Deck 35: Bacteria

Question 1

Compared to eukaryotes, prokaryotes

A) do not have a cytoskeleton.
B) have no membrane-bound organelles.
C) have a semirigid cell wall.
D) do not have a nucleus.
E) All of the answers are correct.

Answer 1

All of the answers are correct.

Question 2

One piece of evidence for the common origin of all cellular organisms is that all cellular organisms have

A) the same biochemical metabolism.
B) membrane-bound organelles.
C) genetic information in the form of DNA.
D) a nucleus.
E) mitochondria.

Answer 2

genetic information in the form of DNA.

Question 3

Cellular structures to surround the cytoplasm evolved early in the evolutionary history of organisms. These structures were initially beneficial because they

A) allowed anaerobic respiration.
B) allowed bacteria to thrive under hot conditions.
C) concentrated biochemicals in one place.
D) gave protection against UV radiation.
E) allowed specific chemicals to be retained within the membrane.

Answer 3

concentrated biochemicals in one place.

Question 4

About 3.5 billion years ago when life first started to develop, the atmosphere of the earth was likely to have

A) been an oxidising atmosphere.
B) had low levels of UV light.
C) had little ozone.
D) been aerobic.
E) only low levels of oxygen.

Question 5

Compared to the modern age, conditions in the sea 3.5 billion years ago would have been

A) cooler and more salty.
B) cooler and less salty.
C) warmer and more salty.
D) warmer and less salty.
E) similar to now.

Question 6

Early bacteria probably obtained their energy by

A) oxidative phosphorylation.
B) aerobic respiration.
C) anoxygenic photosynthesis.
D) utilising UV radiation.
E) breakdown of sulphate.

Question 7

A phylogenetic tree of the evolutionary relationships of the different taxa of microorganisms can best be inferred by

A) fossil remains of bacterial capsules.
B) comparison of DNA segments.
C) vast numbers of bacteria trapped in sediments.
D) comparison of pathogenic bacteria found in animal fossils.
E) a comparison of RNA in chloroplasts.

Question 8

Prokaryotes can be divided into two major lineages: Archaea and Bacteria. Archaea differ from Bacteria in that Archaea

A) have membrane-bound organelles.
B) do not have a cell wall.
C) have distinctive lipids in the cell membrane.
D) have a cytoskeleton.
E) have a larger ribosome similar to eukaryotes.

Question 9

Using modern techniques for sequencing DNA/RNA, cellular organisms have been classified into three major groups:

A) Eukarya, Archaea, Bacteria.
B) Plants, Animals, Bacteria.
C) Prokaryotes, Plants, Animals.
D) Prokaryotes, Eukaryotes, Fungi.
E) Eukarya, Archaea and Prokaryotes.

Question 10

Penicillin and cephalosporins are effective antibiotics because eukaryotic and prokaryotic cells have different

A) metabolic requirements.
B) microfilaments and microtubules.
C) cell wall structures.
D) types of organelles.
E) cytoplasmic membranes.

Question 11

A common reference system for classifying bacteria used by taxonomists is

A) the Linnaean system.
B) the DNA sequences.
C) gram staining.
D) the Bergey system.
E) Phenotypic characteristics.

Question 12

'Blue-green algal blooms' in Australian waterways are usually caused by

A) cyanobacteria.
B) microalgae.
C) dinoflagellates.
D) euglenoids.
E) stromatolites.

Question 13

A microorganism is isolated from a salty hot spring. It will not grow at room temperature. You would predict that it is a species of

A) microalgae.
B) cyanobacteria.
C) dinoflagellate.
D) Archaea.
E) euglenoids.

Question 14

Which of the following statements about bacteria is CORRECT?

A) The majority of microorganisms in the gut of humans are eukaryotes.
B) Bacteria make up about a third of human faecal material.
C) Most people have a low population of skin bacteria.
D) Current identification of pathogenic bacteria is by PCR (polymerase chain reaction.).
E) The majority of bacteria are pathogenic.

Question 15

An organism that uses carbon dioxide as a carbon source for growth and uses inorganic substances, such as ferrous iron, as an energy source would be classified as a

A) photoheterotroph.
B) photoautotroph.
C) chemoheterotroph.
D) chemoautotroph.
E) chemoheterotroph and chemoautotroph.

Question 16

Bacteria obtain energy by all of the following methods EXCEPT

A) photosynthesis.
B) anaerobic fermentation.
C) aerobic respiration.
D) hydrolysis of water.
E) glycolysis.

