Question 1

Evolutionary biologists have always used a broad range of modern organisms to infer the characteristics that ancestral organisms may have possessed.Genomic sequences are now available for an increasing number of species, and scientists studying evolutionary processes can take advantage of this enormous amount of data to bring evolution into the arena of molecular studies.By aligning the sequences of homologous genes and looking for regions of similarity and where changes have occurred, it is possible to infer the sequence of the ancestral gene.
A.What term is used to describe the changes in gene sequences that have occurred? How can we use what we know about this process to construct a time line showing when various sequence changes occurred and when they led to the modern sequences that we know today?
B.It is possible to express an ancestral gene sequence in modern organisms and subsequently compare the function of its product with that of the modern protein.Why might this approach give misleading conclusions?

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The answer of Evolutionary biologists have always used a broad...

Question 2

Cellular processes are often regulated by unknown mechanisms.In many cases, biologists work backward in an attempt to understand a process in which they are interested.This was the case when Nurse and Hartwell were trying to understand how cell division is controlled in yeast.Describe the process by which they "broke" the system and then supplied the "missing parts" to get the cell cycle running again.What further evidence did they collect to show that human cells and yeast cells regulate the cell cycle using a similar mechanism?

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The answer of Cellular processes are often regulated by unknown...

Question 3

Match between columns Premises: Lysosomes are small organelles where fatty acid synthesis occurs.
The number of mitochondria inside a cell remains constant over the life of the cell.
Membrane components in the cell are made in the endoplasmic reticulum.
The Golgi apparatus is made up of a series of membrane-enclosed compartments through which materials destined for secretion must pass.
With respect to cellular respiration, the only organelles used by animal cells are mitochondria, while plant cells use both mitochondria and chloroplasts.

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The Answer of False and True is...

Question 4

Genes that have homologs in a variety of species have been discovered through the analysis of genome sequences.In fact, it is not uncommon to find a family of homologous genes encoding proteins that are unmistakably similar in amino acid sequence in organisms as diverse as budding yeast, archaea, plants, and humans.Even more remarkably, many of these proteins can substitute functionally for their homologs in other organisms (i.e., if we delete a native gene and replace it with a homologous gene from another species, the protein will be produced and its function preserved).Use your understanding of evolution to explain how this is possible.

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The answer of Genes that have homologs in a variety...

Question 5

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; each word or phrase should be used only once.
$\begin{array}{lll}
\text { chloroplast } & \text { cytosol } & \text { nucleus } \
\text { chromosome } & \text { endoplasmic reticulum } & \text { ribosomes } \
\text { cytoskeleton } & \text { mitochondrion } &
\end{array}$

Eukaryotic cells are bigger and more elaborate than prokaryotic cells.By definition, all eukaryotic cells have a __________, usually the most prominent organelle.Another organelle found in essentially all eukaryotic cells is the __________, which generates the chemical energy for the cell.In contrast, the __________ is a type of organelle found only in the cells of plants and algae, and performs photosynthesis.If we were to strip away the plasma membrane from a eukaryotic cell and remove all of its membrane-enclosed organelles, we would be left with the __________, which contains many long, fine filaments of protein that are responsible for cell shape and structure, and thereby form the cell's __________.

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The answer of For each of the following sentences, fill...

Question 6

Generate an analogy to describe the cell as the simplest unit of life to somebody who has not studied biology.Be sure to incorporate the observable features of living organisms, which distinguishes them from inanimate objects.

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The answer of Generate an analogy to describe the cell...

Question 7

Match between columns Premises: Thermal energy promotes random movement of proteins, vesicles, and small molecules in the cytosol.
Plants do not require a cytoskeleton because they have a cell wall that lends structure and support to the cell. The cytoskeleton is used as a transportation grid for the efficient, directional movement of cytosolic components.

Accepted Answer

The Answer of False and True is...

Question 8

Cellular populations in bacterial colonies and the human body both start with single founder cells, yet these two collections of cells are vastly different.What is the primary reason for these differences?

Accepted Answer

The answer of Cellular populations in bacterial colonies and the...

