Biology Week 1: Cystic Fibrosis and Phospholipids
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Questions and Answers

Which of the following is NOT a key piece of evidence supporting the RNA World Hypothesis?

  • Ribozymes act as enzymes, indicating RNA's catalytic capabilities.
  • RNA is highly stable due to its double-stranded nature, making it ideal for long-term information storage. (correct)
  • RNA's complex 3D structure allows for catalytic functions, similar to proteins.
  • RNA can self-replicate under certain conditions, essential for early life's replication.

    • Which organelle in the endomembrane system is responsible for the synthesis of lipids?

  • Smooth ER (correct)
  • Golgi Apparatus
  • Rough ER
  • Nucleus

    • Which of the following steps in gene expression occurs in the cytoplasm or on the rough ER?

  • Replication
  • Translation (correct)
  • Protein Folding
  • Transcription

    • What is the primary role of lysosomes within the endomembrane system?

    <p>Waste Breakdown (A)</p> Signup and view all the answers

    What technique is primarily used for visualizing the ultrastructures of the endomembrane system?

    <p>Transmission Electron Microscopy (D)</p> Signup and view all the answers

    Which of the following molecules is amphipathic, meaning it has both hydrophobic and hydrophilic regions?

    <p>Phospholipid (B)</p> Signup and view all the answers

    What key feature of DNA makes it a more stable molecule for long-term information storage than RNA?

    <p>DNA is double-stranded and contains deoxyribose sugar, providing greater stability. (D)</p> Signup and view all the answers

    Which of the following statements correctly describes the difference between hypertonic and hypotonic solutions?

    <p>Hypertonic solutions have a higher concentration of solutes than hypotonic solutions. (D)</p> Signup and view all the answers

    Which of the following is NOT a component of pre-mRNA processing?

    <p>Translation (D)</p> Signup and view all the answers

    Which type of mutation leads to a premature stop codon in the mRNA sequence?

    <p>Nonsense mutation (B)</p> Signup and view all the answers

    What is the key role of snRNPs in pre-mRNA processing?

    <p>Recognizing and removing introns (B)</p> Signup and view all the answers

    How does DNA methylation typically affect gene expression?

    <p>Decreases gene expression (D)</p> Signup and view all the answers

    Which of the following is the correct order of events in gene expression?

    <p>Transcription, pre-mRNA processing, translation (C)</p> Signup and view all the answers

    Alternative RNA splicing can lead to:

    <p>The production of multiple mRNA isoforms from a single gene (B)</p> Signup and view all the answers

    What is the difference between a coding strand and a template strand?

    <p>The coding strand is identical to the RNA sequence (except for T instead of U), while the template strand is complementary to the RNA sequence. (A)</p> Signup and view all the answers

    What is the relationship between transcription rate and DNA assembly speed?

    <p>Faster DNA assembly leads to faster transcription. (D)</p> Signup and view all the answers

    What is the primary mechanism behind the thick, sticky mucus buildup in individuals with Cystic Fibrosis?

    <p>A defect in the CFTR protein, leading to impaired chloride ion transport. (B)</p> Signup and view all the answers

    Which of the following accurately describes the structural components of a phospholipid?

    <p>A hydrophilic head composed of a glycerol backbone and a phosphate group, and two hydrophobic fatty acid tails. (B)</p> Signup and view all the answers

    How does the amphipathic nature of phospholipids contribute to the formation of a phospholipid bilayer?

    <p>Hydrophobic tails interact with each other, forming the inner layer of the bilayer, while hydrophilic heads interact with the aqueous environment. (C)</p> Signup and view all the answers

    Which of the following molecules can readily diffuse across a cell membrane without the assistance of transport proteins?

    <p>Small, nonpolar molecules like oxygen (O2) and carbon dioxide (CO2). (B)</p> Signup and view all the answers

    What is the primary difference between the FECA (First Eukaryotic Common Ancestor) and the LECA (Last Eukaryotic Common Ancestor) in terms of cellular organization?

    <p>LECA possessed a fully developed nucleus and mitochondria, while FECA lacked these complex organelles. (D)</p> Signup and view all the answers

    Which of the following correctly describes the function of the Golgi apparatus?

    <p>Modifies, sorts, and packages proteins and lipids. (B)</p> Signup and view all the answers

    What is the primary difference between membrane-bound organelles and proteinaceous organelles?

