Skip to main content
Back

General Biology: Genes, Gene Expression, Meiosis, and Inheritance

Control buttons has been changed to "navigation" mode.
1/28
  • Define a gene based on current understanding

    A gene is a DNA segment that contains the instructions to produce functional products, usually proteins, influencing traits and cellular functions.

  • Compare DNA and RNA structure and function

    DNA is double-stranded with deoxyribose sugar, stores genetic info; RNA is single-stranded with ribose sugar, involved in protein synthesis and gene regulation.

  • List types of RNA and their functions

    mRNA: carries genetic code from DNA to ribosomes; tRNA: brings amino acids during translation; rRNA: forms ribosome structure; snRNA: involved in RNA splicing.

  • Main function of transcription

    Transcription synthesizes RNA from a DNA template, producing mRNA that carries the genetic code for protein synthesis.

  • Main function of translation

    Translation uses mRNA to assemble amino acids into a polypeptide chain, forming proteins based on codon sequences.

  • How is RNA synthesized from DNA?

    RNA is synthesized by RNA polymerase using the DNA template strand, matching complementary RNA nucleotides to form a single-stranded RNA molecule.

  • Role of codons in protein synthesis

    Codons are three-nucleotide sequences on mRNA that specify which amino acid is added next during protein synthesis.

  • Function of tRNA and ribosomes in translation

    tRNA delivers specific amino acids to the ribosome, which facilitates peptide bond formation to build the protein chain.

  • Differences in transcription and translation between prokaryotes and eukaryotes

    Prokaryotes perform transcription and translation simultaneously in the cytoplasm; eukaryotes separate them spatially and temporally, with transcription in the nucleus and translation in the cytoplasm.

  • Determine complementary DNA, mRNA, and amino acid sequences from a DNA strand

    Complementary DNA pairs A-T and C-G; mRNA pairs A-U and C-G; amino acids are determined by mRNA codons using the genetic code.

  • Impact of DNA sequence changes on polypeptides

    Mutations can alter amino acid sequences, potentially changing protein structure and function, which may affect cellular processes.

  • Why is gene expression essential to cells?

    Gene expression controls which proteins are made, determining cell structure, function, and response to the environment.

  • Where are nucleic acids and proteins found in cells and how are they regulated?

    Nucleic acids are mainly in the nucleus and cytoplasm; proteins are throughout the cell. Their synthesis and activity are regulated at multiple levels including transcription, translation, and post-translation.

  • What is an operon and its function?

    An operon is a cluster of genes under control of a single promoter and operator, allowing coordinated regulation of gene expression in prokaryotes.

  • Define negative control of gene expression

    Negative control uses repressors to block transcription; inducers can deactivate repressors to allow gene expression.

  • Define positive control of gene expression

    Positive control involves activators like CAP binding to DNA to enhance transcription, often regulated by molecules like cAMP.

  • Compare regulation of trp and lac operons

    The trp operon is repressible and turned off by tryptophan; the lac operon is inducible and turned on by lactose presence.

  • How does chromatin structure affect gene expression in eukaryotes?

    Chromatin compaction regulates access to DNA; tightly packed chromatin (heterochromatin) represses genes, while loosely packed (euchromatin) allows expression.

  • Role of acetylation and methylation in gene regulation

    Acetylation of histones usually activates gene expression; methylation can activate or repress genes depending on context.

  • Explain alternative mRNA splicing

    Alternative splicing allows a single gene to produce multiple mRNA variants, increasing protein diversity.

  • Compare meiosis and mitosis

    Mitosis produces two identical diploid cells for growth/repair; meiosis produces four genetically diverse haploid gametes for sexual reproduction.

  • How do independent assortment and crossing over increase genetic variation?

    Independent assortment shuffles chromosomes; crossing over exchanges DNA between homologous chromosomes, both creating new allele combinations.

  • Explain Mendel's Law of Segregation and Independent Assortment

    Segregation: alleles separate during gamete formation; Independent Assortment: genes on different chromosomes assort independently.

  • Define dominant, recessive, codominant, and incompletely dominant alleles

    Dominant alleles mask recessive; codominant alleles both express; incomplete dominance results in intermediate phenotype.

  • What does it mean for genes to be linked?

    Linked genes are close on the same chromosome and tend to be inherited together, affecting inheritance patterns.

  • Define sex-linked genes and their inheritance pattern

    Sex-linked genes are located on sex chromosomes, often showing different inheritance patterns in males and females.

  • How can environment influence phenotype?

    Environmental factors can affect gene expression and phenotype without changing genotype, e.g., temperature affecting fur color.

  • What is genomics and its applications?

    Genomics studies whole genomes; applications include disease research, personalized medicine, and evolutionary studies.