Biology Chapter 2 Quiz
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Questions and Answers

What is the primary reason for the Earth's habitability?

  • The presence of a diverse range of life forms
  • The presence of a protective atmosphere
  • The ideal distance from the sun
  • The abundance of liquid water (correct)

    • What is the chemical formula for Aspartic acid?

  • CO2
  • C4H7NO4 (correct)
  • NH2CH(CH2COOH)COOH
  • H2O

    • Which of these is NOT an emergent property of water?

  • Moderation of Temperature
  • Expansion upon freezing
  • Cohesion/Adhesion
  • Ability to form covalent bonds (correct)

    • What is the main characteristic of carbon that makes it so important for life?

    <p>It has four valence electrons, allowing for diverse bond formations (C)</p> Signup and view all the answers

    Which of the following molecules are NOT composed of carbon compounds?

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

    What is the approximate percentage of water within a typical cell?

    <p>70-95% (D)</p> Signup and view all the answers

    What is the significance of the pH of water within living systems?

    <p>It affects the activity of enzymes (D)</p> Signup and view all the answers

    What is the main factor contributing to the emergent properties of water?

    <p>Its ability to form hydrogen bonds (A)</p> Signup and view all the answers

    Which of the following elements are NOT among the four that make up 96% of living matter?

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

    Which of the following is NOT a class of biological macromolecule?

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

    What is the name of the bond formed when two atoms share electrons?

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

    What type of bond is responsible for the high specific heat of water?

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

    Which of the following statements about polymers is TRUE?

    <p>Polymers are made up of small, repeating units called monomers. (D)</p> Signup and view all the answers

    What is the difference between a cation and an anion?

    <p>A cation is a positively charged ion, while an anion is a negatively charged ion. (D)</p> Signup and view all the answers

    Which of the following is NOT a property of water?

    <p>High specific mass (B)</p> Signup and view all the answers

    Which of the following is NOT a major element found in living organisms?

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

    What type of bond links monosaccharides together?

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

    What is the structural polysaccharide found in fungi?

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

    Which type of glycosidic linkage is found in amylose?

    <p>α-1,4-glycosidic linkage (D)</p> Signup and view all the answers

    What is the main difference between the Fischer and Haworth projections of carbohydrates?

    <p>The Fischer projection shows the linear form of the sugar, while the Haworth projection shows the ring form. (C)</p> Signup and view all the answers

    Where do plants store starch?

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

    Which of the following is a disaccharide?

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

    What is the main function of glycogen in animals?

    <p>Energy storage (A)</p> Signup and view all the answers

    What type of linkage is found in lactose?

    <p>β-1,4-glycosidic linkage (C)</p> Signup and view all the answers

    What distinguishes a hydrophobic amino acid from a hydrophilic amino acid?

    <p>Hydrophobic amino acids have a non-polar R group, while hydrophilic amino acids have a polar R group. (A)</p> Signup and view all the answers

    Which of the following statements accurately describes the type of bond that connects amino acids in a protein chain?

    <p>Peptide bonds form between the carboxyl group of one amino acid and the amino group of the next. (D)</p> Signup and view all the answers

    What is the significance of the amino (N) and carboxyl (C) termini in a protein chain?

    <p>They represent opposite ends of the polypeptide chain, providing directionality. (C)</p> Signup and view all the answers

    Which amino acid is known to introduce a kink into a protein structure?

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

    What type of bond is responsible for forming a disulfide bridge between two cysteine residues in a protein?

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

    Which statement accurately describes the primary structure of a protein?

    <p>The linear sequence of amino acids in the polypeptide chain. (D)</p> Signup and view all the answers

    How do amino acids contribute to the overall structure and function of a protein?

    <p>Each amino acid has a unique R group that contributes to the overall shape and function of the protein. (D)</p> Signup and view all the answers

    Why are some amino acids considered essential?

    <p>They cannot be synthesized by the body and must be obtained from the diet. (B)</p> Signup and view all the answers

    What is the primary process described for synthesizing a polymer?

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

    Which of the following best describes hydrolysis?

