Ribosome and Protein Synthesis
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Questions and Answers

What is the key process that plant cells use chloroplasts for?

  • Photosynthesis (correct)
  • DNA replication
  • Protein synthesis
  • Cellular respiration

    • Which structure is unique to plant cells and not present in animal cells?

  • Mitochondria
  • Cytoskeleton
  • Cell wall (correct)
  • Plasma membrane

    • What function do microtubules serve in animal cells?

  • Photosynthesis
  • Organize cell content (correct)
  • Synthesize proteins
  • Facilitate cellular respiration

    • What is the primary source of glucose for animal cells?

    <p>Food intake</p> Signup and view all the answers

    Which organelle is responsible for microtubule nucleation during cell division?

    <p>Centrosome</p> Signup and view all the answers

    In neurons, what is the primary function of microtubules?

    <p>Transport organelles and materials</p> Signup and view all the answers

    In DNA, which nitrogenous base pairs with Guanine?

    <p>Cytosine</p> Signup and view all the answers

    What type of bonds link adjacent nucleotides in a DNA strand?

    <p>Phosphodiester bonds</p> Signup and view all the answers

    Which sugar is found in DNA but not in RNA?

    <p>Deoxyribose</p> Signup and view all the answers

    What process targets histones in Huntington's disease?

    <p>Deacetylation</p> Signup and view all the answers

    Which groove in the DNA double helix is shallower and narrower?

    <p>Minor groove</p> Signup and view all the answers

    What is the most common function of the phosphate group in nucleotides?

    <p>Allowing interaction with DNA histones</p> Signup and view all the answers

    What is a key difference between prokaryotic and eukaryotic cells?

    <p>Prokaryotic cells contain a membrane-bound nucleus, while eukaryotic cells have DNA in a single circular loop.</p> Signup and view all the answers

    What is a distinctive feature of prokaryotic cells that aids in their movement?

    <p>Pili / flagella structures</p> Signup and view all the answers

    How does the DNA arrangement in prokaryotic cells differ from that in eukaryotic cells?

    <p>Prokaryotic cells contain multiple separate chromosomes, while eukaryotic cells have a single circular loop of DNA.</p> Signup and view all the answers

    Which organelle is present in eukaryotic cells but absent in prokaryotic cells?

    <p>Mitochondria</p> Signup and view all the answers

    What is the primary biological function of microfilaments?

    <p>Cell transport</p> Signup and view all the answers

    Which type of intermediate filaments is most common in cells that undergo mechanical stress?

    <p>Type I keratins</p> Signup and view all the answers

    In what biological process do actin filaments form a contractile ring around the 'waist' of the cell?

    <p>Cell division</p> Signup and view all the answers

    Which cytoskeletal polymer is the most flexible and can cross-link with microtubules and microfilaments?

    <p>Intermediate filaments</p> Signup and view all the answers

    What is the default state of a microfilament when actin monomers are added as quickly as they are removed?

    <p>Treadmilling</p> Signup and view all the answers

    Which disease has been associated with reduced microtubule stability?

    <p>Alzheimer's disease</p> Signup and view all the answers

    How do most pathogens manipulate the host cytoskeleton?

    <p>Manipulating actin-filament networks</p> Signup and view all the answers

    'Treadmilling' is associated with the dynamics of which cytoskeletal component?

    <p>Microfilaments</p> Signup and view all the answers

    What is the name of the chemical substance present in the nucleus that controls all the chemical changes in cells and determines cell type and organism produced?

    <p>Deoxyribonucleic acid(DNA)</p> Signup and view all the answers

    What is the role of the ribosome in protein synthesis?

    <p>Building proteins</p> Signup and view all the answers

    Which process involves the movement of the tRNA from the A site to the P site in protein synthesis?

    <p>Translation</p> Signup and view all the answers

    What happens during translation in protein synthesis?

    <p>Conversion of RNA to protein</p> Signup and view all the answers

    What is a key difference between prokaryotic and eukaryotic DNA?

