bio 2117 final exam

Transfer of DNA between bacterial cells

Conjugation

Copying DNA into mRNA

Transcription

A change into the DNA sequence

Mutation

Conversion of mRNA into protein

Translation

Which of the following pairs is mismatched?

cell wall-toxin

If a bacterial culture shows no clear zone around an antibiotic disk during a disk diffusion test, what can be concluded?

The bacteria are resistant to the antibiotic.

Gram-negative bacteria are generally more resistant to antibiotics than Gram-positive bacteria due to their thicker peptidoglycan layer.

False

What is the primary function of ribosomes in a bacterial cell?

Protein synthesis

What is the main function of the bacteria cell wall?

Protection against osmotic pressure

Which term describes spherical bacteria arranged in chains?

Streptococcus

Which of the following statements regarding infections involving biofilms is FALSE?

biofilms only form in natural environments not in clinical settings

The DNA found in bacterial cells in linear in structure.

False

Endospores are a productive structure.

False

Which of following correctly represents the sequence of information flow in the Central Dogma of molecular biology?

DNA - > mRNA - > Protein

Which of the following types of medulla would not be used to culture aerobes?

reducing media

Fimbriae are used for attachment, while pili can be used for DNA transfer between bacterial cells

True

Which of the following statements is TRUE regarding bacterial growth in closed system?

Waste accumulation and nutrient depletion lead to stationary and death phases.

Which of the following structures is found in ALL prokaryotic cells?

Cell membrane

Which component is found in both Gram-positive and Gram-negative bacterial cell walls?

Peptidoglycan

All prokaryotic cells have a nucleus.

False

Archaea and bacteria are both prokaryotic, but have different cell wall compositions.

True

What is the main difference between archaea and bacteria?

Archaea have cell walls with peptidoglycan, while bacteria have peptidoglycan

You have isolated a motile, gram-positive cell with no visible nucleus. You can assume this cell has

ribosomes

Most bacteria reproduce through binary fission

True

A disease-causing microorganism

pathogen

A harmless microorganism living in the human body

normal microbiota

A nonliving particle that infects cells

virus

Which of the following is not a characteristic of biofilms?

iron deficiency

Which of the following factors does NOT significantly affect microbial growth?

Light intensity

Which of the following best describes fungi

Single- or multi-celled eukaryotes with chitin in their cell walls

All bacteria are harmful and cause diseases in humans

False

In a microbial growth curve, which phase is characterized by a balance between cell division and cell death?

Stationary phase

Gram-positive bacteria have an outer membrane similar to gram-negative bacteria

False

What is the function of mRNA in gene expression?

It carries genetic information from DNA to ribosomes for protein synthesis.

A mutation occurs where a single nucleotide is inserted into a DNA sequence. What is the most likely result?

A frameshift mutation, altering the reading frame

Which of the following statements about binary fission is TRUE?

it results in the production of genetically identical daughter cells

Which of the following statements best explain why bacteria regulate gene expression through operons?

It allows them to conserve energy by only producing proteins when needed.

Which of the following represents the correct formatting of a scientific name?

Escherichia coli

If you were growing a bacterium in a controlled environment and you observed that growth was optimal at a pH of 4 and slowed dramatically as the pH moved toward neutral or basic levels, which of the following could you conclude?

The bacterium is likely an acidophile.

Mannitol salt agar has a high concentration (7.5% NaCl). It also contains both sugar mannitol and the pH indicator phenol red, which changes to yellow when the pH is reduced, as by the acidic byproducts of mannitol fermentation.

What would you expect to observe when a halophile that cannot ferment mannitol is cultured on mannitol salts agar?

Good growth accompanied by no change in color of the medium

Which of the following best explains the structural difference between prokaryotic and eukaryotic cells?

Prokaryotic cells lack membrane-bound organelles, where eukaryotic cells have membrane bound organelles

You observing a gram stain of spherical-shaped microorganisms that are linked in a chain and stain purple. How would you describe these bacteria using the correct terminology for the cell shape and arrangement?

gram-positive streptococci

Bacteria that can grow in the presence of absence of oxygen (O2) are called obligate aerobes

False

Grow best in cold environments

psychrophiles

Grow best at moderate temperatures

mesophiles

grow best in extremely hot environments

thermophiles

Starting with three cells, how many cells would result from 3 rounds of replication?

24

You discovered a unicellular organism that lacks a nucleus and peptidoglycan. You suspect the organism is in the group

Archaea

An infectious protein is a

prion.

