Chapter 2 - Exam Pracrtice Questions (Textbook)
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30 Terms
1. What is the body’s universal energy carrier?
ATP
2. What is the end product of glycolysis?
d. Pyruvate
3. Which of the following plasma membrane components has a head and two tails?
d. Phospholipids
4. Which type of connective tissue forms sheets that provide tensile strength—→ Means when being streched?
a. Collagen ✅
👉 Collagen forms strong sheets and fibers that give tensile strength (resistance to being pulled apart).
Connexon → part of gap junctions (cell communication).
Elastin → gives tissues stretch and flexibility, not tensile strength.
Fibronectin → helps with cell attachment and wound healing, not strength.
5. The Na+–K+ ATPase pump is an example of a(n)
a. active transporter ✅
👉 The Na⁺–K⁺ ATPase pump uses ATP energy to move sodium (Na⁺) out of the cell and potassium (K⁺) into the cell against their gradients.
Ion channel → lets ions flow passively (no ATP).
Facilitated diffusion carrier → helps things move down their gradient, no ATP.
Secondary active transporter → uses the energy from another gradient (not directly ATP).
6. List the four stages of the pathways for production of ATP.
Glycolysis, pyruvate decarboxylation, tricarboxylic acid cycle (kerbs cycle), electron transport chain.
Glycolysis 🥖
Happens in the cytoplasm (cell fluid).
Breaks glucose (sugar) into 2 smaller pieces (pyruvate).
Makes a little ATP + NADH.
Link reaction (Pyruvate → Acetyl-CoA) 🚪
Connects glycolysis to the Krebs cycle.
Pyruvate goes into mitochondria and becomes Acetyl-CoA.
Gives off CO₂.
Krebs Cycle (Citric Acid Cycle) 🔄
Happens in the mitochondria.
Acetyl-CoA is broken down further.
Makes more NADH, FADH₂ (energy carriers), and some ATP.
CO₂ is released.
Electron Transport Chain (ETC) + Oxidative Phosphorylation ⚡
Happens in the inner mitochondrial membrane.
NADH & FADH₂ drop off their electrons.
Electrons power pumps that move protons → makes a proton gradient.
Protons rush back through ATP synthase → makes LOTS of ATP.
Oxygen is the final electron acceptor → makes water 💧
7. List the types of cell junctions.
Desmosomes, tight junctions, gap junctions
Cell junction = how cells “hold hands” or “connect” to each other.
Tight junctions 🤝
Like zippers between cells.
Seal the space so nothing leaks between them (like in the stomach or bladder).
Desmosomes 🧲
Like buttons/snaps.
Provide strong “spot welds” so cells don’t rip apart (important in skin & heart).
Gap junctions 📞
Like little tunnels/bridges between cells.
Allow small molecules & ions to pass so cells can communicate (like in the heart, for synchronized beating).
8. List the four types of chemical messengers. (Read more on!)
Paracrines
Local messengers.
They act on neighboring cells.
👉 Example: growth factors, histamine (in allergies).
Neurotransmitters
Chemicals released from nerve cells to communicate with another nerve, muscle, or gland.
👉 Example: dopamine, acetylcholine.
Hormones
Released into the blood → travel far to reach target cells in other parts of the body.
👉 Example: insulin, cortisol.
Neurohormones
Special messengers released from nerve cells into the blood (so kind of like a mix of neurotransmitter + hormone).
👉 Example: oxytocin, vasopressin.
Hormones → travel through the blood to send messages far away (like insulin).
Neurotransmitters → tiny chemicals that pass between nerve cells (like dopamine).
Paracrines → local messengers that act on neighboring cells (like growth factors).
Autocrines → a cell sends a message to itself (self-talk chemical).
💡 Easy trick: Hormones = far, Neurotransmitters = nerves, Paracrines = neighbors, Autocrines = self.
9. Describe the primary function of gap junctions.
They form connecting junctions between cells to allow communication between cells by allowing the passage of small, water soluble molecules.
