Unit 6 4 Flashcards
What does the phospholipid bilayer descibe?
The arrangement of cell membranes into a hydrophobic region and hydrophilic regions.
What is the hydrophobic layer of the cell membrane made of?
Amino acid chains (fats)
What is the hydrophilic layer made of?
Phosphorus molecules.
What are integral membrane proteins? Are they polar or not?
Integral membrane proteins are proteins that traverse the full thickness of the phospholipid bilayer. They have some hydrophilic (polar) and hydrophobic (non-polar) regions.
What are the proteins attached to the edges of the phospholipid bilayer?
Peripheral proteins
Give some examples of peripheral proteins.
a receptor on the cell surface or an enzyme facing the cytoplasm
What are cytoskeletons made of?
Fibers in the cytoplasm.
What is the sugar coating or carbs located on the outside of a cell called? What is its purpose?
It is called the glycocalyx. It allows cells to recognize each other.
What does cholesterol do? What happens when there is too much of it in a cell?
Cholesterol helps maintain structure and reduce fluidity. Too much cholesterol can make cells lose their felxibility.
Define a junction.
Modifications of the plasma membrane that perform important functions.
What are the 3 types of junction?
Tight junctions, desmosomes, Gap junctions.
What are tight junctions good for? How are they described?
Tight junctions are fusion of adjacent membranes. They prevent the passage of molecules.
What are desmosomes? What are the three parts of a desmosome that help it function?
Desmosomes are anchoring junctions. The two membranes are bound together by linker proteins, held in place by plaques (thicker plates of cell membrane), which is supported by keratin filaments inside the cytoplasm.
What is a gap junction molecule called?
A connexon
What junctions are electrically exciteable?
Gap junctions.
List the 6 functions of these membrane proteins.
- Transport2. Enzymatic activity3. Receptors for signal transduction4. Intercellular joining5. Cell-cell recognition6. Attachment to extracellular membrane
Define interstitial fluid
It is a filtrate of blood that contains salts, sugars, amino acids, vitamins, hormones, and gases.
What three things must a cell do to maintain homeostasis?
Extract materials from outside the cell, keep materials inside the cell, and discard waste from inside the cell.
What are the three types of passive transport?
Simple diffusion, facilitated diffusion, and Osmosis
What are the three influencers of diffusion?
- The concentration gradient2. Molecule size3. Temperature
What types of molecules take part in simple diffusion?
Lipid soluble molecules.