Second Exam Flashcards by D T

What do lipids do in cells?

Used as secondary energy sources
Major component of membranes

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Why are lipids used for energy?

High energy to weight ratio
Harder to metabolize

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What are triglycerides?

Storage lipids like fats and oils that consist of a glycerol bound to three fatty acids

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What are fatty acids?

Long hydrocarbon chain with a carboxylic head

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What are the two forms of fatty acids?

Saturated and Unsaturated

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What are ester bonds?

The bond between the hydroxyl of a glycerol and the carboxyl of a fatty acid

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What form do saturated fatty acids take?

Solid

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What form do unsaturated fatty acids take?

Oils, liquid

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What are phospolipids?

Glycerol ester bonded to 2 fatty acids and a phosphate group which is bound to a variable hydrophilic molecule

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What is the cystol?

Aqueous part of the cytoplasm of the cell

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What is the lumen?

Extracellular space

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How does hydrocarbon tail length effect fluidity?

The shorter the tail, the greater the fluidity

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How does unsaturation effect fluidity?

Unsaturated means more fluidity

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What do sterols in membranes do to fluidity?

Decrease it

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How does temp effect fluidity?

Fluidity increases with temp

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Where are new phospholipids made?

Cystolic side of smooth ER membrane

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What are scramblase enzymes?

Randomly moves phospholipids to even out the membrane

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What does flippase and floppase do?

Move specific phospholipids to different sides of the layer

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What are the membrane proteins?

Transporters
Anchors
Enzymes
Channels
Receptors

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What are integral proteins?

Tightly associated with membranes, some embedded, sometimes transmembrane, and commonly are alpha and beta folded

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What are peripheral proteins?

Loosely associated with membrane, may be linked to other substances

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What are glycolipids?

Lipid tails attached to a sugar head, the head is exposed to the cell exterior

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What are proteoglycans?

Proteins attached to long chains of repeating sugars

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What are glycoproteins?

Proteins attached to short, highly branched sugar chains

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What is glycocalyix?

Sugar coating of plasma membrane, promotes biofilm formation

What is a cell cortex?

specialized layer of cytoplasmic proteins on the inner face of the cell membrane

What is spectrin?

Protein that lines the intracellular side of the plasma membrane

What can cell cortex abnormalities result in?

Anemia

What can move through semi-permeable cell membranes?

Small nonpolar molecules and some uncharged polar molecules

What can not move through semi-permeable cell membranes?

Charged molecules and ions

What is passive transport?

No energy, movement goes with the gradient

What is active transport?

Needs energy, goes against the gradient

What factors affect passive transport?

Chemical gradient Membrane potential Electrochemical gradient

What is the chemical gradient?

the difference in molecule concentrations across a cell membrane

What is membrane potential?

the electrical potential difference across the plasma membrane

What is the electrochemical gradient?

measure of the free energy available to carry out transporting the molecule across the membrane

What are ways a cell tries to reach equilibrium?

Simple diffusion Osmosis Facilitated diffusion

What is isotonic?

Equal concentrations

What is hypotonic?

high solute inside cell, high water outside cell

What is hypertonic?

high solute outside cell, high water inside cell

What is osmolysis?

rupture of a cell membrane due to excessive water intake

What is plasmolysis?

Shriveling of a cell due to loss of water

How to protozoans regulate equilibrium

They discharge contractile vacuoles of water

What is a uniporter?

Facilitates the diffusion of a single substance

What is a symporter?

proteins that simultaneously transport two molecules across a membrane in the same direction

What is a antiporter?

protein that transports two molecules at the same time in the opposite direction

What are the different Transport Ion Channel Gates?

Voltage Gated Ligand Gated Mechanically Gated

What is a voltage gated channel?

Channel stimulated by membrane potentials

What is a ligand gated channel?

Channel stimulated by ligand binding

What is a mechanically gated channel?

Channel stimulated by mechanical force or stress

What is resting membrane potential?

Voltage across a membrane when cell is at rest

What is action membrane potential?

Change in membrane voltage that opens ion channels and allows ions to flow across the membrane

What are the facilitated diffusion transports?

Carriers Channels

What do carrier transports do?

bind the specific solute to be transported and undergo a series of conformational changes to transfer the bound solute across the membrane

What do channel transports do?

acts like a pore in the membrane that lets water molecules or small ions through quickly

What are examples of Primary Active Transport?

ATP driven pumps Light driven pumps Bulk Transport

What is Secondary Active Transport?

Uses energy from ion movement going with the gradient to power the transport of ions against the gradient

What are examples of bulk transport?

Endocytosis - Phagocytosis - Pinocytosis Exocytosis

What is endocytosis?

Bringing substances into the cell using vesicles

What is phagocytosis?

"cell eating"

What is pinocytosis?

"cell drinking"

What is exocytosis?

Releasing substances using a vesicle

What is clathrin?

Proteins involved in shaping vesicles and engulfments

What are adaptins?

Molecules that secure the clathrin coat to the membrane and hold cargo receptors that bind to target molecules

What is dynamin?

Molecules that pinch off the cell membrane into a vesicle

What are lysosomes?

Vesicles full of digestive enzymes

What terminus are signal sequences found on?

N-terminus

How are improperly folded proteins disposed of?

They are retained in the ER by chaperone proteins and degraded

What do vesicles shed to allow for membrane interaction?

Clathrin coat

What are the transmembrane proteins?

SNAREs Rab proteins Tethering proteins

Where do condensing vesicles go?

They remain in the cell

Where do secretory vesicles go?

They are exocytosed

What are the secretory pathways?

Constitutive Regulated

What is the constitutive secretory pathway?

Unregulated exocytosis

What is the regulated secretory pathway?

Holds vesicles at the cell membrane then releases them all at once, such as the release of insulin

What is a nuclear localization signal?

The mark on proteins that are selected for nucleus import

How is a nuclear localization signal recognized?

cytosolic nuclear transport receptors that are attached to nuclear pore fibrils