Lecture 2: Chemical Organization Level
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Questions and Answers

What is the primary function of messenger RNA (mRNA)?

  • Carries amino acids to ribosomes
  • Forms part of the ribosome structure
  • Translates genetic code into proteins
  • Encodes messages from genes to ribosomes (correct)

    • All organisms use ribonucleic acid (RNA) as their genetic material.

    False

    What are the structural components of a nucleotide?

    Nitrogenous base, pentose sugar, phosphate group

    DNA undergoes __________ to create identical copies.

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

    Match the following types of RNA with their functions:

    <p>mRNA = Carries genetic information from DNA rRNA = Component of ribosomes tRNA = Brings amino acids to the ribosome snRNA = Participates in RNA splicing</p> Signup and view all the answers

    What property of water allows it to absorb a lot of energy before increasing in temperature?

    <p>High specific heat</p> Signup and view all the answers

    Solid water, or ice, sinks in liquid water.

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

    What is the pH range that must be maintained in blood?

    <p>7.35-7.45</p> Signup and view all the answers

    Water is a polar molecule, allowing it to dissolve __________ substances easily.

    <p>polar and charged</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Cohesion = Molecules sticking together Hydrophilic = Water-attracting substances Hydrophobic = Water-repelling substances Buffer = Minimizes changes in pH</p> Signup and view all the answers

    Which of the following is an example of a hydrophobic substance?

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

    Explain why freshwater organisms can survive the winter.

    <p>Ice floats on water, providing an insulating layer that keeps the water below it liquid.</p> Signup and view all the answers

    Hydrogen bonds play a significant role in the properties of water and life.

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

    Organic molecules contain ______________.

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

    What are compounds that contain only carbon and hydrogen called?

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

    Functional groups do not affect the chemical properties of organic molecules.

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

    What are the four classes of biological monomers?

    <p>Carbohydrates, Lipids, Proteins, Nucleic acids</p> Signup and view all the answers

    Which of the following functional groups is commonly found in carbohydrates?

    <p>Hydroxyl group</p> Signup and view all the answers

    Monosaccharides are the ______________ of carbohydrates.

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

    Match the following biological monomers with their class:

    <p>Monosaccharides = Carbohydrates Fatty acids = Lipids Amino acids = Proteins Nucleotides = Nucleic acids</p> Signup and view all the answers

    Steroid hormones are modified structures based on cholesterol.

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

    What percentage of total body mass do carbohydrates constitute?

    <p>2-3%</p> Signup and view all the answers

    Which of the following statements is true regarding polymers?

    <p>Polymers are composed of a few subunits called monomers.</p> Signup and view all the answers

    What is the primary structure of proteins determined by?

    <p>Gene sequence</p> Signup and view all the answers

    All proteins have a quaternary structure.

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

    What type of bond is formed when amino acids undergo dehydration synthesis?

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

    A protein that is soluble in water is classified as a __________ protein.

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

    Match the following protein structures with their descriptions:

    <p>Primary Structure = Amino acid sequence Secondary Structure = Repeated folds such as alpha helices and beta sheets Tertiary Structure = Three-dimensional shape of a single polypeptide Quaternary Structure = Arrangement of multiple polypeptide chains</p> Signup and view all the answers

    Which of the following bonds helps stabilize secondary protein structure?

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

    Denatured proteins are biologically active.

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

    What are the main types of secondary protein structures?

    <p>alpha helices and beta sheets</p> Signup and view all the answers

    The __________ are covalent bonds formed between sulfhydryl groups and play a role in tertiary structure.

    <p>disulfide bridges</p> Signup and view all the answers

    Which type of protein forms long parallel bundles and is water-insoluble?

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

    What is the main function of enzymes?

    <p>To lower activation energy and accelerate reactions</p> Signup and view all the answers

    Enzymes are biological catalysts that do not accelerate the rate of chemical reactions.

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

    What term is used for nonprotein molecules that assist enzyme catalysis?