10. What are aquaporins?
Aquaporins = water channels (tiny doorways in the cell membrane just for water). 🚪💧
They make it easy and fast for water to flow in and out of cells.
Important in kidneys, brain, eyes → anywhere water balance matters.
Aquaporins are membrane channels that allow the passage of water.
1. Using your knowledge of cellular metabolism, during which stage is the most ATP produced under aerobic conditions?
d. Electron transport chain
2. Which of the following descriptions is best associated with diffusion?
a. A substance moves with its concentration gradient.
Diffusion = particles move from high concentration → low concentration (like perfume spreading in a room).
It’s passive → no energy needed.
3. For all types of carrier-mediated transport, which one of the following statements is correct?
d. They saturate. ✅
Simple Explanation:
Carrier-mediated transport = when a protein “carrier” in the membrane helps move molecules.
These carriers can only work so fast (like buses that can only carry so many passengers).
Once all carriers are busy → the system is saturated (can’t go faster even if you add more molecules).
Why the others are wrong:
a. Always require ATP ❌ → not true, some use energy (active transport), some don’t (facilitated diffusion).
b. Low specificity ❌ → carriers are actually specific (like a lock and key).
c. Always down an electrical gradient ❌ → not always, depends on the type.
4. For which type of vesicular transport does the cell extend pseudopods (a temporary arm-like projection of a eukaryotic cell membrane that is emerged in the direction of movement) that surround a particle?
b. Phagocytosis ✅
Simple Explanation:
Phagocytosis = “cell eating.” 🍽
The cell stretches out pseudopods (little arms) to surround a big particle (like bacteria or debris).
Then it pulls it inside to digest it.
Why not the others?
a. Endocytosis → general word for bringing things into the cell (phagocytosis + pinocytosis are types of this).
c. Pinocytosis → “cell drinking,” cell takes in tiny drops of fluid. 🥤
d. Receptor-mediated endocytosis → cell uses special “locks” (receptors) to bring in very specific things (like cholesterol). 🔑
5. Using your knowledge of diffusion, identify what happens when water is added to a solution containing a solute.
b. The solution becomes more dilute.
6. Compare and contrast the differences between facilitated diffusion and active transport.
Both facilitated diffusion and active transport are carrier-mediated transports, meaning that a membrane-bound protein is required for the movement of non-membrane permeable solutes. In facilitated diffusion, this carrier moves a solute down its concentration gradient and does not require energy. In active transport, this carrier moves a solute against its concentration gradient, and this process requires energy in the form of ATP.
7. Differentiate between tight junctions and gap junctions.
Tight junctions adhere firmly to each other at points of direct contact between cells to seal off the passageway between them. In contrast, gap junctions form small, connecting tunnels out of connexons. These communication junctions allow small water-soluble compounds, but prevent large compounds such as proteins, to move between cells
8. Compare how much ATP is produced by aerobic versus anaerobic metabolism of one glucose molecule.
Under aerobic conditions one glucose molecule can produce between 30 and 32 molecules of ATP through the processes of glycolysis, Krebs cycle, and the electron transport chain. However, in the absence of oxygen, pyruvate does not enter the TCA cycle to produce more high energy compounds. Instead, it is converted to lactic acid and only two ATP molecules are produced.
9. What are the differences between pinocytosis and phagocytosis?
Both pinocytosis and phagocytosis are forms of endocytosis. How they differ is that in pinocytosis the membrane dips inward to engulf a droplet of extracellular fluid. In contrast, select cell types, such as white blood cells, internalize large particles by phagocytosis. In this process, pseudopods extend to engulf the particle, which is then internalized.
10. Differentiate between hormones and neurohormones.
Hormones are compounds released by secretory cells directly into the blood stream, where they travel to a distant target to have an effect. In contrast, neurohormones are released into the blood by neurosecretory neurons. These secretions functions as hormones
Hormones 🩸
Made and released by endocrine glands (like thyroid, pancreas, adrenal).
Travel in the blood to reach target cells far away.
👉 Example: Insulin from the pancreas lowers blood sugar.
