Microbiology – Week 4a ( Bacteria ) – Flashcards

Q.1 The cytoplasmic (plasma) membrane of bacteria: a) retains the cytoplasm and its contents b) acts as a selectively permeable barrier, allowing some molecules to pass while preventing the movement of others c) is the major site of ATP synthesis (respiration) in aerobes d) all of the above

The lipopolysaccharide (LPS) that is found in the outer membrane of Gram-negative bacteria is also known as: a) exotoxin b) teichoic acid c) murein d) endotoxin

Which of the following is not true of bacterial plasmids? a) they can replicate independently of the chromosome b) they may carry genes for drug resistance c) they are required for host growth and/or reproduction d) they may carry genes that enhance the metabolic capabilities of the bacterium

Gram-positive cells retain the primary stain whereas Gram-negative cells do not because: a) the alcohol removes the outer membrane and, therefore, the trapped stain from Gram-negative bacteria b) the alcohol shrinks the pores of the thick peptidoglycan layer of Grampositive cells, thereby, trapping the stain c) a and b d) none of the above

Which of the following is/are true of capsules? a) they help bacteria escape phagocytosis by host cells b) they retain water and help prevent desiccation of the bacteria c) they prevent entry of many bacterial viruses d) all of the above

Proteins that are loosely attached to the cytoplasmic membrane are called proteins. a) peripheral b) integral c) external d) internal

Proteins that are embedded within the cytoplasmic membrane and not easily extracted are called proteins. a) peripheral b) integral c) external d) internal

Lipids with polar and nonpolar ends are said to be: a) hydrophilic b) hydrophobic c) amphipathic d) none of the above

Although penicillin inhibits peptidoglycan synthesis, bacterial cells will continue to grow normally in the presence of penicillin in a(n) _______ environment. a) hypotonic b) isotonic c) hypertonic d) nonpolar

Endospores represent a challenge to the fields of industrial and medical microbiology because: a) they are resistant to harsh environments, thus allowing survival of spore forming organisms under conditions in which non-sporulating cells would not survive b) spore forming organisms are often dangerous pathogens c) spores are significantly smaller than vegetative cells d) a and b are correct

Which of the following are present in prokaryotic cells? a) nucleus b) mitochondrion c) golgi complex d) vacuole e) cell wall

Which is not a distinguishing characteristic of prokaryotic cells? a) their DNA is not enclosed within a membrane b) they lack membrane-enclosed organelles c) they have cell walls containing peptidoglycan d) their DNA is not associated with histones e) none of the above

Which of the following statements about bacterial endospores is true? a) endospores are for reproduction b) endospores allow a cell to survive environmental changes c) endospores are easily stained in a Gram stain d) a cell produces an endospore and keeps growing e) a bacterial cell can produce many endospores

Which of the following is not a structure found in prokaryotic cells? a) flagellum b) axial filament c) cilia d) pilus e) glycocalyx

You have isolated a motile, Gram-positive cell with no visible nucleus. You can safely assume that the cell a) has a mitochondrion b) lives in extreme environments c) has pili d) has a cell wall e) is photosynthetic

True or False : Plasma membranes in bacteria are have a similar composition and structure to eukaryotic membranes

True or False : The major difference between Gram-positive and Gram-negative bacteria is the composition and structure of their peptidoglycan.

True or False : The major role of the plasma membrane is to protect the cell against osmotic lysis.

True or False : Gram-positive bacteria stain purple.

True or False : Bacterial respiration occurs in mitochondria.

True or False : Lipopolysaccharide is present in Gram-negative, but not Gram-positive bacteria.

True or False : Most bacteria reproduce by transverse binary fission.

True or False : Genetic variation occurs in bacteria when they exchange chromosomes

True or False : All bacteria are motile.

True or False : Endospores are an important means of replication in bacteria.