    <p>Membrane-bound organelles are enclosed by a single membrane, while proteinaceous organelles are not. (D)</p> Signup and view all the answers

    Which of the following is NOT considered an endosymbiotic organelle?

    <p>Golgi apparatus (D)</p> Signup and view all the answers

    What is one of the key benefits of having a nucleus in eukaryotic cells?

    <p>It separates transcription from translation. (C)</p> Signup and view all the answers

    Which component is NOT part of a nucleotide?

    <p>Ribose Sugar (B)</p> Signup and view all the answers

    What role do hydrogen bonds play in the structure of DNA?

    <p>They hold the two DNA strands together. (A)</p> Signup and view all the answers

    What type of bond links nucleotides in a DNA molecule?

    <p>Phosphodiester Bonds (C)</p> Signup and view all the answers

    Which enzyme is responsible for winding the DNA double helix?

    <p>DNA Helicase (B)</p> Signup and view all the answers

    What effect do mutations in the DNA sequence have on protein function?

    <p>They can alter protein function and cause diseases. (D)</p> Signup and view all the answers

    What is the significance of DNA melting temperature (Tm)?

    <p>It indicates the temperature at which DNA strands separate. (A)</p> Signup and view all the answers

    Which nitrogenous base pairs with adenine in DNA?

    <p>Thymine (D)</p> Signup and view all the answers

    What is the relationship between G-C pairs and the melting temperature (Tm) of DNA?

    <p>More G-C pairs contribute to a higher Tm because they have three hydrogen bonds. (C)</p> Signup and view all the answers

    Which statement describes a characteristic of heterochromatin?

    <p>It is tightly packed and transcriptionally inactive. (B)</p> Signup and view all the answers

    What constitutes a nucleosome?

    <p>Eight histone proteins with DNA wrapped around them. (C)</p> Signup and view all the answers

    Which of the following best describes the genome of an organism?

    <p>It consists of all genetic material, including genes and non-coding regions. (B)</p> Signup and view all the answers

    Which best defines an allele?

    <p>A variant form of a gene. (A)</p> Signup and view all the answers

    What is primarily measured to determine the melting temperature of DNA?

    <p>Changes in absorbance at 260 nm. (C)</p> Signup and view all the answers

    Which of the following correctly describes euchromatin?

    <p>It is loosely packed and actively transcribed. (D)</p> Signup and view all the answers

    What type of bond links nucleotides together in a DNA strand?

    <p>Phosphodiester bonds. (D)</p> Signup and view all the answers

    How do histone modifications affect gene expression?

    <p>They influence chromatin structure and gene accessibility. (B)</p> Signup and view all the answers

    What role do methylation-sensitive restriction enzymes play in research?

    <p>They are used to detect methylation patterns by cleaving DNA when certain patterns are absent. (A)</p> Signup and view all the answers

    What is a key function of transcription factors?

    <p>They regulate gene transcription. (B)</p> Signup and view all the answers

    What characterizes the pre-initiation complex?

    <p>It involves the assembly of RNA polymerase and transcription factors at the promoter. (C)</p> Signup and view all the answers

    Which statement about mRNA processing is correct?

    <p>It includes modifications such as splicing and polyadenylation to produce mature mRNA. (B)</p> Signup and view all the answers

    What distinguishes the coding strand from the template strand of DNA?

    <p>The template strand is used by RNA polymerase to create RNA. (A)</p> Signup and view all the answers

    What is the main role of the spliceosome?

    <p>To remove introns from pre-mRNA. (B)</p> Signup and view all the answers

    How does alternative RNA splicing function?