Question 9

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; each word or phrase should be used only once.
$\begin{array}{lll}
\text { amino acids } & \text { micrometer(s) } & \text { viruses } \
\text { DNA } & \text { millimeter(s) } & \text { yeast } \
\text { fatty acids } & \text { plants } & \
\text { meter } & \text { plasma membranes } &
\end{array}$

Cells can be very diverse: superficially, they come in various sizes, ranging from bacterial cells such as Lactobacillus, which is a few __________ in length, to larger cells such as a frog's egg, which has a diameter of about 1 __________.Despite the diversity, cells resemble each other to an astonishing degree in their chemistry.For example, the same 20 __________ are used to make proteins.Similarly, the genetic information of all cells is stored in their __________.Although __________ contain the same types of molecules as cells, their inability to reproduce themselves by their own efforts means that they are not considered living matter.

Accepted Answer

The answer of For each of the following sentences, fill...

Question 10

Match between columns Premises: Primitive plant, animal, and fungal cells probably acquired mitochondria after they diverged from a common ancestor. Protozoans are single-celled eukaryotes with cell morphologies and behaviors that can be as complex as those of some multicellular organisms.
The first eukaryotic cells on Earth must have been aerobic; otherwise, they would not have been able to survive when the planet's atmosphere became oxygen-rich.

Accepted Answer

The Answer of True and False is...

Question 11

Match between columns Premises: The human genome is roughly 30 times larger than the Arabidopsis genome, but contains approximately the same number of protein-coding genes.
The variation in genome size among protozoans is larger than that observed across all species of mammals, birds, and reptiles.
The vast majority of our genome encodes functional RNA molecules or proteins and most of the intervening DNA is nonfunctional.

Accepted Answer

The Answer of False and True is...

Question 12

The protozoan Didinium feeds on other organisms by engulfing them.Describe the cellular characteristics necessary to feed this way and explain why this is not a mechanism by which bacteria can acquire energy.Are bacteria, in general, unable to feed on other cells in this way?

Accepted Answer

The answer of The protozoan Didinium feeds on other organisms...

Question 13

Match between columns
                        Premises: The nucleus of an animal cell is round, small, and difficult to distinguish using light microscopy.
The cytosol is fairly empty, containing a limited number of organelles, which allows room for rapid movement via diffusion.
The extracellular matrix is the space between individual cells and is exclusively composed of proteins.
The presence of the plasma membrane can be inferred by the well-defined boundary of the cell.

Accepted Answer

The Answer of False and True is...

Question 14

Describe the benefits and limitations of utilizing electron microscopy to understand biological systems.

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The answer of Describe the benefits and limitations of utilizing...

Question 15

Number the following cells based on when they are believed to have evolved.
___ anaerobic eukaryote
___ aerobic prokaryote
___ anaerobic prokaryote
___ photosynthetic eukaryote
___ aerobic eukaryote
___ photosynthetic prokaryote

Accepted Answer

The answer of Number the following cells based on when...

Question 16

The antibiotic streptomycin inhibits protein synthesis in bacteria.If this antibiotic is added to a culture of animal cells, protein synthesis in the cytosol continues normally.However, over time, the population of mitochondria in the cell becomes depleted.Specifically, it is observed that the protein-synthesis machinery inside the mitochondria is inhibited.
A.Explain this observation based on what you know about the origins of the modern eukaryote.
B.What do you expect to observe if, in a new experiment, animal cells are treated with diphtheria toxin, a compound that is known to block cytosolic protein synthesis but does not have any impact on bacterial growth?

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The answer of The antibiotic streptomycin inhibits protein synthesis in...

Question 17

You fertilize egg cells from a healthy plant with pollen (which contains the male germ cells) that has been treated with DNA-damaging agents.You find that some of the offspring have defective chloroplasts, and that this characteristic can be passed on to future generations.This surprises you at first because you happen to know that the male germ cell in the pollen grain contributes no chloroplasts to the fertilized egg cell and thus to the offspring.What can you deduce from these results?

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The answer of You fertilize egg cells from a healthy...

Question 18

Employ the principles of evolution discussed in this chapter to explain how the specific features and predatory behaviors of some primitive eukaryotes may have given them a selective advantage over others 1.5 billion years ago.

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The answer of Employ the principles of evolution discussed in...

