Chapter 4: Exploring Life possible question

A researcher wants to observe the dynamic movement of live organelles inside a cell. Which type of microscopy should they use, and why?

A.Transmission electron microscope, because it passes electrons through living tissues without harming them.

B.Scanning electron microscope, because it provides the highest magnification needed to view living internal cell structures.

C.Light microscope, because it can display living cells, whereas standard electron microscopy techniques kill the specimen.

D.Unaided eye, because most internal organelles are larger than 1 mm and easily viewed without magnification.

C.Light microscope, because it can display living cells, whereas standard electron microscopy techniques kill the specimen.

Light microscopes utilize light rays to view live specimens without killing them, making them ideal for observing dynamic organelle movement.

Which of the following features is found in both prokaryotic and eukaryotic cells?

A.Multiple compartmentalized membrane-bound organelles

B.Membrane-bound nucleus containing DNA

C.Ribosomes suspended in cytosol

D.An extensive endomembrane system

C.Ribosomes suspended in cytosol

Both cell types require ribosomes to translate genetic instructions into proteins within the fluid cytoplasm.

Which metabolic compartment contains enzymes for breaking down substances but does NOT originate from the endomembrane system?

A.Golgi apparatus

B.Smooth endoplasmic reticulum

C.Peroxisome

D.Lysosome

C.Peroxisome

Peroxisomes are metabolic compartments involved in breakdown processes that do not originate from the endomembrane system.

Which path correctly traces a protein destined for secretion outside the cell, starting from its synthesis?

A.Nucleus → Golgi apparatus → Rough ER → transport vesicle → plasma membrane

B.Ribosome → peroxisome → transport vesicle → Golgi apparatus → plasma membrane

C.Smooth ER → lysosome → Golgi apparatus → plasma membrane

D.Rough ER → transport vesicle → Golgi apparatus → transport vesicle → plasma membrane

D.Rough ER → transport vesicle → Golgi apparatus → transport vesicle → plasma membrane

Proteins manufactured by bound ribosomes on the rough ER are transported via vesicles to the Golgi for processing before being routed to the plasma membrane.

According to the functional classification of eukaryotic organelles, which pair of structures is correctly matched with its primary functional group?

A.Mitochondria and lysosomes — Energy processing

While mitochondria process cellular energy, lysosomes belong to the manufacturing, distribution, and breakdown category.

B.Nucleus and ribosomes — Genetic control

C.Smooth ER and peroxisomes — Structural support and movement

D.Golgi apparatus and chloroplasts — Manufacturing and breakdown

B.Nucleus and ribosomes — Genetic control

The nucleus stores genetic instructions and ribosomes carry out protein synthesis, placing both in the genetic control category.

How do the inner membrane folds (cristae) of a mitochondrion contribute to its primary cellular function?

A.They prevent solutes from diffusing across the outer membrane.

B.They allow chloroplasts to attach and synthesize sugar molecules.

C.They store genetic material separate from the mitochondrial matrix.

D.They increase the total surface area available to enhance ATP production during cellular respiration.

D.They increase the total surface area available to enhance ATP production during cellular respiration.

Extensive folding of the cristae provides abundant surface area for electron transport chains and enzymes that synthesize ATP.

What evidence supports the endosymbiont theory regarding the evolutionary origins of mitochondria and chloroplasts?

A.Both organelles are directly produced by the Golgi apparatus within the endomembrane system.

B.Neither organelle possesses an internal membrane structure or matrix.

C.Both organelles contain their own circular DNA and ribosomes, resembling prokaryotes.

D.Both organelles are found exclusively in prokaryotic cells such as domain Bacteria.

C.Both organelles contain their own circular DNA and ribosomes, resembling prokaryotes.

The presence of independent circular chromosomes and prokaryote-like ribosomes indicates evolutionary descent from engulfed prokaryotes.

Which cytoskeletal element is composed of tubulin subunits, measures approximately 25 nm in diameter, and acts as a track along which vesicles move?

A.Extracellular matrix fibers

B.Microtubules

C.Intermediate filaments

D.Microfilaments

B.Microtubules

Microtubules are 25 nm hollow rods of tubulin proteins that serve as structural tracks for vesicle transport.

What is the characteristic structural arrangement of microtubules found within eukaryotic cilia and flagella?

A.A random lattice of unorganized tubulin proteins

B.A single central microfilament core wrapped in actin

C.Nine triple helices composed of intermediate filaments

D.A "9 + 2" pattern of microtubule doublets

D.A "9 + 2" pattern of microtubule doublets

Eukaryotic cilia and flagella share a standard core composed of nine outer microtubule doublets surrounding two central single microtubules.

In animal tissues, how does the extracellular matrix (ECM) communicate signals and structural support to the interior of the cell?

A.ECM fibers pass directly through plasmodesmata channels into the nucleus.

B.ECM proteins fuse with the smooth ER to directly deliver ATP.

C.ECM lipids dissolve into the phospholipid bilayer and act as competitive enzyme inhibitors.

D.ECM glycoproteins bind to transmembrane receptor proteins called integrins, which connect to microfilaments inside the cytoplasm.

D.ECM glycoproteins bind to transmembrane receptor proteins called integrins, which connect to microfilaments inside the cytoplasm.

Integrins span the plasma membrane to transmit signals between ECM glycoproteins on the outside and microfilaments on the inside.

A liver cell responsible for detoxifying harmful drugs and synthesizing lipids would be expected to have an unusually high concentration of which organelle?

A.Lysosomes

B.Chloroplasts

C.Smooth endoplasmic reticulum

D.Rough endoplasmic reticulum

C.Smooth endoplasmic reticulum

Smooth ER contains enzymes specialized for lipid synthesis, drug detoxification, and metabolic processing of toxins.