General Biology 1 - Genetics Unit 2

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Questions and Answers

What is the process called when information is transferred from DNA to RNA?

Replication

Transformation

Transcription (correct)

Translation

Which of the following statements correctly describes semi-conservative replication?

Each new DNA molecule consists of one original and one newly synthesized strand. (correct)

Each new DNA molecule consists of two original strands.

It produces two identical copies without using any original DNA.

Replication occurs in a random manner and does not follow a specific pattern.

What is the primary function of RNA polymerase during transcription?

Binding to ribosomes

Facilitating tRNA attachment

Proofreading RNA sequences

Synthesizing RNA (correct)

Which step of transcription involves the formation of a transcription bubble?

Initiation Signup and view all the answers

During which step of the central dogma is protein synthesis directly carried out?

Translation Signup and view all the answers

How do mutations in the promoter region typically affect gene expression?

They inhibit RNA polymerase binding Signup and view all the answers

What direction does DNA synthesis always begin?

5’-3’ direction Signup and view all the answers

The CFTR gene responsible for Cystic Fibrosis is located on which chromosome?

Chromosome 7 Signup and view all the answers

What is the role of transcription factors in transcription?

They assist RNA polymerase in binding to the promoter region Signup and view all the answers

During which process is peptide bond formation a critical step?

Elongation Signup and view all the answers

What are RNA primers required for during DNA replication?

To initiate the process of replication Signup and view all the answers

What is the primary mechanism through which tetracycline affects bacterial protein synthesis?

Binding to the 30S ribosomal subunit Signup and view all the answers

What does the term 'origin of replication' refer to?

The specific location where DNA replication begins Signup and view all the answers

Which of the following is NOT a characteristic of DNA replication?

It is dependent on RNA polymerase. Signup and view all the answers

In prokaryotes, transcription and translation can occur simultaneously due to what key difference?

Lack of nuclear membrane Signup and view all the answers

Which components play a crucial role during the initiation phase of translation?

tRNA and mRNA Signup and view all the answers

What is the role of RNA primers in DNA replication?

To initiate synthesis of the new DNA strand Signup and view all the answers

Which protein is responsible for unwinding the DNA strands during replication?

Helicase Signup and view all the answers

What happens to the lagging strand during DNA replication?

It is synthesized in fragments Signup and view all the answers

Which of the following correctly describes the process of elongation during DNA replication?

Leading and lagging strands are synthesized differently Signup and view all the answers

What is the role of DNA ligase in the replication process?

To seal gaps between Okazaki fragments Signup and view all the answers

In which phase of DNA replication does priming occur?

Initiation Signup and view all the answers

Which of the following is a characteristic of DNA replication?

It is semi-discontinuous for strand synthesis Signup and view all the answers

How does the Central Dogma view the processes after DNA replication?

Transcription must occur before translation Signup and view all the answers

What is a key characteristic of prokaryotic mRNA?

It can encode multiple proteins. Signup and view all the answers

Where does transcription occur in prokaryotic cells?

In the cytoplasm. Signup and view all the answers

Which of the following processes is NOT part of eukaryotic mRNA processing?

Encoding multiple proteins. Signup and view all the answers

What role does the Shine-Dalgarno sequence play in prokaryotic translation?

It aligns with rRNA to position the start codon. Signup and view all the answers

Which of these statements about ribosomes is true?

Eukaryotic ribosomes are 80S in size. Signup and view all the answers

How does the initiation of translation differ between prokaryotes and eukaryotes?

Eukaryotes have a more complex initiation process with multiple factors. Signup and view all the answers

What is the function of the 3' poly-A tail in eukaryotic mRNA?

To enhance mRNA stability and facilitate export. Signup and view all the answers

What feature distinguishes eukaryotic genes from prokaryotic genes?

Eukaryotic genes contain introns. Signup and view all the answers

Study Notes

Central Dogma of Molecular Biology

Central Dogma describes the flow of genetic information from DNA to RNA to proteins.
Information is stored in DNA, transferred to RNA during transcription, and decoded into proteins during translation.
Genes are segments of DNA that contain instructions for producing proteins.

Gene Expression

Gene expression involves converting genes into functional products, namely proteins.
Transcription: DNA is transcribed into RNA.
Translation: RNA is translated into proteins.

DNA Replication

DNA replication is semi-conservative; each new DNA molecule has one original and one new strand.
Initiation occurs at origins of replication, specific sequences where replication begins.
Synthesis proceeds in the 5’-3’ direction, requiring RNA primers to start the process.
Replication can be unidirectional or bidirectional and consists of both leading and lagging strands.
Core proteins involved:
- Topoisomerase: Prevents DNA torsion.
- Helicase: Unwinds DNA strands.
- Primase: Synthesizes RNA primers.
- Single-strand binding proteins: Prevent reannealing of DNA strands.
- DNA polymerase: Synthesizes new DNA strands.
- DNA ligase: Joins gaps in the DNA.

Transcription Process

Initiation: Involves promoter regions where RNA polymerase binds to start transcription.
Elongation: RNA is synthesized, with proofreading processes to ensure accuracy.
Termination: Occurs when a termination signal is reached, releasing the RNA transcript.

Translation Process

Initiation: Involves assembling ribosomal subunits and tRNA binding at the start codon.
Elongation: RNA is read in codons; peptide bonds form between amino acids.
Termination: Occurs when a stop codon is recognized, releasing the polypeptide chain.

Translation in Prokaryotes vs. Eukaryotes

Prokaryotes:
- Transcription and translation occur simultaneously in the cytoplasm.
- Ribosomes are 70S, with a simpler initiation process involving the Shine-Dalgarno sequence.
Eukaryotes:
- Transcription occurs in the nucleus, followed by mRNA processing before translation in the cytoplasm.
- Ribosomes are 80S, and initiation is more complex, involving multiple factors and a 5' cap.

Case Studies

Cystic Fibrosis: Caused by mutations in the CFTR gene on chromosome 7, affecting salt and water regulation in cells.
Thalassemia: A blood disorder due to mutations in the HBB gene that impact hemoglobin production.
Antibiotics: Tetracycline inhibits bacterial protein synthesis by binding to the ribosomal subunit, affecting translation processes.

Implications of Genetic Editing

Advances in CRISPR-Cas9 technology offer potential to correct genetic disorders by targeting specific mutations in genes such as CFTR and HBB.

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Description

Explore the Central Dogma of Molecular Biology in this quiz covering Unit 2 of General Biology 1 for SY 2024 - 2025. Understand the key processes of gene expression, replication, and the relationship between DNA, RNA, and proteins. Test your knowledge and delve into the exciting possibilities of genetic editing.