    <p>It allows the same gene to produce different proteins by varying included exons. (B)</p> Signup and view all the answers

    Signup and view all the answers

    Study Notes

    Week 1 Learning Objectives

    • Explore and outline the symptoms of Cystic Fibrosis (CF): persistent coughing with thick mucus, frequent lung infections, wheezing, shortness of breath, and poor growth despite a good appetite. Difficulty with bowel movements.
    • Hypothesize the mechanism behind CF symptoms: Mutations in the CFTR gene affecting the CFTR protein, which regulates chloride ion transport. Defective ion transport leads to thick, sticky mucus buildup primarily in the lungs and digestive system.
    • Identify the different parts of a phospholipid: Fatty acid tails (hydrophobic), glycerol backbone, and phosphate group (hydrophilic).
    • Relate the amphipathic nature of phospholipids to bilayer formation: Amphipathic means possessing both hydrophobic and hydrophilic regions. In aqueous environments, hydrophobic tails face inward, and hydrophilic heads face outward, creating a phospholipid bilayer.
    • Determine molecules that can diffuse through the membrane: Small, nonpolar molecules (e.g., O2, CO2) and some small polar molecules (e.g., H2O) diffuse easily, whereas large or charged molecules require transport proteins.
    • Discuss membrane selective permeability: Allows certain substances to pass while restricting others, based on the molecule's size, polarity, and charge.
    • Define osmosis: The passive movement of water molecules across a selectively permeable membrane from areas of low solute concentration to high solute concentration.
    • Define three major categories of organelles: membrane-bound (e.g., nucleus, ER, Golgi apparatus), proteinaceous (e.g., ribosomes), and endosymbiotic (e.g., mitochondria, chloroplasts).
    • Evolution of the nucleus and endomembrane system (FECA vs. LECA): FECA (First Eukaryotic Common Ancestor) possessed simple membrane systems as precursors to eukaryotes.

    Week 2 Learning Objectives

    • Evidence supporting RNA as the early information- storing molecule: RNA World Hypothesis suggesting RNA was the first genetic material, able to store information and catalyze reactions. Key evidence includes ribozymes (RNA molecules acting as enzymes), 3-D structure necessary for catalytic functions, and RNA self-replication.
    • Why DNA is better for information storage than RNA: DNA's double-stranded structure and deoxyribose sugar offer greater stability. DNA has repair mechanisms and longevity due to its lack of a 2'-hydroxyl group, making it less reactive and less prone to degradation.
    • Benefits of a Nucleus: Separation of processes (transcription in nucleus, translation in cytoplasm), protection of DNA from harmful cytoplasmic reactions, and efficient regulation of gene expression.

    Week 2 Learning Objectives--Continued

    • Monomeric & Polymeric forms of DNA: Monomer: Nucleotide (nitrogenous base, deoxyribose sugar, phosphate group). Polymer: DNA, linking nucleotides through phosphodiester bonds.
    • DNA polymer formation & base pairing rules: Phosphodiester bonds link the sugar-phosphate backbone. Base pairing rules ensure accurate DNA replication, Adenine (A) pairs with Thymine (T) via 2 hydrogen bonds and Guanine (G) pairs with Cytosine (C) via 3 hydrogen bonds.
    • Role of hydrogen bonds in DNA structure: Hydrogen bonds hold the two DNA strands together, creating the double helix. They break easily for strand separation in replication or transcription.
    • How changes in DNA structure impact function: Mutations alter protein function and structural alterations can impair replication and gene expression.

    Week 2 Learning Objectives--Continued

    • Major DNA modifying enzymes: DNA Helicase unwinds the double helix, DNA Polymerase synthesizes new DNA strands, DNA Ligase seals nicks in the DNA backbone, Topoisomerase relieves supercoiling during replication, Nucleases cut DNA strands, and Methyltransferases add methyl groups to modify gene expression.
    • DNA melting & temperature (Tm) analysis: DNA melting is the process of double-stranded DNA separating into single strands upon heating. Tm is the temperature at which 50% of the DNA is denatured, higher Tm means more G-C pairs due to three hydrogen bonds. Measures DNA melting by tracking absorbance change at 260nm
    • Relationship between DNA, chromosome, genes, and alleles (example: cystic fibrosis). DNA carries genetic instructions, Chromosomes are long DNA molecules containing many genes, Genes are segments of DNA coding for a specific protein & alleles are different versions of a gene. For example, CFTR gene in cystic fibrosis with mutant vs normal alleles.
    • Nucleosome structure: Nucleosome is a basic unit of DNA packaging, containing core proteins (H2A, H2B, H3, H4) and DNA tightly wrapped around it for efficient packaging. Linker DNA connects nucleosomes with H1 histone for stabilization.
    • Euchromatin vs. Heterochromatin: Euchromatin is loosely packed, actively transcribed, light-staining. Heterochromatin is tightly packed, transcriptionally inactive, dark-staining, concentrated at nuclear periphery.