Neurohormones 🧠🩸
Made by nerve cells (neurons) instead of glands.
But like hormones, they are released into the blood → travel far.
👉 Example: Oxytocin and vasopressin (ADH), made in the hypothalamus and secreted into blood.
✅ Key Difference:
Hormones = come from glands.
Neurohormones = come from neurons (nerves).
Both travel in the bloodstream to act on distant targets.
1. Large, nonpolar molecules would not be able to cross the membrane if which of these plasma membrane components were absent?
✅ Correct Answer: c. Membrane proteins
Because large molecules (even if nonpolar) are too big to just slide through the bilayer. They need carrier proteins or transporters to help them cross.
2. Increasing the efficiency of the electron transport chain would have what effect on ATP synthesis?
a. Increase ✅
Simple Explanation:
The electron transport chain (ETC) passes electrons step by step, pumping protons (H⁺) across the mitochondrial membrane.
These protons create a gradient (like water behind a dam).
The more efficient the ETC = the more protons pumped = the stronger the gradient.
A stronger gradient = ATP synthase can make more ATP (like more water turning the turbine).
3. In the absence of collagen, which one of the following effects would occur?
b. The tissues would become more fragile.
b. The tissues would become more fragile. ✅
Simple Explanation:
Collagen = the “rope” protein of your body.
It gives tissues tensile strength (resistance to tearing/pulling).
Without collagen → skin, bones, tendons, ligaments would be weak and fragile (easy to tear or break).
Why not the others?
a. Increased stretch ❌ → that’s elastin’s job, not collagen.
c. Cell adhesion decreased ❌ → that’s more about fibronectin & integrins.
d. Cell-to-cell communication ❌ → that’s gap junctions.
4. Increasing the salt concentration in the extracellular fluids has what effect on cells?
a. Water leaves the cells.
a. Water leaves the cells. ✅
Simple Explanation:
If the outside fluid (extracellular) has more salt than the inside, it becomes hypertonic.
Water always moves to where there is more solute (salt) to try to balance things.
So water will leave the cell → making the cell shrink (crenation).
Why not the others?
b. The cells swell ❌ → happens if the outside is less salty (hypotonic), not more salty.
c. Salt is moved into the cells ❌ → cells don’t pull salt in automatically; it’s water that moves.
d. Extracellular fluid becomes hypotonic ❌ → actually it becomes hypertonic (more concentrated).
5. In the absence of ATP, which one of the following transport processes would be affected the greatest?
d. Active transport
6. Applying your knowledge of the Na+–K+ ATPase pump, hypothesize a cellular consequence that would occur if there was insufficient ATP.
If the Na+–K+ ATPase transporter could not function normally, there would be an imbalance of intracellular Na+ and K+, cells would be unable to regulate their internal volume, and processes depending on secondary active transport would also be impacted.
7. Why is a person able to only briefly perform anaerobic exercise (such as lifting or holding a heavy weight) but can sustain aerobic exercise (such as walking or cycling) for long periods?
ATP is required for muscle contraction. Muscles are able to store limited supplies of nutrient fuel for use in the generation of ATP. During anaerobic exercise, muscles generate ATP from these nutrient stores by means of glycolysis, which yields two molecules of ATP per glucose molecule processed. During aerobic exercise, muscles can generate ATP by means of oxidative phosphorylation, which yields 36 molecules of ATP per glucose molecule processed. Because glycolysis inefficiently generates ATP from nutrient fuels, it rapidly depletes the muscle’s limited stores of fuel, and ATP can no longer be produced to sustain the muscle’s contractile activity. Aerobic exercise, in contrast, can be sustained for prolonged periods. Not only does oxidative phosphorylation use far less nutrient fuel to generate ATP, but it can be supported by nutrients delivered to the muscle by means of the blood instead of relying on stored fuel in the muscle. Intense anaerobic exercise outpaces the ability to deliver supplies to the muscle by the blood, so the muscle must rely on stored fuel and inefficient glycolysis, thus limiting anaerobic exercise to brief periods of time before energy sources are depleted.
