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140 Cards in this Set
- Front
- Back
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What is the term that describes the scientific study of cells?
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Cytology --> began when Robert Hooke coined the word "cellulae" to describe empty cell walls of cork
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Which scientist concluded that all animal tissues are made of cells?
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Theodor Schwann
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Which scientist established beyond any reasonable doubt that "cells arise only from other cells"?
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Louis Pasteur
"Cells arise only from other cells" refutes the idea of spontaneous generation, which states that living things arise from nonliving matter. |
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All organisms are composed of __________.
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cells
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Which structural and functional properties of living organisms are cells responsible for?
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workings of the human body
mechanisms of disease rationale of therapy |
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Humans are _________-cell organisms.
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single
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List the 5 tenets of the modern cell theory.
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1) All organisms are composed of cells and cell products.
2) The cell is the simplest structural and functional unit of life. 3) An organism's structure and functions are due to the activities of its cells. 4) Cells come only from preexisting cells, not from nonliving matter. 5) Cells of all species have many fundamental similarities in their chemical composition and metabolic mechanisms. |
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Which type of cell can be described as thin and flat with a nucleus creating bulge?
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squamous
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Which type of cell can be described as a irregularly angular shape with four or more sides?
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polygonal
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Which type of cell can be described as a starlike shape?
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stellate
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Which type of cell can be described as squarish and about as tall as is wide?
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cuboidal
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Which type of cell can be described as taller than wide?
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columnar
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Which type of cell can be described as round to oval?
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spheroid to ovoid
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Which type of cell can be described as disc-shaped?
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discoid
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Which type of cell can be described as thick in the middle, tapered toward the ends?
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fusiform
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Which type of cell can be described as a threadlike shape?
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fibrous
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What is the normal human cell size? egg cells? nerve cells?
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human cells: most from 10-15 micrometers (µm) in diameter
egg cells: very large 100 µm diameter (barely visible to the naked eye) nerve cell: 1 meter long (longest human cell; too slender to be seen with the naked eye) |
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_______________ increases volume more than surface area.
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Cell growth
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Surface area of a cell is proportional to the ____________ of its diameter.
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square
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Volume of a cell is proportional to the ___________ of its diameter.
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cube
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What is the fluid between the nucleus and surface membrane called?
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cytoplasm
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What basic components of the cell are revealed under a light microscope?
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plasma membrane, nucleus, and cytoplasm
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What basic components of the cell are revealed by resolution (ability to reveal detail)?
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ultrastructure = organelles, cytoskeleton, and cytosol (ICF)
Increased resolution reveals the finer details. |
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Which basic component of the cell is made of proteins and lipids, surrounds the cell, and defines boundaries?
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plasma (cell) membrane
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Which basic component of the cell consists of organelles, cytoskeleton, and cytosol (intracellular fluid, ICF)?
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cytoplasm
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What is the fluid outside of the cell?
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extracellular fluid (ECF)
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What is the difference between cytoplasm and cytosol?
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cytoplasm has things suspended in it
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Which side of the plasma membrane faces the cytoplasm?
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intracellular face
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Which side of the plasma membrane faces outward?
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extracellular face
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Which component of the plasma membrane forms the bored of the cell and many of its organelles?
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unit membrane
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98% of molecules in the plasma membrane are _________.
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lipids
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Phospholipids are amphiphilic. Explain this.
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Hydrophilic phosphate heads face water on each side of the membrane.
Hydrophobic tails are directed toward the center, avoiding water. |
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75% of the lipids in the membrane are _______________.
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phospholipids
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Which lipid holds phospholipids still and can stiffen membrane?
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Cholesterol --> 20% of the membrane lipids
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Which lipid contributes to glycocalyx--carbohydrate coating on the cell surface?
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glycolipids --> 5% of the membrane lipids
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Which proteins pass through the membrane, have hydrophilic regions in contact with cytoplasm and extracellular fluid, and have hydrophobic regions that pass back and forth through the lipid of the membrane?
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transmembrane proteins
Most transmembrane proteins are glycoproteins. |
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Which proteins adhere to one face of the membrane and are usually tethered to the cytoskeleton?
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peripheral proteins
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How do receptors communicate?
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through chemical signals
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What are surface proteins on the plasma membrane of the target cell?
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receptors
Receptors are usually specific for one substrate. |
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What are some functions of proteins?
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receptors
second-messenger systems enzymes ion channels carriers cell-identity markers cell-adhesion molecules |
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How are second-messenger systems initiated?
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The messenger (chemical) binds to a surface receptor, which triggers changes within the cell that produce a second messenger in the cytoplasm.
involves transmembrane proteins and peripheral proteins |
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Which component in the plasma membrane carries out final stages of starch and protein digestion in the small intestine?