    Week 3 Learning Objectives

    • Genome definition: The complete set of an organism's genetic material, including genes and non-coding regions.
    • Variation between organisms: Genome size and structure vary across organisms. Larger, multicellular organisms generally have more complex genomes to regulate a higher number of genes.
    • Regulatory and structural components of a eukaryotic genome: Regulatory components include promoters, enhancers, silencers, which control gene expression. Structural components consist of genes (exons and introns) and non-coding regions to maintain genome integrity.
    • Connection between multicellularity and genome size: Multicellular organisms typically have larger, more complex genomes to regulate gene expression across different cell types, tissues, and developmental stages.

    Week 3 Learning Objectives--Continued

    • Differential gene expression: The process where different cells in an organism express different genes based on cell type, developmental stage, and environmental factors, leading to cellular specialization.
    • DNA-binding proteins in the transcription initiation complex (TIC): Basal transcription factors are essential for the basic transcription machinery. Co-activators, activators, and repressors impact transcription by binding and enhancing or preventing gene expression.
    • Relationship between DNA-binding proteins and target DNA sequences: Enhancers increase, silencers decrease transcription. Specific DNA sequences such as the TATA box act as binding sites for basal transcription factors.
    • Formation of the TIC and effects of alterations: The TIC assembles at the promoter. Alterations can disrupt transcription initiation and result in reduced or absent expression.
    • RNA polymerase positioning at the start of transcription: RNA Polymerase binds to promoter region with the help of transcription factors to start transcription.
    • How the transcription rate is altered: Transcription rate depends on the efficiency of the TIC formation. More efficient TIC assembly results in more rapid transcription.
    • DNA ends (5' and 3') in transcription: 5' end is the start point, and RNA is synthesized from 5' to 3’. The 3' end is the end of the synthesized RNA.

    Week 3 Learning Objectives--Continued

    • Coding vs. template strand: Coding strand has the same sequence as the RNA. Template strand is used by RNA polymerase to synthesize RNA, substituting Thymine (T) for Uracil (U).
    • Pre-mRNA to mature mRNA formation: Splicing removes introns, 5' capping protects and signals. Addition of a Poly-A tail at the 3' end helps with stability.
    • RNA and protein components of snRNPs: snRNPs (small nuclear ribonucleoproteins) play a role in splicing, identifying splice sites, and catalyzing intron removal.
    • Alternative RNA splicing: A process enabling one gene to produce multiple mRNA isoforms leading to diverse proteins.
    • Cellular locations and functions of transcription, pre-mRNA processing, and translation. Transcription occurs in the nucleus. Pre-mRNA processing and splicing also occur in the nucleus. Translation occurs in the cytoplasm..
    • Mutation vs. epigenetic regulation. A mutation is a permanent change in DNA sequence. Epigenetic modification regulates gene expression without changing the DNA sequence.
    • Three types of single nucleotide mutations. Silent, missense and nonsense.
    • Role of Epigenetics in Gene Expression: Epigenetic mechanisms regulate gene expression by altering chromatin, without changing the DNA sequence.
    • DNA methylation vs. histone modification: DNA methylation is the addition of a methyl group to cytosine residues which typically silences gene expression. Histone modification (e.g., acetylation, methylation) affects chromatin structure and gene accessibility.
    • Methylation-sensitive restriction enzymes used to detect methylation patterns in DNA.
    • mRNA processing: Modifications such as capping, splicing, and polyadenylation to produce mature mRNA. Spliceosome processes removal of introns. Alternative splicing enables creation of different proteins from the same gene through different mRNA isoforms. Mutations differ from epigenetics as mutations are permanent DNA changes while epigenetics are heritable changes in gene expression without changing the DNA sequence, e.g., methylation.
    • Post-translational modifications affect proteins' function after translation, impacting their function. RNAi and miRNA are small RNA molecules.

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    Exam 1 Learning Objectives PDF

    Description

    This quiz covers the learning objectives for Week 1, focusing on the symptoms and mechanisms of Cystic Fibrosis, as well as the structure and properties of phospholipids. Explore how CFTR gene mutations lead to disease symptoms and the role of phospholipids in membrane formation. Test your understanding of these essential biology concepts!

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