Biological Molecules: Proteins & Nucleic Acids
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Questions and Answers

How do amphipathic molecules behave when in water?

  • They self-assemble. (correct)
  • They dissolve completely.
  • They spread evenly throughout the water.

    • What is the orientation of the hydrophilic heads in a lipid bilayer?

  • They face the aqueous environment. (correct)
  • They form hydrophobic interactions with each other.
  • They face inward towards the hydrophobic tails.
  • They are distributed randomly.

    • What does the lipid bilayer primarily function as?

  • A structural support.
  • A source of energy.
  • A selective permeability barrier. (correct)
  • A signaling pathway.

    • Why do amphipathic molecules spontaneously assemble into compartments?

    <p>To avoid free edges due to energetic favorability.</p> Signup and view all the answers

    What are the components that make up triglycerides?

    <p>Glycerol and fatty acids</p> Signup and view all the answers

    Which type of molecules are likely to diffuse across the lipid bilayer?

    <p>Small nonpolar molecules.</p> Signup and view all the answers

    Which type of fatty acid contains no double bonds?

    <p>Saturated fatty acids</p> Signup and view all the answers

    What is a characteristic feature of lipids?

    <p>They do not form long repeating polymers</p> Signup and view all the answers

    What is the chemical process called that links glycerol and fatty acids to form triglycerides?

    <p>Dehydration reaction</p> Signup and view all the answers

    How do saturated and unsaturated fatty acids differ?

    <p>In the number of double bonds</p> Signup and view all the answers

    What role do lipids play in biological systems?

    <p>Insulation, energy storage, cell structure, and signaling</p> Signup and view all the answers

    What component is a characteristic of glycerol?

    <p>It is a three-carbon alcohol</p> Signup and view all the answers

    What health risks are associated with saturated fats?

    <p>Increased risk of cardiovascular disease</p> Signup and view all the answers

    What is the primary structural unit of nucleic acids?

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

    Which of the following correctly describes a polypeptide?

    <p>A molecule with one or more folded 3D chains of amino acids</p> Signup and view all the answers

    How many different amino acids are used to build polypeptides?

    <p>20</p> Signup and view all the answers

    What is the main function of nucleic acids?

    <p>Storage and transmission of genetic information</p> Signup and view all the answers

    Which sugar is found in RNA?

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

    How many bases are present in DNA?

    <p>4</p> Signup and view all the answers

    What type of bond links nucleotides together in a polynucleotide?

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

    Which of the following is a characteristic of RNA?

    <p>Contains uracil instead of thymine</p> Signup and view all the answers

    What are surface markers on white blood cells important for?

    <p>Triggering an immune response</p> Signup and view all the answers

    How are the ABO blood groups differentiated?

    <p>By the types of carbohydrates on the RBC membrane</p> Signup and view all the answers

    What role does the spike protein of SARS-CoV-2 play in infection?

    <p>It binds to hACE2 receptors on host cells</p> Signup and view all the answers

    What is one potential use of understanding the SARS-CoV-2 spike protein's mechanism?

    <p>To provide a target for anti-viral drug development</p> Signup and view all the answers

    What type of proteins do antibodies target to probe for specific antigens?

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

    What is the primary reason the body recognizes 'non-self' foreign materials?

    <p>The specificity of white blood cell surface markers</p> Signup and view all the answers

    What happens to the viral membrane during the SARS-CoV-2 infection process?

    <p>It fuses with the host cell membrane</p> Signup and view all the answers

    What component is critical for the attachment of the SARS-CoV-2 virus to the host cell?

    <p>hACE2 receptor</p> Signup and view all the answers

    What are the principal components of the plasma membrane?

    <p>Lipids, proteins, and carbohydrates</p> Signup and view all the answers

    Which function is NOT performed by the plasma membrane?

    <p>Carrying out protein synthesis</p> Signup and view all the answers

    How do proteins contribute to the plasma membrane's functions?

    <p>They perform sensing and transport functions</p> Signup and view all the answers

    What role does the lipid bilayer play in the plasma membrane?

    <p>It serves as a permeability barrier</p> Signup and view all the answers

    What is a key application of extracted DNA in laboratories?