Question 17

The conversion of CH₂O + HCO₃ $\rightarrow$ CO₂ + CH₄ would occur during

A) aerobic respiration.
B) anaerobic respiration.
C) photorespiration.
D) chemorespiration.
E) photosynthesis.

Question 18

Nitrogen fixation in soil is carried out by

A) bacteria.
B) fungi.
C) viruses.
D) mycorrhizae.
E) algae.

Question 19

Methanogenic bacteria

A) produce all the methane implicated in global warming.
B) are chemoautotrophs, implying that they require organic carbon molecules as a carbon source.
C) are found in the intestine of mammals, waterlogged soils and garbage tips.
D) use hydrogen gas and oxygen to generate energy.
E) produce hydrogen from methane.

Question 20

To generate energy and make sugars, methanogenic bacteria utilise

A) methane and carbon dioxide.
B) hydrogen and carbon dioxide.
C) hydrogen and methane.
D) methane and oxygen.
E) hydrogen and oxygen.

Question 21

Normal bacterial flora is beneficial to humans and animals because

A) they limit nutrients available to incoming pathogens.
B) they limit space available to incoming pathogens.
C) they can produce antibiotics and viruses that inhibit incoming pathogens.
D) may assist in the breakdown of foods.
E) All of the answers are correct.

Question 22

The use of antibiotics by humans can sometimes result in an opportunistic infection because

A) antibiotics inhibit immune cells, leaving the immune system in a weakened state.
B) antibiotics do not distinguish between 'good' and 'bad' bacteria.
C) some bacteria become resistant to antibiotics.
D) opportunistic pathogens have a symbiotic relationship with the primary pathogen.
E) antibiotics depress cellular energy production in some bacteria and so allow the rapid growth of other bacteria.

Question 23

In a series of experiments, DNA was extracted from pneumonia-causing bacteria and added to a tube containing mutant bacteria of the same species. The mutants had lost the ability to cause pneumonia. Mice were injected with either the mixture or with the mutant strain. Only the mice injected with the mixture died. The results can be best be explained by

A) transduction.
B) transformation.
C) conjugation.
D) mutation.
E) transfection.

Question 24

A bacterium picks up and incorporates some free DNA from its environment, which is then integrated into the bacterial cell. This process is called

A) transformation.
B) transcription.
C) transduction.
D) conjugation.
E) transfection.

Question 25

Genetic variation can arise from conjugation in bacteria. During conjugation

A) there is no physical contact between the bacteria.
B) a bacteriophage acts as a vector for DNA.
C) the incoming DNA is always broken down by enzymes in the recipient bacteria.
D) the incoming DNA may be integrated into DNA in the recipient bacteria or may be maintained as an independent plasmid.
E) small pieces of DNA are transferred from one bacteria to another through bacterial pili.

Question 26

Bacteriophages

A) are bacteria which parasitise other bacteria.
B) may transfer DNA from one bacterium to another.
C) are involved in conjugation.
D) are circular pieces of DNA that exist in the bacterial cell independent of chromosomal DNA.
E) are small viruses that infect bacteria and fungi.

Question 27

A plasmid

A) may act as a vector for transferring DNA.
B) may carry genes for antibiotic resistance.
C) is a small circular piece of DNA.
D) may carry genes from the host DNA.
E) All of the answers are true.

Question 28

Genetic variation in bacteria is achieved by

A) meiosis.
B) being diploid.
C) incorporation of foreign DNA.
D) sexual reproduction.
E) All of the answers are correct.

Question 29

Domain Archaea include species which are able to

A) produce methane.
B) live at extremely high temperatures.
C) replicate under high salt conditions.
D) live in acidic environments.
E) All of the answers are correct.

Question 30

Bacteria are used by humans for many beneficial activities. Such activities include all of the following EXCEPT

A) production of cheese and yoghurt.
B) synthesis of antibiotics.
C) sewage treatment and recycling of waste products.
D) corrosion of concrete pipes.
E) insect control.

Question 31

Which of the following statements about bacteria evolution is CORRECT?

A) Fossil evidence and DNA sequences have been used to determine the phylogenetic relationships of early prokaryotes.
B) Archaea, which are very old life forms, are more closely related to Eukarya than are Bacteria.
C) Prokaryotes able to perform photosynthesis evolved when oxygen became plentiful in the atmosphere.
D) Early prokaryotes were capable of anoxygenic photosynthesis to obtain energy.
E) The earliest forms of microscopic life resembles all modern bacterial forms.

