biology chapter 4

Which component is the most important in determining the fluidity of the cell membrane?

cholesterol

The "fingerprint" found on the outside of cells is the best underlying explanation for why:

it is difficult to transplant a liver from one person into another.

Mitochondria are thought to have evolved from free-living bacteria that were incorporated into eukaryotic cells by endosymbiosis. Which piece of evidence for this hypothesis is false?

Mitochondria can survive and reproduce independently when removed from the host cell.

Which organelles are enclosed by a double membrane?

mitochondria and chloroplasts

The rough endoplasmic reticulum:

modifies proteins that will be shipped elsewhere in the organism.

Osmosis is ______ specialized than diffusion because it involves _________.

more; water

Diffusion across the cell's outer membrane:

occurs without the input of energy.

The functions of cell vacuoles include storing nutrients, physically supporting the surrounding cell, deterring predators from eating the cell, and managing waste. What additional service do vacuoles provide?

producing flashy pigments

Mammalian cells take in many molecules including hormones, antibodies, and blood proteins. This process, which is coordinated by proteins that recognize their specific target molecule, is best described as:

receptor-mediated endocytosis.

Which statement is not part of the modern cell theory?

Cells are able to synthesize their entire complement of biomolecules.

Which statement about phospholipids is false?

In the plasma membrane, phospholipids' tails extend toward the extra- and intracellular fluid.

Which statement is not true about prokaryotic cells?

They all have a rigid cell wall instead of a plasma membrane.

Which structure is not present in the cell membrane?

a glycogen band between the phospholipid layers

What might you expect to find in a eukaryotic cell, such as a liver cell, that processes a lot of larger nutrients?

a large number of lysosomes

The diagram shows the action of beta-blockers in reducing anxiety. In this diagram, the green figures represent ________________, the yellow figures represent ______________, and the purple figures represent ______________.

adrenaline; beta-blocker chemicals; beta-receptors

Cells that are metabolically active and use a lot of energy:

are densely packed with numerous mitochondria.

Cell walls:

are not completely solid, having many small pores.

Active transport, which is the moving of molecules from areas of low concentration to those of high concentration across the membrane, is usually coupled with processes that:

cost energy.

The cell connections represented here are:

desmosomes.

The nucleus:

directs cellular activity and stores hereditary information.

Given that a cell's structure reflects its function, what would you predict that the function of a cell with a large Golgi apparatus would be?

secretion of digestive enzymes

Two drugs, called colchicine and cytochalasin, are known to disrupt the cytoskeleton within a eukaryotic cell, such as an amoeba. Which cell function would be most affected by addition of these drugs to an amoeba?

the ability of the amoeba to crawl and change shape

A scientist tries to build a eukaryotic cell in her laboratory. She remembers to include most of the organelles, but forgets one. Among other abnormalities, her newly created cell cannot synthesize the enzymes needed to detoxify drugs and poisons. Which organelle is missing?

the smooth endoplasmic reticulum

A cell's interior is considered isotonic to the surrounding fluid when:

the solute concentrations are the same within and outside the cell.