BIOL exam 1 part 2

What is the most recent date when all cells on Earth still lacked a membrane-enclosed nucleus? A. 2 billion years ago B. 3.5 billion years ago C. 1 billion years ago D. 1.5 billion years ago E. 3 billion years ago

A. 2 billion years ago

Different arrangements and structures of flagella contribute to changes in speed and direction when necessary. Which of the following correctly relates motility to flagellation? A. Bacteria with peritrichously arranged flagella change direction by changing the flagellar rotation and "tumbling." B. Bacteria with lophotrichously arranged flagella change direction only by changing the flagellar rotation. C. Certain flagellated prokaryotes exhibit gliding motility, a slower and smoother form of movement along the long axis of a cell. D. Peritrichously arranged flagella may only rotate counterclockwise.

A. Bacteria with peritrichously arranged flagella change direction by changing the flagellar rotation and "tumbling."

________ are charged molecules that are partially responsible for the ________ charge of the gram-positive bacterial cell surface. A. Teichoic acids / negative B. Lipopolysaccharides / negative C. Phospholipids / negative D. Diaminopimelic acids / positive E. Peptide interbridges / neutral

A. Teichoic acids / negative

What is the most likely outcome for the treatment of a suspension containing equal numbers of bacterial and archaeal cells in a hypotonic solution with lysozyme? A. Only the Bacteria will be lysed. B. None of the cells will be lysed. C. Only the Archaea will be lysed. D. All cells will be lysed.

A. Only the Bacteria will be lysed.

Compared to Eukaryotes, Bacteria and Archaea have ________ surface-to-volume ratios, causing ________ nutrient exchange and growth rates. A. higher / higher B. lower / lower C. higher / lower D. lower / higher

A. higher / higher

Arrange the following types of microorganisms in the order in which they evolved on Earth. A. anaerobes, anoxygenic phototrophs, oxygenic phototrophs, aerobes, multicellular organisms B. anaerobes, multicellular organisms, aerobes C. anaerobes, anoxygenic phototrophs, aerobes, oxygenic phototrophs, multicellular organisms D. oxygenic phototrophs, aerobes, anoxygenic phototrophs, anaerobes, multicellular organisms

A. anaerobes, anoxygenic phototrophs, oxygenic phototrophs, aerobes, multicellular organisms

The earliest stromatolites were probably formed by A. anoxygenic phototrophs. B. oxygenic lithotrophs. C. anoxygenic lithotrophs. D. oxygenic phototrophs.

A. anoxygenic phototrophs.

You are studying 12 new isolates from the human skin. Their 16S rRNA gene sequence identity is 97%.The isolates would most likely be A. classified as individual strains of the same species. B. classified as individual species of the same genus. C. classified as the same species if they can mate via conjugation. D. split into different families.

A. classified as individual strains of the same species. (prof. Taller says B. is a better answer because supposed to be <3% to be same species)

To speed up the growth rate in a chemostat, the ___ should be increased. To increase the cell yield as well, _____ should be increased. A. dilution rate / limiting nutrient B. limiting nutrient / limiting nutrient C. dilution rate / dilution rate D. limiting nutrient / dilution rate

A. dilution rate / limiting nutrient

The Par system is necessary for A. distribution of genetic material in replicating Caulobacter. B. elongation of bacillus prior to cell division. C. formation of a replication fork in Escherichia coli. D. septum formation.

A. distribution of genetic material in replicating Caulobacter.

Accurately counting cells in a biofilm would be challenging when using A. microscopic direct county, turbidity measurement, and viability counts with spread plating. B. microscopic direct counting. C. viability counts with spread plating. D. turbidity measurement.

A. microscopic direct county, turbidity measurement, and viability counts with spread plating.

Which of the following bacterial structures serves the same function as adipose tissue (fat) in animals? A. polyhydroxyalkanoate granules B. sulfur globules C. polyphosphate granules D. magnetosomes

A. polyhydroxyalkanoate granules

The curved-rod shape typical of Caulobacter is due to A. crescentin. B. crescentin and MreB. C. MreB. D. neither crescentin nor MreB.