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enzymes
Enzymes also help produce second messengers (cAMP). |
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What are transmembrane proteins with pores that allow water and dissolved ions to pass through the membrane called?
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channel proteins
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How do gated channels function?
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open and close in response to stimuli
ligand (chemically)-regulated gates voltage-regulated gates mechanically regulated gates (stretch and pressure) |
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What is consumed by pumps in the process of transmembrane proteins transferring glucose, electrolytes, and other solutes across the membrane?
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ATP
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Which membrane protein acts like a cell's "identification tag"?
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Glycoproteins --> enables our bodies to identify which cells belong to it and which are foreign invaders
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What is the role of cell-adhesion molecules (CAMs)? Why is this important?
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adhere cells to each other and to extracellular material
Cells do not grow or survive normally unless they are mechanically linked to the extracellular material. (binding of an immune cell to a cancer cell requires CAMs) |
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Explain the process of second messengers.
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Chemical first receptor (epinephrine) binds to a surface receptor, which triggers changes within the cell that produce a second messenger in the cytoplasm.
Receptor activates G protein G protein relays signal to adenylate cyclase, which converts ATP to cAMP (second messenger) cAMP activate a kinase in the cytosol Kinases add phosphate group to other cellular enzymes, activating enzymes and inactivating others while triggering a wide variety of physiological changes in cells. |
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What is the unique fuzzy coat external to the plasma membrane called?
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glycocalyx --> carbohydrate moieties of membrane glycoproteins and glycolipids
unique and everyone but identical twins |
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What are the functions of the glycocalyx?
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protection
immunity to infection defense against cancer transplant compatibility cell adhesion fertilization embryonic development |
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Which component of the membrane serves to increase cell's surface area for absorption?
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microvilli --> gives 15-40 times more absorptive surface area
On some cells they are very dense and appear as a fringe-- "brush border" |
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What shortens microvilli?
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actin filaments --> this pushes absorbed contents down into the cell
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What are hairlike processes 7-10 µm long which act as "antenna" for monitoring nearby conditions?
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cilia --> nonmotile primary cilium found on nearly every cell
sensory in inner ear, retina, nasal cavity, and kidney |
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Where are motile cilia found?
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respiratory tract, uterine tubes, ventricles of the brain, efferent ductules of testes --> power stroke
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What is the core of the cilia that is the structural basis for ciliary movement called?
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axoneme
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Describe the structure of the axoneme.
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has 9 + 2 structure of microtubules
9 pairs from basal body inside the cell membrane--> anchors cilium dyneim arms "crawl" up adjacent microtubule, bending the cilia saline layer - chloride pumps Cl- into ECF, Na+ and H2O follow The cilia beat freely in saline layer. |
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What is the hereditary diseases in which cells make chloride pumps, but fail to install them in the plasma membrane?
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cystic fibrosis
Thick mucus plugs pancreatic ducts and respiratory tracts. |
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What is the whiplike structure with axoneme identical to cilium that is the tail of a sperm?
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flagella --> only functional flagellum
No power stroke or recovery stroke as in cilia! |
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What is the barrier and gateway between the cytoplasm and ECF?
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plasma membrane
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Describe passive transport mechanisms.
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require no ATP --> random molecular motion of particles provides the necessary energy
filtration, diffusion, osmosis |
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Describe active transport mechanisms.
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consumes ATP
active transport and vesicular transport |
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Describe carrier-mediated mechanisms.
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use a membrane protein to transport substances from one side of the membrane to the other
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What is the process in which particles are driven through a selectively permeable membrane by hydrostatic pressure?
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filtration
hydrostatic pressure = force exerted on a membrane by water |
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What is the net movement of particles from area of high concentration to areas of low concentration?
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simple diffusion
also known as the movement down the concentration gradient |
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What is the term that describes the concentration of a substance that differs from one point to another?
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concentration gradient
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What is the flow of water from one side of a selectively permeable membrane to the other? In which direction?
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osmosis
from side with higher water concentration to side with lower water concentration |
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Which factors affect diffusion rate through the membrane and in what ways?
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temperature INCREASES = INCREASED motion of particles
molecular weight INCREASES = particles move SLOWER steepness of concentrated gradient INCREASES = INCREASED rate membrane surface area INCREASES = INCREASED rate membrane permeability INCREASES = INCREASED rate |
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In the process of simple diffusion, what can be diffused through the lipid bilayer?
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nonpolar, hydrophobic, lipid-soluble substances
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In the process of simple diffusion, what is diffused through channel proteins?
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water and charged, hydrophilic solutes
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How do cells control permeability?
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by regulating number of channel proteins
OR by opening and closing gates |
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How are hydration spheres formed and what is their function?
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Hydration spheres are formed by reversible attractions of water to solute particles.
This makes water molecules less available to diffuse back to the side from which they came. |
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What are channel proteins in plasma membrane specialized for passage of water called?
