④ Genetics (short answers)

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Questions and Answers

Explain how a single gene can lead to the production of multiple proteins.

Alternative splicing allows different combinations of exons to be included in the final mRNA, leading to different protein isoforms from a single gene.

Describe the role of the promoter region in gene expression.

The promoter region is a DNA sequence where RNA polymerase binds to initiate transcription. It controls when and where a gene is transcribed.

Outline the steps involved in the initiation of translation in eukaryotes.

The small ribosomal subunit binds to the mRNA, the initiator tRNA carrying methionine binds to the start codon (AUG), and then the large ribosomal subunit joins the complex.

Explain how a frameshift mutation can have a more significant impact than a point mutation.

<p>A frameshift mutation alters the reading frame of the mRNA, leading to a completely different amino acid sequence downstream, whereas a point mutation typically affects only a single amino acid.</p> Signup and view all the answers

Describe the role of tRNA in the process of translation.

<p>tRNA molecules carry specific amino acids to the ribosome and match them to the mRNA codon via their anticodon, ensuring the correct amino acid sequence is assembled.</p> Signup and view all the answers

Explain how epigenetic modifications can lead to phenotypic changes without altering the DNA sequence.

<p>Epigenetic modifications, such as DNA methylation and histone modification, can alter chromatin structure and gene expression patterns, leading to heritable changes in phenotype without changing the underlying DNA sequence.</p> Signup and view all the answers

Describe how the environment might influence gene expression through epigenetic mechanisms.

<p>Environmental factors, such as diet or exposure to toxins, can cause epigenetic modifications like DNA methylation or histone acetylation, which in turn can alter gene expression patterns.</p> Signup and view all the answers

Explain the difference between missense and nonsense mutations.

<p>A missense mutation results in a codon that codes for a different amino acid, while a nonsense mutation results in a premature stop codon.</p> Signup and view all the answers

Describe the function of ribosomes in the process of translation.

<p>Ribosomes are the site of protein synthesis. They bind to mRNA, facilitate the binding of tRNA to mRNA codons, catalyze peptide bond formation between amino acids, and move along the mRNA to continue the translation process.</p> Signup and view all the answers

Explain the role of RNA polymerase in transcription.

<p>RNA polymerase binds to the promoter region of a gene and synthesizes a complementary RNA molecule (mRNA) using the DNA template.</p> Signup and view all the answers

Describe the process of 5' capping and its importance.

<p>5' capping involves adding a modified guanine nucleotide to the 5' end of pre-mRNA. It protects the mRNA from degradation and enhances translation efficiency.</p> Signup and view all the answers

Describe the key differences between transcription in prokaryotes and eukaryotes.

<p>In prokaryotes, transcription and translation occur simultaneously in the cytoplasm. In eukaryotes, transcription occurs in the nucleus, and the pre-mRNA undergoes processing before translation in the cytoplasm. Eukaryotic transcription also involves more complex regulation with transcription factors.</p> Signup and view all the answers

Explain the function of aminoacyl-tRNA synthetases.

<p>Aminoacyl-tRNA synthetases are enzymes that catalyze the attachment of the correct amino acid to its corresponding tRNA molecule, forming an aminoacyl-tRNA. This is essential for accurate translation.</p> Signup and view all the answers

Describe the role of the poly(A) tail in mRNA.

<p>The poly(A) tail is a sequence of adenine nucleotides added to the 3' end of mRNA. It protects the mRNA from degradation and enhances translation efficiency.</p> Signup and view all the answers

Explain how mutations in non-coding regions of DNA can still affect gene expression.

<p>Mutations in non-coding regions, such as promoters, enhancers, or silencers, can alter the binding of transcription factors, affecting the rate and level of gene transcription.</p> Signup and view all the answers

Describe the process of RNA splicing and its significance.

<p>RNA splicing is the process of removing introns (non-coding regions) from pre-mRNA and joining together exons (coding regions) to form mature mRNA. It allows for alternative splicing, increasing protein diversity.</p> Signup and view all the answers

Explain how the redundancy of the genetic code minimizes the impact of certain point mutations.

<p>The genetic code is redundant because multiple codons can code for the same amino acid. This means that a point mutation in the third base of a codon, for example, might not change the amino acid sequence of the protein.</p> Signup and view all the answers

Describe the role of release factors in translation termination.

<p>Release factors bind to the stop codon in the A site of the ribosome, causing the hydrolysis of the bond between the tRNA and the polypeptide chain, releasing the polypeptide.</p> Signup and view all the answers

Explain how histone acetylation affects gene expression.

<p>Histone acetylation adds acetyl groups to histone proteins, which loosens the chromatin structure, making DNA more accessible to transcription factors and RNA polymerase, thus increasing gene expression.</p> Signup and view all the answers

Describe the role of chaperones in protein folding and function.

<p>Chaperones are proteins that assist in the correct folding of other proteins, prevent aggregation, and help transport proteins across cellular membranes, ensuring proper protein function.</p> Signup and view all the answers

Flashcards

Transcription

The process of synthesizing RNA from a DNA template.

Translation

The process of synthesizing a polypeptide chain from mRNA.

Mutation

A change in the nucleotide sequence of DNA.

Epigenetics

Heritable changes in gene expression that do not involve changes to the underlying DNA sequence.

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Study Notes

  • Genetics is a key topic within biology.

Transcription

  • Transcription is a biological process.

Translation

  • Translation is a biological process.

Mutation

  • Mutation is a biological process.

Transcription

  • Transcription is a biological process.

Translation

  • Translation is a biological process.

Epigenetics

  • Epigenetics is a field of study within biology.

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