    <p>Prokaryotic DNA is linear, while eukaryotic DNA is circular.</p> Signup and view all the answers

    What feature distinguishes plant cells from animal cells?

    <p>Having cell walls</p> Signup and view all the answers

    Which characteristic is unique to archaea among prokaryotes?

    <p>Cell wall composition</p> Signup and view all the answers

    What is the function of release factors in protein synthesis termination?

    <p>Releasing completed polypeptide chains</p> Signup and view all the answers

    Which organelle is responsible for energy production in eukaryotic cells?

    <p>Mitochondrion</p> Signup and view all the answers

    What type of symbiosis describes one organism living inside another?

    <p>Endosymbiosis</p> Signup and view all the answers

    What distinguishes unicellular prokaryotic cells from eukaryotic cells?

    <p>DNA structure</p> Signup and view all the answers

    What is a major difference between translation and transcription in protein synthesis?

    <p>Transcription produces mRNA, while translation produces proteins.</p> Signup and view all the answers

    Which type of metabolism involves using acetate as an electron donor and ferrihydrite as an electron acceptor without fermentation?

    <p>Anaerobic metabolism</p> Signup and view all the answers

    What is a unique characteristic of the RNA complex in Archae body cells?

    <p>Contains 10 subunits</p> Signup and view all the answers

    What is the key difference in the composition of DNA between prokaryotic and eukaryotic cells?

    <p>Prokaryotic DNA is circular without proteins, while eukaryotic DNA is linear with proteins.</p> Signup and view all the answers

    Which type of cells has ribosomes with a size of 70S?

    <p>Prokaryotic cells</p> Signup and view all the answers

    In the cell cycle, during which phase does DNA replication occur?

    <p>S phase</p> Signup and view all the answers

    What is the primary function of the cytoskeleton in eukaryotic cells?

    <p>Support cell structure and movement using flexible cilia and flagellin</p> Signup and view all the answers

    What is the main form of motility in prokaryotic cells?

    <p>Rotating flagellum made by flagella</p> Signup and view all the answers

    'Okazaki fragments' are primarily involved in which process during DNA replication?

    <p>Lagging strand replication</p> Signup and view all the answers

    What is the central dogma of molecular biology?

    <p>Genetic information flows from DNA to RNA to protein</p> Signup and view all the answers

    How does the nucleus control the cell?

    <p>By regulating gene expression and controlling DNA replication</p> Signup and view all the answers

    What is the function of histones in chromosomes?

    <p>Support the structure of chromosomes</p> Signup and view all the answers

    What is the role of ribosomes in protein synthesis?

    <p>Decoding mRNA and assembling amino acids into proteins</p> Signup and view all the answers

    What is the relationship between a gene and a sequence of triplets on DNA?

    <p>A gene is a sequence of triplets that code for a complete protein</p> Signup and view all the answers

    What happens when a cell divides?

    <p>DNA replication results in identical DNA in each nucleus</p> Signup and view all the answers

    How does the genetic code control protein production?

    <p>By controlling the order in which amino acids are joined up</p> Signup and view all the answers

    What is the function of nerve growth factors in nerve cells?

    <p>To transcribe genes related to nerve cell growth and survival</p> Signup and view all the answers

    Why are chromosomes considered to be made up of DNA and proteins?

    <p>Proteins provide structural support to DNA in chromosome formation</p> Signup and view all the answers

    What distinguishes one gene from another?

    <p>The varying number of triplets within a gene</p> Signup and view all the answers

    Why is mRNA transported from the nucleus to the cytosol?

    <p>To serve as a template for protein synthesis</p> Signup and view all the answers

    What is the main role of cohesins in the cell during mitosis?

    <p>Facilitate separation of sister chromatids</p> Signup and view all the answers

    During which phase of the cell cycle does a cell stop dividing and enter a resting phase?

    <p>Gap 0</p> Signup and view all the answers

    What is the main function of the centrosome in a eukaryotic cell?

    <p>Initiate spindle formation</p> Signup and view all the answers

    Which statement best describes prometaphase in mitosis?