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aquaporins
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How can cells increase the rate of osmosis?
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by the installation of more aquaporins
decrease rate by removing them |
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What is the term that describes the amount of hydrostatic pressure required to stop osmosis?
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osmotic pressure
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What is the term that describes the ability of a solution to affect fluid volume and pressure in a cell?
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tonicity --> depends on the concentration and permeability of the solute
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The heart drives water out of capillaries by reverse osmosis (or capillary filtration in this case). Explain reverse osmosis.
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pressure is applied to one side, overrides pressure, drives against concentration gradient
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Which type of solution has a high water concentration and causes cells to absorb water, swell, and possibly burst (lyse)?
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hypotonic solution
has a lower concentration of nonpermeating solutes than intracellular fluid (ICF) |
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Which type of solution has a low water concentration and causes cells to lose water and shrivel (crenate)?
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hypertonic solution
has a higher concentration of nonpermeating solutes than intracellular fluid (ICF) |
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Which type of solution causes no changes in cell volume or cell shape and has normal saline?
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isotonic solution
the concentrations in cell and ICF are the same net diffusion of water = 0 |
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Which proteins carry solutes from one side of the plasma membrane to the other?
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transport proteins
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Describe the specificity for transport proteins.
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Transport proteins are specific for a certain ligand.
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Which mechanisms use transport proteins?
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carrier-mediated transport (facilitated diffusion and active transport)
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What is the term that describes the transport rate when all carriers are occupied?
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transport maximum
As the solute concentration rises, the rate of transport rises, but only to a point--transport maximum (Tm) |
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Which type of carrier-mediated transport carries only one solute at a time?
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uniport
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Which type of carrier-mediated transport carries two or more solutes simultaneously in the same direction?
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symport (cotransport)
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Which type of carrier-mediated transport carries two or more solutes in opposite directions?
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antiport (countertransport)
Sodium-potassium pump brings in K+ and removes Na+ from cell. |
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Which carrier-mediated transport mechanism does not consume ATP and transports the solute through a membrane down its concentration gradient?
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facilitated diffusion
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Which carrier-mediated transport mechanism consumes ATP and transports the solute through a membrane up or against its concentration gradient?
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primary active transport
ATP energy is consumed to change carrier. |
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An example of primary active transport includes the sodium-potassium pump. Explain this and why it is necessary.
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each pump cycle consumes 1 ATP and exchanges 3 Na+ for 2 K+
keeps K+ concentration higher in the cell and the Na+ concentration lower than in ECF necessary because Na+ and K+ constantly leak through the membrane |
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Which carrier-mediated transport mechanism does not consume ATP and maintains the steep concentration gradient between one side of the membrane and the other?
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secondary active transport (water behind a dam)
Sodium-glucose transport protein (SGLT) simultaneously binds Na+ and glucose and carries both into the cell. |
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What is the process that moves large particles, fluid droplets, or numerous molecules at once through the membrane in vesicles--bubblelike enclosures of the membrane?
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vesicle transport
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Explain exocytosis.
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vesicular transport process that discharges material from the cell
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Explain endocytosis.
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vesicular transport process that brings material into the cell
Phagocytosis - "cell eating"; engulfing large particles Pinocytosis - "cell drinking"; taking in droplets of ECF containing molecules useful in the cell Receptor-mediated endocytosis - particles bind to specific receptors on the plasma membrane |
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Describe phagocytosis.
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a vesicular process that brings material into the cell (endocytosis) through "cell eating" of large particles
pseudopods, phagosomes, macrophages |
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Describe pinocytosis.
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a vesicular process that brings material into the cell (endocytosis) through "cell drinking" of droplets of ECF containing molecules useful in the cell
pinocytic vesicle |
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Describe receptor-mediated endocytosis.
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a vesicular process that consists of the binding of particles to specific receptors on plasma membrane
clathrin-coated vesicle (ex: uptake of LDL from bloodstream) more selective endocytosis |
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What determines the shape of the cell, lends structural support organizes its contents, directs movement of substances through the cell, and contributes to the movements of the cell as a whole?
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cytoskeleton
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What is the cytoskeleton composed of?
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microfilaments: 6 nm thick, actin, forms terminal web
intermediate fibers: 8-10 nm, support, strength, and structure microtubules: 25 nm, tubulin, movement |
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What is a cylinder of 13 parallel strands known as protofilaments called?
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microtubule --> not permanent structures, they come and go moment by moment
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What radiates from centrosomes and hold organelles in place, form bundles that maintain cell shape and rigidity, and act somewhat like railroad tracks?
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microtubules
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What is the largest organelle?
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nucleus
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List the membranous organelles.
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nucleus
mitochondria lysosomes peroxisomes endoplasmic reticulum Golgi complex |
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List the nonmembranous organelles.
