Cell Biology MCQs | BIO201 MCQs | Set 6

MCQs (Multiple Choice Questions)

1)    A complete 3 billion base genome would take _______ gigabytes of storage space.

    a)        4

    b)        5

    c)        6

    d)        3

Correct Answer: 

The correct answer is  'c'.

Explanation:

The storage requirements for a genome can vary depending on the specific format used and the accompanying data, but 6 gigabytes is a reasonable estimate for a human genome in certain common file formats.

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2)    The eukaryotic subunit of RNA polymerase homologous to the `\omega` subunit of bacterial RNA polymerase is _____

    a)        RPB2

    b)        RPAI  

    c)        RPB6

    d)        RPC5

Correct Answer:

The correct answer is  'c'.

Explanation:

In eukaryotic RNA polymerase II, which is responsible for transcribing protein-coding genes, RPB6 is an essential component. It helps stabilize the RNA polymerase complex and is involved in various functions related to transcription initiation and elongation. The `\omega` subunit in bacterial RNA polymerase has some functional similarities to RPB6, which is why they are considered homologous.

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3)    ______ rise causes membrane proteins to permit a massive flow of water from the blood into the intestinal lumen, causing diarrhea.

    a)       GTP

    b)       cAMP

    c)       ATP

    d)       GDP

Correct Answer: 

The correct answer is  'b'.

Explanation:

cAMP (cyclic adenosine monophosphate) can cause membrane proteins to permit a massive flow of water from the blood into the intestinal lumen, leading to diarrhea. This process can occur through the activation of specific signaling pathways and ion transport in the intestines.

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4)    When human cell is subject to stressful condition ________  is activated.

    a)        helicase

    b)        protein kinase

    c)        synthetase

    d)        isomerase

Correct Answer: 

The correct answer is  'b'.

Explanation:

When a human cell is subjected to stressful conditions, protein kinase is often activated. Protein kinases are enzymes that play a critical role in various cellular signaling pathways, including those involved in the cell's response to stress. They phosphorylate target proteins, leading to changes in their activity and contributing to the cell's stress response and adaptation.

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5)    Pre-synthesized mRNAs are stored in the _________ in an inactive state.

    a)        nucleus

    b)        nuclear membrance

    c)        plasma membrance

    d)        cytoplasm

Correct Answer: 

The correct answer is  'd'.

Explanation:

Pre-synthesized mRNAs are stored in the cytoplasm in an inactive state. This is because the cytoplasm is where the ribosomes are located, which are responsible for translating mRNA into proteins. When the cell needs to produce a particular protein, the pre-synthesized mRNA is transported from the cytoplasm to the nucleus, where it is translated into protein by the ribosomes.

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6)     Which of the elongation factor binds to amino acyl tRNA?

    a)       Ef-Tu

    b)       GDP

    c)        Ef-Ts

    d)       Ef-G

Correct Answer:

The correct answer is  'a'.

Explanation:

Elongation factor Tu (Ef-Tu) is responsible for binding to aminoacyl tRNA (tRNA molecules charged with amino acids) during the process of protein synthesis in the ribosome. Ef-Tu is part of the protein synthesis machinery in both prokaryotes and eukaryotes.

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7)   Ligand binding causes a structural change permitting G protein to bind to _______.

    a)        Promoter region only

    b)        Introns

    c)        Exons

    d)       Intron-Exon boundries

Correct Answer: 

The correct answer is  'c'.

Explanation:

Ligand binding causes a structural change permitting G protein to bind to the receptor. This is a fundamental mechanism in G protein-coupled receptor (GPCR) signaling, where ligand binding induces a conformational change in the receptor that allows it to interact with and activate a G protein.

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8)    In bacteria, mRNAs bound to small metabolites are called ___________.

    a)        heterochromatin

    b)        nucleosome

    c)        euchromatin

    d)        riboswitches

Correct Answer: 

The correct answer is  'd'.

Explanation:

Riboswitches are regulatory elements in the untranslated regions of mRNAs that can change their structure upon binding to specific small molecules or metabolites. This structural change can affect gene expression by either allowing or preventing translation or transcription of the mRNA, depending on the presence or absence of the bound metabolite. 

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9)    Transcriptional activators consist of _________ domains.

    a)        1

    b)        3

    c)         4

    d)        2

Correct Answer: 

The correct answer is  'd'.

Explanation:

These domains are often referred to as the DNA-binding domain and the activation domain. The DNA-binding domain allows the activator to bind to specific regulatory sequences in the promoter or enhancer regions of target genes, while the activation domain interacts with other components of the transcriptional machinery to stimulate gene transcription.

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10)    ______spread signal from one pathway to another.

    a)        Regulatory Proteins

    b)        Bifurcation proteins

    c)        Messenger Proteins

    d)       Adaptor Proteins

Correct Answer: 

The correct answer is  'c'.

Explanation:

Messenger proteins spread signal from one pathway to another. They are proteins that bind to signaling molecules (ligands) and transmit the signal to other proteins inside the cell. Messenger proteins can be small molecules, such as cyclic AMP (cAMP), or they can be large proteins, such as mitogen-activated protein kinase (MAPK).

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