Exam 5: Cells: the Working Units of Life

A student collects water from a freshwater pond and views samples of the water under a microscope.She observes several unicellular organisms and begins to classify them as prokaryotic or eukaryotic.To do this, she looks for the presence or absence of _______ structures inside the cells.

Refer to the table below, which was created to summarize similarities and differences between prokaryotic and eukaryotic cells. Which statement best evaluates the accuracy of the information as it is shown in the table?

Refer to the figure below showing a labeled sketch of a prokaryote. Which two structures have had their labels switched?

The figure below shows the beginning steps in the evolutionary process that biologists hypothesize led to the formation of the cell nucleus and the rise of eukaryotic cells. Identify the process shown in the figure, and name a structure other than the nucleus that was likely formed in this same process.

In a mixture of ground-up plant cells, one membrane-bound organelle stains positive for hydrogen peroxide.This organelle is probably a

Five observations of modern cells are listed.Which observation best supports the endosymbiosis theory?

Researchers have identified and sequenced the genes encoding proteins associated with nuclear pores in both yeast and vertebrates.They have used these data to determine the amino acid sequences of these proteins and have applied molecular modeling techniques to predict the three-dimensional structures of the proteins.All contain nearly identical folding regions that may serve to hold lipid membranes in sharp curves.Because this finding has been demonstrated in both yeast and vertebrates (representing organisms that diverged long ago in evolutionary history), it provides evidence of a possible mechanism for the evolution of a subcellular structure.Which subcellular structure is this?

The cytoplasm of a prokaryotic cell

Suppose that you were discussing cell theory with someone who has little understanding of biology.Which object could you best use as an analogy to explain the evolutionary history of modern cells?

Biologists say that life is continuous.Explain what is meant by this statement, and give an example to illustrate your explanation.

Regions of DNA from a human liver cell show the same base sequences as regions of DNA from a cell of the bacterium Escherichia coli.Scientists use this as evidence that humans and bacteria present on Earth today share a common _______ in their evolutionary histories.

It is found that a particular type of cell isolated and growing in culture secretes a much larger amount of protein than human liver cells grown under the same conditions.From this, you hypothesize that these cells must have a large number or amount of

The _______ is a major feature of a prokaryotic cell.

Refer to the figure below. The very large organelle shown in the figure, which contains the genetic material of a cell, is a _______.

Muscle cells need large amounts of calcium and ATP for contraction.Based on these requirements, you would expect that muscle cells would have an increased number of what type of organelles (per unit volume)?

The substances that enter the Golgi apparatus come from the _______ in vesicles.

A researcher growing cells in culture observed that the cells always divided once they reached a certain size.When she added more nutrients to the culture medium or adjusted the temperature of the growing chamber, the cells grew at different rates but always divided once they reached a certain size.Which statement explains these observations?

Specialized cellular appendages of prokaryotes that help bacteria adhere to one another when they exchange genetic material are called

Refer to the sketch of a prokaryote below. The arrow points to the nucleoid, a region that contains a single molecule of _______.

Galactose-substituted diglycerides and sulfolipids are the most abundant lipids in the biosphere because of their presence in _______, which are highly abundant in plant cells.