Q: Which equation correctly represents the central dogma of molecular biology as described by Crick?

$$\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$$

Question 1

Which statement best summarizes the modern cell theory as established by Schwann and Virchow?

Accepted Answer

All organisms consist of one or more cells, and all cells arise only from preexisting cells.

Question 2

A scientist is using a light microscope to observe a specimen. What is the approximate limit of resolution for this instrument?

Accepted Answer

$$200-350\ nm$$

Question 3

Which microscopy technique would be most appropriate for visualizing the spatial distribution of a specific protein in a living cell?

Accepted Answer

Fluorescence microscopy using GFP-tagged proteins

Question 4

During an experiment, a researcher uses centrifugation to separate cellular organelles based on their size and density. Which branch of cell biology does this technique primarily belong to?

Accepted Answer

Biochemistry

Question 5

Which of the following statements about the use of model organisms in cell biology is correct?

Accepted Answer

Model organisms are used because they are easy to manipulate and provide insights into fundamental cellular processes.

Question 6

A researcher wants to separate DNA fragments by size. Which technique should they use?

Accepted Answer

Electrophoresis

Question 7

Which historical experiment first demonstrated that a compound found in living organisms could be synthesized in the laboratory, challenging the idea of 'vitalism'?

Accepted Answer

Wohler's synthesis of urea

Question 8

Which equation correctly represents the central dogma of molecular biology as described by Crick?

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 9

A scientist uses CRISPR-Cas9 to introduce a double-stranded break at a specific location in the genome. What is the role of the guide RNA (gRNA) in this process?

Accepted Answer

It directs the Cas9 enzyme to the target DNA sequence.

Question 10

Which of the following is NOT a reason why early cell biology was limited in its progress?

Accepted Answer

Cells were too large to be studied with available technology.

Question 11

Which of the following units would be most appropriate for measuring the diameter of a ribosome?

Accepted Answer

$$nm$$

Question 12

Which statement best describes the difference between transmission electron microscopy (TEM) and scanning electron microscopy (SEM)?

Accepted Answer

SEM visualizes the surface of specimens, while TEM visualizes internal structures.

Question 13

Which of the following is a plausible consequence of using fixed and stained samples in brightfield microscopy?

Accepted Answer

It may introduce distortions not present in living cells.

Question 14

Which of the following best explains why bioinformatics has become essential in modern cell biology?

Accepted Answer

It enables the organization and interpretation of large-scale sequencing and molecular data.

Question 15

A scientist is studying the transcriptome of a cell. What is the focus of this research?

Accepted Answer

All the genes transcribed in the cell

Question 16

Which of the following statements about scientific 'facts' is most accurate according to the study materials?

Accepted Answer

Scientific facts are provisional and may be replaced as new evidence emerges.

Question 17

Which process is used to introduce foreign DNA into a cell, allowing for genetic modification?

Accepted Answer

DNA transformation

Question 18

Which of the following is a key advantage of confocal microscopy over traditional fluorescence microscopy?

Accepted Answer

It allows for the illumination of a single plane, reducing background fluorescence.

Question 19

Which of the following best describes the role of restriction enzymes in recombinant DNA technology?

Accepted Answer

They cut DNA at specific sequences, enabling the creation of recombinant DNA molecules.

Question 20

A scientist designs an experiment where only one condition is varied while all others are kept constant. What is the variable that is intentionally changed called?

Accepted Answer

Independent variable

Chapter 1: A Preview of Cell Biology – Foundations, Microscopy, and Cell Theory

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