Biology Quiz: Macromolecules and Cells
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Questions and Answers

Which type of carbohydrate is not considered a reducing sugar?

  • Maltose
  • Lactose
  • Sucrose (correct)
  • Glucose

    • What distinguishes unsaturated fatty acids from saturated fatty acids?

  • Unsaturated fatty acids are solid at room temperature.
  • Unsaturated fatty acids contain C=C double bonds. (correct)
  • Unsaturated fatty acids have more hydrogen atoms.
  • Unsaturated fatty acids are more soluble in water.

    • Which of the following statements about polysaccharides is correct?

  • Polysaccharides are made up of amino acids.
  • Polysaccharides consist of long chains of monosaccharides. (correct)
  • Polysaccharides are formed through hydrolysis reactions.
  • Polysaccharides are always sweet and soluble in water.

    • What is the primary structure of proteins composed of?

    <p>Amino acids</p> Signup and view all the answers

    What characteristic describes the majority of proteins?

    <p>They are globular and compact.</p> Signup and view all the answers

    Phospholipids are critical for which cellular function?

    <p>Cell membrane structure</p> Signup and view all the answers

    Which disaccharide is formed from glucose and galactose?

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

    Which of the following correctly describes triglycerides?

    <p>Contain glycerol and fatty acid chains.</p> Signup and view all the answers

    What effect does increased blood cholesterol levels have on arteries?

    <p>It forms atheroma and can lead to artery blockage.</p> Signup and view all the answers

    What is a distinguishing feature of prokaryotic cells compared to eukaryotic cells?

    <p>Prokaryotic cells lack a nucleus.</p> Signup and view all the answers

    Which factor increases the likelihood of blood clot formation?

    <p>Increased blood turbulence and pressure.</p> Signup and view all the answers

    What microscope is required to view the ultrastructure of a cell?

    <p>Electron microscope.</p> Signup and view all the answers

    How does carbon monoxide affect blood function?

    <p>It decreases the amount of hemoglobin available for oxygen transport.</p> Signup and view all the answers

    What is the role of LDLs in the blood?

    <p>They deposit cholesterol in arteries.</p> Signup and view all the answers

    Which unit conversion factor is used to convert centimeters to millimeters?

    <p>× 10.</p> Signup and view all the answers

    What does the term 'resolution' refer to in microscopy?

    <p>The closeness at which two points can be distinguished.</p> Signup and view all the answers

    What is the primary function of villi and microvilli in the intestinal epithelium?

    <p>To provide a large surface area for absorption</p> Signup and view all the answers

    How does the thin epithelium of the intestine benefit nutrient absorption?

    <p>It minimizes the length of the absorption pathway</p> Signup and view all the answers

    What role does the dense capillary network in the intestinal wall serve?

    <p>It allows for rapid absorption of amino acids and sugars</p> Signup and view all the answers

    What is a key source of energy for active transport in epithelial cells?

    <p>ATP from mitochondria</p> Signup and view all the answers

    What mechanism do carrier proteins in epithelial membranes primarily facilitate?

    <p>Facilitated diffusion of polar molecules</p> Signup and view all the answers

    Which enzyme is responsible for breaking down maltose into glucose?

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

    What is a common consequence of reduced levels of lactase in the digestive system?

    <p>Inability to digest lactose leading to lactose intolerance</p> Signup and view all the answers

    What process drives the movement of food through the digestive system?

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

    Which of the following describes the role of enzymes embedded in the epithelial membrane?

    <p>They promote enzyme-substrate complexes nearby carrier proteins</p> Signup and view all the answers

    How do mitochondria contribute to the function of epithelial cells in the intestine?

    <p>By supplying energy for active transport</p> Signup and view all the answers

    What is the purpose of the pulmonary vein in the circulatory system?

    <p>Carries oxygenated blood to the heart from the lungs</p> Signup and view all the answers

    Why does the left ventricle have a thicker wall compared to the right ventricle?

    <p>It needs to generate a higher pressure to pump blood throughout the whole body</p> Signup and view all the answers

    What occurs when ventricular pressure exceeds atrial pressure?

    <p>Atrioventricular valves shut to prevent backflow</p> Signup and view all the answers

    What does stroke volume refer to in the context of cardiac function?

    <p>The volume of blood pumped with each heartbeat</p> Signup and view all the answers

    How is cardiac output calculated?

