Q: Which equation best represents the flow of genetic information in the central dogma of molecular biology?

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

Question 1

Which structural feature of DNA allows it to serve as the hereditary material across generations?

Accepted Answer

Its double-stranded, antiparallel structure with complementary base pairing

Question 2

A scientist is studying a bacterial cell that contains a small, circular DNA molecule separate from its main chromosome. What is this molecule called, and what is its significance?

Accepted Answer

Plasmid; it can carry genes for antibiotic resistance and be transferred between cells

Question 3

During transcription, which strand of DNA serves as the template for RNA synthesis, and in which direction does RNA polymerase synthesize the new RNA strand?

Accepted Answer

The non-coding (antisense) strand; 5' to 3'

Question 4

Which modification occurs to eukaryotic mRNA before it is translated, and what is its function?

Accepted Answer

Addition of a poly-A tail; increases mRNA stability and facilitates export from the nucleus

Question 5

Alternative splicing of mRNA can result in:

Accepted Answer

Production of multiple protein variants from a single gene

Question 6

In prokaryotes, transcription and translation can occur simultaneously. Which structural feature of prokaryotic cells enables this?

Accepted Answer

Absence of a nuclear membrane

Question 7

A retrovirus infects a cell and uses reverse transcriptase to produce DNA from its RNA genome. What is the equation representing this process?

Accepted Answer

RNA $\rightarrow$ DNA $\rightarrow$ RNA $\rightarrow$ Protein

Question 8

Which of the following best describes the function of the lac operon in E. coli?

Accepted Answer

It enables the cell to metabolize lactose only when lactose is present and glucose is absent

Question 9

Epigenetic inheritance involves changes in gene expression without altering the DNA sequence. Which mechanism is commonly associated with epigenetic regulation?

Accepted Answer

Methylation of DNA bases

Question 10

A mutation changes a single nucleotide in a gene, resulting in a different amino acid in the protein product. What type of mutation is this, and what is its potential effect?

Accepted Answer

Missense mutation; it may alter protein function depending on the amino acid change

Question 11

Which equation best represents the flow of genetic information in the central dogma of molecular biology?

Accepted Answer

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

Question 12

Which of the following is a real-world application of the Polymerase Chain Reaction (PCR)?

Accepted Answer

Amplifying specific DNA sequences for forensic analysis

Question 13

Restriction enzymes are used in genetic engineering because they:

Accepted Answer

Cut DNA at specific sequences, enabling insertion or removal of genes

Question 14

Which process allows prokaryotes to acquire new genetic material from their environment, leading to genetic variation?

Accepted Answer

Transformation

Question 15

A cell expresses a combination of genes specific to its tissue type. What is this process called, and what is its significance?

Accepted Answer

Cell differentiation; it allows cells to perform specialized functions

Question 16

Which of the following best explains how environmental stimuli can affect gene expression in mature cells?

Accepted Answer

Environmental signals can activate or repress transcription factors, altering gene expression patterns

Question 17

A scientist uses gel electrophoresis to analyze DNA samples. What principle allows DNA fragments to be separated in this technique?

Accepted Answer

DNA fragments move through a gel matrix based on size when an electric field is applied

Question 18

Which of the following is an example of a negative regulatory molecule in gene expression?

Accepted Answer

A repressor protein that binds to an operator and blocks transcription

Question 19

If a mutation occurs during meiosis that results in an extra chromosome, what is the likely outcome for the organism?

Accepted Answer

The organism may exhibit a genetic disorder due to altered chromosome number, such as trisomy 21 (Down syndrome)

AP Biology Unit 6: Gene Expression and Regulation – Study Notes

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