MCB2010 MDC Study Guide 1 Questions with

MCB2010 MDC Study Guide# 1 Questions with 100% Verified Correct Answers 2024/2025 Which of the following statements is INCORRECT regarding prokaryotic cells?

• Their DNA is not enclosed within a membrane.
• They lack membrane-enclosed organelles.
• They typically have a circular chromosome.
• They reproduce by binary fission.
• They lack a plasma membrane. - Correct Answer They lack a plasma membrane.

2.Each of the following statements concerning the gram-positive cell wall is true EXCEPT

• it maintains the shape of the cell.
• it is sensitive to lysozyme.
• it protects the cell in a hypertonic environment.
• it contains teichoic acids.
• it is sensitive to penicillin. - Correct Answer it protects the cell in a hypertonic environment.

3.Which of the following statements best describes what happens when a bacterial cell is placed in a solution containing 5% NaCl?

• Sucrose will move into the cell from a higher to a lower concentration.
• The cell will undergo osmotic lysis.
• Water will move out of the cell.
• Water will move into the cell.
• No change will result; the solution is isotonic. - Correct Answer Water will move out of the cell.

4.A gram-positive bacterium suddenly acquires resistance to the antibiotic methicillin. This trait most likely occurred due to acquisition of new genetic information through

• conjugation.
• binary fission.
• meisosis. 1 / 4

• transformation.
• transduction. - Correct Answer conjugation.

5.By which of the following mechanisms can a cell transport a substance from a lower to a higher concentration?

• simple diffusion
• facilitated diffusion
• active transport
• extracellular enzymes
• aquaporins - Correct Answer active transport

6.Which of the following is NOT a typical characteristic of most bacterial plasma membranes?

• site of energy production
• composed of a phospholipid bilayer
• contains proteins
• contains cholesterol
• is selectively permeable - Correct Answer contains cholesterol

7) Which one of the following organisms has a cell wall?

• protoplasts
• fungi
• L forms
• mycoplasmas
• animal cells - Correct Answer B) fungi

8) Which of the following statements is TRUE?

• Endospores are for reproduction.
• Endospores allow a cell to survive environmental changes by producing a dormant period with no

growth.

• Endospores are easily stained in a Gram stain. 2 / 4

• A cell produces one endospore and keeps growing.
• A cell can produce many endospores. - Correct Answer B) Endospores allow a cell to survive

environmental changes by producing a dormant period with no growth.9) Which of the following pairs is mismatched?

• endoplasmic reticulum — internal transport
• Golgi complex — secretion
• mitochondria — ATP production
• centrosome — food storage
• lysosome — digestive enzymes - Correct Answer D) centrosome — food storage

10) Which of the following organelles most closely resembles a prokaryotic cell?

• nucleus
• mitochondrion
• Golgi complex
• vacuole
• cell wall - Correct Answer B) mitochondrion

11) Antibiotics that target cell wall synthesis ultimately cause bacterial cell death as a result of

• osmotic lysis.
• inhibition of molecular transport.
• decreased synthesis of plasma membrane.
• plasmolysis.
• cell shrinkage - Correct Answer A) osmotic lysis.

12) Bacteria are a commonly used organism for studies of genetic material in the research laboratory.The nucleic acids must first be isolated from the cells for these studies. Which of the following would most likely be used to lyse gram-positive bacterial cells for nucleic acid isolation?

• lysozyme
• polymixins
• alcohol
• water 3 / 4

• mycolic acid - Correct Answer A) lysozyme

13) Which of the following statements about gram-negative cell walls is FALSE?

• They protect the cell in a hypotonic environment.
• They have an extra outer layer composed of lipoproteins, lipopolysaccharides, and phospholipids.
• They are toxic to humans.
• They are sensitive to penicillin.
• Their Gram reaction is due to the outer membrane. - Correct Answer D) They are sensitive to

penicillin.14) Which of the following structures is NOT found in some prokaryotic cells?

• flagellum
• axial filament
• cilium
• pilus
• peritrichous flagella - Correct Answer C) cilium

15) Functions of the glycocalyx include all of the following EXCEPT

• biofilm formation.
• increased virulence.
• source of nutrition.
• protection against dehydration.
• binary fission. - Correct Answer E) binary fission.

16) Which structure acts like an "invisibility cloak" and protects bacteria from being phagocytized?

• slime layer
• fimbriae
• capsule
• cell membrane
• cell wall - Correct Answer C) capsule
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