    <p>Stroke volume multiplied by heart rate</p> Signup and view all the answers

    What is the first sound in the heartbeat known as?

    <p>Lub sound</p> Signup and view all the answers

    What role does the vena cava play in the circulatory system?

    <p>Returns deoxygenated blood to the right atrium</p> Signup and view all the answers

    Which chamber of the heart contracts to push blood into the pulmonary artery?

    <p>Right ventricle</p> Signup and view all the answers

    What is the actual length of an object magnified by a factor of x1000 if the image length is 40 mm?

    <p>0.04 mm</p> Signup and view all the answers

    Which factor ultimately limits the resolution of a microscope?

    <p>The wavelength of light used</p> Signup and view all the answers

    Which color of light is often used to improve the resolution in microscopy?

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

    What is a stage micrometer used for in microscopy?

    <p>To provide a known scale for measurement</p> Signup and view all the answers

    What type of microscopy utilizes a beam of electrons rather than light to illuminate the specimen?

    <p>Electron Microscopy</p> Signup and view all the answers

    How can the size of a structure seen under a microscope be estimated?

    <p>By comparing it to a known linear scale</p> Signup and view all the answers

    What is the function of a graticule in microscopy?

    <p>To fit inside the eyepiece and provide measurement</p> Signup and view all the answers

    What type of microscopy is most widely used for examining living specimens?

    <p>Light Microscopy</p> Signup and view all the answers

    What is a primary advantage of transmission electron microscopes compared to light microscopes?

    <p>They have a higher resolution due to shorter wavelengths.</p> Signup and view all the answers

    Which of the following is a disadvantage of using a transmission electron microscope?

    <p>Specimen preparation can be complex and time-consuming.</p> Signup and view all the answers

    What aspect of transmission electron microscopes allows for better detail in imaging?

    <p>The short wavelength of electrons.</p> Signup and view all the answers

    Why is it important to calibrate a microscope using a stage micrometer?

    <p>To determine the actual size of the specimens.</p> Signup and view all the answers

    Which of the following describes a common limitation regarding the images produced by transmission electron microscopes?

    <p>They are typically black and white.</p> Signup and view all the answers

    Which factor primarily dictates the resolution capability of a microscope?

    <p>The wavelength of the radiation used for imaging.</p> Signup and view all the answers

    In preparing a specimen for a transmission electron microscope, which step can potentially alter the appearance of the specimen?

    <p>Sectioning and staining the specimen.</p> Signup and view all the answers

    What is a necessary condition for operating a transmission electron microscope effectively?

    <p>Creating a vacuum chamber.</p> Signup and view all the answers

    How can the magnification of an image be determined when using a microscope?

    <p>By using the formula: Image Size/Actual Size of Image.</p> Signup and view all the answers

    What is one reason why transmission electron microscopes can only examine very thin specimens?

    <p>Electrons cannot penetrate thick materials.</p> Signup and view all the answers

    Study Notes

    Unit 1

    • This unit covers the basic building blocks of life, including carbohydrates, lipids, and proteins.

    Carbohydrates

    • Monosaccharides: simple sugars, sweet, water-soluble, reducing agents (except sucrose).
      • Examples include glucose, fructose, and galactose.
    • Disaccharides: formed by two monosaccharides joined by glycosidic bonds.
      • Examples include sucrose (glucose + fructose), lactose (glucose + galactose), and maltose (glucose + glucose).
    • Polysaccharides: long chains of monosaccharides, often used for storage.
      • Examples include starch (storage in plants), glycogen (storage in animals), and cellulose (structural component in plant cell walls).

    Lipids

    • Triglycerides: formed by glycerol and three fatty acids.
      • Fatty acids can be saturated (no double bonds) or unsaturated (double bonds).
      • Fats are insoluble in water.
      • Phospholipids have a phosphate group replacing one fatty acid and are integral to cell membranes due to hydrophillic head and hydrophobic tails.

    Proteins

    • Polymers of amino acids.
    • Amino acids have an amino group, a carboxyl group, and a variable R group.
    • Protein structure:
      • Primary: Linear sequence of amino acids.
      • Secondary: Local folding of the polypeptide chain (alpha helices and beta pleated sheets).
      • Tertiary: 3D structure of the polypeptide due to interactions between R groups.
      • Quaternary: Interactions between multiple polypeptide chains.
    • Functions: Enzymes, hormones, structural components, etc.

