A&P 2.14 cell membranes & cellular transport Flashcards Preview

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Flashcards in A&P 2.14 cell membranes & cellular transport Deck (42)
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Basic cell anatomy

Plasma membrane
Nucleus
Cytoplasm

1

Plasma membrane

Cell membrane and boundary, maintains its integrity,
Protein molecules embedded in the plasma membrane perform various functions

2

Nucleus

Holds the genetic code which dictates protein synthesis, thereby playing an essential role in other cell activities, namely cell transport, metabolism and growth

3

Cytoplasm

Gel-like substance, includes various organelles suspended in a watery fluid called cytosol (intercellular fluid)

4

Components of the plasma membrane

Phospholipid bilayer
Membrane proteins

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Phospholipid bilayer

Maintains cell integrity

Made of membrane proteins and receptor molecules allow for transport of molecules, hormones, and other chemicals involved in signal transduction

Enzymes catalyze specific reactions that regulate metabolic reactions

6

Phospholipid bilayer consists of

Six main types of proteins in the cell membrane
Layer is studded with membrane proteins performing various functions

Two layers: hydrophobic (lipid) tails and hydrophilic (phosphate) heads

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Membrane layers

Phospho head - outer - water liking

Lipid tail - inner - water hating

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Membrane proteins

Act as channels or carriers of molecules - controls transport of water soluble molecules from one compartment to another

Bind molecules outside the cell that form connections between cells & other structures (tissue fibers or other cells)

Those that bind to support filaments within the cytoplasm maintain shape and movement

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Membrane proteins

Glycoproteins

Are proteins in the membrane that act as markers that recognize cells or organelles

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Functions of membrane proteins

Formation of a channel
Transporter proteins
Receptor proteins

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Membrane proteins

4

Ion channels
Carriers (transporters)
Receptors
Cell identity markers

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Ion channels

Pores or holes through which specific ions can flow to get into or out of the cell (most ion channels are selective - one type of ion)

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Carriers (transporters)

Selectively move a polar substance or ion from one side of the membrane to the other

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Receptors

Cellular recognition sites, recognizes and binds a specific type of molecule ( insulin receptor)

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Cell identity markers

Enable a cell to recognize other cells of the same kind or identify foreign cells (blood type)

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Elements defined

Substances that cannot be broken down into a simpler form by ordinary chemical means (pure)

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96 % of the human body is composed of

4 major elements:

Carbon
Oxygen
Nitrogen
Hydrogen

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Compounds

More than one element combined

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Classes of compounds

2

Inorganic

Organic

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Inorganic compound

70% +\- of our body is water (the most abundant and important compound)

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Organic compound

Presences of carbon and they are protein, carbohydrates, lipids and nucleic acids ( RNA & DNA)

Carbon hydrogen bond

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Transport across the membrane

2 types

Passive

Active

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Passive transport

Movement of substances down a concentration gradient until equilibrium is reached,

Does not require cellular energy in the form of ATP

Particles move using energy they already have

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Three types of passive transport

Diffusion
Osmosis
Facilitated diffusion

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Diffusion

Movement of a substance by kinetic energy down a concentration gradient until equilibrium is reached

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Simple diffusion

Passive movement of a substance through the lipid bilayer of the plasma membrane

Tendency of small particles to spread out evenly within a given space

Requires a concentration gradient

Measurable concentration difference between areas

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Osmosis

Movement of WATER molecules through/across a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration

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Facilitated diffusion

Passive movement of a substance down a concentration gradient aided by ion channels and carrier molecules

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Active transport

Defined

Movement of substances against a concentration gradient
Requires cellular energy in the form of ATP

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Active transport

How it works

Transport in which the cell expends energy to move a substance across the membrane against its concentration gradient aided by MEMBRANE PROTEINS that act as PUMPS

Use energy supplied by ATP

Particles are actively PULLED across the membrane

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Transport across the plasma membrane

2 types

Endocytosis

Exocytosis

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Transport in vesicles

Movement of substances into or out of a cell in vesicles that bud from the plasma membrane

Requires energy supplied by ATP

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Endocytosis

Movement of substance into a cell in vesicles

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Endocytosis

2 types

Phagocytosis

Pinocytosis

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Phagocytosis

"Cell eating"
Movement of a solid particles into a cell after pseudopods engulf it

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Pinocytosis

"Cell drinking"
Movement of extracellular fluid into a cell by in folding of plasma membrane

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Exocytosis

Movement of substances out of a cell in secretory vesicles that fuse with the plasma membrane and release their contents in to the extracellular fluid

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How do neurotransmitters interact with the plasma membrane?

They bind to receptors on their surface

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OBTURATOR internus

A, I, O

A -lateral rotation and extension of the femur

O - proximal attachment - internal surface of OBTURATOR membrane and rim of the pubis and ischium

I - distal attachment - medial aspect of the greater trochanter

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OBTURATOR externus

A, O, I

A -lateral rotation and extension of the femur

O - proximal attachment - external surface of the OBTURATOR membrane and the rim of the pubis and ischium

I - distal attachment - medial aspect of the greater trochanter

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Quadratus femoris

A, I, O

A -lateral rotation and extension of the femur

O - proximal attachment - upper part of the ischial tuberosity

I - distal attachment - just inferior to the greater trochanter (linea quadrata)