3.1 Plasma Membrane Flashcards
The Lipid bilayer is made up of which parts?
-About 75% of the membrane lipids are lipids that contain phosphorus. -A steroid with an attached OH (hydroxyl) group,
-glycolipids (about 5%), lipids with attached carbohydrate groups.
Membraneproteins are classified as either
integral or peripheral
integral Proteins are ?
Integral proteins extend into or through the lipid bilayer and are firmly embedded in it.
peripheral proteins are?
not as firmly embedded in the membrane. They are attached to the polar heads of membrane lipids or to integral proteins at the inner or outer surface of the membrane.
What is the glycocalyx?
glycoproteins form an extensive sugary coat called the glycocalyx
-the glycocalyx acts like a molecular “signature” that enables cells to recognize one another.
When stimulating a cell, the hormone insulin first binds to a protein in the plasma membrane. This action best represents which membrane protein function?
Receptor integral Protein
True Or False
In ion channels, Integral Proteins. Most ion channels are not selective
False
Most ion channels are selective
What is interesting about Carriers Integral Proteins
are also known as transporters.
What is a ligand?
specific molecule that binds to a receptor is called a ligand
“kink” in the fatty acid tail (see Figure 2.18), which increases membrane fluidity by preventing lipid molecules from packing tightly in the membrane
What factors contribute to an electrochemical gradient?
a positively charged substance will tend to move toward a negatively charged area, and a negatively charged substance will tend to move toward a positively charged area. The combined influence of the con- centration gradient and the electrical gradient on movement of a particular ion is referred to as its electrochemical gradient.
the inner surface of the plasma membrane is more negatively charged and the outer surface is more positively charged
What are the three sides of the Golgi Complex?
-entry (cis) face is a cistern that faces the rough ER.
-The concave exit (trans) face is a cistern that faces the plasma membrane.
- Sacs between the entry and exit faces are called medial cisterns. Transport vesicles (desc
Function of the Cis face in a Golgi Complex?
The entry face receives and modifies proteins produced by the rough ER
Function of the exit (trans) in a Golgi Complex?
The exit face modifies the molecules further and then sorts and packages them for transport to their destinations.
Function of the medial cistern in a Golgi Complex?
The medial cisterns add carbohydrates to proteins to form glycoproteins and lipids to proteins to form lipoproteins.
What are the three general destinations for proteins that leave the Golgi complex?
1: transport vesicles carry digestive enzymes to lysosomes;
2: Some of the processed proteins leave the exit face and are stored in secretory vesicles.
What is the name of the process by which worn-out organelles are digested by lysosomes?
autophagy
How do the mitochondrial cristae contribute to its ATP-producing function?
the elaborate folds of the cristae pro- vide an enormous surface area for the chemical reactions that are part of the aerobic phase of cellular respiration, the reactions that produce most of a cell’s ATP
Mitochondria also play an important and early role in apopto- sis
cytochrome c and other substances initiate a cascade of activation of protein-digesting enzymes that bring about apoptosis.
Are Mitochondria maternal or paternal?
mitochondrial genes are inherited only from your mother. This is due to the fact that all mitochondria in a cell are descendants of those that were present in the oocyte (egg) during the fertilization process.
Which organelles contribute to synthesizing protein hormones and packaging them into secretory vesicles?
Golgi complex