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ribosomes
centrosomes centrioles basal bodies |
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Where are ribosomes produced?
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nucleoli
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What is the system of interconnected channels called cisternae enclosed by a unit membrane?
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endoplasmic reticulum
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Which form of ER is composed of parallel, flattened sacs covered with ribosomes?
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rough ER
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Describe the functions of rough ER.
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produces the phospholipids and proteins of the plasma membrane
synthesizes proteins that are packaged in other organelles or secreted from the cell |
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Describe the functions of smooth ER.
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synthesizes steroids and other lipids
detoxifies alcohol and other drugs manufactures all membranes of the cell |
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What are small granules of protein and RNA which read coded genetic messages (messenger RNA) and assemble amino acids into proteins specified by the code?
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ribosomes
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What is a small system of cisternae that synthesize carbohydrates and put the finishing touches on protein and glycoprotein synthesis?
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Golgi complex
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Describe the functions of the Golgi complex.
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receives newly synthesized proteins from rough ER
sorts them, cuts and splices some of them, adds carbohydrate moieties to some, and packages the protein into membrane-bound Golgi vesicles |
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____________-face of the Golgi complex faces the nucleus, while the __________-face of the Golgi-complex faces away from the nucleus.
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cis-face = faces the nucleus
trans-face = faces away from the nucleus |
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What are the functions of lysosomes?
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intracellular hydrolytic digestion of proteins, nucleic acids, complex carbohydrates, phospholipids, and other substances
autophagy - digest and dispose of worn out mitochondria and other organelles autolysis - "cell suicide": some cells are meant to do a certain job and then destroy themselves |
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What is the functions of peroxisomes?
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to use molecular oxygen to oxidize organic molecules --> these reactions produce hydrogen peroxide (H2O2)
neutralize free radicals, detoxify alcohol, other drugs and a variety of blood-borne toxins break down fatty acids into acetyl groups for mitochondrial use in ATP synthesis are abundant in liver and kidney |
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What is the role of catalase?
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breaks down excess peroxide to H2O2 and O2
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Which organelles are specialized for synthesizing ATP?
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mitochondria --> powerhouse of the cell
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What is the mitochondrial matrix composed of?
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ribosomes
enzymes used for ATP synthesis small circular DNA molecule |
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How did mitochondria evolve?
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Mitochondria evolved from bacteria that invaded another primitive cell, survived in the cytoplasm, and became permanent residents.
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What are two advantages of mitochondria?
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has its own DNA (mtDNA)
replicates independently of nuclear DNA |
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Why is mitochondrial DNA almost exclusively inherited through the mother?
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When sperm fertilizes the egg, any mitochondria introduced by the sperm are usually destroyed, and only those provided by the egg are passed on to the developing embryo.
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Mitochondrial DNA mutates more readily than nuclear DNA. What are the disadvantages of this?
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no mechanism for DNA repair
produces rare hereditary diseases |
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What is a short cylindrical assembly of microtubules arranged in nine groups of three microtubules each?
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centriole --> arranged in 9 groups of 3 microtubules each
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What is the small, clear area of cytoplasm that includes two centrioles perpendicular to each other?
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centrosome
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List the stored cellular product inclusions.
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glycogen granules
pigments fat droplets |
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List the foreign body inclusions.
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viruses
intracellular bacteria dust particles other debris phagocytized by a cell |
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True or false: The most important advantage of transmission electron (TEM) over light microscope (LM) is higher resolution.
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true
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True or false: If a cell is doubled in diameter, it would have twice as much cytoplasm to maintain.
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false
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True or false: In the plasma membrane, glycolipids and glycoproteins face toward the cytoplasm, while peripheral proteins always face toward the ECF.
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false
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True or false: A cell's second messengers serve to transport material through the plasma membrane.
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false
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True or false: Microvilli and cilia differ in their function but have the same internal structure.
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false
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True or false: Ligand-gated channels are membrane proteins that open or close in response to the binding of a chemical.
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true
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True or false: The greater the concentration gradient, the faster the diffusion rate.
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true
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True or false: The Na+-K+ ATPase is a countertransport antiport carrier, which always requires energy.
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true
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True or false: The sodium-glucose transport protein (SGLT) is one example of an active-transport process involving a uniport carrier.
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false
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True or false: One example of pinocytosis is the uptake of low-density lipoproteins (LDLs) by endothelial cells.
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false
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True or false: Both the nucleus and the mitochondrion are surrounded by two layers of unit membrane.
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true
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True or false: The nucleus is the largest organelle in most cells.
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true
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True or false: Ribosomes are made of protein and RNA.
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true
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True or false: The Golgi complex makes peroxisomes but mot lysosomes.
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false
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True or false: A crystal of calcium phosphate in the cytoplasm of a cell should be classified as an inclusion.
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true
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