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Flashcards in Interaction of the Cell With its Environment Deck (23):

Where do cells receive messages

Messages being to be processed
1. at the cell membrane
2. need to pass through the cell membrane to be interpreted


What are proteins

Molecules formed by amino acids


What are the functions of proteins

Hemoglobin (O2 transporting via blood)
Hormones (cell communication)
Antibodies (body protection)
DNA replication
Metabolism (enzymes)


What are the 4 membrane proteins

ion channels
membrane carriers


What are the role of membrane proteins

To bring nutrients in, waste out, and communicate with other cells


What are the 5 mechanisms of membrane transport

1. Endo/exocytosis
2. Diffusion through the lipid bilayer
3. Diffusion through protein channels
4. Facilitated diffusion
5. Active transport


What is the definition of simple diffusion

The movement of molecules from an area of high [ ] to an area of low [ ] due to a molecules random thermal motion


What are the 6 factors that affect the rate of diffusion for lipid soluble molecules?

1. Composition of the lipid bilayer
2. Membrane surface area
3. Lipid solubility
4. Molecular size of molecule
5. Membrane thickness
6. [ ] gradient


What are the 4 factors that affect the diffusion of water-soluble molecules?

1. [ ] Gradient
2. Molecule Size
3. Charge
4. Number of channels


What does glucose and amino acids need in order to pass the lipid bilayer?

Carrier proteins


What are the 2 main differences between transport mechanisms for water soluble molecules and facilitated diffusion?

Differentiated by either channels or proteins
1. ion channel moves molecules quicker
2. channels are continuous


What is the definition of active transport?

A process that moves molecules against their [ ] gradient
-requires ATP


What is a common example of active transport?

Na+/K+ pump
-helps maintain the Na and K [ ] gradient across the membrane


What kind of signals can cells use to maintain homeostasis

Cells can send electrical or chemical signals to communicate to other cells.


What is long distance communication

When cells have the ability to send messages that travel long distances


What is local communication

When cells send signals only to their neighbours


How is most long distance cell communication mediated

Endocrine (hormones) and Nervous (chemical) Systems


How is most local cell communication mediated

If cells are not of the endocrine or nervous system, they can communicate with one another through chemical and physical means


What is an autocrine signal

Used in cell communication when one cell releases a signal and it is self stimulating


What is a paracrine signal

Used in cell communication when one cell releases a signal and it stimulates neighbouring cells


What is a contact dependent signal

Used in cell communication when one cell membrane binds to a membrane protein of another cell


What are gap junctions

Protein channels make bridges between to cells made from connexins
-direct transfer of chemical and electrical signals


What is the ratio of the Na+/K+ pump?

For 1 molecule of ATP, you get 3 Na+ OUT and 2K+ IN