Question 32

A major difference between Bacteria and Archaea is

A) the absence of a nucleus in Bacteria.
B) the presence of introns in Archaea.
C) the presence of multiple RNA polymerases in Archaea.
D) the presence of plasmids in Bacteria.
E) the ability of some bacteria to fix nitrogen.

Question 33

Cyanobacteria are an important subgroup of Bacteria. Which of the statements about cyanobacteria is INCORRECT?

A) The ability of some cyanobacteria to fix nitrogen is used in rice cultivation.
B) Cyanobacteria may grow extensively in water and produce peptide toxins which are harmful to animals.
C) Early photosynthetic cyanobacteria are thought to be responsible for the earth's atmosphere becoming oxygen rich.
D) Stromatolites, which are formed by cyanobacteria are the oldest fossil evidence of life on earth.
E) Cyanobacteria contain chlorophyll and like other photosynthetic organisms, generate molecular oxygen during photosynthesis.

Question 34

The major difference between prokaryotes and eukaryotes is that prokaryotes

A) are able to obtain energy by photosynthesis.
B) have a cell wall.
C) lack a nucleus.
D) are unicellular.
E) All of the answers are correct.

Question 35

Bacteria extract energy from a diverse range of products. Bacteria that are chemoautotrophs

A) metabolise organic substances for both carbon and energy.
B) use light as an energy source, similar to plants and algae.
C) reduce inorganic substances as sources of energy.
D) use organic compounds for growth and development.
E) include green bacteria which use hydrogen as a reductant instead of water.

Question 36

Clostridium difficile can be a particularly dangerous bacterium because

A) it produces exospores with a particularly resilient cell wall.
B) it has resistance to ampicillin and kanamycin.
C) it mutates rapidly.
D) it produces endospores, a toxin and has inherent antibiotic resistance.
E) it produces exospores, a low pH resistant toxin and can accept multiple plasmids.

Question 37

Pseudomembranous colitis can be caused by

A) Lactobacillus rapi.
B) Acetobacter fabarum.
C) Clostridium difficile.
D) Bacillus anthracis.
E) Sclerotinia sclerotiorum.

Question 38

A bacterial strain is identified that is resistant to all known antibiotics. What might be one other effective method of treatment?

A) Tail of a newt
B) Eye of a toad
C) Veined wing of the cicada
D) Fingernail of an orang-utan
E) Halteres of a dipteran

Question 39

A bacterial species is discovered in an aquatic, chemically stratified habitat that possesses intracellular Fe minerals. What might be an unusual feature of these bacteria?

A) The ability to detect north or south
B) Using iron or iron compounds as an electron donor
C) Tolerance to high alkalinity
D) Production of iron oxides, resulting from reacting iron with oxygen
E) Transmission of electro-magnetic waves

Question 40

A microbiologist is asked to identify a species of bacteria which is approximately 300nm in diameter. What means would the microbiologist need to use to accurately visualise the bacteria in some detail?

A) Light microscopy
B) Ultraviolet reflectance microscopy
C) Matrix assisted laser desorption/ionisation-time of flight mass spectrometry
D) Cyanin and/or methylene blue endocytotic staining
E) Scanning electron microscopy

Question 41

Why did the first bacteria to evolve use anoxygenic metabolism?

A) Because molecular oxygen was not present at high enough levels for oxygenic metabolism until after the action of oxygen-producing photosynthetic bacteria increased atmospheric levels
B) Because the Earth's surface was too warm for oxidative phosphorylation to occur
C) Because C-fixation was not oxygen dependant
D) Because the TCA cycle had not yet evolved
E) Because the electron transport chain is oxygen sensitive and compartmentalisation had not yet developed to efficiently partition oxygen within the cell

Question 42

The domain Archaea is most closely related to which super kingdom?

A) Bacteria
B) Eubacteria
C) Eukarya
D) Archaeobacteria
E) Chordata

Question 43

Which of the following characteristics is NOT used to classify bacteria?

A) Size
B) Shape
C) Colour
D) Motility
E) Staining

Question 44

A particularly gullible consumer decides to waste his money and buy one of the ubiquitous hand cleaning products that claims to kill 99.9% of germs. Soon after using the product, the poorly informed consumer found that his hands were again teeming with bacteria. This could be because

A) bacteria spontaneously generated on his hands.
B) the product does not kill bacteria.
C) the bacteria have developed resistance to the product.
D) some bacteria have an impermeable intracellular layer that prevents the entry of all substances.
E) some bacteria produce endospores that are resistant to soaps and disinfectants.