Cell Structure Test MCQ: Quiz!

1.

Using the Electron Microscope you study the structures of the cell grown in the rich and minimal media. Compared to the cells grown in the minimal media, the cells grown in the rich media possess much larger versions of a many-layered structure peppered with dark spots. What is the interpretation?

A.

The cells grown in the rich media have larger mitochondria.
B.

The cells grown in the minimal media cannot build full sized mitochondria.
C.

The cells grown in the minimal media have defective Golgi Apparatus
D.

The cells grown in the rich media produce more proteins within ER.
E.

The cells grown in rich media have more genes.

Correct Answer
D. The cells grown in the rich media produce more proteins within ER.

Explanation
The explanation for the correct answer is that the larger versions of the many-layered structure with dark spots observed in the cells grown in the rich media indicate an increase in protein production within the endoplasmic reticulum (ER). The rich media provides more nutrients and resources for the cells to produce proteins, leading to the enlargement of the ER and the presence of dark spots, which could be ribosomes attached to the ER. This suggests that the cells grown in the rich media are actively synthesizing more proteins compared to the cells grown in the minimal media.

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2.

Why are peroxisomes mostly found in kidney and liver cells?

A.

They oxidise toxic materials
B.

They contain oxidising agents
C.

They have reducing agents
D.

They have 2 and hence carry out 1

Correct Answer
D. They have 2 and hence carry out 1

Explanation
Peroxisomes are mostly found in kidney and liver cells because they carry out the oxidation of toxic materials. This is supported by the fact that they have 2, which implies that they contain oxidizing agents. Therefore, the presence of peroxisomes in kidney and liver cells allows for the detoxification of harmful substances, making these organs vital for maintaining overall health and well-being.

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3.

Plating 0.1 ml of a 10-3 dilution of a microbial culture yields 50 colonies. What is the viable count of the original culture?

A.

5 x 10-3 cells.ml-1.
B.

5 x 103 cells. ml-1.
C.

5 x 104 cells. ml-1.
D.

5 x 105 cells. ml-1
E.

5 x 10-5 cells. ml-1

Correct Answer
D. 5 x 105 cells. ml-1

Explanation
The given information states that plating 0.1 ml of a 10-3 dilution of the microbial culture yields 50 colonies. This means that there are 50 colonies in 0.1 ml of the diluted culture. To find the viable count of the original culture, we need to account for the dilution factor. Since the dilution is 10-3, the original culture was diluted by a factor of 1000 (10-3 = 1/1000). Therefore, the viable count of the original culture is 50 x 1000 = 50,000 cells in 0.1 ml. To express this in ml-1, we multiply by 10, as there are 10 sets of 0.1 ml in 1 ml. Therefore, the viable count of the original culture is 50,000 x 10 = 500,000 cells.ml-1, which is equivalent to 5 x 105 cells.ml-1.

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4.

Moderate halophiles would be most likely found in?

A.

Fresh water
B.

Cold water
C.

Hot water
D.

Sea water
E.

Bottled water.

Correct Answer
D. Sea water

Explanation
Moderate halophiles are microorganisms that can tolerate and thrive in environments with moderate levels of salt concentration. Sea water, being a naturally occurring saline environment, contains a significant amount of salt, making it an ideal habitat for moderate halophiles. Fresh water, cold water, hot water, and bottled water typically have lower salt concentrations and therefore would not be suitable for the growth and survival of moderate halophiles.

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5.

A few bacteria have very waxy envelopes that make them __________ , meaning that, once stained with strong carbon fuchsin dye, they resist decolorisation with acid or alcohol. These include Mycobacterium tuberculosis and Mycobacterium leprae.

A.

Acid-fast
B.

Acid-deactivators
C.

Acid-reactive
D.

Acid-resistant
E.

Acid-slow

Correct Answer
A. Acid-fast

Explanation
Bacteria that are "acid-fast" have a waxy envelope that makes them resistant to decolorization with acid or alcohol after being stained with strong carbon fuchsin dye. This property is observed in bacteria such as Mycobacterium tuberculosis and Mycobacterium leprae.

