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39 Cards in this Set

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What are the Structures within the cytoplasm of a typical bacterial cell?
include the Nucleoid,Plasmid and Transposons, Ribosomes, and Inclusion Bodies
What are the Structures within the Extracellular structures of a typical bacterial cell?
include formation of Endospores, Glycocalyx (Capsule), S-layer, Flagella, and Pili.
Define genome
the sum of an organism's genetic material
What is the difference between eukaryyotic nucleus and the bacterial nucleoid?
Unlike the eukaryotic nucleus, the bacterial nucleoid has no nuclear membrane or nucleoli.
Describe the composition of the bacterial nucleoid
DNA
histone-like proteins
DNA gyrase
DNA topoisomerases
Name the enzymes that enables bacterial DNA to become circular, super coiled and unwind during DNA replication
DNA topoisomerase
What is nucleioid?
genetic material of the bacterium
Which of bacterial or mammalian DNA has a high frequency of unmethylated cytosine guanine dinucleotide sequences?
Bacterial
What is plasmid?
non-chromosomal DNA which contain about 5 to 100 genes
Where is plasmid located?
in the cytoplasm but maybe integrated into the micobe's chromosome
Describe plasmid s and indicate their possible benefit to bacteria
contain genetic material
can be beneficial in certain environmental conditions (eg. antibiotic resistance)
Plasmids code for synthesis of a few proteins not coded for by the nucleoid

True or false?
true
State the functions of transposons
small pieces of DNA
that encode enzymes that transpose the transposon, that is, move it from one DNA
location to another.
Where are transposons located?
found as part of a bacterium's nucleoid or in plasmids
How many genes are contained in the transposons?
between 1 and 12 genes
What are transposases?
Transposase is the enzyme that catalyses the cutting and resealing of the DNA
during transposition.
What are the means of getting antibiotic resistance genes?
integrons and transposons
What are integrons?
Integrons are transposons that can carry multiple gene clusters called gene cassettes that move as a unit from one piece of DNA to another
Describe structure and chemical composition of bacterial ribosomes and state their function
Two subunits: 50S and 30S => combine to form 70S

function: mRNA attach to 30S and amino acid carrying tRNAs attach to the 50S. Proteins are generated
Name two common genera of bacteria capable of producing endospores
Bacillus
Clostridium
Briefly describe the structure and function of endospore
Structure: consists of multiple layers of resistnat coats surrounding a nucleoid, some ribosomes, RNA and enzymes

Function: a resistant, dormant survival form of the organism. Resistant to high temp, disinfectants, radiation, drying
What triggers endospores formation?
starvation (lack of C and N)
Define sporulation
Formation of endospores under conditions of starvation
Define germination
outgrowth of a single vegetative bacterium from endospore state
List a two factors that contribute to heat resistance of endospores
- Calcium-dipicolinate, abundant within the endospore, may stabilize and protect the endospore's DNA.
- Specialized DNA-binding proteins saturate the endospore's DNA and protect it from heat, drying, chemicals, and radiation.
Name three infections that may be transmitted to humans by endospores
Anthrax, tetanus, botulism, gas gangrene, ‘C-diff
State the functions of at least two types of inclusion bodies
storage

cyanophycin granules: N, Carboxysomes: enzymes used for CO2 fixation,
inorganic bodies: P, S,
organic bodies: glycogen
What are the two forms of glycocalyx? Describe them
capsule (tightly bound)
and slime layer (loosely attached)
Glycocalyx is composed of ?
polysaccharide
Functions of glycocalyx?
Resist phagocytic engulfment by white blood cells

Adhere to surfaces to colonize, resist flushing
What is S-layer?
similar function as capsule but thinner.
protect bacteria from harmful enzymes and pH change
What are the composition of flagella?
filament, hook, basal body
What protein makes up flagella?
flagellin
does flagella flex?
no, it does not flex
which part of flagella acts as molecular motor?
basal body
what is a pilus?
Pili are thin, protein tubes originating from the cytoplasmic membrane and are found in virtually all gram-negative bacteria but not in many gram-positive bacteria.
what are the two types of pili?
attachment pili
conjugation pili (sex pili)
Whhat are the functions of pili?
attachment pili: ahdesion to surfaces
conjugation pili: transfer of DNA
what is the composition of a pilus?
The pilus has a shaft composed of a protein called pilin. At the end of the shaft is the adhesive tip structure having a shape corresponding to that of specific glycoprotein or
glycolipid receptors on a host cell.