Chapter 5 (Exam Two) Flashcards by Lexie Schoenrock

The __________ is common to all cells.

Plasma membrane

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The _________ is a phospholipid bilayer with embedded proteins and cholesterol.

Plasma membrane

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Phospholipids are ________ molecules, having both hydrophilic and hydrophobic regions; nonpolar tails (hydrophobic) are directed ____, polar heads (hydrophilic) are directed _____ to face both extracellular and intracellular fluid.

Amphipatic; inward; outward

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Nonpolar tails are?

Hydrophobic

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Polar heads are?

Hydrophillic

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Proteins in the plasma membrane can be _____ or _____?

Peripheral; Integral

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_____ are found on one side of the inner membrane suface?

Peripheral protiens

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____ are partially or wholly embedded (transmembrane) in the plasma membrane?

Integral protiens

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_____ are usually found in the membrane and are held in place by the cytoskeleton and the extracellular matrix (ECM).

Integral proteins

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The _____ is only found in animals and its function includes supporting the plasma membrane and communicating between cells.

EMC

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____ affects the fluidity of the membrane?

Cholesterol

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The ______________ describes the plasma membrane.

Fluid-Mosaic model

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Fluidity of the plasma membrane allows cells to be ____

Pliable

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Proteins bond to the _____ and/or _____ to prevent movement in the fluid phospholipid bilayer

ECM; Cytoskeleton

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_____ have a structure similar to phospholipids except the hydrophilic head is a variety of sugar; they are protective and assist in various functions.

Glycolipids

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_____ have an attached carbohydrate chain of sugar that projects externally.

Glycoprotiens

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_____ have an attached carbohydrate chain of sugar that projects externally.

Glycoproteins

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In animal cells, the ____ is a “sugar coat” of carbohydrate chains and has several functions?

Glycocalyx

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The immune system recognizes foreign tissues that have ______________

Inappropriate carbohydrate chains

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Carbohydrate chains are the basis for ____________ in humans?

A, B, and O blood groups

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3 Components of the Plasma Membrane?

Lipid component referred to as phospholipid bilayer
Protein molecules
Cholesterol

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What allows passage of molecules through membrane(cross a membrane) via a channel in the protein?

Channel Protiens

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What combines with the substance to be transported
and assists passage of molecules through membrane?
-Also ____ selectively interact with a specific molecule so it can cross the plasma membrane?

Carrier protiens

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Are glycoproteins

and allow/help the body’s immune system recognize foreign substances and body cells?

Cell Recognition Protiens

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What are shaped so a specific molecules can bind to it?

Receptor Protiens

What carries out specific metabolic reactions directly?

Enzymatic Proteins

What attaches adjacent/animal cells so tissues can function?

Junction Protiens

The plasma membrane is _________ only certain molecules can pass through.

Selectively Permeable

Small non polar molecules such as ________pass through the membrane freely?

Carbon dioxide , oxygen

Small molecules such as _________move “down” a ________, i.e., from high to low concentration.

Carbon dioxide, oxygen/ Concentration gradient

Cells have channel proteins called ______ that allow water to cross a plasma membrane more quickly than expected.

Aquaporins

Ions and charged molecules cannot readily pass through the hydrophobic component of the bilayer and usually combine with _____

carrier proteins.

Large particles enter or exit a cell through _______

bulk transport

_________ or chemical messengers, “talk” to other cells and may change cells, tissues, or organs.

signaling molecules

Once the signaling molecule is bound to a receptor, the signal follows through a _______

Transduction Pathway

The cell’s response to the ________ can change the shape or movement of the cell, alter the metabolism or function of the cell, or alter the gene expression and amount of a cell protein.

transduction pathway

___ is fusion of a vesicle with the plasma membrane moves a particle to outside the membrane

Exoxytosis

_____ is vesicle formation moves a particle to inside the plasma membrane

Endocytosis

A solution consists of ____ and _____

a solvent and a solute

_____ is the movement of molecules from higher to lower concentration (i.e., “down” the concentration gradient).

Diffusion

A solvent is usually a?

Liquid

A solute is usually a?

dissolved solid

In the case of a dye diffusing in water, the dye is a _____ and water is the _____?

Solute/Solvent

Once a solute is evenly distributed, random movement continues but with no _____

net change

The chemical and physical properties of a membrane allow only a few types of molecules to cross by _____

diffusion

Gases readily diffuse through the _______

lipid bilayer

____, ____, ____, and ____ influence the rate of diffusion.

Temperature, pressure, electrical currents, and molecular size

_____ is the diffusion of water across a differentially (selectively) permeable membrane.

osmosis

________ is the pressure that develops in a system due to osmosis.

Osmotic pressure

______ results in water being absorbed by the kidneys and water being taken up by the capillaries in the tissues.

Osmotic pressure

______ are solutions where the solute concentration and the water concentration inside and outside the cell are equal.

Isotonic Solutions

_____ refers to the strength of the solution

Tonicity

A 0.9% salt solution is used in injections because it is _____ to red blood cells (RBCs).

Isotonic

_________ has a solute concentration that is less than another solution; when a cell is placed in a hypotonic solution, water enters the cell and it may undergo cytolysis (“cell bursting”).

