Biology Week 1: Plasma Membrane & Transport
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Questions and Answers

What component is an important structural part of the plasma membrane?

  • Proteins
  • Cholesterol (correct)
  • Carbohydrates
  • Nucleic acids

    • LDL cholesterol is beneficial and does not cause blockages in the arteries.

    False

    What role do double bonds in fatty acids play in the plasma membrane?

    They help maintain membrane fluidity.

    The plasma membrane is _____ to small, non-charged molecules.

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

    Match the following substances with their permeability status regarding the plasma membrane:

    <p>Alcohol = Permeable Lipids = Permeable Small Molecules = Permeable Polar and larger molecules = Impermeable</p> Signup and view all the answers

    What type of hydrocarbon tails are described as viscous?

    <p>Saturated hydrocarbon tails</p> Signup and view all the answers

    Water is not essential for life to persist.

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

    What are the roles of transport proteins in cell membranes?

    <p>They facilitate the movement of substances across the cell membrane.</p> Signup and view all the answers

    In a __________ solution, water concentration is lower than solute concentration.

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

    Which membrane protein helps in recognition during pathogen invasion?

    <p>Recognition protein</p> Signup and view all the answers

    Match the following types of cellular components with their functions:

    <p>Channel proteins = Transport molecules across membranes Carrier proteins = Facilitate diffusion Adhesion proteins = Fasten adjacent cells together Receptor proteins = Receive signaling molecules</p> Signup and view all the answers

    Molecules move from an area of lower solute concentration to an area of higher solute concentration during osmosis.

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

    What happens to plant cells when they lack sufficient water?

    <p>They wilt.</p> Signup and view all the answers

    Which of the following is NOT one of the six steps of bulk transport?

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

    Facilitated transport occurs against the concentration gradient and requires energy.

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

    What are the two types of endocytosis mentioned?

    <p>Phagocytosis and receptor-mediated endocytosis</p> Signup and view all the answers

    Transport vesicles fuse with the __________ membrane to release their contents outside the cell.

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

    Exocytosis primarily transports which of the following?

    <p>Hormones, neurotransmitters, and digestive enzymes</p> Signup and view all the answers

    Match the types of vesicular transport with their descriptions:

    <p>Exocytosis = Transporting molecules out of the cell Phagocytosis = Engulfing large particles or cells Endocytosis = Taking molecules into the cell Receptor-mediated endocytosis = Capturing specific molecules</p> Signup and view all the answers

    What is the characteristic function of receptor-mediated endocytosis?

    <p>Capturing specific molecules</p> Signup and view all the answers

    Name one type of exocytosis.

    <p>Constitutive exocytosis</p> Signup and view all the answers

    What is the primary function of phospholipids in a cell membrane?

    <p>Contribute to fluidity</p> Signup and view all the answers

    Amino acids are the building blocks of carbohydrates.

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

    Name one type of R group that amino acids can have.

    <p>Non-polar and aliphatic R group</p> Signup and view all the answers

    Phospholipids contain a head that includes a __________ group.

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

    Match the following types of R groups of amino acids with their characteristics:

    <p>Non-polar and aliphatic = Hydrophobic Polar and uncharged = Hydrophilic Negatively charged = Acidic Positively charged = Basic</p> Signup and view all the answers

    What characteristic is true of saturated fatty acids?

    <p>They have a straight-chain conformation.</p> Signup and view all the answers

    Waxes are primarily produced by animals to retain moisture.

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

    Name one example of a steroid.

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

    Trans fats are commonly found in _______ foods.

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

    Match the type of lipid with its characteristic:

    <p>Fats and Oils = Glycerol with three fatty acid chains Waxes = Water repellent layers produced by plants Cholesterol = Example of a steroid Trans Fats = Produced from hydrogenation</p> Signup and view all the answers

    What are chylomicrons primarily responsible for?

    <p>Carrying triglycerides from the intestine.</p> Signup and view all the answers

    Unsaturated fatty acids have a straight-chain conformation.

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

    Describe the primary role of lipids in biological systems.

    <p>Energy storage and insulation.</p> Signup and view all the answers

    What is the primary source of sugars for plant cells?

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

    All monosaccharides contain multiple sugar units.

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

    What is the chemical structure of glucose classified as?

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

    _____ is a disaccharide made up of glucose and fructose.

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

    Match the following carbohydrates with their descriptions:

    <p>Glucose = A simple sugar and monomer of carbohydrates Maltose = A disaccharide fermented for alcoholic beverages Lactose = Sugar found in cow’s milk Starch = Primary storage polysaccharide in plants</p> Signup and view all the answers

    Which of the following carbohydrates is a trisaccharide?

