Chapter 6 Practice and Application Questions

A cell has DNA in a nucleoid and no membrane-bound organelles. What type of cell is it?

Prokaryotic.

A cell has a nucleus, mitochondria, and endoplasmic reticulum. What type of cell is it?

Eukaryotic.

You observe a cell with no nucleus. Does that automatically mean it has no DNA?

No. Prokaryotic cells have DNA, but it is located in the nucleoid rather than a membrane-bound nucleus.

You observe ribosomes floating freely in a cell. Does this prove that the cell is prokaryotic?

No. Both prokaryotic and eukaryotic cells have ribosomes, and eukaryotic cells can have free ribosomes.

A cell has a nucleus but no chloroplasts. Could it be an animal cell?

Yes.

A cell has a cell wall, chloroplasts, and a large central vacuole. What type of cell is it?

Eukaryotic plant cell.

A cell has a nucleus, mitochondria, and a cell wall but no chloroplasts. Based only on these characteristics, is it necessarily an animal cell?

No. The course material states that some eukaryotes other than plants also have cell walls, so the cell wall alone does not identify a plant cell.

A cell needs to synthesize a protein that will eventually be secreted from the cell. Which organelle is especially involved in its synthesis?

Rough ER.

Why would a protein destined for secretion be associated with the rough ER?

Ribosomes on the rough ER synthesize proteins that enter the ER and can then be transported through the endomembrane system.

A protein has been synthesized in the rough ER and needs to be modified, sorted, and packaged. Which organelle handles this?

Golgi apparatus.

A transport vesicle is traveling from the ER to the Golgi. Which side of the Golgi does it arrive at?

The cis face.

A vesicle is leaving the Golgi to deliver a modified protein elsewhere. From which side does it leave?

The trans face.

A cell needs to synthesize lipids. Which part of the ER would be most directly involved?

Smooth ER.

A cell is detoxifying medications or poisons. Which organelle is especially involved?

Smooth ER.

A cell needs to break down worn-out organelles. Which organelle is primarily responsible?

Lysosome.

A cell needs to break down very long-chain fatty acids. Which organelle is involved?

Peroxisome.

A cell needs to produce ATP through cellular respiration. Which organelle is most directly involved?

Mitochondrion.

A cell needs to capture energy from sunlight and build G3P. Which organelle performs this function?

Chloroplast.

You find an organelle with two membranes, its own DNA, and its own ribosomes. Which two organelles should you consider?

Mitochondria and chloroplasts.

You find an organelle with its own DNA and ribosomes, and it is involved in capturing energy from sunlight. What is it?

Chloroplast.

You find an organelle with its own DNA and ribosomes, and it produces ATP through cellular respiration. What is it?

Mitochondrion.

Why are mitochondria and chloroplasts especially important to endosymbiont theory?

Their bacterial-like characteristics, including their own DNA, ribosomes, and double membranes, support the idea that they originated from bacteria.

A cell has no membrane-bound organelles but does have ribosomes. Is this consistent with a prokaryotic cell?

Yes.

A cell has multiple membrane-bound organelles. Is it likely prokaryotic or eukaryotic?

Eukaryotic.

A cell needs to move a protein from the ER to the Golgi. What structure transports it?

A vesicle.

A protein has been modified in the Golgi and needs to be released outside the cell. What structure can transport it to the plasma membrane?

A vesicle.

A cell needs a structure that acts as a selective boundary between itself and its environment. What is it?

Plasma membrane.

A researcher observes two animal cells that are sealed tightly together so material cannot easily leak between them. What junction is involved?

Tight junction.

Two animal cells need to be strongly anchored together. What junction would accomplish this?

Desmosome.

Two animal cells need to exchange materials or signals directly through channels. What junction is involved?

Gap junction.

Two neighboring plant cells need channels that connect them through their cell walls. What are these channels called?

Plasmodesmata.

What is the key difference between gap junctions and plasmodesmata?

Gap junctions are channels between animal cells, while plasmodesmata are channels between plant cells.

A cell needs to maintain its shape and organize or anchor internal structures. Which cellular structure is especially important?

Cytoskeleton.

A cell is forming a mitotic spindle. Which cytoskeletal component is involved?

Microtubules.

A cell needs fibers that help hold organelles in place. Which cytoskeletal component is especially associated with this function?

Intermediate filaments.

A cell needs fibers that line the cell membrane and form the cellular cortex. Which cytoskeletal component is involved?

Microfilaments.

A plant cell needs to maintain pressure against its cell wall. Which structure is especially important?

Central vacuole.

A plant cell needs to perform photosynthesis. Which organelle is required?

Chloroplast.

A cell has mitochondria but no chloroplasts. Can it be a plant cell?

No, based on the course material, plant cells have chloroplasts.

A cell has mitochondria and chloroplasts. What type of eukaryotic cell is it most consistent with?

Plant cell.

A cell has a nucleus and rough ER. What does this tell you about the cell?

It is eukaryotic.

A structure contains ribosomes but is not surrounded by a membrane. What structure is it?

A ribosome.

A structure has a membrane and contains digestive enzymes that function at low pH. What organelle is it?

Lysosome.

A structure has no ribosomes attached and is involved in lipid synthesis. What organelle is it?

Smooth ER.

A structure has ribosomes attached to its surface and is involved in protein synthesis. What organelle is it?

Rough ER.

A structure consists of flattened membranous sacs and modifies and sorts proteins and lipids. What is it?

Golgi apparatus.

A structure has a highly folded inner membrane and produces ATP. What is it?

Mitochondrion.

A structure has two membranes, its own DNA, and its own ribosomes and is involved in photosynthesis. What is it?

Chloroplast.