Question 1

Which of the following is associated with eukaryotic cells but not with prokaryotic cells?

Accepted Answer

Eukaryotic cells have a nucleus, which is a membrane-bound organelle that contains the cell's genetic material. Prokaryotic cells do not have a nucleus, and their genetic material is located in the cytoplasm. A, B, C, and D are all found in both eukaryotic and prokaryotic cells.

Question 2

Gram-positive and Gram-negative bacteria are most commonly differentiated in the laboratory by whether__________.

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer in their cell walls that trap the crystal violet dye used in the Gram staining procedure, making them appear purple. Gram-negative bacteria have a thinner peptidoglycan layer and an outer membrane that prevents the dye from entering, making them appear red or pink.

Question 3

Although both humans and bacteria have ribosomes,streptomycin-which blocks ribosome function-does not harm a human who ingests it.Why?

Accepted Answer

Streptomycin specifically targets the ribosomes of bacteria because they have a unique structure that is different from human ribosomes. Therefore, streptomycin cannot bind to human ribosomes and harm human cells.

Question 4

The two major components of cell membranes are _______ and _______.

Accepted Answer

Phospholipids are the main structural component of cell membranes, forming a phospholipid bilayer. Proteins are also an important component, as they are embedded within the phospholipid bilayer and help regulate the transport of molecules in and out of the cell. The other answer choices are incorrect because DNA and peptidoglycan are not major components of all cell membranes, and peptidoglycan is only found in bacterial cell walls.

Question 5

Penicillin interferes with __________________,causing bacteria to die from ______________.

Accepted Answer

Penicillin interferes with cell wall synthesis in bacteria, leading to the swelling and rupturing of the cell, which ultimately causes bacterial death.

Question 6

Fungi are eukaryotic organisms.Scientists have found it more challenging to develop treatments for fungal infections (e.g. ,yeast infections,athlete's foot,and certain nail infections)than for bacterial infections.Why is this so?

Accepted Answer

Fungi are eukaryotes like humans, thus their cellular components are similar. This makes it more challenging to develop treatments for fungal infections as drugs that target fungal cells may also harm human cells.

Question 7

Which of the following types of transport are most closely related in terms of the energy requirements for moving material across a membrane?

Accepted Answer

Simple diffusion and facilitated diffusion are both passive transport mechanisms that do not require energy from ATP. They rely on the concentration gradient to move substances across the membrane.

Question 8

Which of the following is not found in prokaryotic cells?

Accepted Answer

Mitochondria are found only in eukaryotic cells and are not present in prokaryotic cells.

Question 9

Which of the following statements best explains why bacteria are considered living organisms?

Accepted Answer

Bacteria are considered living organisms because they are made of cells.

Question 10

Water is moving across a membrane from solution A into solution B.What can be inferred?

Accepted Answer

The movement of water across a membrane occurs from an area of lower solute concentration to an area of higher solute concentration, in an attempt to balance the concentration gradient. Therefore, Solution A must have a lower solute concentration than Solution B for water to be moving from A into B.

Question 11

Which of the following accurately describes why specific material uses a protein to cross the membrane?

Accepted Answer

The hydrophobic core of a membrane prevents polar or charged substances from passing through easily, necessitating the use of membrane proteins for their transport.

Question 12

What does the cell theory state?

Accepted Answer

The cell theory states that all living things are made of cells and those cells come from existing cells. This encompasses the statements made in options A and B, but does not specifically mention organelles, as stated in option C. Option E is a combination of statements unrelated to the cell theory.

Question 13

Which of the following accurately compares prokaryotic and eukaryotic cells?

Accepted Answer

C) Both prokaryotic and eukaryotic cells contain ribosomes, which are essential for protein synthesis and the utilization of genetic information.

Question 14

Which of the following cellular components would not be a good target for an antibiotic?

Accepted Answer

Phospholipids are a component of the cell membrane, which is also found in animal cells. Targeting phospholipids would not be specific to bacteria and could harm the host organism's cells. Therefore, it would not be a good target for an antibiotic.

Question 15

Many foods-for example,bacon and salt cod-are preserved with high concentrations of salt.How can high concentrations of salt inhibit the growth of bacteria?

Accepted Answer

High concentrations of salt make the environment hypertonic, meaning the concentration of solutes outside the bacterial cell is higher than inside the cell. This causes water to leave the cell, leading to shrinkage and ultimately death of the bacteria.

Question 16

Which of these cellular components is(are)associated with all cells?

Accepted Answer

The cell membrane is present in all cells as it is responsible for separating the inside of the cell from the outside environment. Ribosomes are also present in all cells as they are responsible for protein synthesis. DNA is also present in all cells as it carries the genetic information necessary for cell function and reproduction. Therefore, the correct answer is E: cell membrane, ribosomes, and DNA.

Question 17

If a solute is moving through a phospholipid bilayer from an area of higher concentration to an area of lower concentration without the assistance of a protein,the manner of transport must be _______.

Accepted Answer

If a solute is moving through a phospholipid bilayer from an area of higher concentration to an area of lower concentration without the assistance of a protein, this is characteristic of simple diffusion. Facilitated diffusion requires the assistance of a protein, while active transport moves molecules against their concentration gradient and requires energy input. The answer D is incorrect since the manner of transport is determined by the solute and its characteristics, but in this scenario, the question is specifically stating that the solute is moving without the assistance of a protein. Answer E is incorrect because a solute can cross the phospholipid bilayer through simple diffusion.

Question 18

Sugars are large,hydrophilic molecules that are important energy sources for cells.Sugars can enter cells from an environment with a very high concentration of sugar by

Accepted Answer

Sugars are large, hydrophilic molecules that cannot easily cross the hydrophobic lipid bilayer of cell membranes through simple diffusion. Facilitated diffusion, however, allows these molecules to enter cells with the help of specific transport proteins, without the expenditure of energy, following their concentration gradient from a region of high concentration to one of lower concentration.

Question 19

Which of these statements is TRUE about prokaryotes and eukaryotes?

Accepted Answer

Prokaryotes are generally smaller in size compared to eukaryotes and lack the membrane-bound internal compartments (organelles) that eukaryotes have. Prokaryotes have a simpler internal structure, without a nucleus or other organelles, and their DNA is in direct contact with the cytoplasm. Eukaryotes have a nucleus and other membrane-bound organelles, such as mitochondria, chloroplasts, and endoplasmic reticulum. Therefore, option C is the only statement that is true.

Question 20

You find a single-cell organism with a cell wall in the soil of a forest-can this organism be an animal? Which of the following characteristics would indicate that the organism is a bacterium and not a plant?

Accepted Answer

Animals do not have cell walls, so a single-cell organism with a cell wall cannot be an animal. The presence of a cell wall made of peptidoglycan indicates the organism is a bacterium, as plant cell walls are made of cellulose, not peptidoglycan.

Quiz 3: Cell Structure and Function