Q: Which equation best represents the amphipathic nature of a phospholipid molecule?

$\text{Phospholipid} = \text{Hydrophilic Head} + \text{Hydrophobic Tail}$

Question 1

Which of the following best explains why the hydrophilic heads of phospholipids face outward in a biological membrane?

Accepted Answer

Hydrophilic heads are attracted to the aqueous environments inside and outside the cell due to their affinity for water.

Question 2

A scientist observes a cell with no internal membrane-bound organelles and a single circular chromosome. Which type of cell is this most likely to be?

Accepted Answer

A prokaryotic cell

Question 3

Which of the following is a function of proteins embedded in the biological membrane?

Accepted Answer

They allow specific ions and small molecules to cross the membrane.

Question 4

Why can transcription and translation occur simultaneously in prokaryotic cells?

Accepted Answer

Prokaryotic cells lack a nuclear membrane, allowing ribosomes to access mRNA as it is being transcribed.

Question 5

Which of the following statements about the phospholipid bilayer is correct?

Accepted Answer

It is impermeable to water, all ions, and almost all hydrophilic small molecules.

Question 6

A bacterial cell wall is composed primarily of which substance?

Accepted Answer

Peptidoglycan

Question 7

Which of the following is a key distinction between Gram-positive and Gram-negative bacteria?

Accepted Answer

Gram-positive bacteria have a thick cell wall and no outer membrane, while Gram-negative bacteria have a thin cell wall and an outer membrane.

Question 8

Which organelle is responsible for energy production in eukaryotic cells?

Accepted Answer

Mitochondrion

Question 9

What is the primary function of the Golgi apparatus in eukaryotic cells?

Accepted Answer

Modifying, sorting, and packaging proteins and lipids for secretion or delivery to other organelles.

Question 10

Which of the following best describes the role of cholesterol in the plasma membrane?

Accepted Answer

It controls membrane rigidity and fluidity.

Question 11

A mutation causes a cell to lack all membrane proteins. Which of the following would most likely occur?

Accepted Answer

The cell would be unable to transport specific ions and molecules across the membrane.

Question 12

Which of the following is NOT a function of biological membranes?

Accepted Answer

Storing genetic information

Question 13

Which equation best represents the amphipathic nature of a phospholipid molecule?

Accepted Answer

$	ext{Phospholipid} = 	ext{Hydrophilic Head} + 	ext{Hydrophobic Tail}$

Question 14

Which of the following best explains why eukaryotic cells can have specialized functions?

Accepted Answer

They contain internal membrane-bound organelles that compartmentalize cellular processes.

Question 15

A cell is observed to have simultaneous transcription and translation occurring on the same mRNA strand. What does this indicate about the cell?

Accepted Answer

It is a prokaryotic cell.

Question 16

Which of the following is a direct consequence of the lack of internal membranes in prokaryotic cells?

Accepted Answer

All cellular processes occur in the same compartment.

Question 17

Which of the following statements about the movement of substances across biological membranes is correct?

Accepted Answer

Proteins embedded in the membrane allow specific ions and small molecules to cross.

Question 18

Which of the following best describes the function of lysosomes in eukaryotic cells?

Accepted Answer

They break down waste materials and cellular debris.

Question 19

Which of the following is a similarity between prokaryotic and eukaryotic cells?

Accepted Answer

Both contain ribosomes for protein synthesis.

Question 20

Which of the following best explains why the phospholipid bilayer forms spontaneously in water?

Accepted Answer

The hydrophobic tails avoid water while the hydrophilic heads interact with water, leading to bilayer formation.

Cellular Organization and Organelles: Structure, Function, and Membranes

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