Biology Study Sheet
Chapter 5 Workfile/Study Sheet
1.What type of organisms contain biomembranes?
All living organisms contain biomembranes.
2.Describe the nature of cellular membranes.
Cellular membranes are fluid by nature.
3.What is the major lipid found in membranes?
Phospholipids
4.What component of the cell membrane might contribute to maintaining the fluidity of the plasma membranes?
Chlosterol
5.Describe globular proteins found in the membrane.
They are compacted and folded
Amino acids.
6.What percentage of all genes encode membrane proteins?
25%
7.Give some of the common functions of cellular membranes.
To protect the integrity of the interior of the cell by allowing certain substances into the cell, while keeping other substances out.
8.What does the flippase enzyme do?
Aids in the process of phospholipids that flip
Across the lipid bilayer.
9.What is the fluid-mosaic model?
A model conceived by S.J. Singer and
Garth Nicolson in 1972 to describe the structural features of biological membranes.
10.How might a plant cell compensate for the excessive membrane fluidity that occurs during prolonged exposures to elevated temperature?
Alter the lipid composition to have longer fatty acyl tails and fewer double bonds.
11.Glycosylated proteins and lipids within the plasma membrane are important for what?
Cell recognition
12.What is the function of transmembrane proteins?
Provide channels in which molecules and ions can
Pass into the cell.
13.Placing celery sticks in fresh water will make them more turgid and harder. Describe how this works.
Water enters throught the cell membranes and
Enters into the vacuoles, which fill with water,
Which causes the celery to become harder.
14.Which types of molecules can pass through a lipid bilayer most readily?
Water, and small molecules
15.Animal cells are permeable to water and urea but NOT to sucrose. The inside of a cell contains
1 M sucrose and 1 M urea and the outside 1 M
1.What type of organisms contain biomembranes?
All living organisms contain biomembranes.
2.Describe the nature of cellular membranes.
Cellular membranes are fluid by nature.
3.What is the major lipid found in membranes?
Phospholipids
4.What component of the cell membrane might contribute to maintaining the fluidity of the plasma membranes?
Chlosterol
5.Describe globular proteins found in the membrane.
They are compacted and folded
Amino acids.
6.What percentage of all genes encode membrane proteins?
25%
7.Give some of the common functions of cellular membranes.
To protect the integrity of the interior of the cell by allowing certain substances into the cell, while keeping other substances out.
8.What does the flippase enzyme do?
Aids in the process of phospholipids that flip
Across the lipid bilayer.
9.What is the fluid-mosaic model?
A model conceived by S.J. Singer and
Garth Nicolson in 1972 to describe the structural features of biological membranes.
10.How might a plant cell compensate for the excessive membrane fluidity that occurs during prolonged exposures to elevated temperature?
Alter the lipid composition to have longer fatty acyl tails and fewer double bonds.
11.Glycosylated proteins and lipids within the plasma membrane are important for what?
Cell recognition
12.What is the function of transmembrane proteins?
Provide channels in which molecules and ions can
Pass into the cell.
13.Placing celery sticks in fresh water will make them more turgid and harder. Describe how this works.
Water enters throught the cell membranes and
Enters into the vacuoles, which fill with water,
Which causes the celery to become harder.
14.Which types of molecules can pass through a lipid bilayer most readily?
Water, and small molecules
15.Animal cells are permeable to water and urea but NOT to sucrose. The inside of a cell contains
1 M sucrose and 1 M urea and the outside 1 M