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6.

Assume you inoculated 100 cells into 100ml of nutrient broth and 100 cells in 200ml of nutrient broth. After incubation for 24hrs, the cultures have entered the stationary phase. You should have:

A.

More cells per ml in the 100ml
B.

More cells per ml in the 200ml
C.

The same number of cells per ml in each

Correct Answer
C. The same number of cells per ml in each

Explanation
The correct answer is the same number of cells per ml in each. In the stationary phase, the growth of cells slows down and the number of cells remains relatively constant. Since the initial number of cells inoculated in both the 100ml and 200ml cultures is the same, and they have both entered the stationary phase, the number of cells per ml in each culture would be the same.

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7.

A culture medium on which only gram-positive organisms grow and a yellow halo surrounds Staphylococcus aureus colonies is called a?

A.

Selective medium
B.

Differential medium
C.

Enrichment culture
D.

A and b
E.

B and c

Correct Answer
D. A and b

Explanation
A culture medium on which only gram-positive organisms grow is called a selective medium. Additionally, the presence of a yellow halo surrounding Staphylococcus aureus colonies indicates that the medium is also a differential medium, as it allows for the differentiation of different types of bacteria based on their ability to produce a specific pigment. Therefore, the correct answer is a and b.

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8.

What are the characteristics of viruses?

A.

Obligate Intracellular parasites of bacteria, plants,animals, fungi and algae
B.

Nucleic Acid can be DNA or RNA but not both
C.

Do not independently fulfill the characteristics of life
D.

Lack enzymes for most of the metabolic processes
E.

All of the Above

Correct Answer
E. All of the Above

Explanation
Viruses are obligate intracellular parasites, meaning they can only replicate inside host cells of bacteria, plants, animals, fungi, and algae. They can contain either DNA or RNA, but not both at the same time. Viruses do not independently fulfill the characteristics of life, as they cannot reproduce or carry out metabolic processes on their own. Additionally, viruses lack enzymes for most metabolic processes. Therefore, all of the given characteristics are true for viruses.

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9.

Which is not matched correctly?

A.

Helical Virus - TMV, Influenza
B.

Enveloped Virus - Pox Virus, Herpes Virus
C.

Non Enveloped Virus - Adeno Virus, Idino Virus, Papo Virus, Parvo Virus
D.

Enveloped RNA Virus - Retro Virus, Paramyxovirus, Corona Virus
E.

None of The Above

Correct Answer
E. None of The Above

Explanation
The given correct answer is "None of The Above". This means that all the options provided in the question are matched correctly. Helical Virus is matched correctly with TMV and Influenza, Enveloped Virus is matched correctly with Pox Virus and Herpes Virus, Non Enveloped Virus is matched correctly with Adeno Virus, Idino Virus, Papo Virus, and Parvo Virus, and Enveloped RNA Virus is matched correctly with Retro Virus, Paramyxovirus, and Corona Virus.

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10.

Action of Antibiotics

A.

Aminoglycosides - Inhibits protein Synthesis of Gram (-) Bacteria
B.

Cephalosporins - Inhibits protein Synthesis of wide range of Bacteria
C.

Fluoroquinolones - Inhibits RNA & DNA Synthesis of Gram (-) Bacteria
D.

Macrolides - Inhibits Protein Synthesis
E.

All of the Above Match

Correct Answer
E. All of the Above Match

Explanation
The correct answer is "All of the Above Match" because each type of antibiotic listed inhibits a specific process in bacterial cells. Aminoglycosides inhibit protein synthesis in Gram (-) bacteria, Cephalosporins inhibit protein synthesis in a wide range of bacteria, Fluoroquinolones inhibit RNA & DNA synthesis in Gram (-) bacteria, and Macrolides inhibit protein synthesis. Therefore, all of the statements match the actions of the antibiotics listed.

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