AP Bio Chapter 6 Objectives
Why use a scanning electron microscope?
2D thin slices of the specimen but have high resolution and magnification.
Name the intercellular junctions found in plant and animal cells and function of each type of junction.
3 main types: tight junctions, desmosomes, and gap junctions.Tight junctions: Plasma membranes of cells that are next to each other are pressed together and bound by specific proteins. Cellular leakage:prevented since continuous seals are made around the cells. (Sweat glands) Desmosomes: (Anchoring junctions) Fasten cells together in sheets. Anchored in the cytoplasms by filaments made of sturdy keratin proteins. Desmosomes: attach muscle cells to one another within a muscle. Gap Junctions: Provide cytoplasmic channels to adjacent cells and consist of membrane proteins that surround a pore where ions, sugars, amino acids, and other small molecules can go through.
Why use a transmission electron microscope?
3D image, high resolution, and have high magnification but pictures in black and white.
Distinguish between amyloplasts, chromoplasts, and chloroplasts.
Amyloplasts: Colorless plastid that stores starch. Chromoplasts: a colored plastid other than a chloroplast, typically containing a yellow or orange pigment provide color to flowers and fruit. Chloroplasts: A plastid that contains chlorophyll and in which photosynthesis takes place.
Describe the structure of a mitochondrion and explain the importance of compartmentalization in mitochondrial function.
Bound by a double membrane (smooth outer and folded inner with spaces in between called cristae) and proteins made by free ribosomes and the ribosomes in it. Has its own unique, maternally inherited DNA that controls the synthesis of the proteins in its membrane. Compartmentalization provides a large surface area that enhances the productivity of the mitochondrion, cellular respiration, ATP, energy production, and provides a unique internal environment for reactions.
3 functional compartments of a chloroplast. Explain the importance of compartmentalization in chloroplast function.
Bound by a double membrane and proteins, made by free ribosomes and ribosomes in it. Has its own unique circular DNA that controls the synthesis of the proteins in the membrane. Has thylakoids (flattened structures of space and membrane), grana (stacks of flattened structures), and stroma (fluid, where DNA is located) Contains green pigment and enzymes that allow for photosynthesis.Compartmentalization provides chloroplasts with more surface area for the enzymes to instigate the reactions required for conversion of light energy to chemical energy, photosynthesis.
Roles of peroxisomes in eukaryotic cells.
Breaks down fatty acids for energy or detoxifying alcohol and other poisons. Oxidation Peroxisomes are specialized metabolic compartments bounded by a single membrane. Peroxisomes produce hydrogen peroxide and convert it to water. Oxygen is used to break down different types of molecules
Ultrastructure of cilia and flagella relate to their functions
Cilia and flagella are constructed like a wheel spoke with two microtubules at the center like the hub of a wheel, and 9 microtubules making up the wheel, connected by spoke-like "arms" made from dynein, which are a motor protein that slide when they come in contact with ATP, which is how cilia and flagella move.
Advantages of compartmentalization in eukaryotic cells
Different environments are provided for the different metabolic functions making it so functions that are incompatible can happen inside a single cell.
3 different kinds of vacuoles and their functions
Food, contractile and central. Food vacuoles contain large food molecules and combine with lysosomes to digest the polymers. Contractile vacuoles pump excess water out of freshwater protists. Central vacuoles occur in plants and contain a solution called cell sap that stores inorganic ions for the plant.
Free Vs. Bound ribosomes (location and function)
Free ribosomes are suspended in the cytosol, and bound ribosomes are attached to the outside of the endoplasmic reticulum. Free ribosomes produce proteins that are used by the cell, while bound ribosomes produce proteins that are transported out of the cell.
Why use a light microscope?
High magnification and cost less but have low resolution.
Structure, monomers, and functions of microtubules, microfilaments, and intermediate filaments.
Hollow tubes of protein about 25 nanometers in diameter, support the cell and moves organelles within the cell. Long, thin fibers that function in the movement and support of the cell and strengthen the cell and help maintain its shape, stabilize the positions of organelles and the position of the cell.
