Week 2 Lecture 3

Front 1

What are the Structures within the cytoplasm of a typical bacterial cell?

Back 1

include the Nucleoid,Plasmid and Transposons, Ribosomes, and Inclusion Bodies

Front 2

What are the Structures within the Extracellular structures of a typical bacterial cell?

Back 2

include formation of Endospores, Glycocalyx (Capsule), S-layer, Flagella, and Pili.

Front 3

Define genome

Back 3

the sum of an organism's genetic material

Front 4

What is the difference between eukaryyotic nucleus and the bacterial nucleoid?

Back 4

Unlike the eukaryotic nucleus, the bacterial nucleoid has no nuclear membrane or nucleoli.

Front 5

Describe the composition of the bacterial nucleoid

Back 5

DNA
histone-like proteins
DNA gyrase
DNA topoisomerases

Front 6

Name the enzymes that enables bacterial DNA to become circular, super coiled and unwind during DNA replication

Back 6

DNA topoisomerase

Front 7

What is nucleioid?

Back 7

genetic material of the bacterium

Front 8

Which of bacterial or mammalian DNA has a high frequency of unmethylated cytosine guanine dinucleotide sequences?

Back 8

Bacterial

Front 9

What is plasmid?

Back 9

non-chromosomal DNA which contain about 5 to 100 genes

Front 10

Where is plasmid located?

Back 10

in the cytoplasm but maybe integrated into the micobe's chromosome

Front 11

Describe plasmid s and indicate their possible benefit to bacteria

Back 11

contain genetic material
can be beneficial in certain environmental conditions (eg. antibiotic resistance)

Front 12

Plasmids code for synthesis of a few proteins not coded for by the nucleoid

True or false?

Back 12

true

Front 13

State the functions of transposons

Back 13

small pieces of DNA
that encode enzymes that transpose the transposon, that is, move it from one DNA
location to another.

Front 14

Where are transposons located?

Back 14

found as part of a bacterium's nucleoid or in plasmids

Front 15

How many genes are contained in the transposons?

Back 15

between 1 and 12 genes

Front 16

What are transposases?

Back 16

Transposase is the enzyme that catalyses the cutting and resealing of the DNA
during transposition.

Front 17

What are the means of getting antibiotic resistance genes?

Back 17

integrons and transposons

Front 18

What are integrons?

Back 18

Integrons are transposons that can carry multiple gene clusters called gene cassettes that move as a unit from one piece of DNA to another

Front 19

Describe structure and chemical composition of bacterial ribosomes and state their function

Back 19

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

Front 20

Name two common genera of bacteria capable of producing endospores

Back 20

Bacillus
Clostridium

Front 21

Briefly describe the structure and function of endospore

Back 21

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

Front 22

What triggers endospores formation?

Back 22

starvation (lack of C and N)

Front 23

Define sporulation

Back 23

Formation of endospores under conditions of starvation

Front 24

Define germination

Back 24

outgrowth of a single vegetative bacterium from endospore state

Front 25

List a two factors that contribute to heat resistance of endospores

Back 25

- 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.

Front 26

Name three infections that may be transmitted to humans by endospores

Back 26

Anthrax, tetanus, botulism, gas gangrene, ‘C-diff

Front 27

State the functions of at least two types of inclusion bodies

Back 27

storage

cyanophycin granules: N, Carboxysomes: enzymes used for CO2 fixation,
inorganic bodies: P, S,
organic bodies: glycogen

Front 28

What are the two forms of glycocalyx? Describe them

Back 28

capsule (tightly bound)
and slime layer (loosely attached)

Front 29

Glycocalyx is composed of ?

Back 29

polysaccharide

Front 30

Functions of glycocalyx?

Back 30

Resist phagocytic engulfment by white blood cells

Adhere to surfaces to colonize, resist flushing

Front 31

What is S-layer?

Back 31

similar function as capsule but thinner.
protect bacteria from harmful enzymes and pH change

Front 32

What are the composition of flagella?

Back 32

filament, hook, basal body

Front 33

What protein makes up flagella?

Back 33

flagellin

Front 34

does flagella flex?

Back 34

no, it does not flex

Front 35

which part of flagella acts as molecular motor?

Back 35

basal body

Front 36

what is a pilus?

Back 36

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.

Front 37

what are the two types of pili?

Back 37

attachment pili
conjugation pili (sex pili)

Front 38

Whhat are the functions of pili?

Back 38

attachment pili: ahdesion to surfaces
conjugation pili: transfer of DNA

Front 39

what is the composition of a pilus?

Back 39

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.