    <p>A process that adds water to break down polymers (A)</p> Signup and view all the answers

    Which macromolecule is generally not considered a true polymer?

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

    What is the ratio of hydrogen to oxygen to carbon in simple sugars?

    <p>1 : 2 : 1 (D)</p> Signup and view all the answers

    What is the general term for the single units that make up polymers?

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

    Which of the following is NOT a type of biological macromolecule mentioned?

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

    Simple sugars are primarily used by organisms for which purpose?

    <p>Energy source for metabolism (D)</p> Signup and view all the answers

    In the synthesis of a longer polymer from unlinked monomers, what is removed during the dehydration reaction?

    <p>A water molecule (D)</p> Signup and view all the answers

    What distinguishes prions from other types of pathogens?

    <p>Prions are misfolded proteins without DNA or RNA. (D)</p> Signup and view all the answers

    Which of the following diseases is associated with prion pathogens?

    <p>Creutzfeldt-Jakob disease (B)</p> Signup and view all the answers

    How do prions propagate within a healthy organism?

    <p>By inducing the misfolding of properly folded proteins (B)</p> Signup and view all the answers

    Which of the following best describes proteins in biological systems?

    <p>Composed of amino acid subunits with varied functions. (B)</p> Signup and view all the answers

    What is a common feature of the diseases caused by prions?

    <p>They lead to the accumulation of misfolded proteins in tissues. (D)</p> Signup and view all the answers

    Study Notes

    Biology 1 - Cells, Molecular Biology and Genetics (BIOL 1000)

    • This is a course on cells, molecular biology, and genetics, taught by Dr. Michael Cardinal-Aucoin during Winter 2025 at York University.
    • Students are expected to know about proteins, carbohydrates, lipids, and nucleic acids consumed as breakfast.
    • The course will cover the building blocks of life including chemistry of life, biological macromolecules, polymers, carbohydrates, lipids, proteins, and nucleic acids.

    Review Chapter 2

    • Building Blocks: Matter, element, atom, neutron, proton, electron, nucleus, atomic mass, atomic number, isotope, valence electron, ion (cation, anion)
    • Bonds: Ionic, covalent (non-polar, polar), electronegativity, hydrogen, van der Waals forces
    • Chemical Reactions: Reactants, products, reversible, equilibrium, specificity, properties of water (polarity, cohesion, adhesion, high specific heat), functional groups

    The Molecules of Life

    • All cells are made of four classes of biological macromolecules: carbohydrates, lipids, nucleic acids, and proteins.
    • All these macromolecules have a carbon skeleton.
    • The macromolecules have a wide variety of ways to be built and combined.

    The Chemistry of Life

    • 20-25% of 92 elements are crucial for life.
    • Approximately 96% of living material is made up of carbon, hydrogen, oxygen, and nitrogen.
    • Other elements like calcium, phosphorus, potassium, sulfur, sodium, chlorine, and magnesium make up the remaining 4%.

    Table 2.1 Elements in the Human Body (Summary)

    • Oxygen is the most abundant element in the human body (65%).
    • Other percentages of elements listed for the human body, including water.

    Water and Life

    • Water is the biological medium on Earth, crucial for life's evolution.
    • All living things need water more than any other substance.
    • Most cells are surrounded by water, making up 70-95% of a cell's composition.
    • Cells are essentially bags of molecules dissolved in water, and the availability of liquid water makes Earth habitable.

    Summary

    • The four emergent properties of water (expansion upon freezing, cohesion/adhesion, moderation of temperature, and versatility as a solvent) are mainly due to its polarity and formation of hydrogen bonds; important for life on Earth.
    • The pH of water is tightly regulated in living systems.

    The Backbone of Life

    • Living things are mainly composed of carbon-based compounds.
    • Carbon's ability to form complex and diverse molecules makes it a key component of life and abundant in the cosmos.
    • Proteins, DNA, carbohydrates, and other molecules that differentiate living matter are all built from carbon compounds.

    A Note about Formulae

    • Aspartic acid is an amino acid, a building block of proteins.
    • Chemical formula (C4H7NO4)
    • Condensed structural formula (NH2CH(CH2COOH)COOH)
    • A visual representation of its structure showing the bonds and atoms.

