Unit 1 Study

Define gene expression.

• The process by which DNA is replicated.

• The process by which information from a gene is used to synthesize a functional gene product, usually a protein.

• The process of cell division.

• The process of DNA mutation.

Answer explanation

Gene expression is the process by which information from a gene is utilized to produce a functional gene product, typically a protein, which plays a crucial role in cellular functions and traits.

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Explain why gene expression is important in the life of an organism.

• It allows for the replication of DNA.

• It enables the organism to grow, develop, and respond to its environment by producing necessary proteins.

• It prevents mutations from occurring.

• It is responsible for the elimination of waste products.

Answer explanation

Gene expression is crucial as it allows organisms to produce proteins necessary for growth, development, and environmental responses, making it essential for survival and adaptation.

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Describe one way in which genes are turned on during cell differentiation.

• By the removal of introns from mRNA.

• Through the binding of transcription factors to specific DNA sequences.

• By the replication of DNA.

• Through the process of mitosis.

Answer explanation

Genes are turned on during cell differentiation primarily through the binding of transcription factors to specific DNA sequences, which facilitates the transcription of genes necessary for the development of specialized cell types.

Interpret the following diagram showing the process of turning genes on and off. What does the presence of a repressor protein indicate?

• The gene is being actively transcribed.

• The gene is turned off and not being transcribed.

• The gene is undergoing mutation.

• The gene is being replicated.

Answer explanation

The presence of a repressor protein indicates that the gene is turned off and not being transcribed, as repressors inhibit the transcription process.

Explain how DNA technology is used to construct recombinant DNA molecules.

• By using enzymes to cut and paste DNA sequences from different sources.

• By replicating the entire genome of an organism.

• By sequencing the DNA of an organism.

• By transcribing mRNA into DNA.

Answer explanation

DNA technology constructs recombinant DNA by using enzymes to cut specific DNA sequences from different sources and paste them together, allowing for the creation of new genetic combinations.

What is the role of proteins in gene expression?

• Proteins are the building blocks of DNA.

• Proteins act as enzymes and structural components, and they regulate gene expression.

• Proteins are responsible for the replication of DNA.

• Proteins are used to store genetic information.

Answer explanation

Proteins play a crucial role in gene expression by acting as enzymes that facilitate biochemical reactions and as structural components that help regulate the transcription of genes, making the correct choice essential.

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Describe how DNA can be inserted into the cells of other organisms to alter their protein production.

• By using a microscope to manually insert DNA.

• By using vectors such as plasmids or viruses to deliver the DNA into the host cells.

• By heating the cells to make them absorb DNA.

• By mixing DNA with the organism's food.

Answer explanation

DNA can be inserted into cells using vectors like plasmids or viruses, which effectively deliver the DNA into host cells, allowing for the alteration of protein production. Other methods are less effective or impractical.

Explain how gene expression affects the development of cells.

• It determines the rate at which cells divide.

• It controls which proteins are produced, influencing cell function and specialization.

• It ensures that all cells in an organism are identical.

• It prevents cells from undergoing apoptosis.

Answer explanation

Gene expression controls which proteins are produced in a cell. This influences cell function and specialization, determining how cells develop and what roles they play in an organism.

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What is the significance of cell differentiation in gene expression?

• It allows cells to become specialized for specific functions.

• It causes cells to lose their genetic material.

• It prevents cells from dividing.

• It leads to the death of cells.

Answer explanation

Cell differentiation is crucial as it allows cells to become specialized for specific functions, enabling the formation of diverse tissues and organs, each performing unique roles essential for the organism's overall function.

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Strategically plan how you would use evidence to determine if a gene is turned on or off in a cell.

• Measure the amount of DNA present in the cell.

• Analyze the presence of mRNA transcripts for the gene in question.

• Count the number of cells in the organism.

• Observe the physical appearance of the cell.

Answer explanation

To determine if a gene is turned on or off, analyzing the presence of mRNA transcripts is crucial. If mRNA is present, it indicates that the gene is actively being expressed, thus turned on.