    <p>'Late prophase' where chromosomes are condensed</p> Signup and view all the answers

    What is the specific role of the 16S ribosomal RNA in translation initiation?

    <p>Binds to the Shine-Dalgarno sequence</p> Signup and view all the answers

    In agarose gel electrophoresis, what primarily determines the movement of charged particles within the electric field?

    <p>Size of the molecules</p> Signup and view all the answers

    What is the purpose of loading buffer/dye when preparing DNA samples for gel electrophoresis?

    <p>To help DNA sink to the bottom of the well</p> Signup and view all the answers

    What is a key consideration for maintaining sterility inside a biological safety cabinet?

    <p>Minimizing clutter inside the cabinet</p> Signup and view all the answers

    Which end of the gel is attached to the Cathode (-) during electrophoresis?

    <p>Top loading end</p> Signup and view all the answers

    What is a recommended practice when working inside a biological safety cabinet to avoid contamination?

    <p>Touching face and hair with gloves on</p> Signup and view all the answers

    What is the purpose of warming cell culture media and additives to 37˚C in a water bath before using them?

    <p>To ensure optimal temperature for cellular growth and viability</p> Signup and view all the answers

    Why must all materials be disinfected with 70% ethanol before starting cell culture procedures?

    <p>To ensure a sterile working environment and prevent contamination</p> Signup and view all the answers

    What is the consequence of seeding cells at a high cell count/density in cell culture?

    <p>Overpopulation leading to cell death</p> Signup and view all the answers

    During meiosis I, what happens in Anaphase I that distinguishes it from Anaphase in mitosis?

    <p>Homologue pairs are separated</p> Signup and view all the answers

    What is the purpose of using trypan blue in mammalian cell culture and viability staining?

    <p>To stain cells that have already died</p> Signup and view all the answers

    What occurs during Prophase I of meiosis that does not happen in mitosis?

    <p>Crossing over between homologous chromosomes</p> Signup and view all the answers

    How does 100% ethanol treatment affect bacterial cells?

    <p>Ruptures the cell membrane, killing the bacteria</p> Signup and view all the answers

    What happens to live cells with intact membranes when stained with trypan blue?

    <p>They are not colorized by trypan blue</p> Signup and view all the answers

    What is the main difference between Mitosis and Meiosis II?

    <p>Separation of sister chromatids</p> Signup and view all the answers

    In metaphase of meiosis where do the homologous chromosomes line up?

    <p>Metaphase plate</p> Signup and view all the answers

    Which stage of cell division marks the transition from a haploid state to a diploid state?

    <p>Telophase I</p> Signup and view all the answers

    What is the main outcome of crossing over during Prophase I of meiosis?

    <p>Exchange of genetic material between nonsister chromatids</p> Signup and view all the answers

    Which organelle is responsible for forming a new cell wall in plant cells during cytokinesis?

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

    What is the key challenge in ensuring an equal split between new cells during cell division?

    <p>Attachment of kinetochores to the spindle</p> Signup and view all the answers

    What happens during Anaphase II of meiosis?

    <p>Sister chromatids separate and move to opposite poles</p> Signup and view all the answers

    What is the primary function of the synaptonemal complex during Prophase I of meiosis?

    <p>Holding together homologous chromosomes</p> Signup and view all the answers

    What is a distinguishing feature of Meiosis II compared to Meiosis I?

    <p>Sister chromatids separate</p> Signup and view all the answers

    How do the resulting cells differ after meiosis compared to mitosis?

    <p>Resulting cells are haploid after meiosis and diploid after mitosis</p> Signup and view all the answers

    Which site in the ribosome does the first, empty tRNA drift out from after the peptide bond is formed?

    <p>E site</p> Signup and view all the answers

    What type of codons signal the termination of translation in mRNA?

    <p>Stop codons</p> Signup and view all the answers

    In prokaryotes, what is the main factor that influences the regulation of gene expression?

    <p>Nutrient availability</p> Signup and view all the answers

    Which component of an operon binds to the operator and halts transcription?