B. crescentin and MreB.

While examining a rock surface, you have discovered an interesting new organism. Which of the following criteria will allow you to classify the organism as belonging to Bacteria but not Archaea or Eukarya? A. The organism lacks a nucleus. B. Cell walls are made primarily of peptidoglycan. C. The lipids in its plasma membrane consist of glycerol bonded to isoprenoid side chains. D. It can survive at a temperature over 100°C.

B. Cell walls are made primarily of peptidoglycan.

All of the following regarding endospores are true EXCEPT A. All endospore-forming bacteria are gram-positive Firmicutes. B. Endospores serve as reproductive structures and enable survival in harsh environments. C. Endospore formation begins when growth ceases due to the lack of an essential nutrient. D. Botulism, tetanus and several foodborne bacterial infections are caused by endospore-forming bacteria.

B. Endospores serve as reproductive structures and enable survival in harsh environments.

Type IV pili are involved in A. twitching motility and attachment of cells to surfaces. B. attachment to surfaces, twitching motility, and pathogenesis. C. twitching motility. D. pathogenesis. E. attachment of cells to surfaces.

B. attachment to surfaces, twitching motility, and pathogenesis.

The early energy reactions used hydrogen, which is a powerful ________ and could have been used to form ________. A. oxidant / the proton motive force B. electron donor / the proton motive force C. electron acceptor / oxygen D. oxidant / oxygen

B. electron donor / the proton motive force

Based on recent research, eukaryotic cells are believed to have arisen A. by mutations that led to changes in plasma membranes, leading to internal membrane-bound organelles. B. from a fusion of archaeal cells and bacterial cells. C. from the fusion of multiple archaeal cells into a larger, more complex cell. D. independently from prokaryotic cells by mutations that led to changes in plasma membranes, leading to internal membrane-bound organelles. E. independently from prokaryotic cells.

B. from a fusion of archaeal cells and bacterial cells.

An organism of the genus Staphylococcus is ________, while an organism of the genus Spirochaeta is ________. A. spherical / rod shaped B. spherical / spiral C. rod shaped / spiral D. spiral / spherical

B. spherical / spiral

Which statement about endotoxins is true? A. Endotoxins are components of the cell wall of gram-positive bacteria. B. The source of endotoxins is endospores. C. Endotoxins are released only when Gram negative bacteria die and their cell walls break down. D. Endotoxins are released by lysozyme. E. Endotoxins are proteins secreted by prokaryotes.

C. Endotoxins are released only when Gram negative bacteria die and their cell walls break down.

Which of the following statements regarding LUCA is FALSE? A. LUCA is the ancestor of archaea and bacteria. B. LUCA fixed carbon and nitrogen. C. LUCA was the first form of life. D. None of the statements are false. E. LUCA was likely a hyperthermophile living at hydrothermal vents.

C. LUCA was the first form of life.

Gliding motility in bacteria involves which of the following? A. Specialized cell-surface proteins B. Slimy polysaccharides C. Specialized cell-surface proteins and slimy polysaccharides D. Specialized cell-surface proteins, flagella, and slimy polysaccharides E. Flagella

C. Specialized cell-surface proteins and slimy polysaccharides

Diglycerol tetraether lipids A. form typical bilayer membranes. B. are found in some bacteria and some Archaea. C. are a characteristic feature of thermophilic Archaea. D. tend to make the membrane less rigid. E. All of the choices are correct.

C. are a characteristic feature of thermophilic Archaea.

All of the following are TRUE statements concerning binary fission of microbial cells EXCEPT A. elongation of the cell occurs and the chromosomes are pushed apart. B. the chromosome of the cell is replicated. C. daughter cells produced can be of different sizes. D. a septum is formed across the midline of the cell.