    Biochemical Tests

    • Tests can be used to identify specific chemical compounds.
      • Iodine test for starch (blue-black).
      • Benedict's test for reducing sugars (orange-red).
      • Benedict’s + acid + bicarb test for non-reducing sugars (initial green, then orange-red after boiling and neutralizing).
      • Ethanol/water test for lipids (milky emulsion).
      • Biuret test for proteins (purple color).

    Unit 2

    • This unit builds on the foundational biochemistry of unit 1 and examines more complex biological molecules, including DNA, and relates this to the cell cycle and meiosis

    DNA

    • DNA structure: Double helix;
    • Deoxyribose sugar;
    • Phosphate backbone;
    • Four nitrogenous bases (A, T, C, G): adenine with thymine and guanine with cytosine; held together by hydrogen bonds
    • Antiparallel strands.
    • Sequence controls the production of proteins
      • This is called the genetic code;
      • Each triplet of DNA base pairs (codon), defines one amino acid;
    • Semi-conservative replication.

    Cell Cycle

    • Interphase: G1, S, and G2 phases. (growth of cell, DNA replication, and further preparation for cell division respectively) - G1 phase (first gap), is when the cell is active and growing. - S phase (synthesis), is when the cell replicates its DNA - G2 phase (second gap), is when the cell prepares for division.
    • Mitosis/Meiosis: Processes are used for growth, repair, and reproduction

    Meiosis

    • The cell divides twice to produce four haploid daughter cells, half the number of chromosomes of the parent cell
    • Important for sexual reproduction, because it results in genetically different cells.

    Unit 3

    • Cell membranes, transport process, and the principles of homeostasis

    Cell Membranes

    • Phospholipid bilayer (hydrophilic heads, hydrophobic tails)
    • Proteins embedded (transport, receptor)
    • Cholesterol (fluidity)
    • Fluid mosaic model (dynamic nature)

    Transport across Membranes

    • Passive transport: Diffusion, osmosis, and facilitated diffusion (no energy).
    • Active transport: Requires energy (e.g., carrier proteins, pumps).

    Investigating molecules

    • Test for lipids using ethanol and water.
    • Test for proteins using the Biuret test.

    Water potential

    • Water moves from areas of higher to lower water potential.
    • Water potential is affected by the concentration of solutes.

    Osmosis

    • Movement of water across a selectively permeable membrane from a region of high water potential to a region of lower water potential.
    • Osmotic pressure is caused by water tending to enter a solution by osmosis.

    Homeostasis

    • Maintenance of a stable internal environment

    Unit 4

    • This unit focuses primarily on the mammalian circulatory system, respiration, the heart and blood vessels

    The Heart and Blood Vessels

    • Heart structure and function
    • Cardiac cycle( the sequence of events to pump blood)
    • Blood vessels: arteries, veins and capillaries: structure and function
    • Components of blood.

    Respiration

    • Function in gas exchange in the body
    • Mechanisms of gas exchange in animals (eg. lungs).
    • Mechanisms of gas exchange in plants - diffusion though stomates in leaves - gas exchange in insects(tracheoles), in fish(gills), and in mammals(lungs).

    Unit 5

    • This unit focuses on the immune system, defense mechanisms, antibiotics, and how these work in responding to pathogens.

    Defence Mechanisms

    • General defence mechanisms:
      • Skin (physical barrier)
      • Tears, saliva, mucus, stomach acid (chemical barrier)
      • Phagocytosis/macrophages/phagocytes (cellular response)
    • Specific defence mechanisms:
      • Antibody production (B lymphocytes create antibody specific to antigens to form antigen-antibody complex )
      • Cell-mediated responses (T lymphocytes)
    • Vaccination and antibody production: The use of antigens in a vaccine (attenuated/killed, isolated toxins or isolated antigens) will stimulate the adaptive immune response to generate antibodies. There will be faster and greater production of antibodies through future exposures to the same microorganism.

    Antibiotics and Antibiotic Resistance

    • Antibiotics: Chemicals that kill or inhibit the growth of bacteria.
    • Resistance development:
      • Mutations in bacteria (genetic changes)
      • Horizontal gene transfer (transfer of genes between bacteria via plasmids)
      • Overuse of antibiotics (selective pressure)

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    Description

    Test your knowledge on the structure and function of carbohydrates, proteins, and lipids in this comprehensive biology quiz. Explore key concepts such as reducing sugars, fatty acids, and cellular functions to gauge your understanding of biological macromolecules and cellular structures.

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