    <p>Repressor protein</p> Signup and view all the answers

    In the Lac Operon, what molecule can turn on gene expression by preventing the repressor protein from binding to the operator?

    <p>Inducer</p> Signup and view all the answers

    What is the primary function of the trp operon in E.coli when tryptophan is available in the environment?

    <p>Synthesizing more tryptophan</p> Signup and view all the answers

    What is the function of the repressor protein produced by the regulatory gene in the trp operon?

    <p>Inhibit gene expression</p> Signup and view all the answers

    How are the genes in the trp operon transcribed?

    <p>As a continuous strand of mRNA</p> Signup and view all the answers

    What does the Lac Operon turn on when a specific small molecule is present?

    <p>Inducer binding to repressor</p> Signup and view all the answers

    What is the role of corepressors in regulating gene expression in repressible operons like Trp Operon?

    <p>Turn off gene expression</p> Signup and view all the answers

    What happens when an inducer molecule binds to a repressor protein in inducible operons like Lac Operon?

    <p>Prevents repressor from binding to operator, allowing transcription</p> Signup and view all the answers

    During transcription, what is the role of promoters on DNA?

    <p>Serving as recognition points for binding of RNA polymerase</p> Signup and view all the answers

    What happens during transcription termination?

    <p>RNA polymerase transcribes a sequence known as a terminator</p> Signup and view all the answers

    Which process involves the removal of introns and the splicing of exons in mRNA?

    <p>RNA splicing</p> Signup and view all the answers

    What is the function of 5' capping during RNA processing?

    <p>Preventing mRNA degradation</p> Signup and view all the answers

    What is a key characteristic of tRNA molecules?

    <p>Have an anticodon complementary to mRNA codon</p> Signup and view all the answers

    Which component of the ribosome holds the tRNA molecule carrying the next amino acid to be added to the growing polypeptide chain?

    <p>A site</p> Signup and view all the answers

    What is the function of aminoacyl-tRNA synthetases?

    <p>Attach specific amino acids to tRNA molecules</p> Signup and view all the answers

    Which stage of protein synthesis involves the assembly of the initiation complex with mRNA and ribosomal subunits?

    <p>Initiation</p> Signup and view all the answers

    What provides the energy for assembling the initiation complex during translation initiation?

    <p>GTP</p> Signup and view all the answers

    What does translation elongation involve?

    <p>tRNA moving from P site to A site in ribosome</p> Signup and view all the answers

    What is the role of splicing during RNA processing?

    <p>Join coding exons while removing introns from pre-mRNA</p> Signup and view all the answers

    What is the function of 'm7G' addition during RNA processing?

    <p>Protect mRNA from degradation and aid in translation initiation at ribosome</p> Signup and view all the answers

    What is the function of lacA in the lac operon?

    <p>Function unclear</p> Signup and view all the answers

    In prokaryotic transcription initiation, which DNA sequence is essential for starting transcription?

    <p>Pribnow box</p> Signup and view all the answers

    What occurs when Rho factor reaches the transcription bubble in Rho-dependent termination?

    <p>Rho pulls the RNA transcript and DNA strand apart</p> Signup and view all the answers

    What causes RNA polymerase to stall in Rho-independent termination?

    <p>Complementary binding of C and G nucleotides</p> Signup and view all the answers

    What is the role of the Shine-Dalgarno sequence in prokaryotic translation?

    <p>Complementary to 16S rRNA in the ribosome</p> Signup and view all the answers

    What is the composition of prokaryotic ribosomes?

    <p>*30S and *50S subunits</p> Signup and view all the answers

    Which type of termination strategy relies on a stable hairpin structure?

    <p>*Rho-independent termination</p> Signup and view all the answers

    Translation elongation is characterized by:

    <p>*Formation of peptide bonds between amino acids</p> Signup and view all the answers

    Transcription initiation in prokaryotes requires:

    <p>*Interaction with Pribnow box at -10 site</p> Signup and view all the answers

    Translation termination involves:

    <p>*Release of polypeptide from ribosome</p> Signup and view all the answers

    Study Notes

    Plant and Animal Cell Differences

    • Chloroplasts in plant cells facilitate photosynthesis, converting light energy into chemical energy.
    • Plant cells possess a cell wall, a feature absent in animal cells.
    • Microtubules in animal cells provide structural support, aid in cell shape, and facilitate intracellular transport.