C. daughter cells produced can be of different sizes.

Which of the following habitats is home to the largest percentage of prokaryotic biomass on Earth? A. oceans B. surface soils C. marine subsurface D. freshwater E. terrestrial subsurface

C. marine subsurface

Bioremediation is _____. A. the use of prokaryotes in producing transgenic organisms B. the use of prokaryotes in producing pharmaceutical products C. the use of organisms to remove pollutants from the environment D. the modification of prokaryotes for industrial purposes E. the use of biological processes to remedy diseases

C. the use of organisms to remove pollutants from the environment

You are working with a newly described microorganism that has a rotatary appendage that is solid, 10 nm in diameter, and driven by the hydrolysis of ATP. Based on the nature of this appendage, which type of organism is this? A. Bacteria B. Algae C. Bacteria or Archaea D. Archaea E. Protozoa

D. Archaea

Which of the following statements is FALSE? A. There are no known pathogenic Archaea. B. Eighty percent of life's history on Earth is exclusively microbial. C. Microbial biomass on Earth likely exceeds that of higher organisms. D. Humans contain 10 times more bacterial cells than human cells. E. Estimates of the total number of prokaryotic cells on Earth are about 2.5 x10^30.

D. Humans contain 10 times more bacterial cells than human cells.

What is one piece of evidence that supports the RNA world hypothesis? A. Early cells relied more heavily on RNA than on DNA. B. There are traces of RNA that have been dated and found to be older than any traces of DNA. C. RNA is more stable than DNA and therefore more likely to have been able to exist in such a harsh environment. D. RNAs can have catalytic activity. E. RNAs can replicate themselves.

D. RNAs can have catalytic activity.

The site of septum formation in E. coli is determined by the MinCDE proteins. Which of the following statements regarding the positioning of the septum are correct? A. MinCDE proteins are fixed at the site of septum formation. B. The concentration of MinCDE proteins is highest in the midpoint of the cell. C. MinCDE proteins form the scaffold for septum construction. D. The concentration of MinCDE proteins is lowest in the midpoint of the cell.

D. The concentration of MinCDE proteins is lowest in the midpoint of the cell.

What was produced by photosynthesis before the cyanobacterial lineage developed on Earth? A. oxygen B. hydrogen sulfide C. ferrous iron D. elemental sulfur

D. elemental sulfur

Scientists have identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains? A. microscopically observed staining characteristics of the cell wall B. ecological characteristics such as the ability to survive in extreme environments C. metabolic characteristics such as the production of methane gas D. genetic characteristics such as ribosomal RNA sequences E. metabolic characteristics such as chemoautotrophy and photosynthesis

D. genetic characteristics such as ribosomal RNA sequences

All of the following structures contribute to the ability of pathogenic bacteria to cause disease EXCEPT A. exotoxins B. lipopolysaccharide. C. fimbriae. D. inclusions. E. capsules.

D. inclusions.

Gram-negative bacteria have __________ peptidoglycan than gram-positive cells, and their cell walls are __________ complex structurally. A. more ... less B. more ... more C. less ... less D. less ... more E. None of the listed responses is correct.

D. less ... more

β-lactam antibiotics inhibit peptidoglycan A. glycan tetrapeptide precursor formation. B. transglycosylation and transpeptidation. C. autolysins. D. transpeptidation. E. transglycosylation.

D. transpeptidation.

Both lysozyme and penicillin disrupt the bacterial cell wall peptidoglycan, leading to cell lysis. However, their mechanisms of action are different, based on the fact that __________. A. penicillin cleaves the peptide cross-links in peptidoglycan. B. penicillin kills both bacterial and eukaryotic cells C. penicillin cleaves the glycosidic bonds in the peptidoglycan D. lysozyme cleaves the peptide cross-links in peptidoglycan. E. penicillin kills only growing cells

E. penicillin kills only growing cells