    <p>Genetic profiling and forensics</p> Signup and view all the answers

    Which statement best describes the relationship between the plasma membrane and cellular processes?

    <p>The plasma membrane regulates entry/exit and mediates various processes</p> Signup and view all the answers

    What is the primary purpose of cell communication mediated by the plasma membrane?

    <p>Coordinating responses to external signals</p> Signup and view all the answers

    Which type of biomolecule is primarily responsible for the structural integrity of the plasma membrane?

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

    Study Notes

    Proteins

    • Proteins are biologically functional molecules that consist of one or more polypeptide chains
    • Polypeptides are linear polymers constructed from a set of 20 amino acids linked by covalent peptide bonds
    • A protein's structure determines its function
    • Proteins can be categorized based on their size: Dipeptides (2 amino acids), Oligopeptides (up to ~20 amino acids), and Polypeptides (20 – thousands of amino acids).

    Nucleic Acids

    • Nucleic acids are involved in the storage, transmission, and use of genetic information
    • They are also called polynucleotides
    • A polynucleotide is a chain of nucleotides linked together by covalent phosphodiester bonds
    • There are two types of nucleic acids: DNA and RNA

    DNA (Deoxyribonucleic Acid)

    • Composed of four bases: adenine (A), cytosine (C), guanine (G), and thymine (T)
    • Contains deoxyribose sugar
    • Double stranded

    RNA (Ribonucleic Acid)

    • Composed of four bases: adenine (A), cytosine (C), guanine (G), and uracil (U)
    • Contains ribose sugar
    • Single stranded

    Lipids

    • Lipids are a class of large molecules that contain mostly hydrocarbons (C, H) and are non-polar
    • They are insoluble in water (hydrophobic)
    • They are used for insulation, energy storage, cell structure, and cell signaling
    • Three types of lipids are:
      • Triglycerides (Fats)
      • Phospholipids
      • Steroids

    Triglycerides (Fats)

    • Constructed from two types of smaller molecules: glycerol and fatty acids
    • Glycerol is a three-carbon alcohol with a hydroxyl group on each carbon
    • Fatty acids consist of a carboxyl group attached to a long carbon tail
    • Fatty acids are linked to glycerol via a dehydration reaction to form a covalent ester bond

    Saturated Fats

    • Have the maximum number of hydrogen atoms possible and no double bonds

    Unsaturated Fats

    • Have one or more double bonds

    The Plasma Membrane

    • The plasma membrane is a phospholipid bilayer that serves as a permeability barrier
    • It regulates the entry and exit of molecules into and out of the cell
    • The bilayer is composed of phospholipids and cholesterol, as well as proteins and carbohydrates (glycoproteins and glycolipids)

    Membrane Proteins

    • Play important roles in cellular processes
    • Their functions include: sensing the environment, transporting molecules across the membrane, and mediating cellular communication

    The ABO Blood Groups

    • are characterized by different carbohydrate structures on the glycoproteins of red blood cell (RBC) membranes
    • Carbohydrate tails of glycoproteins on the RBC membrane are responsible for different blood types

    Antibodies

    • Can be used to probe for specific cell-surface antigens (markers that trigger an immune response)

    Sars-CoV-2

    • The Sars-CoV-2 virus attaches to the host cell via its spike protein, which binds to a specific receptor protein (hACE2) on the host cell's surface
    • The spike protein also contains parts that facilitate the fusion of the viral membrane with the host cell membrane to deliver the viral genome inside the cell

    Crude DNA Extraction Lab Activity

    • A basic procedure in laboratories
    • Important for the study of genetics
    • Used in:
      • genetic profiling (DNA fingerprinting) to diagnose genetic diseases
      • establishing paternity
      • forensic analysis
    • The extracted DNA can be manipulated for biomedical purposes

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    Week 1 Cohort 2 - Lipids and the Cell Membrane Instructor(1) PDF

    Description

    Explore the essential structures and functions of proteins and nucleic acids in this informative quiz. Learn about polypeptides, amino acids, and the differences between DNA and RNA in terms of their composition and roles. Gain a deeper understanding of how these biological molecules contribute to life.

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