Unit 1 Test Review
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Questions and Answers

What is the total number of points for the Unit 1 Test?

  • 50 points
  • 30 points
  • 60 points (correct)
  • 40 points

    • Which type of bond is characterized by the complete transfer of electrons?

  • Hydrogen bond
  • Ionic bond (correct)
  • Metallic bond
  • Covalent bond

    • Which of the following represents a polar covalent bond?

  • C-C bond in ethane
  • O-O bond in oxygen gas
  • N-H bond in ammonia (correct)
  • C-H bond in methane

    • What is the primary characteristic of hydrocarbons?

    <p>They only contain carbon and hydrogen.</p> Signup and view all the answers

    What is the primary reason that hydrogen bonds can form between molecules?

    <p>Hydrogen is part of a polar covalent bond.</p> Signup and view all the answers

    Why do fatty acid tails in phospholipids exhibit hydrophobic behavior?

    <p>Electrons are evenly distributed, leading to no net charges.</p> Signup and view all the answers

    What is a characteristic of Van der Waals forces?

    <p>They are due to transient dipoles.</p> Signup and view all the answers

    Which property of water is explained by hydrogen bonding?

    <p>Low density of ice</p> Signup and view all the answers

    How do isomers differ from one another?

    <p>They have the same molecular formula but different structures.</p> Signup and view all the answers

    Why can carbon not form hydrogen bonds?

    <p>Carbon lacks sufficient electronegativity.</p> Signup and view all the answers

    What is a key feature of enantiomers?

    <p>They are mirror images of each other.</p> Signup and view all the answers

    Which of the following accurately describes a characteristic of a compound?

    <p>It is formed from more than one type of atom.</p> Signup and view all the answers

    What determines the specific arrangement of enantiomers?

    <p>Chiral centers where a carbon is bound to four different substituents.</p> Signup and view all the answers

    What impact can the arrangement of a molecule have biologically?

    <p>It can significantly alter the molecule's emergent properties.</p> Signup and view all the answers

    What type of bond joins nucleotides in nucleic acids?

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

    Which nitrogenous base is found in RNA but not in DNA?

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

    What type of isomer maintains the same covalent bonds but has a different spatial arrangement due to double bonds?

    <p>Geometric isomers</p> Signup and view all the answers

    Which statement correctly describes the central dogma of biology?

    <p>DNA → RNA → Protein</p> Signup and view all the answers

    What is a common feature of fatty acids and phospholipids?

    <p>Both can store and release energy.</p> Signup and view all the answers

    What is the main function of transfer RNA (tRNA)?

    <p>Brings amino acids to ribosomes</p> Signup and view all the answers

    How many hydrogen bonds are formed between guanine and cytosine when they bond?

    <p>3</p> Signup and view all the answers

    What significant event marked the increase of oxygen levels in Earth's atmosphere?

    <p>The oxygen revolution</p> Signup and view all the answers

    What does the Miller-Urey experiment demonstrate regarding the origins of life?

    <p>Abiotic synthesis of small organic molecules</p> Signup and view all the answers

    Which process led to the formation of protocells?

    <p>Vesicles formed from lipids</p> Signup and view all the answers

    What characteristic of RNA allows it to act as a self-replicating molecule?

    <p>Ability to bend and form complex shapes</p> Signup and view all the answers

    Which of the following was NOT a consequence of the oxygen revolution?

    <p>Development of multicellular eukaryotes</p> Signup and view all the answers

    What determines the properties of organic molecules?

    <p>The carbon skeleton and the functional group attached</p> Signup and view all the answers

    Which of the following statements is true about saturated fats?

    <p>They are solid at room temperature and have a linear structure</p> Signup and view all the answers

    What is a characteristic of unsaturated fats?

    <p>They contain cis bonds causing kinks</p> Signup and view all the answers

    What type of biological molecule are steroids categorized as?

    <p>4-carbon ring lipids</p> Signup and view all the answers

    What forms a peptide bond between amino acids?

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

    What determines the tertiary structure of a protein?

    <p>Interactions between R-groups</p> Signup and view all the answers

    Which functional groups are present in an amino acid?

    <p>Amino and carboxyl groups</p> Signup and view all the answers

    What is the optimal condition for enzyme activity in our stomach?