    Diversity of chemical functional groups constructed with carbon.

    • Various chemical groups commonly connected to carbon atoms are mentioned, along with their properties.

    The Molecules of Life (Summary)

    • Carbohydrates: provide energy and support structural components.
    • Lipids: make up cell membranes, store energy, and serve as signaling molecules.
    • Nucleic acids: store and transmit genetic information.
    • Proteins: provide structural support and act as catalysts (enzymes) in chemical reactions.

    Polymers (Summary)

    • Most biological macromolecules are polymers, made from repeating units called monomers.
    • Proteins, for instance, are made of monomers, amino acids.
    • Polymers are assembled and disassembled through dehydration and hydrolysis reactions respectively.

    Carbohydrates

    • Simple sugars have a 1:2:1 C:H:O ratio (CH2O), making them essential energy sources for many life forms.
    • Examples: glucose, fructose, ribose, etc.
    • Monosaccharides differ based on carbon number (triose, tetrose, pentose, hexose) and C=O position (aldose, ketose).
    • Numerous structural variations exist in carbohydrate polymers formed from these monomers.
    • Glycosidic bonds link monosaccharides to create disaccharides and polysaccharides such as starch, glycogen, and cellulose.

    Disaccharides

    • Disaccharides comprise two monosaccharides linked together via glycosidic bonds.
    • Important examples include sucrose (glucose + fructose), lactose (glucose + galactose), and maltose (glucose + glucose).
    • Disaccharides have crucial roles in the transport and storage of sugars within organisms.

    Polysaccharides

    • Polysaccharides consist of long linked monosaccharide chains.
    • Common examples are starch, glycogen, and cellulose.
    • Starch (amylose and amylopectin) in plants along with glycogen in animals and fungi, serve as energy storage molecules.
    • Cellulose in plants provides structural support, while chitin plays a similar role in fungi.

    Lipids

    • Lipids differ from proteins, nucleic acids, and carbohydrates since the units aren't repeating monomers.
    • Lipids are hydrophobic.
    • Important lipid types include neutral fats (or triglycerides), phospholipids (crucial membrane constituents), and steroids (for hormones and membranes).
    • Neutral fats are for energy storage, insulation, protection of internal organs.
    • Phospholipids form cell membranes.
    • Steroids are hormones and components of membranes

    Nucleic Acids

    • Nucleic acids are made of nucleotides composed of a nitrogenous base, a pentose (5-carbon sugar), and a phosphate group.
    • Nucleotides are linked together by phosphodiester bonds during dehydration synthesis creating a chain.
    • DNA stores hereditary information in a double helix.
    • RNA carries information from DNA and plays a role in protein synthesis.
    • The Central Dogma describes DNA instructions being transformed into proteins with the aid of mRNA

    Proteins

    • Proteins are polypeptides or polymers formed by amino acid subunits.
    • Important protein functions include catalysis (enzymes), defense (antibodies), transport (hemoglobin), storage (ovalbumin) and movement.
    • Protein functions are related to their structures.
    • Different protein structures include (Primary, Secondary, Tertiary, and Quaternary).

    Denaturation

    • The tertiary structure of a protein determines its function.
    • Proteins can be denatured or disrupted through high temperatures or chemical treatments, causing a loss of function.

    Quaternary Structure

    • Some proteins consist of multiple polypeptide chains, forming a quaternary structure.

    • Hemoglobin in red blood cells, a good example, is composed of four subunits (2α and 2β).

    Proteins

    • Some amino acids are essential, meaning they must be obtained from diet.

    Summary

    • The course will touch on the various aspects of the chemistry of life, covering polymers (carbohydrates, lipids, nucleic acids, and proteins), summarizing each class's structure, function, and importance.

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    Biology 1 – Cells, Molecular Biology and Genetics (Biol 1000) Winter 2025 PDF

    Description

    Test your knowledge on the fundamental principles of biology and the chemistry of life with this quiz on Chapter 2. Questions cover topics such as water's properties, carbon's role in life, and chemical bonding. Perfect for students looking to assess their understanding of essential biological concepts.

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