Hypotonic Solution

Swelling of a plant cell in a hypotonic solution creates ______; this is how plants maintain an erect position.

Turgor pressure

_____ solution has a solute concentration that is higher than another solution

Hypertonic solution

when a cell is placed in a hypertonic solution, water leaves the cell and it shrivels (a condition called _____).

Crenation

_____ is shrinking of the cytoplasm due to osmosis in a hypertonic solution; as the central vacuole loses water, the plasma membrane pulls away from the cell wall.

Plasmolysis

_______ is transport of a specific solute across plasma membranes “up” or “against” (from low to high) its concentration gradient through use of cellular energy (ATP).

Active transport

Iodine is concentrated in cells of the thyroid gland, _____ is completely absorbed into the lining of the digestive tract, and _____ is mostly reabsorbed by the kidney tubule lining.

glucose, sodium

_______ requires both carrier proteins and ATP; therefore cells must have a high number of _____ near membranes where active transport occurs.

Active Transport, Mitochondria

_____ involved in active transport are often called “pumps”

Protiens

The _______ is an important carrier protein in nerve and muscle cells.

sodium-potassium pump

_________ results from a faulty chloride channel protein, causing thick mucus in bronchial tubes and pancreatic ducts.

Cystic fibrosis

In ______, a vesicle formed by the Golgi body fuses with the plasma membrane as secretion occurs; insulin leaves insulin-secreting cells by this method.

exocytosis

During _______, cells take in substances by vesicle formation as plasma membrane pinches off by phagocytosis, pinocytosis, or receptor-mediated endocytosis.

Endocytosis

In _______, cells engulf large particles (e.g., bacteria, food particles), forming an endocytic vesicle.

phagocytosis

______ is commonly performed by amoeboid-type cells (e.g., amoebas and macrophages).

Phagocytosis

When the ______ fuses with a lysosome, digestion of the internalized substance occurs.

endocytic vesicle

______ occurs when vesicles form around a liquid or very small particles; this is only visible with electron microscopy.

Pinocytosis

Cells that use _____ to ingest substances are: blood cells, cells that line the kidney tubules or the intestinal wall, and plant root cells.

Pinocytosis

________, a form of pinocytosis, occurs when specific macromolecules bind to plasma membrane receptors.

Receptor-mediated endocytosis

The _____ are shaped to fit with specific substances (vitamin, hormone, lipoprotein molecule, etc.), and are found at one location in the plasma membrane.

Receptor protiens

______ are associated with exchange of substances between cells (e.g., maternal and fetal blood).

Pits

_______ (transported in a molecule called a low-density lipoprotein, LDL) enters a cell from the bloodstream via receptors in coated pits

Cholesterol

In _________, the LDL receptor cannot bind to the coated pit and the excess cholesterol accumulates in the circulatory system

familial hypocholesterolemia

The ________ is a meshwork of polysaccharides and proteins in animal cells.

Extracellular matrix

_____ gives the matrix strength and elastin gives it resilience.

Collagen

______ and ____ membrane receptors and permit communication between matrix and cytoplasm

Fibronectins and integrins

which proteins also form “highways” that direct the migration of cells during development.

Fibronectins and integrins

______ are glycoproteins that provide a packing gel that joins the various proteins in matrix and most likely regulate signaling proteins that bind to receptors in the plasma protein.

Proteoglycans

______ are points of contact between cells that allow them to behave in a coordinated manner.

Junctions Between Cells

______ mechanically attach adjacent cells.

Adhesion junctions

In _____, internal cytoplasmic plaques, firmly attached to cytoskeleton within each cell, are joined by integral membrane proteins

desmosomes

_____ hold cells together where tissues stretch (e.g., in heart, stomach, bladder).

desmosomes

In _____, plasma membrane proteins attach in zipper-like fastenings

Tight Junctions

_____ hold cells together so tightly that the tissues are barriers (e.g., epithelial lining of stomach, kidney tubules, blood-brain barrier).

Tight Junctions

A ______ allows cells to communicate; formed when two identical plasma membrane channels join.

Gap junction

_____ provide strength to the cells involved and allow the movement of small molecules and ions from the cytoplasm of one cell to the cytoplasm of the other cell.

Gap junctions

______ permit flow of ions for heart muscle and smooth muscle cells to contract.

Gap Junctions

Plant cells are surrounded by a porous _____

Cell wall

The ______ varies in thickness, depending on the function of the cell.

Cell wall

____ cells have a primary cell wall composed of cellulose polymers united into threadlike microfibrils that form fibrils.

Plant

______ form a framework whose spaces are filled by non-cellulose molecules.

Cellulose fibrils

_____ allow the cell wall to stretch and are abundant in the middle lamella that holds cells together.

Pectins

_______ polysaccharides harden the wall of mature cells.

Non-cellulose

_____ adds strength and is a common ingredient of secondary cell walls in woody plants.

Lignin

______ are narrow membrane-lined channels that pass through cell walls of neighboring cells and connect their cytoplasms, allowing direct exchange of some molecules and ions between neighboring plant cells.

Plasmodesmata