Assume a patient has influenza. During which time on the graph in Figure 13.2 would the patient show the symptoms of the illness?

C

Into which group would you place a multicellular heterotroph with chitin cell walls?

Fungi

Which of the following is NOT utilized to culture viruses?

culture media

An envelope is acquired during which of the following steps?

release

Why do most scientists agree that viruses are nonliving entities?

They are not composed of cells.

Which of the following statements about the members of the Kingdom Animalia is FALSE?

They undergo photosynthesis

Plasmogamy, karyogamy, and meiosis are stages of the fungal sexual life cycle.

True

Which of the following bacteria is gram-positive?

Streptococcus

Which type of organism might be found growing near hydrothermal vents on the ocean floor?

hyperthermophilic

The characteristic most notable regarding the mycoplasmas is that they

lack cell walls.

In the cladogram shown in the figure above, which two organisms are most closely related?

Micrococcus and Mycobacterium

A lytic virus has infected a patient. Which of the following would best describe what is happening inside the patient?

The virus is causing the death of the infected cells in the patient.

You have isolated an aerobic gram-positive, endospore-forming bacterium that grows well on nutrient agar. To which of the following groups does it most likely belong?

bacillales

Which of the following is an intracellular parasite?

Rickettsia

Which of the following statements regarding fungi is FALSE?

Fungi are eukaryotic autotrophs

Oncogenic viruses

cause tumors to develop.

Some species of dinoflagellates produce neurotoxins that cause fish kills and red tides.

True

Assume a patient had chickenpox (human herpesvirus 3) as a child. Which line on the graph in Figure 13.2 would show the number of viruses present in this person as a 60-year-old with shingles (human herpesvirus 3)?

E

Which of the following organisms produce endospores?

Bacillus species

In Figure 13.1, which structure is a complex virus?

B

All fungi are multicellular.

False

In the figure above, species "c." is most closely related to which of the following?

D

Which of the following statements about viral spikes is FALSE?

They are found only on nonenveloped viruses.

Which of the following is a characteristic of dimorphic fungi?

They can switch between yeast and mold forms

Borrelia is classified as a spirochete because it

possesses an axial filament.

Fungal infections in humans are known as _____________

Mycoses

In the scientific name Enterobacter aerogenes, Enterobacter is the __________________

Genus

The arrangement of organisms into taxa ______________

shows degrees of relatedness between organisms.

A virus's ability to infect an animal cell depends primarily upon the

presence of receptor sites on the cell membrane.

In the figure above, the closest ancestor for both species "a." and species "b." would be which of the following?

5

All gram-negative bacteria are classified as proteobacteria.

False

Which one of the following bacteria does NOT belong with the others?

Escherichia

Which of the following statements concerning Pseudomonas is true?

The bacteria can metabolize a wide variety of substrates.

Enterics are

gram-negative facultative anaerobes that are found in the intestines of animals

Helical and icosahedral are terms used to describe the shapes of a virus envelope.

False

Into which group would you place a photosynthetic cell that lacks a nucleus?

Bacteria

Some viruses, such as human herpesvirus 1, infect a cell without causing symptoms. These are called

latent viruses.

All of the following are characteristic of algae EXCEPT which ONE of the following?

They are currently classified as plants.

Mycobacteria are acid-fast.

True

Which of the following is the best evidence for a three-domain system?

Nucleotide sequences in ribosomal RNA vary between all three domains.

Yeast infections are caused by

Candida albicans.

How do all viruses differ from bacteria?

Viruses are not composed of cells.

Bacteriophage replication differs from animal virus replication because only bacteriophage replication involves

injection of naked nucleic acid into the host cell.

Opportunistic pathogens are those that infect healthy individuals

False

Which of the following statements regarding lichens is FALSE?

Lichens are a mutualistic relationship between a fungus and a protozoan.

The definition of lysogeny is

phage DNA is incorporated into host cell DNA.

The genus of bacteria that are particularly problematic in hospital settings due to their ability to grow in solutions with minute traces of unusual carbon sources is

Pseudomonas.

Escherichia coli belongs to the

proteobacteria.

Which of the following statements is FALSE?

Fungal spores are used for survival, not reproduction

________ are a diverse group of eukaryotic organisms that are similar in rRNA sequences, but quite different from each other in motility types and ecology. They have been used previously as a "catch-all" for organisms that couldn't be easily classified into other groups.

Protists

Pure cultures of the same species are not always identical in all ways.

True