building a model of a lung and experimenting with different ways to breath.

Supplies:

In the Lab Kit

One round 9" balloon (one lung, we donât need two for this)
medium-sized plastic bag large enough to fit over bottom end of bottle (diaphragm)
medium-size, thin rubber band

You supply

plastic 2-liter soda bottle with bottom cut off (thoracic cavity)

Tape (optional)

Directions:

1. Insert the balloon through the open bottom of a modified 2-liter soda bottle and up over the neck of the bottle. Pull the end of the balloon over the edges of the neck of the bottle. The balloon is held open by the neck of the bottle.

2. Place the plastic bag over the bottom (open) end of the 2-liter bottle and use the rubber band to hold it in place. This will serve as the diaphragm. To inflate the lung, blow into the balloon just before you fasten the rubber band. You can also wrap tape over the edges of the plastic bag to minimize air leaks

3. Grasp the bottom of the plastic bag and pull it down and push it up. Watch as the "lungs" (the balloon) expand and contract as you do this. The balloon has to change size because the air space between the balloon and bottle must remain constant. (Well, it would if the seal around the plastic bag and bottle were perfect).

You may block the "trachea" (the neck of the bottle) so that the air supply is cut off and watch as nothing happens when the "diaphragm" is pushed in and out.

This model isnât perfect. None of the joints are air tight as they would be in a real thoracic cavity. Pull the âdiaphragm down and watch the lungs expand . If you hold it in place, the lungs will collapse again over time. This is because of leaks and is not how real lungs work. Pushing the diaphragm in and pulling it out over and over does give you an idea of how lungs work. As the diaphragm tightens, contracts (pull down on the plastic bag) the lungs fill with air. As the diaphragm relaxes (push up on the plastic bag) air is expelled from the lungs .

There are several different ways we breath, i.e. expand our thoracic cavity so that our lungs can expand. You have just made a demonstration model of the diaphragm at work. You can also use your rib cage to expand and contract so that you can inhale and exhale. There are muscles between and around your ribcage which you can use to change the size of your thoracic cavity.

This is approximately what your model of a lung will look like.

Answer the questions on the Report Page

Report Page Name

1. Put a hand on your lower ribcage and try moving your ribs out and in. Does air also move in and out?

2. Someone with an upper back or neck injury may not have the options of using diaphragm or ribs to breath. They can learn to use the clavicle and the muscles attached to expand their thoracic cavity a small amount and breathe independently for short periods of time. Put your hand on you clavicle and try to raise and lower just that bone without using your diaphragm or your ribs. It isnât easy but you should be able to get a little air into and out of your lungs this way. How effective do you think this way of breathing is?

3. When you take a really deep breath you use all these muscle groups to help. Take a really deep breath and notice that your ribs expand, your lower abdomen comes out (a sign that the diaphragm has contracted) and your shoulders lift a little (the upper chest and clavicle are working). Now take a relaxed breath. Only your abdomen should go in and out. The movement of your abdomen is a result of the contracting diaphragm pushing on the contents of your âgutâ which forces your abdomen to push out.

Do you breath in or out when your diaphragm contracts?\

4. If a hole were poked in your thoracic wall (the wall of the pop bottle â the hole should be at least the diameter of a pencil)

a. what would happen when you tried to breath? (This is a pneumothorax).

b. Is the space between the balloon and plastic bottle still required to remain constant?

5. Would it be possible to live with a paralyzed diaphragm? Explain your answer.

fuchsiamuskrat152

Value: 1

Anabolic pathways of metabolism are pathways that:

a. build complex molecules from simple ones.

b. release stored chemical energy.

c. take place primarily in skeletal muscle

d. make large quantities of ATP.

Value: 2

The sum of all chemical reactions in a cell is referred to as _______________.

Value: 3

Organisms that derive both their energy and carbon from organic compounds are:

a. photoautotrophs.

b. chemoautotrophs.

c. chemoheterotrophs.

d. photoheterotrophs

Value: 4

It is often stated that the phosphate bonds in ATP are "high energy," but in fact, they are not notably high in energy. Rather, they are easy to break, and the âG of hydrolysis is a "useful" quantity of energy. What makes the phosphate bonds easy to break?

a. They are close to the destabilizing nitrogenous base adenosine

b. Positive charges on amino groups repel each other.

c. Negative charges on phosphate groups repel each other

d. High acidity attacks bonds between amino acids.

Value: 5

Which of the following describes ATP hydrolysis? Select all that apply

[mark all correct answers]
a. exergonic

b. spontaneous

c. often coupled to a reaction that has a positive ÎG

Value: 6

Which of the following describes catabolic reactions?

a. They are endergonic and have a negative change in free energy

b. They are exergonic and have a negative change in free energy

c. They are exergonic and have a positive change in free energy.

d. They are endergonic and have a positive change in free energy.

Value: 7

Why are cells not infinitely big?

a. Because they wouldn't fit in an organism

b. Because they would have a small surface area:volume ratio and substances would diffuse in and out too slowly

c. Because they would have a large surface area to volume ratio and substances would diffuse in and out too quickly

Value: 9

How is organelle movement around cells controlled?

a. the nucleus directs the movement of organelles in a cell

b. the cytoskeleton is like a monorail that moves organelles in a cell via motor proteins

c. organelles do not move, they have a fixed position in the cell

d. organelles move by facilitated diffusion in the cell

Value: 10

1. Prokaryotic cells lack:

a. a. A nucleus

b. organelles

c. cell membrane

d. DNA

e. A and B

Value: 11

Rough endoplasmic reticulum (rER)

a. a. Makes cell membranes

b. has ribosomes attached

c. are a site of protein synthesis

d. all of the above

Value: 12

Match the items.

The task is to match the lettered items with the correct numbered items. Appearing below is a list of lettered items. Following that is a list of numbered items. Each numbered item is followed by a drop-down. Select the letter in the drop down that best matches the numbered item with the lettered alternatives.

a. help to digest worn-out or damaged organelles.
b. Takes in molecules in transport vesicles, modifies them, and sends them back out in vesicles
c. makes sugar
d. makes ATP
e. assembles the ribosomes
f. gives the cell structure
g. move material around the cell

1. vesicles	a b c d e f g
2. cytoskeleton	a b c d e f g
3. the golgi apparatus	a b c d e f g
4. lysosomes	a b c d e f g
5. mitochondrion	a b c d e f g
6. chloroplast	a b c d e f g
7. nucleolus

Biology 2601A/B Midterm: Midterm 2 Notes

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