    <p>Slightly acidic pH and moderate temperature</p> Signup and view all the answers

    Study Notes

    Test Information

    • Unit 1 Test Review: September 22, 2024
    • Exam Date: September 24, 2024 (In-person)
    • Accounts for 12% of total grade
    • Format: Canvas Quiz featuring 18 multiple-choice questions (1.5 pts each) and 3 free-response questions (total 33 pts)
    • Total exam score: 60 points
    • Proctored via Respondus; practice exam required
    • Exam duration: 60 minutes (9:30 am - 10:30 am)

    Chemistry Basics

    • Element: A substance made of only one type of atom (e.g., Na)
    • Compound: A substance made of more than one type of atom (e.g., NaCl)
    • Covalent Bonds: Formed by sharing valence electrons between non-metals (e.g., CH4 - methane)
      • Non-polar: Equal electron sharing (e.g., C-H bond)
      • Polar: Unequal sharing due to differences in electronegativity
    • Ionic Bonds: Formed by complete transfer of electrons, resulting in ions (e.g., NaCl)

    Intermolecular Forces

    • Van der Waals Forces: Weak attractions due to transient dipoles in molecules
    • Hydrogen Bonds: Formed between hydrogen covalently bound to F, O, or N and similar atoms in another molecule; crucial in water and DNA

    Properties of Water

    • Hydrogen bonding in water facilitates life through:
      • Cohesion: Attraction between water molecules
      • Adhesion: Interaction of water with other substances

    Hydrocarbons and Isomers

    • Hydrocarbons: Organic compounds consisting solely of C and H; significant for energy storage and release (e.g., combustion)
    • Isomers: Molecules with the same formula but different structures and properties
      • Geometric Isomers (Cis/Trans): Same bonds but different spatial arrangements; restricted rotation due to double bonds
      • Enantiomers: Mirror images of each other, significant due to chiral centers (carbon with four different substituents)

    Functional Groups and Lipids

    • Organic molecule properties depend on carbon skeleton and functional groups:
      • Lipids: Not true polymers; consist of smaller units (e.g., fatty acids, glycerol)
      • Types of Lipids:
        • Fats: Formed via ester linkages between glycerol and fatty acids
        • Phospholipids: Composed of 2 fatty acids and a phosphate group
        • Sterols: Four-carbon ring structure (e.g., cholesterol)

    Saturated vs. Unsaturated Fats

    • Saturated Fats: Solid at room temperature; linear structure
    • Unsaturated Fats: Liquid at room temperature; contain kinks from cis bonds

    Proteins

    • Composed of 20 amino acids distinguished by R groups
    • Peptide Bonds: Formed through dehydration synthesis between two amino acids
    • Protein Structure Levels:
      • Primary: Unique amino acid sequence
      • Secondary: Coils and folds in polypeptide chains
      • Tertiary: Interactions among side chains
      • Quaternary: Multiple polypeptide chains together
    • Protein function is shaped by environmental factors such as pH and temperature

    Nucleic Acids

    • Polymers of nucleotides linked by phosphodiester bonds; essential for genetic information
    • Central Dogma: DNA → RNA → Protein
      • DNA stores information; RNA transmits and helps express it; proteins perform cellular functions

    RNA vs. DNA

    • RNA: Single-stranded; contains uracil instead of thymine; ribose sugar
    • DNA: Double-stranded helix; stores genetic material; deoxyribose sugar

    Geological Record and Life's Origin

    • Fossil record exhibits significant extinction events; biased towards long-lived, abundant species
    • Miller-Urey Experiment: Showed abiotic synthesis of organic compounds; small molecules can form macromolecules
    • Cyanobacteria: Contributed to oxygen accumulation through photosynthesis
      • Resulted in the "Oxygen Revolution," allowing for aerobic respiration but also posing risks to early life

    Evolutionary Milestones

    • Evolution from prokaryotes to multicellular eukaryotes involved:
      • Oxygen accumulation enabling aerobic organisms
      • Colonization of land by plants and fungi, followed by animals during the Cambrian Explosion

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    Fall 24 Exam 1 Review PDF

    Description

    Prepare for your Unit 1 Test with this review session. The exam includes multiple-choice and free-response questions, and is worth 12% of your total grade. Make sure to check out the recording on Canvas under the 'Zoom' tab for additional support.

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