Chapter 3
Match the structures from the chapter to the basic physiological themes in the right column and give an example or explanation for each match. A structure may match with more than one theme. a. cell junctions b. cell membrane c. cytoskeleton d. organelles e. cilia 1. communication 2. molecular interactions 3. compartmentation 4. mechanical properties 5. biological energy use
(a) 1 (gap junctions), 2 (tight junction proteins), 4 (strength of desmosomes); (b) 1 (receptors), 2 (enzymes), 3 (barrier), 4 (fluidity), 5 (ATP-dependent transporters); (c) 2 (microtubules direct movement), 4 (strength), 5 (ATP required for actin-myosin interaction); (d) 2 (mRNA binds to ribosomes), 3 (membrane-bounded organelles), 5 (ATP-dependent processes); (e) 2 (microtubules and dynein), 4 (flexibility), 5 (ATP-dependent movement)
Match each protein to its function. Functions in the list may be used more than once. a. cadherin b. CAM c. collagen d. connexin e. elastin f. fibrillin g. fibronectin h. integrin i. occludin 1. membrane protein used to form cell junctions 2. matrix glycoprotein used to anchor cells 3. protein found in gap junctions 4. matrix protein found in connective tissue
(a) 1, (b) 1, (c) 4, (d) 3, (e) 4, (f) 4, (g) 4, (h) 1, (i) 1
Differentiate between the terms in each set below: lumen and wall cytoplasm and cytosol myosin and keratin
(a) lumen—hollow inside of an organ or tube; wall—cell layer. (b) cytoplasm—everything inside the cell except the nucleus; cytosol—semi-gelatinous, intracellular fluid. (c) myosin—motor protein filament; keratin—structural protein fiber.
Define cytoskeleton. List five functions of the cytoskeleton.
A flexible, changeable, three-dimensional scaffold of actin, microfilaments, intermediate filaments, and microtubules. Functions: mechanical strength stabilize position of organelles transport material link cells together movement.
List, compare, and contrast the three types of cell junctions and their subtypes. Give an example of where each type can be found in the body and describe its function in that location.
Anchoring junctions (skin)—allow twisting and stretching of tissue. Tight junctions (epithelia)—prevent movement of materials between cells. Gap junctions (some muscles)—allow material to pass directly from cytoplasm of one cell to another.
When a tadpole turns into a frog, its tail shrinks and is reabsorbed. Is this an example of necrosis or apoptosis? Defend your answer.
Apoptosis—it is a normal part of development.
List the four general functions of the cell membrane.
Barrier between cell and ECF; regulate exchange of material between cell and ECF; transfer information between the cell and other cells; provide structural support. barrier transfer mat transfer info structure
Compare and contrast the structure, locations, and functions of bone and cartilage.
Bone is rigid due to calcification; cartilage is firm but elastic. Bones are the primary support structure for the body; cartilage forms the ear, nose, larynx, and spine and helps hold bones together at the joints.
Explain how inserting cholesterol into the phospholipid bilayer of the cell membrane decreases membrane permeability.
Cholesterol molecules fill space between phospholipid tails.
One result of cigarette smoking is paralysis of the cilia that line the respiratory passageways. What function do these cilia serve? Based on what you have read in this chapter, why is it harmful when they no longer beat? What health problems would you expect to arise? How does this explain the hacking cough common among smokers?
Cilia sweep mucus and particles up and out of the airways. When they fail, inhaled pathogens are more likely to reach the lungs, resulting in infections, inflammation, or cancer. The smoker's cough removes the mucus that would normally be swept away by the cilia.
Define and distinguish between inclusions and organelles. Give an example of each.
Inclusions: particles of insoluble material, such as glycogen and ribosomes. Organelles, such as mitochondria and Golgi apparatus, are separated from cytosol by membranes.
What might happen to normal physiological function if matrix metalloproteinases are inhibited by drugs?
MMPs are enzymes that dissolve the extracellular matrix, so blocking them might inhibit tissue growth and repair.
Cancer is abnormal, uncontrolled cell division. What property of epithelial tissues might (and does) make them more prone to developing cancer?
Many epithelia are vulnerable to damage and need to be replaced frequently. Cells undergoing frequent mitosis are more likely to develop abnormal cell division.
Which would have more rough endoplasmic reticulum: pancreatic cells that manufacture the protein hormone insulin, or adrenal cortex cells that synthesize the steroid hormone cortisol?
Rough ER is where proteins are made, so pancreatic cells would have more.
Sketch a short series of columnar epithelial cells. Label the apical and basolateral borders of the cells. Briefly explain the different kinds of junctions found on these cells.
See fig Tight junctions prevent movement of material between cells; leaky junctions allow some material to pass between cells.
Explain why a stratified epithelium offers more protection than a simple epithelium.
Stratified has many cell layers for protection; simple epithelium has only one layer.
In some instances, the extracellular matrix can be quite rigid. How might developing and expanding tissues cope with a rigid matrix to make space for themselves?
The matrix can be broken down, then reassembled.
A number of organelles can be considered vesicles. Define vesicle and describe at least three examples.
Vesicles—membranous spheres. Examples: lysosomes, peroxisomes, secretory vesicles.
Match each term with the description that fits it best: a. cilia b. centriole c. flagellum d. centrosome 1. in human cells, appears as single, long, whiplike tail 2. short, hairlike structures that beat to produce currents in fluids 3. a bundle of microtubules that aid in mitosis 4. the microtubule-organizing center
a. 2 b. 3 c. 1 d. 4
Match each organelle with its function: a. endoplasmic reticulum b. Golgi apparatus c. lysosome d. mitochondrion e. peroxisome 1. powerhouse of the cell where most ATP is produced 2. degrades long-chain fatty acids and toxic foreign molecules 3. network of membranous tubules that synthesize biomolecules 4. digestive system of cell, degrading or recycling components 5. modifies and packages proteins into vesicles
a. 3 b. 5 c. 4 d. 1 e. 2
List the four major tissue types. Give an example and location of each.
connective tissue (tendons that hold muscles to bones); epithelium (skin); neural tissue (the brain); and muscular tissue (heart and skeletal muscles)
______ glands release hormones, which enter the blood and regulate the activities of organs or systems.
endocrine
Arrange the following compartments in the order a glucose molecule entering the body at the intestine would encounter them: interstitial fluid, plasma, intracellular fluid. Which of these fluid compartments is/are considered extracellular fluid(s)?
intracellular fluid; interstitial fluid; plasma. Interstitial fluid and plasma are ECF.
The term matrix can be used in reference to an organelle or to tissues. Compare the meanings of the term in these two contexts
mitochondrial matrix—the internal compartment; tissue matrix—noncellular material found outside cells
What are the two primary types of biomolecules found in the cell membrane?
phospholipids and proteins
In 1972, Singer and Nicolson proposed the fluid mosaic model of the cell membrane. According to this model, the membrane is composed of a bilayer of _____ and a variety of _____embedded , with ______on the extracellular surface.
phospholipids; proteins; carbohydrates
Mapping exercise: Transform this list of terms into a map of cell structure. Add functions where appropriate.
see fig
Exocrine glands produce watery secretions (such as tears or sweat) called _____ secretions, or stickier solutions called ________ secretions.
serous; mucous
The largest and heaviest organ in the body is the .
skin
What types of glands can be found within the skin? Name the secretion of each type.
sweat glands—sweat; apocrine glands—waxy or milky secretions; sebaceous glands—a mixture of lipids
What process activates the enzymes inside lysosomes?
very acidic conditions