question

cells

answer

the basic unit which make up all living organisms, over 200 different types found in the body

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3 parts of basic cell

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1. plasma membrane 2. cytoplasm 3. nucleus

question

The ______ ______ acts as a boundary between the intracellular fluid and extracellular fluid.

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plasma membrane

question

Describe the composition of the plasma membrane.

answer

bilayer of phospholipids with proteins embedded in it

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fluid mosaic model

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model of the plasma membrane

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What part do proteins play in the "fluid mosaic model"?

answer

mosaic pattern

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What part do phospholipids play in the "fluid mosaic model"?

answer

fluidity

question

2 major components of plasma membrane

answer

1. phospholipid 2. protein

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Phospholipid

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has polar "head" region which is hydrophilic has nonpolar "tail" region of 2 fatty acid chains which is hydrophobic

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Protein

answer

gives stability to the membrane found throughout the membrane - providing an everchanging mosaic pattern

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2 types of membrane proteins

answer

1. integral 2. peripheral

question

____ proteins are inserted into the membrane - most span entire width of the membrane.

answer

integral

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____ proteins are attached to integral proteins.

answer

peripheral

question

What component makes up 20% of the membrane lipids and provides stability to the membrane?

answer

cholesterol

question

What is the function of the glycocalyx?

answer

bio markers > cells recognize each other so body doesn't attack the cells

question

3 types of membrane junctions that help to bind cells together

answer

1. tight junctions 2. desmosomes 3. gap junctions

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tight junctions

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this type of junction is formed by the fusing of protein molecules of adjacent cells, thereby producing an impermeable junction.

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desmosomes

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this type of junction is formed by anchoring junctions that bind adjacent cells together by the use of protein filaments that extend out from plaques.

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gap junctions

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this type of junction is formed by channels between cells which allow chemical substances to pass between the cells.

question

The plasma membrane plays a part in membrane transport - it is said to be a _____ barrier, letting some substances through while not allowing others.

answer

selective

question

2 ways substances pass through the plasma membrane

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1. passive 2. active

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passive transport

answer

processes occur without the input of energy

question

active transport

answer

transport requires the input of energy in the form of ATP

question

Diffusion

answer

- passive process - the movement of molecules from areas of their higher concentration to areas of their lower concentration (so molecules are said to move down their concentration gradient)

question

3 types of diffusion

answer

1. simple diffusion 2. facilitated diffusion 3. osmosis

question

simple diffusion

answer

-occurs when nonpolar and lipid-soluble substances move through the membrane

question

examples of nonpolar and lipid-soluble substances

answer

oxygen carbon dioxide fat-soluble vitamins alcohol

question

facilitated diffusion

answer

occurs when substances move through the membrane by protein carriers or water-filled protein channels - so this is a highly selective process

question

osmosis

answer

the diffusion of water through the selectively permeable membrane

question

tonicity

answer

deals with solutions which change the shape of cells

question

isotonic

answer

solution has the same concentration of nonpenetrating solutes as the cell - so the cell will retain its same shape in this type of solution

question

hypertonic

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solution has a higher concentration of nonpenetrating solutes than the cell - so cell will lose water and shrink aka CRENATE

question

hypotonic

answer

solution has lower concentration of nonpenetrating solutes than the cell - so cell will gain water and swell and possibly burst aka LYSE (LYSIS)

question

Active transport is similar to facilitated diffusion in that it uses carrier proteins - but in active transport, _____ _____ are used to move substances against their concentration gradient.

answer

solute pumps

question

2 types of active transport determined by their source of energy

answer

1. primary active 2. secondary active

question

primary active transport

answer

- energy comes from ATP - example is the sodium-potassium pump where Na+ and K+ leak slowly through channels along their concentration gradient - if these 2 ions are left alone they would eventually balance themselves on both sides of the membrane, but the body pumps 2 K+ in and pumps 3 Na+ out during the action of the sodium-potassium pump. - this ionic concentration difference is essential for excitable cells like muscle and nerve cells to function

question

secondary active transport

answer

- energy indirectly comes from primary active transport pumps , like Na+ - K+ pump. - all these systems are coupled which means they move more than one molecule at a time - after Na is pumped out by the Na+ - K+ pump, as NA moves back into the cell by facilitated diffusion it drags other substances with it like glucose

question

vesicular transport

answer

- type of active transport that moves large particles and fluids across the membrane in membranous sacs called vesicles with the use of energy - exocytosis & endocytosis

question

exocytosis

answer

moves substances out of the cell - a substance is first enclosed in a vesicle which moves to the membrane, fuses with it and then releases the substance out of the cell

question

endocytosis

answer

moves substances inside the cell - Clathrin-coated vesicles are the major way how this occurs - substance is first enclosed by infolding of the membrane which leaves a clathrin coat produced by the cytoplasm side of the membrane forming then a vesicle - 3 types

question

3 types of endocytosis

answer

1. phagocytosis 2. pinocytosis 3. receptor-mediated endocytosis

question

phagocytosis

answer

"cell eating" occurs when substance is engulfed by the cell - vesicle formed is called a phagosome and fuses with lysosome to allow digestion of the contents

question

pinocytosis

answer

"cell drinking" occurs when membrane infolds forming a vesicle to take in fluid

question

receptor-mediated endocytosis

answer

most common of all 3 types of endocytosis selective type of endocytosis because there are specific receptors on the membrane for only certain substances to bind to

question

3 structures that compose the cytoplasm

answer

1. cytosol 2. organelles 3. inclusions

question

cytosol

answer

the fluid in which organelles and such are found

question

organelles in cytoplasm

answer

mitochondria ribosomes endoplasmic reticulum (rough & smooth) golgi apparatus lysosomes peroxisomes cytoskeleton centrioles cellular extensions

Chapter 3: Cells: Living Units – Flashcards

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