Question 19

Match between columns
                        Premises: The branchlike extensions that sprout from a single nerve cell in a mammalian brain can extend over several hundred micrometers.
Cells of different types can have different chemical requirements.
The Paramecium is a multicellular microorganism covered with hair-like cilia.

Accepted Answer

The Answer of True and False is...

Question 20

You have been following the recent presidential elections and have heard some candidates disparaging excessive and "unnecessary" federal government expenditures.One particular candidate asks: "Why are we spending millions of dollars studying fruit flies? How can that possibly help us find a cure for cancer?" Use your knowledge of model organisms to explain why studies in D.melanogaster (the fruit fly) are actually an excellent use of research funding.

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The answer of You have been following the recent presidential...

Quiz 1: Cells: The Fundamental Units of Life

Indicate whether the following statements are TRUE or FALSE.If the statement is false, explain why it is false.

Generate an analogy to describe the cell as the simplest unit of life to somebody who has not studied biology.Be sure to incorporate the observable features of living organisms, which distinguishes them from inanimate objects.

Indicate whether the following statements are TRUE or FALSE.If the statement is false, explain why it is false.

Cellular populations in bacterial colonies and the human body both start with single founder cells, yet these two collections of cells are vastly different.What is the primary reason for these differences?

Indicate whether the following statements are TRUE or FALSE.If the statement is false, explain why it is false.

Indicate whether the following statements are TRUE or FALSE.If the statement is false, explain why it is false.

The protozoan Didinium feeds on other organisms by engulfing them.Describe the cellular characteristics necessary to feed this way and explain why this is not a mechanism by which bacteria can acquire energy.Are bacteria, in general, unable to feed on other cells in this way?

Indicate whether the following statements are TRUE or FALSE.If the statement is false, explain why it is false.

Describe the benefits and limitations of utilizing electron microscopy to understand biological systems.

Number the following cells based on when they are believed to have evolved. _ anaerobic eukaryote _ aerobic prokaryote _ anaerobic prokaryote _ photosynthetic eukaryote _ aerobic eukaryote _ photosynthetic prokaryote

Employ the principles of evolution discussed in this chapter to explain how the specific features and predatory behaviors of some primitive eukaryotes may have given them a selective advantage over others 1.5 billion years ago.

Indicate whether the following statements are TRUE or FALSE.If the statement is false, explain why it is false.

Quiz 1: Cells: The Fundamental Units of Life

Indicate whether the following statements are TRUE or FALSE.If the statement is false, explain why it is false.

Generate an analogy to describe the cell as the simplest unit of life to somebody who has not studied biology.Be sure to incorporate the observable features of living organisms, which distinguishes them from inanimate objects.

Indicate whether the following statements are TRUE or FALSE.If the statement is false, explain why it is false.

Cellular populations in bacterial colonies and the human body both start with single founder cells, yet these two collections of cells are vastly different.What is the primary reason for these differences?

Indicate whether the following statements are TRUE or FALSE.If the statement is false, explain why it is false.

Indicate whether the following statements are TRUE or FALSE.If the statement is false, explain why it is false.

The protozoan Didinium feeds on other organisms by engulfing them.Describe the cellular characteristics necessary to feed this way and explain why this is not a mechanism by which bacteria can acquire energy.Are bacteria, in general, unable to feed on other cells in this way?

Indicate whether the following statements are TRUE or FALSE.If the statement is false, explain why it is false.

Describe the benefits and limitations of utilizing electron microscopy to understand biological systems.

Number the following cells based on when they are believed to have evolved. ___ anaerobic eukaryote ___ aerobic prokaryote ___ anaerobic prokaryote ___ photosynthetic eukaryote ___ aerobic eukaryote ___ photosynthetic prokaryote

Employ the principles of evolution discussed in this chapter to explain how the specific features and predatory behaviors of some primitive eukaryotes may have given them a selective advantage over others 1.5 billion years ago.

Indicate whether the following statements are TRUE or FALSE.If the statement is false, explain why it is false.

Number the following cells based on when they are believed to have evolved. _ anaerobic eukaryote _ aerobic prokaryote _ anaerobic prokaryote _ photosynthetic eukaryote _ aerobic eukaryote _ photosynthetic prokaryote