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

    The inactive forms of enzymes that must be processed to become active are called __________.

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

    Which of the following correctly describes the process of enzyme action?

    <p>Subtrates bind to the enzyme's active site.</p> Signup and view all the answers

    Enzymes can work on any substrate without specificity.

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

    What is activation energy?

    <p>The amount of energy required to break a bond</p> Signup and view all the answers

    The type of organic cofactors that assist enzymes are known as __________.

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

    Which mechanism describes how substrates fit into an enzyme's active site?

    <p>Lock and key mechanism</p> Signup and view all the answers

    Match the following terms related to enzymes with their definitions:

    <p>Cofactors = Nonprotein molecules that assist enzyme activity Substrates = Reactants that enzymes act upon Proenzymes = Inactive forms of enzymes Active Site = Region where substrates bind to the enzyme</p> Signup and view all the answers

    Study Notes

    Water Properties

    • Water exhibits cohesion, resulting in molecules sticking to each other.
    • Moderates temperature by absorbing significant energy before heating.
    • Releases heat at night, focusing on temperature control, including sweating.
    • Water expands upon freezing, causing ice to float due to ordered hydrogen bonds forming a lattice structure.
    • Freshwater organisms survive winter because ice insulating water beneath it.
    • Water is a polar solvent, dissolving hydrophilic (water-loving) substances easily while hydrophobic (water-hating) substances, such as oils, do not dissolve.
    • Buffers stabilize pH levels; blood pH maintained between 7.35-7.45.

    Organic Molecules

    • Organic molecules contain carbon and are characterized by carbon skeletons linked via covalent bonds.
    • Hydrocarbons consist solely of carbon and hydrogen.
    • Functional groups attached to carbon skeletons dictate chemical properties and functions of organic molecules.
    • Biological molecules, mainly polymers, consist of repeating monomers.

    Carbohydrates

    • Composed of carbon, hydrogen, and oxygen; represent 2-3% of body mass.
    • Monosaccharides (simple sugars) act as the monomers of carbohydrates, combining through dehydration synthesis.
    • Disaccharides consist of two monosaccharides bonded together.

    Proteins

    • Formed from amino acids linked via peptide bonds through dehydration synthesis.
    • Small proteins consist of a single polypeptide; large proteins consist of multiple polypeptides.
    • Primary structure defined by amino acid sequence; secondary structure includes α-helices or β-sheets stabilized by hydrogen bonds.
    • Tertiary structure represents a protein's three-dimensional shape, influenced by various bonds and interactions, including disulfide bridges and hydrophobic interactions.
    • Quaternary structure refers to the arrangement of polypeptide chains in multi-peptide proteins.
    • Fibrous proteins are water-insoluble and function in structural roles; globular proteins are water-soluble and often serve as enzymes or antibodies.
    • Denaturation leads to a loss of structure and biological activity of proteins.

    Enzymes

    • Enzymes function as biological catalysts that speed up chemical reactions without being consumed.
    • They can include cofactors and coenzymes, which assist in catalysis.
    • Enzymes are highly specific, efficiently increasing reaction rates by lowering activation energy.
    • Proenzymes are inactive forms that require specific conditions for activation.

    Nucleic Acids

    • Composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus; exist as DNA or RNA.
    • Genes, segments of DNA, code for specific proteins and are transcribed into RNA and translated into proteins.
    • Nucleotides serve as monomers, consisting of a nitrogenous base, pentose sugar, and phosphate group.
    • DNA contains the bases A, T, C, G; RNA contains A, U, C, G.
    • DNA features a double helix structure, while RNA is single-stranded with various functional types including mRNA, rRNA, and tRNA.
    • DNA replication creates duplicates, while mutations signify changes in nucleotide sequences.

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    Description

    This quiz covers the chemical level of organization, focusing on fundamental concepts such as atomic and molecular structure, properties of water, and acid-base chemistry. Please refer to pages 43-57 for detailed information. A review of pages 28-43 is recommended for those needing a refresher.

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