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Flashcards in Membrane Deck (31):
1

Phospholipid Bilayer

Key term describing the structure of the membrane, 2 layers of phospholipids with polar heads on the outside and non-polar tails on the inside.

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Phospholipids are classified as?

Phosphoglycerides and sphingolipids

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Glycolipids can be classified as?

glycophosphoglycerides and glycosphingolipids

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what are the classifications of sterols

cholesterol in animals, phytosterol in plants and hopanoids in bacteria

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name the non protein things in the membrane

phospholipids, glycolipids and sterols

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describe the structure of a phospholipid

The head group is a phosphate group attached to an R group. The head is connected to the tail with a glycerol. The tail is a fatty acid, either saturated or unsaturated, which can bond to a sterol.

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Thermophiles

Organisms that live at high temperatures

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Psychrophiles

Organisms that live at room temperatures

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Mesophiles

organisms that live in low temperatures

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Lateral Mobility

The movement of lipids within one layer

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Flip flopping

the movement of lipids from one layer to the other

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Lipid Flippase

An enzyme responsible for flip flopping

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Integral proteins

proteins imbeded in the membrane. Interact strongly with lipids, require detergents to remove, include enzymes, antigens and receptors.

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Integral monotopic proteins

proteins that sit in one layer of the membrane

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single pass proteins

a protein that passes once through the membrane

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multipass protein

proteins that pass through the membrane multiple times

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multi-subunit proteins

multiple seperate polypeptides each passing through the membrane

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Peripheral membrane proteins

proteins loosely attached to the membrane, easy to remove

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lipid anchored

covalently bonded to lipids. Classified as fatty acid/prenyl/GPI anchored.

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functions of membrane proteins

cell junctions, enzymatic roles, structural roles, transport, sensing and recognising self vs. not self.

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The role of carbohydrates in the cell membrane

attach to proteins (glycoproteins) and lipids (glycolipids) to serve as ID tags for identification of self vs. not self

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Simple diffusion

Basically osmosis, requires no energy or special proteins

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Isotonic

Equal concentration with in and without the cell, nothing happens

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Hypertonic

higher concentration of solute outside the cell than in, leads to shrivelling

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Hypotonic

Higher concentration of solute inside the cell than out, leads to swelling and bursting

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Facilitated diffusion

diffusion across the membrane in line with the concentration gradient, proteins help overcome the permeability barrier. this requires no energy.

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Permeases

Proteins that allow for passage across the membrane, highly selective

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Active Transport

Transport acts against concentration gradient which requires energy. Used for nutrient uptake, waste removal and ion concentration maintenance

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Symport

2 different compounds going the same way

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Antiport

2 different compounds going in different directions

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uniport

1 compound traveling in one direction