. Anaerobic exercise (no oxygen, short bursts) 🏃♂💨
Uses glycolysis → breaks 1 glucose → only 2 ATP (tiny energy).
Must use the fuel already stored inside the muscle.
Very wasteful = fuel runs out fast.
That’s why you can only sprint hard for a short time before your muscles burn out.
2. Aerobic exercise (with oxygen, longer activity) 🚴♀🏊♂
Uses oxidative phosphorylation → 1 glucose → 36 ATP (lots of energy).
Can use fuel brought by the blood (like glucose and fats from food).
Much more efficient = muscles can keep working for a long time.
👉 Big picture:
Anaerobic = short, fast, wasteful, runs out quick.
Aerobic = steady, efficient, lasts long.
8. What would happen in a tissue if there was a disruption of the desmosomes?
Since desmosomes act as spotrivets to hold adjacent cells together, their disruption would lead to a loss of tissue integrity. For example, in tissues that undergo a lot of stretch, such as the skin, a lack of desmosomes would lead to the cells being ripped apart.
9. Why is ATP not stored?
ATP is not stored primarily because it is not efficient and also because of its effect on cellular tonicity. If we assume an average of 31 ATP molecules being produced from a single glucose molecule, we can say that means it is 31 times more efficient to store glucose instead of ATP. The further storage of glucose as glycogen enhances this efficiency. If we look at cellular tonicity (a solution's capacity to change a cell's volume by altering its water content through osmosis.) , storing large amounts of ATP in the cytoplasm would have an osmotic effect to bring water into the cell and disrupt the internal environment. To avoid this, ATP is stored as glucose and glucose is stored as glycogen until ATP needs to be produced.
10. If osmosis is really only the diffusion of water, why is it important enough to be considered a special type of diffusion?
First: What’s diffusion?
Diffusion = stuff spreads out from high → low concentration.
👉 Example: perfume spreads in a room.
Normally, this could be solutes (like sugar, salt, oxygen).
Now: What’s osmosis?
Osmosis = special diffusion, but only for water 💧.
Water moves from where there is more water (less solute) → to where there is less water (more solute).
👉 Example: If you put raisins in water, water goes inside to balance the sugar.
Why is osmosis treated as “special”?
Because in our cells, the cell membrane lets water move freely but blocks many solutes (like proteins, ions).
So solutes can’t just move across to balance out.
Instead, water has to move until things are equal.
This water movement changes the size of cells and the amount of fluid outside cells.
In simple words:
Diffusion = solutes move.
Osmosis = only water moves, because solutes are “stuck.”
It’s important because it controls whether cells shrink, swell, or stay the same.
Osmosis is the movement of water down its concentration gradient. However, when we consider that cell membranes limit the movement of solute between the intracellular fluid and the extracellular fluid, osmosis becomes very important as water can freely cross cell membranes until the osmotic hydrostatic pressures equalize. This is a major determinant of both cell and ECF volumes.
Why don’t cells store lots of ATP?
Not efficient ⚡
1 glucose → about 31 ATP.
If you store glucose, you can make ATP whenever needed.
Much more efficient to keep energy as glucose (and even better as glycogen = storage form of glucose).
👉 Example: Instead of carrying around 31 tiny batteries 🔋🔋🔋, you carry one big power bank (glucose/glycogen) and charge the batteries when needed.
Tonicity problem 💧
If the cell stored tons of ATP, it would mean lots of charged molecules floating in the cytoplasm.
That would pull water inside by osmosis.
The cell would swell and maybe burst.
👉 Example: Too much salt inside a balloon = water rushes in = balloon pops 🎈💦.
✅ So what does the cell do?
Stores glucose (and as glycogen in liver & muscles).
When energy is needed → glucose is broken down → ATP is made on demand.
👉 Kid version:
ATP = small, leaky batteries (not good to keep many).
Glucose/glycogen = a safe fuel tank ⛽.
Cell only makes ATP when it’s ready to use it, so it doesn’t mess up water balance.
Note 
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