Chapter 11 -> Membrane Structure Flashcards
What are the 3 functions of the Cell Membrane?
1) Receiving information
2) Importing and Exporting small molecules
3) Ability to move and expand
Bacteria have a _____ membrane while eukaryotic cells have a membrane as well as ______ membranes
Single, Multiple
Give some examples of organelles within a eukaryotic cell that have their own membrane
Mitochondria, Golgi apparatus, ER
All cell membranes are composed of _____ and _______ and share the general structure of lipids that form a lipid bilayer (about _ nm thick)
Proteins, Lipids, 5
Lipids bilayer consists of phospholipids that have a _____ head and a _______ tail
Hydrophilic, Hydrophobic
The most abundant lipids in cell membranes are _____ which can be further categorized into ________, one of the most abundant phospholipids in the membranes of animals and plants
Phospholipids, Phosphatidylcholine
Give two examples of membrane lipids that are amphipathic
Glycolipids and Cholesterol
The closer and more regular the packing of tails in the cell membrane, the ____ fluid the bilayer will be
Less
What are the two major properties of hydrocarbon tails that affect how tightly they pack in the bilayer?
Their length and the number of double bonds they contain
Lipid bilayers that contain a large proportion of unsaturated hydrocarbon tails are _____ fluid than those with lower proportions
MORE
What are the three types of movement that the membrane can do and which one rarely occurs?
Rotation, Flexion, and Flip-flop which rarely occurs
In animal cells, around _____ % of the membrane lipids are cholesterol, which tends to _______ the bilayer
20, stiffen
The cell membrane is ____ and ____ and is therefore strengthened and supported by a framework of _______ which constitute around _____ % of the mass of most plasma membranes
thin, fragile, proteins, 50
What proteins attach other proteins to the membrane
Transmembrane proteins
What is the cell cortex?
Meshwork of fibrous proteins attached to the cytosolic surface of the membrane which determines the shape of the cell and mechanical properties of plasma membrane
What is the main component of the RBCs cortex that forms the meshwork and provides support and gives it that distinct biconcave shape?
Spectrin
What are the 5 Functional categories of proteins?
Transporters, Ion Channels, Anchors, Receptors, and Enzymes
What does Transporter proteins do? (Functional Category)
Give an Example
Transport particular nutrients, metabolites, and ions
Na+ PUMP
What do Anchor Proteins do? (Functional Category)
Give an Example
Anchor the membrane to macromolecules on either side
Integrins in the cell membrane
What do Receptor Proteins do? (Functional Category)
Give an Example
Detect chemical signals in the cell’s environment and relays them to interior
PDGF
What do Ion Channel Proteins do? (Functional Category)
Give an example
Allows for movement of molecules in and out of cell
K+ Leak channel
What do Enzyme Proteins do? (Functional Category)
Give an Example
Catalyze specific reactions
Adenylyl cyclase
What are the four Structural Categories of proteins?
Transmembrane, Monolayer Associated, Lipid-linked, Protein Attached
Of the four Structural Categories of proteins, which is amphipathic?
Transmembrane
How are glycolipids attached to the membrane and where are they attached?
They are attached by their sugar part on the non cytosolic side of lipid bilayer
What is a proteoglycan
Protein that has one or more long polysaccharide chains attached to it
What three molecule form carbohydrate layer of cell membrane?
Glycolipids, Glycoproteins, and Proteoglycans
The many functions of the Carbohydrate layer
- Holds ______, creating slimy surface
- Helps cell not stick to one another
- Involved in ______ response
Water, Inflammatory
In the early stages of bacterial infection, carbohydrates on the surface of white blood cells are recognized by ______ on cells lining blood vessels at site of infection, causing WBC to adhere to vessel wall and migrate to infected site
Lectins
In epithelial cells lining the gut, _____ proteins are close to the surface facing the gut to get the nutrients
transport
_______ junction barrier maintains distribution of membrane proteins
Tight
