Question 1

Are the cells which emerge from the Chlamydomonas cyst genetically identical to those which entered it? Identify the correct statement:

Accepted Answer

While some genetic diversity may arise from mutations during the growth of the Chlamydomonas cyst, some of the emerged cells may still have the same genetic makeup as the cells that entered the cyst. However, it is unlikely that all of the emerged cells will be genetically identical to those that entered the cyst due to potential mutations that could occur during the adaptive cycle.

Question 2

A haploid Chlamydomonas replicates asexually under favorable environmental conditions.What happens when growth conditions deteriorate?

Accepted Answer

Under deteriorating conditions, Chlamydomonas can switch from asexual to sexual reproduction, forming gametes that fuse with another gamete to ensure survival through genetic recombination and potentially more resistant diploid zygotes.

Question 3

Which of these best describes the process of meiosis in eukaryal cells?

Accepted Answer

Meiosis involves one round of DNA replication followed by two rounds of cell division, resulting in the production of haploid cells.

Question 4

Which alga is commonly used as a model eukaryal organism to study flagellar operation?

Accepted Answer

Chlamydomonas reinhardtii is commonly used as a model eukaryal organism to study flagellar operation because it possesses two flagella that are necessary for its motility and is genetically tractable.

Question 5

Identify the correct association between organism and characteristics:

Accepted Answer

Algae are known to have cellulose cell walls, while fungi have chitin cell walls. Chloroplasts are found in plants and some protists, but not in fungi. Protozoa also have chitin cell walls, and slime molds are not known to have any cell wall material. Fungi generally do not have flagella, although some do have motile spores.

Question 6

In which organismal comparison might you best investigate intracellular signaling mechanisms?

Accepted Answer

The answer of In which organismal comparison might you best...

Question 7

Haploid Dictyostelium replicate by mitosis when nutrients are plentiful.What happens when growth conditions deteriorate?

Accepted Answer

When growth conditions deteriorate, haploid Dictyostelium cells aggregate to form a multicellular slug. This is the first step in their differentiation process leading to the formation of a fruiting body. The slug is capable of moving towards a better growth environment where it can produce a stalk and spores for dispersal.

Question 8

The prokaryotic kingdom Monera no longer exists as new molecular evidence proved that it was inadequate to describe prokaryotc diversity.Which of the eukaryotc kingdoms do you predict will be the next to fall for the same reason?

Accepted Answer

The kingdom Protista contains a diverse group of unicellular and simple multicellular eukaryotes, including algae, amoebas, and protozoans. However, recent molecular evidence suggests that this group is polyphyletic, meaning that it does not represent a monophyletic group with a common ancestor. Instead, it is likely that some members of Protista are more closely related to plants, animals, or fungi than they are to other members of the group. Therefore, the kingdom Protista is no longer considered a valid group and is likely to be replaced with more accurately defined clades in the future.

Question 9

Identify the correct association between organism and characteristic:

Accepted Answer

The answer of Identify the correct association between organism and...

Question 10

Which organism displays the most recent evolutionary ancestry?

Accepted Answer

The answer of Which organism displays the most recent evolutionary...

Question 11

Which organism appears displays the oldest evolutionary ancestry?

Accepted Answer

Glaucophytes are believed to be one of the earliest-diverging groups of photosynthetic organisms, and their unique characteristics suggest that they may provide important insights into the evolution of photosynthesis itself. Studies of their genetic material have indicated that they have a very ancient lineage, which likely dates back almost 1.5 billion years. Furthermore, many of their features, such as the presence of a distinct peptidoglycan layer and a cyanobacterial-like photosynthetic apparatus, suggest that they may be closely related to the ancestral forms of higher plants.

Question 12

The appearance of mitochondria within eukaryal cells is defined as an evolutionary Big Bang.Which landmark ability might have preceded it?

Accepted Answer

Phagocytosis, the ability to engulf and digest particles, likely preceded the appearance of mitochondria as it allowed for the incorporation of aerobic bacteria within the ancestral eukaryotic cell, giving rise to the endosymbiotic relationship that led to the evolution of mitochondria.

Question 13

The eukaryal cell emerged on Earth approximately ______ years ago.

Accepted Answer

The oldest known eukaryotic fossils are approximately 1.8 billion years old, so it is estimated that eukaryotic cells emerged on Earth around two billion years ago.

Question 14

Given your biological knowledge of cellular and acellular slime molds,select the correct reproductive strategy employed by Dictyostelium:

Accepted Answer

Dictyostelium undergoes asexual reproduction during the single celled phase and meiotic divisions within the fruiting body, which is consistent with the reproductive strategy employed by cellular slime molds. Asexual reproduction occurs when two haploid spores that are genetically different fuse and form a dikaryote, which eventually undergoes meiosis to form haploid spores. These spores can then give rise to new haploid amoebae. During the multicellular phase, Dictyostelium forms a fruiting body, which is composed of stalk and spore cells. The stalk cells undergo programmed cell death, while the spore cells undergo meiosis to produce haploid spores.

Question 15

Giardia lamblia is of significance because:

Accepted Answer

Giardia lamblia is of significance because it causes disease in around one billion individuals around the world. It is a common cause of diarrhea and can cause chronic gastrointestinal problems if left untreated.

Question 16

The signaling substance used to direct the aggregation of cells during the Dictyostelium growth cycle indicates:

Accepted Answer

The signaling substance used to direct the aggregation of cells during the Dictyostelium growth cycle is cyclic AMP (cAMP), which is produced by starving cells that lack sufficient nutrients for growth and development. Therefore, choice C (low levels of nutrients have led to an energy shortage) is the correct answer.

Question 17

The definition of a clade is "a group of organisms sharing a common phylogenetic history.Which of the following pairings shows organisms from the same clade?

Accepted Answer

The answer of The definition of a clade is "a...

Question 18

The Endosymbiotic Theory is used to explain the origin of the ____ in the eukaryal cell.

Accepted Answer

The Endosymbiotic Theory proposes that mitochondria, along with chloroplasts in photosynthetic eukaryotic cells, were originally free-living prokaryotic organisms that were engulfed by ancestral eukaryotic cells and became mutualistic endosymbionts. As a result, mitochondria contain their own DNA and reproduce independently within eukaryotic cells.

Question 19

The result of meiosis is the production of:

Accepted Answer

Meiosis is a cell division process that leads to the formation of four haploid daughter cells from a diploid parent. This process involves two rounds of cell division, resulting in four daughter cells that contain half the number of chromosomes as the parent cell. Therefore, the correct answer is A) four haploid cells.

Question 20

When the fungus Saccharomyces cerevisiae completes meiosis,the resulting ascospores:

Accepted Answer

The resulting ascospores may combine to form a diploid cell through fertilization or they may replicate as haploid cells through mitosis. This is because Saccharomyces cerevisiae is capable of both sexual and asexual reproduction.

Quiz 3: Eukaryal Microbes