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Cell Structures and Processes

This information for this unit of work is found in chapters 1, 2, 5, and 18 of Biology: The Study of Life.

Chapter 1

1)    Explain each of the following terms as they apply to life processes: nutriton, transport, respiration, synthesis and assimilation, growth, excretion, regulation, reproduction, and metabolism.

Chapter 2

2)    Explain the difference between magnification and resolution.

3)    Explain the terms fixation, embedding, sectioning and staining.

Chapter 5

4)    Summarize the three points of cell theory.

5)    Describe the structure and function of the following cellular components:  cell wall, cell membrane, nucleus, nucleus membrane, nucleoplasm, nucleolus, chromatin, cytoplasm, endoplasmic reticulum, ribosome, golgi apparatus, lysosome, mitochondrion, microtubules and microfilaments, centriole, cilia and flagella, vacuole, chloroplast and plastids.

6)    Differentiate between cells, tissues, organs and systems.

7)    Explain and give the function for: epithelial, connective (bone and cartilage, blood), muscle and nervous tissue in animals and meristem, parenchyma, xylem and phloem tissue in plants (Chap. 19, page 298-300).

8)    Explain the terms: solution, solute, solvent, isotonic, hypotonic, and hypertonic.

9)    Describe and give examples of the cell processes of: diffusion, osmosis, plasmolysis, active transport, endocytosis and exocytosis.

10)    Explain how materials move in and out of cells based on concentration gradient.

11)    Give word equations for aerobic and anaerobic respiration.

Answers

1) Nutrition - The process by which materials from the environment are taken into an organism and changed into usable forms.

        Transport - All the processes by which substances pass into or out of cells and circulate within the organism.

        Respiration - The process by which orangisms obtain the energy they need by releasing chemical energy stored in nutrients.
 

        Synthesis - A process in which simple substances are conbined chemically to form more complex substances.
 
        Assimilation - The incorporation of materials into the body of an oragnism.
 
        Growth - The process by which living organisms increase regulates the opening and closing of the stomates.
 
        Excretion - The process by which the wastes of cellular metabolism are removed from an organism.

        Regulation - The processes by which an organism maintains a stable internal environment in a constantly changing external environment.

        Reproduction - The process by which living things produce new organisms of their own kind.

        Metabolism - All the chemical reactions of the life processes of an organism.

(glossary of terms)

2)       Magnification refers to enlargement in one direction, such as length, not a change in area or "size."

       Resolution refers to the sharpness of an image.  If a small, blurred dot is magnified without increasing the resolution, the view will just be a big, blurred dot.
(page 16-17)

3)    Most biological materials are too thick to allow the passage of light.  For this reason they must first be fixed, embedded, and then sliced into thin sections.  Fixation is done by first cutting the material into relatively small pieces, and then allowing it to soak in a fixative, such as formalin.  The fixed material is then embedded in liquid wax or plastic, which is allowed to harden.  The wax or plastic holds the material in place so that it can be sliced, or sectionedStaining allows us to see biological specimens with compound microscopes in greater detail.
(page 17-18)

4)    Cell theory:

(page 67-68)

5) Cell Wall - Is composed of cellulose, gives shape and protection to cell (page70) see fig 5-4 page 70

        Cell Membrane - is composed of a phospholipid bilayer with protein molecules embedded in them, it separates the cell from the surrounding environment and controls the movement of materials into and out of the cell. (page 70-71) see fig 5-5 page 71

        Nucleus - Is a round, dense body surrounded by a double membrane that serves as the control centre for cell metabolism and reproduction.  (page 72) see fig 5-6 page 72

        Nuclear Membrane - Is composed of a phospholipid bilayer with well-defined pores, it allows certain chemicals to pass into the nucleus while others not to.  (page 72)

        Nucleoplasm - Much of the Nucleoplasm consists of chromatin, the chromatin are involved in cell division.  (page 72)

        Nucleolus - A dense, granular body that is found in the nucleus of cells and that is a site of RNA production. (glossary)

        Cytoplasm - Is all the material in the cell between the cell membrane and the nucleus.  It is very watery.  It provides for a place in which chemical reactions can take place.  (page 73)

        Endoplasmic Reticulum - Consists of a system of fluid-filled canals or channels enclosed by membranes.  These serve as a path for transport of materials through the cell.  It is like a tunnel for cars.  (page 73)

        Ribosome - Are the site of protein systhesis in the cell.  (page 74)

        Golgi Apparatus - Consist of a stack of membranes forming flattened sacs and small spherical sacs, or vesicles.  It also serves as processing, packaging, and storage centres for the secretory products of the cell.  (page 74)

        Lysosomes - Small, saclike structures surrounded by a single membrane, they contain strong digestive, or hydrolytic enzymes.  Lysosomes break down worn-out cell organelles, defense against disease in some animals.  (page 74)

        Mitochondria - Round or slipper shaped organelles (see fig 5-10 page 75) surounded by two membrane.  This is the place where cell respiration takes place. (page 75)

 

6)      A cell is the smallest living thing.  Many similar cells make up tissue.  Many heart cells make up heart tissue.  A system is comprised of many different kinds of tissue that serve for one common purpose such as blood transportation.  In blood transportation there is heart tissue, artery tissue and vien tissue involved in the system.

(glossary of terms page 729)

7)

8)  Solution - A mixture, usually liquid, in which one substance, in the form of molecules or ions, is uniformly (evenly) distributed (mixed, dissolved) through another substance.    (glossary)

        Solute - A substance that is dissolved in water.    (glossary)

        Solvent - The liquid substance that makes up the bulk of a solution.  The most common solvent is water.    (glossary)

        Isotonic solution- This is when the concentration of solute is the same on the inside of the cell as on the outside.    (page 82)

        Hypertonic solution - This is when the concentration of solute in the solution is higher than the concentration of solute inside the cell.  Hyper means higher.    (page 83)

        Hypotonic - This is when the concentration of solute in the solution is lower than the concentration of solute inside the cell.  Hypo means lower.  Think of hypothermia.    (page 82)

9) Diffusion - is the movement of molecules or particles from an area of greater concentration to an area of lesser concentration.  Diffusion occurs simply because the molecules are in constant random motion.    (page 80)

        Osmosis - is the diffusion of water across a semipermeable membrane from a region of high concentration of water to a region of low concentration of water.  It is simply the diffusion of water.  This takes place because water molecules are very small and are constantly in motion.

        Plasmolysis - is the shrinking of cytoplasm by osmosis.  This can occurr when a cell is placed in a hypertonic solution and water flows out of the cell due to osmosis, this causes the cell to shrink.

        Active Transport - is the process that takes place when movement of materials across a cell membrane requires the expenditure of cellular energy.  This usually involves the movement of materials against a concentration gradient, that is, from a low concentration of that particular material to a high concentration of that particular material.

        Endocytosis - is active transport that brings material into the cell.

        Exocytosis - is active transport that takes material out of the cell.

10)    A concentration gradient is when there is a difference in the concentration of a certain chemical inside the cell than outside the cell.  The process of diffusion says that molecules will arange themselves in such a way to use up all the space possible.  If the concentration of that chemical is higher outside the cell than inside the cell, the chemical will move into the cell to use up all available space.  Think what would happen if many people were on an elevator during a hot summer day.  When the door opens everyone will rush out and away from each other to use up all the available space.

11)    Aerobic Respiration
            Glucose + 6 Oxygen produces 6 Carbon Dioxide + 6 Water + 36 ATP
            (page 119)

            Anaerobic Respiration
            Glucose produces Lactic Acid (in muscle cells) + 2 Carbon Dioxide
            (page 115)

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