    Microtubules and DNA Structure

    • The centrosome organizes microtubule nucleation during cell division.
    • In neurons, microtubules support structural integrity and facilitate axonal transport.
    • Guanine pairs with Cytosine in DNA interactions.
    • Phosphodiester bonds link adjacent nucleotides in the DNA strand.
    • Deoxyribose sugar is found in DNA; Ribose is found in RNA.

    Genetic and Cellular Processes

    • Histone modifications are targeted during Huntington's disease.
    • The minor groove of the DNA double helix is shallower and narrower compared to the major groove.
    • The phosphate group in nucleotides primarily functions in energy transfer and structural stability.
    • Prokaryotic cells lack membrane-bound organelles, while eukaryotic cells possess them.

    Prokaryotic Features

    • Prokaryotic cells typically have flagella for movement.
    • Prokaryotic DNA is circular and not associated with histones, in contrast to linear, histone-associated eukaryotic DNA.
    • Eukaryotic cells contain organelles like mitochondria, which are absent in prokaryotic cells.

    Cytoskeletal Components

    • Microfilaments serve critical roles in muscle contraction and cellular movement.
    • Keratin is a common intermediate filament providing mechanical strength in cells under stress.
    • Actin filaments form a contractile ring during cytokinesis.

    General Cellular Biology

    • Microtubules are the most flexible cytoskeletal polymer, capable of cross-linking with microfilaments.
    • The default state of a microfilament is dynamic, undergoing 'treadmilling' based on actin monomer addition and removal.
    • Reduced microtubule stability is associated with diseases like Alzheimer's.
    • Pathogens manipulate the host cytoskeleton for entry and replication.

    Protein Synthesis and Genetic Code

    • Ribosomes synthesize proteins by translating mRNA into amino acid sequences.
    • The A site to P site transition occurs during translation elongation.
    • Transcription and translation differ: transcription synthesizes RNA, while translation builds proteins.

    Cell Cycle and Division

    • DNA replication occurs during the synthesis phase in the cell cycle.
    • The cytoskeleton maintains cell shape and assists in cellular movements.
    • Okazaki fragments are crucial for DNA replication on the lagging strand.

    Mitosis and Meiosis

    • Nerve growth factors promote neuron development and repair.
    • Cohesins ensure sister chromatid cohesion during mitosis.
    • Crossing over in Prophase I of meiosis promotes genetic diversity.
    • During Anaphase I, homologous chromosomes separate, unlike in mitosis where sister chromatids separate.

    Gene Regulation

    • In prokaryotes, gene expression is mainly regulated by operons.
    • The Lac operon is activated by allolactose, which prevents repressor binding.
    • Tryptophan availability controls the trp operon's gene transcription.

    RNA Processing and Translation

    • Introns are removed, and exons are spliced during RNA processing.
    • 5' capping protects mRNA from degradation and facilitates translation initiation.
    • Transfer RNA (tRNA) carries specific amino acids and matches them to codons during protein synthesis.

    Agarose Gel Electrophoresis

    • Movement in agarose gel electrophoresis is influenced by the size and charge of DNA fragments.
    • Loading buffer is essential for visualizing DNA samples during electrophoresis.

    Cell Culture Practices

    • Sterility in biological safety cabinets is essential; 70% ethanol is used for disinfection.
    • Media warmed to physiological temperature promotes optimal cell culture conditions.
    • High cell density can lead to nutrient depletion and waste build-up.

    These notes provide a comprehensive overview of the fundamental concepts of cell biology, genetics, and molecular processes relevant to the topics addressed.

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    Description

    This quiz covers the process of protein synthesis by the ribosome, including initiation, elongation, translocation, and termination. Learn about the steps involved in creating a polypeptide chain.

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