Bio 50: Developmental Genetics

Questions and Answers

What distinguishes RNA from DNA regarding sugar type?

RNA contains deoxyribose, while DNA contains ribose.

DNA contains glucose, while RNA contains ribose.

Both RNA and DNA contain ribose.

RNA contains ribose, while DNA contains deoxyribose. (correct)

Which type of RNA is primarily responsible for carrying genetic information for protein synthesis?

Messenger RNA (correct)

Heterogeneous nuclear RNA

Transfer RNA

Ribosomal RNA

What is the primary function of transfer RNA (tRNA)?

To carry genetic information for protein synthesis.

To combine with proteins to form ribosomes.

To deliver amino acids to the sites for protein synthesis. (correct)

To facilitate the conversion of hnRNA to mRNA.

During the transcription process, what exposes the base sequence of a gene?

The enzyme RNA polymerase unwinding the DNA double helix. Signup and view all the answers

What is the role of small nuclear RNA (snRNA)?

To facilitate the conversion of hnRNA to mRNA. Signup and view all the answers

How does the structure of RNA differ from that of DNA?

RNA is single-stranded, while DNA is a double helix. Signup and view all the answers

What is the primary function of ribosomal RNA (rRNA)?

To combine with proteins to form ribosomes. Signup and view all the answers

What happens during the initiation step of transcription?

The DNA double helix unwinds at the gene location. Signup and view all the answers

What is the central dogma of molecular biology?

DNA to RNA to protein Signup and view all the answers

Which of the following describes gene expression?

Transcription of gene sequences into functional products Signup and view all the answers

What are the two phases of gene expression?

Transcription and translation Signup and view all the answers

How do gene expression and regulation impact cellular functions?

They allow cells to adapt to different conditions Signup and view all the answers

What forms the basis of cell development and differentiation?

Gene expression and regulation Signup and view all the answers

Which types of functional gene products are produced during gene expression?

Proteins and functional RNAs Signup and view all the answers

What role does transcription play in gene expression?

It synthesizes RNA from a DNA template Signup and view all the answers

What is one consequence of controlling the time and location of gene expression?

Enhanced cellular adaptation Signup and view all the answers

Where do promoters typically exist in relation to the genes they regulate?

Upstream of the genes Signup and view all the answers

What does RNA polymerase do during the transcription process?

Links ribonucleotides to form a growing RNA chain Signup and view all the answers

What happens during the elongation stage of transcription?

Ribonucleotides align along the DNA template strand Signup and view all the answers

What is formed when RNA polymerase encounters a stop signal during transcription?

The RNA strand and RNA polymerase are released Signup and view all the answers

What change occurs to the DNA during the process of transcription?

The DNA rewinds to form an original double helix Signup and view all the answers

What is the end product of transcription known as before any processing occurs?

hnRNA Signup and view all the answers

Which nucleobase aligns with adenine during RNA synthesis?

Uracil Signup and view all the answers

What does RNA processing ensure for the primary transcript?

It acquires its mature form Signup and view all the answers

What is the first modification made to eukaryotic pre-mRNAs?

Capping on the 5' end Signup and view all the answers

How is the poly-A tail added to the 3' end of a mRNA?

By poly-A polymerase Signup and view all the answers

What are exons in the context of a gene?

Segments that convey genetic information Signup and view all the answers

What is the primary function of RNA splicing?

To remove introns and join exons Signup and view all the answers

Which particles are primarily involved in the process of RNA splicing?

Small nuclear ribonucleoprotein particles (snRNP) Signup and view all the answers

What distinguishes introns from exons?

Introns do not convey genetic information, exons do Signup and view all the answers

What is the role of spliceosomes in RNA processing?

To convert hnRNA to mRNA Signup and view all the answers

What is a potential outcome of alternative splicing?

Producing multiple proteins from a single gene Signup and view all the answers

Study Notes

Developmental Genetics: Transcription and RNA

The central dogma of molecular biology describes the flow of genetic information: DNA → RNA → Protein.
Gene expression involves transcribing gene sequences into functional products like proteins or functional RNAs (e.g., rRNA, tRNA).
There are two main phases of gene expression: transcription and translation.

Ribonucleic Acids (RNA)

RNA differs from DNA in several key ways:
- Contains ribose sugar, while DNA contains deoxyribose.
- Uracil (U) replaces thymine (T) in RNA.
- Typically single-stranded, while DNA is double-stranded.
- RNA is shorter, ranging from 75 to thousands of nucleotides.

Types of RNA

Heterogeneous nuclear RNA (hnRNA): Direct product of DNA transcription; processed into mRNA.
Messenger RNA (mRNA): Carries genetic instructions for protein synthesis to ribosomes.
Small nuclear RNA (snRNA): Aids in converting hnRNA to mRNA.
Ribosomal RNA (rRNA): Combines with proteins to form ribosomes, the sites of protein synthesis; does not carry genetic information.
Transfer RNA (tRNA): Delivers amino acids to ribosomes for protein assembly.

Messenger RNA (mRNA) Synthesis

Transcription occurs in the nucleus where DNA instructs the synthesis of hnRNA/mRNA.
Genes consist of specific DNA sequences encoding for hnRNA/mRNA.

Steps in the Transcription Process

Initiation:
- The DNA double helix unwinds at a promoter region, allowing RNA polymerase to bind.
- The transcription bubble forms, facilitated by RNA polymerase, which catalyzes the synthesis of a linear RNA chain from ribonucleotides.
Elongation:
- RNA polymerase aligns ribonucleotides with the DNA template strand, forming base pairs.
- In RNA, U pairs with A instead of T.
Termination:
- Transcription concludes when RNA polymerase encounters a stop signal.
- The completed hnRNA is released, and DNA reforms its double helix.

Eukaryotic RNA Processing

RNA processing converts the primary transcript into its mature form through several steps:
Covalent Modification of RNA Ends:
- 5’ cap: A modified guanine nucleotide is added to the RNA's 5' end.
- Polyadenylation: A chain of adenine nucleotides is added to the 3' end by poly-A polymerase.
Removal of Introns:
- Genes contain exons (coding regions) and introns (non-coding regions); both are transcribed.
- RNA splicing removes introns and joins exons to form the final mRNA.
- Splicing is facilitated by a complex of snRNA and proteins, forming spliceosomes.

Alternative Splicing

A single gene can produce multiple mRNA variants through alternative splicing, allowing for diverse protein products by rearranging exons.

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Description

Explore the key concepts of transcription and the role of ribonucleic acids (RNA) in developmental genetics. This quiz will test your understanding of messenger RNA and its significance in biological processes. Perfect for students studying Developmental Biology at Benguet State University.

Bio 50: Developmental Genetics - Lesson 3