Cells and Cell Membranes Flashcards
What did Schwann propose?
Schwann proposed that all living things are composed of cells and cell products.
What did Virchow propose?
Virchow proposed that all cells originate from another existing cell.
Why are large organisms made of many cells rather than one large cell?
The surface area of the cell does not increase fast enough to meet the demands that the increase in volume requires and there are benefits to cell specialization.
What are the requirements of a plasma membrane?
It must contain the contents of the cell, allow transport into and out of the cell, and be flexible.
What makes the phospholipid bilayer flexible?
They are not held together with covalent bonds, but clump together in a specific shape due to their hydrophilic and hydrophobic ends.
Which steroid prevents leaking at high temperatures and solidifying at low temperatures in the phospholipid bilayer?
Cholesterol embedded in the membrane.
What are the two categories of membrane proteins and what do they do?
Integral (goes all the way through the bilayer and acts as transporters and channels) and peripheral (sit on the outside of the bilayer and act as markers).
What direction do carbohydrates such as glycolipids and glycoproteins face?
They face outwards from the phospholipid bilayer.
What is the function of red blood cells?
To transport oxygen and carbon dioxide.
What is an antigen?
A substance that elicits an immune response by binding to receptors of B cells, antibodies, or of T cells
What are the antigens on red blood cells made of?
Glycolipids.
What integral membrane proteins are found on human red blood cells?
D antigen proteins, also known as Rhesus factor.
What is the difference between plant cell plasma membranes and animal cell plasma membranes?
Plant cells have fewer glycolipids, glycoproteins, and cholesterols (other steroids are more common).
How are prokaryotic cell plasma membranes different from animal cell membranes?
They do not have glycolipids, glycoproteins, or steroids.
What are ways plasma membranes can increase their surface area?
With cilia, infoldings, and outfoldings.