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

    Polysaccharides consist of hundreds to thousands of monosaccharide monomers.

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

    What type of sugar is fructose categorized as?

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

    Study Notes

    Week 1

    • Cholesterol is a structural component of the plasma membrane; LDL cholesterol can clog arterial walls.
    • Carbohydrate chains occur on the outside of lipid bilayers or peripheral proteins.
    • Plasma membranes regulate fluidity and provide structural support, consisting of lipids, carbohydrates, and proteins.
    • Molecules embedded in the membrane have double bonds in fatty acids to maintain fluidity.
    • Saturated hydrocarbon tails are viscous, while unsaturated tails have kinks, resulting in fluid structures.
    • Membrane proteins include transporters (channel or carrier), adhesion molecules, and recognition/receptor proteins.

    Permeability of the Plasma Membrane

    • Small, non-charged molecules and alcohol easily pass.
    • Lipids and some small molecules (oxygen, nitrogen, carbon dioxide, and water) are permeable.
    • Polar molecules (glucose, amino acids, nucleic acids) and large molecules are impermeable.

    Cell Transport: Diffusion and Osmosis

    • Water is essential for life.
    • Plants wilt when not watered due to lack of water in their cells.
    • Diffusion is the movement of molecules from high to low concentration.
    • Osmosis is the movement of water from high to low water concentration.

    Tonicity

    • Tonicity refers to the ability of a surrounding solution to cause a cell to gain or lose water based on solute concentration.
    • Isotonic solutions have equal solute concentrations.
    • Hypotonic solutions have lower solute concentration and higher water concentration than the cell.
    • Hypertonic solutions have higher solute concentration and lower water concentration than the cell.

    Cell Transport (Active and Passive)

    • Active transport moves molecules against their concentration gradient (from low to high), requiring energy.
    • Facilitated diffusion assists large molecules to move down their concentration gradient with the help of channel proteins, without requiring energy.

    Week 2: Bulk or Vesicular Transport

    • Vesicles are naturally involved in secretion, uptake, and transport of molecules.
    • Golgi bodies often produce vesicles to transport cell products.
    • Bulk transport involves several steps including budding, scission, uncoating, translocation, tethering, and fusion.
    • Types of vesicle transport include exocytosis (release from the cell) and endocytosis (intake).

    Phagocytosis, Pinocytosis and Receptor-mediated Endocytosis

    • Phagocytosis is a defense and repair mechanism.
    • Pinocytosis involves ingestion of liquids or small particles.
    • Receptor-mediated endocytosis captures specific molecules.

    Week 3: Biomolecules

    • Essential organic molecules, including carbohydrates (sugars), proteins (amino acids), lipids, and nucleic acids, support vital body functions.
    • Carbohydrates are a primary energy source for cells.
    • Excessive carbohydrate consumption can lead to diseases like diabetes and obesity.
    • Sugars like cellulose and chitin are structural molecules.
    • Monosaccharides are simple sugars, like glucose.
    • Disaccharides are two monosaccharides joined together (sucrose, maltose, lactose, raffinose).
    • Polysaccharides are long chains of monosaccharides, like starch, glycogen, cellulose.

    Carbohydrates

    • Carbohydrates have a 1:2:1 ratio of carbon, hydrogen, and oxygen.
    • Photosynthesis is a primary carbohydrate-producing process.
    • Isomers are molecules with the same chemical formula but have a different structure.
    • Glucose, galactose, and fructose are isomers.

    Lipids

    • Lipids are water-insoluble.
    • Triglycerides, phospholipids, and steroids are examples of lipids.
    • Saturated fatty acids have no double bonds; unsaturated fatty acids have one or more, giving them kinks.
    • Phospholipids help contribute to cell membrane fluidity.
    • Steroids maintain structure and participate in regulation.

    Proteins

    • Proteins are made of amino acids.
    • Amino acids contain a central carbon atom with an amino group, a carboxyl group, a hydrogen atom, and an R group.
    • The R group determines the amino acid's properties.
    • There are negatively, positively, and polar/uncharged R groups.

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    Description

    This quiz covers key concepts about the plasma membrane, including its structure and the roles of cholesterol, lipids, and proteins. Additionally, it addresses the permeability of the membrane and the processes of diffusion and osmosis. Test your understanding of these essential biological principles.

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