BIO EXAM TWO ANSWERS

The photo-bleaching experiments we discussed in class demonstrated

The fluid mosaic model of plasma membranes.

What best describes the nature of the nuclear membrane?

A double phospholipid bilayer

Prokaryotic cells do not have

An endomembrane network. a membrane bound nucleus.

What do facilitated diffusion and active transport have in common?

Carrier proteins are used in both facilitated diffusion and active transport.

Which of the following is true of cell membrane fluidity?

Fluidity can be regulated by varying the length and degree of saturation in the fatty acid chains of membrane phospholipids.

Histones are proteins that bind to chromosomal DNA in the nucleus. Based on that knowledge, which of the following is true?

Histone proteins will be synthesized by ribosomes in the cytoplasm.

Animal cells are growing in an incubator at 37°C. The cells are then placed into an incubator at 47°C. Which of the following is most likely to happen?

Initially, the plasma membrane of the cells become more fluid.

Which of the following is true of lysosomes?

Lysosomes may be used to break down "worn out" organelles.Lysosomes contain enzymes that hydrolyze polymers.

Are plant cell walls chemically similar to prokaryotic cell walls? How are they the same or different?

No, Plant cell walls are made of cellulose and bacterial cell walls are made of peptidoglycans.

Which of the following are found in all prokaryotic and eukaryotic cells?

Plasma (cell) membrane. ribosomes

All cells fall into one of two broad categories. What are they?

Prokaryotes and Eukaryotes

Which of the following is not a function of the extracellular matrix (ECM)?

Reinforcing structures within cells that allow mobile cells to move

To be considered alive an organism MUST be able to

Reproduce. grow and metabolize.

Evert Gorter's experiment with red blood cells demonstrated

That plasma membranes are phospholipid bilayers.

Which of the following have no physical contact with the plasma membrane of cells?

The extracellular matrix, the cytoskeleton, integral proteins

Where precisely are ribosomes assembled in eukaryotic cells?

The nucleolus

Within the chloroplast there is a thick liquid substance called

The stroma.

What is most likely true of phospholipids that will become part of a cell's plasma membrane?

They are synthesized in the smooth ER and sent to the plasma membrane by exocytosis.

A symporter is a carrier protein that will

Transport two different molecular species in the same direction at the same time.

Evert Gorter used red blood cells (RBCs) in his experiment for several good reasons. Which reason below is the most important reason that he used RBCs?

Within an individual organism all RBCs are the same size.