Prokaryotic Vs. Eukaryotic
In a prokaryotic cell, the DNA is concentrated in a non-membrane enclosed region. They tend to be smaller and simpler and don't have any membrane bound structures. (Bacteria and Archaea) In a eukaryotic cell, the DNA is in the nucleus, it has cytoplasm which is the area between the nucleus and the plasma membrane. Also, the organelles have specific functions and the cells themselves are generally larger. (Animal and Plant cells)
Magnification Vs. Resolution
Magnification: Taking a small space and making it larger Resolution: The smallest distance between two points on a specimen that can be defined as two separate entities.
Describe the energy conversions carried out by mitochondria and chloroplasts
Mitochondria : Cellular respiration - Generate ATP by extracting energy from sugar, fats and other fuels with the help of oxygen. Chloroplasts : Photosynthesis - Convert solar energy to chemical energy and synthesize new organic compounds such as sugar from CO2 and H2O.
Evidence that mitochondria and chloroplasts are semiautonomous organelles.
Mitochondria and chloroplasts have little bits of their own DNA. They also grow and reproduce within the cell.
How do extracellular matrix may act to integrate changes inside and outside the cell?
Outside the cell: Makes changes Inside the cell: Sends information
3 examples of intracellular digestion by lysosomes
Phagocytosis is the digestion of macromolecules into smaller monomers. Autophagy is the digestion of damaged organelles to remove them from the cell and recycle them. Pinocytosis brings dissolved molecules into the cell.
Basic structure of a plant cell wall. Primary cell wall, middle lamella, and secondary cell wall.
Protects the plant cell, Maintains shape, and Prevents the excessive uptake of water. Primary wall: relatively thin and flexible. Cellulose fibrils take part in actively growing cells by orienting themselves at right angles to the direction of cell expansion. Middle Lamella: a thin layer full of sticky polysaccharides called pectins (thickens jams) Secondary wall: the strongest and made up of sometimes several layers (wood)
How does the nucleus control protein synthesis in the cytoplasm?
RNA is synthesized from directions given by the DNA which are found as chromosomes in the nucleus. Proteins are imported through the pore structures and are made into proteins by the rRNA. Then the DNA of the nucleus synthesize the mRNA and once its constructed, its then transported to the cytoplasm through the pore structure where the genetic material is translated by ribosomes into the primary stage of a polypeptide.
Structure and role of centrioles and basal bodies
Small, cylindrical parts of the cytoskeleton. Aid in cell division.
Significance of the cis and trans sides of the golgi apparatus
The cis receives and trans ships or delivers. During the transport process from the cis to trans side, products of the ER are modified.
Role of nucleolus in protein synthesis
The condensed region of chromatin is where protein synthesis occurs.
Functions of the cytoskeleton
The cytoskeleton helps to maintain cell shape. The internal movement of cell organelles, as well as cell locomotion and muscle fiber contraction could not take place without the cytoskeleton. The cytoskeleton is an organized network of three primary protein filaments: microtubules, actin filaments, and intermediate fibers.
Components of the endomembrane system, and describe the structure and function of each component
The endomembrane system consists of the nuclear envelope, the endoplasmic reticulum, the Golgi apparatus, lysosomes, and various kinds of vesicles and vacuoles. This system carries out the synthesis of proteins, transport of proteins into membranes and organelles or out of the cell, metabolism and movement of lipids, and detoxification of poisons.
Structure and function of the nuclear envelope and role of the pore complex
The nuclear envelope is a double membrane that encloses the nucleus separating its contents from the cytoplasm. Pore complex lines controls the entry and exit of proteins, RNAs, and macromolecules into the nucleus.
What is cell fractionation? Why is it useful?
The process where cells are blended to break them up and then it's placed in a centrifuge that is spun at different speeds to separate the different cell structures by density. It's useful because it separates the cell parts and makes it easier to study different parts or things associated with those parts.
Upper and lower limits to cell size
The size of the cell is determined by individual cell metabolism capabilities and is the ratio of volume to surface area. Also, prokaryotic cells tend to be smaller than eukaryotic cells.
Structure and functions of smooth VS. rough ER
The smooth ER synthesizes lipids (oils, phospholipids, and steroids) and produces sex hormones in vertebrates. The smooth ER is different from the rough ER because it lacks ribosomes on its surface. Rough ER's main function is to secrete proteins, like insulin, from attached ribosomes and grows by adding proteins and phospholipids to its own membrane.
Cisternal maturation model of golgi function (describe)
The vesicles of the Golgi progress forward from the cis to the trans face, carrying and modifying their cargo as the move
