BACTERIAL CELL STRUCTURE MORPHOLOGY AND FUNCTIONS

Question 1

Prokaryotes differ from eukaryotes in ____ and _____

Answer 1

size and simplicity

Question 2

reproduce by fission while some bacteria produce spores.

Answer 2

Archaea

Question 3

consists of three RNA whereas bacteria consists of single RNA.

Answer 3

Archaea

Question 4

can sustain in harsh environments which are extreme such as hot springs, oceans, gut of humans and Marshlands.

Answer 4

Archaea

Question 5

are generally found in organic matter, soil, bodies of animals and plants, water, radioactive waste.

Answer 5

bacteria

Question 6

is a nucleic acid present in all living cells that has structural similarities to DNA.

Answer 6

Ribonucleic acid

Question 7

is the molecule that carries genetic information for the development and functioning of an organism.

Answer 7

Deoxyribonucleic acid

Question 8

determined by plane of division – determined by separation or not

Answer 8

arrangement

Question 8

cocci and rods most common – various others

Answer 8

shape

Question 9

varies

Answer 9

size

Question 10

Shape and Arrangement-1

Answer 10

• Cocci (s., coccus) – spheres
  – diplococci (s., diplococcus) – pairs
  – streptococci – chains
  – staphylococci – grape-like clusters
  – tetrads – 4 cocci in a square
  – sarcinae – cubic configuration of 8 cocc

Question 11

Shape and Arrangement-2

Answer 11

• bacilli (s., bacillus) – rods
  – coccobacilli – very short rods
• vibrios – resemble rods, comma shaped
• spirilla (s., spirillum) – rigid helices
• spirochetes – flexible helices

Question 12

Shape and Arrangement-3

Answer 12

• mycelium – network of long, multinucleate filaments
• pleomorphic – organisms that are variable in shape

Question 13

Bacterial structure is considered at three levels

Answer 13

1. Cell envelope proper: Cell wall and cell membrane.
2. Cellular element enclosed with in the cell envelope: Mesosomes, ribosomes, nuclear apparatus, polyamies and cytoplasmic granules.
3. Cellular element external to the cell envelope: Flagellum, Pilus and Glycocalyx.

Question 14

Bacterial Cell Organization Common Features:

Answer 14

♦ Internal Structure
♦ Surface Structure
♦ Appendages

Question 15

consists of a tangle of double-stranded DNA, not surrounded by a membrane and localized in the cytoplasm.

Answer 15

Nucleoid

Question 15

DNA is stabilized by small polyamines and Mg ions and associated with histone-like proteins

Answer 15

Nucleoid

Question 15

Bacterial DNA is Haploid.

Answer 15

Nucleoid

Question 16

are small, circular, non-chromosomal, double-strand DNA molecules that are capable of self-replication.

Answer 16

Plasmids

Question 17

There are five main types of plasmids:

Answer 17

a. Fertility plasmid
b. Col Plasmid
c. Resistance plasmid
d. Virulence Plasmids
e. Degradative Plasmids

Question 18

Also known as F plasmid. It contains a transferred gene that allows genes to be transferred from one cell to another through conjugation.

Answer 18

Fertility plasmid

Question 19

contains genes that help the bacteria cell defend against the environment, factors such as poisons or antibiotics.

Answer 19

Resistance plasmid

Question 19

contains genes that make bacteriocins (also known as colicins), which are protein that kills other bacteria.

Answer 19

Col Plasmid

Question 20

When a _______ is inside a bacterium, it turns that bacterium into a pathogen, which is an agent of disease.

Answer 20

virulence plasmid

Question 21

help the host bacterium to digest compounds that are not commonly found in nature, such as camphor, xylene, toluene, and salicylic acid.

Answer 21

Degradative Plasmids

Question 22

are minute particles composed of ribosomal RNA (rRNA) and protein.

Answer 22

Ribosomes

Question 23

contains a large number of solute low- and high-molecular weight substances, RNA and ribosomes.

Answer 23

cytoplasm

Question 24

is also frequently used to store reserve substances (glycogen depots, polymerized metaphosphates, lipids).

Answer 24

cytoplasm

Question 25

Also known as the plasma membrane.

Answer 25

cytoplasmic membrane

Question 26

It is basically a double layer of phospholipids with numerous proteins integrated into its structure. The most important of these membrane proteins are permeases, enzymes for the biosynthesis of the cell wall, transfer proteins for secretion of extracellular proteins, sensor or signal proteins, and respiratory chain enzymes.

Answer 26

cytoplasmic membrane

Question 27

The most Important Bacterial Cytoplasmic Membrane Proteins:

Answer 27

- Permeases - Biosynthesis enzymes - Secretion system proteins - Sensor proteins (also known as signal proteins) - Respiratory chain enzymes

Question 28

Active transport of nutrients from outside to inside against a concentration gradient.

Answer 28

Permeases

Question 29

Required for biosynthesis of the cell wall (e.g., its murein)

Answer 29

Biosynthesis enzymes

Question 30

The secretion systems differing in structure and mode of action. Proteins are moved out of the cell with the help of these systems. The common feature of all systems is the formation of protein cylinders that traverse the cytoplasmic membrane and in Gram- negative bacteria, the outer cell wall membrane as well.

Answer 30

Secretion system proteins

Question 31

Transmit information from the cell’s environment into its interior.

Answer 31

Sensor proteins (also known as signal proteins)

Question 32

Occur in bacteria with aerobic metabolism.

Answer 32

Respiratory chain enzymes

Question 33

refers to that portion of the cell envelope that is external to the cytoplasmic membrane and internal to the capsule or glycocalyx.

Answer 33

cell wall

Question 34

is a complex polymer consisting of three parts: A backbone, composed of alternating N-acetylglucosamine and N-acetylmuramic acid connected by β1→4 linkages;

Answer 34

Peptidoglycan

Question 35

This molecular complex is comprised of the lipid A, the core polysaccharide, and the O-specific polysaccharide chain.

Answer 35

Lipopolysaccharide (LPS)

Question 36

is the space between the inner and outer membrane in Gram-negative bacteria.

Answer 36

periplasm

Question 37

Is a network of polysaccharides that project from cellular surfaces of bacteria, found just outside the bacterial cell wall.

Answer 37

Glycocalyx

Question 38

is a well-defined structure of polysaccharide surrounding a bacterial cell and is external to the cell wall.

Answer 38

1.Capsule

Question 39

Refers to a loose network of polysaccharide fibrils that surrounds some bacterial cell walls.

Answer 39

2.Slime Layer

Question 40

are thread-like appendages consist of a basal body, hook, and a long filament composed of a polymerized protein called FLAGELLIN. They are the organs of locomotion for the forms that possess them.

Answer 40

Flagella

Question 41

Three types of arrangement are known:

Answer 41

* monotrichous (single polar flagellum). * lophotrichous (multiple polar flagella). * peritrichous (flagella distributed over the entire cell).

Question 42

They are rigid surface appendages composed of structural protein subunits termed pilins. Minor proteins termed adhesins are located at the tips of pili and are responsible for the attachment properties.

Answer 42

Pili (Fimbriae)

Question 43

Two classes can be distinguished:

Answer 43

Ordinary pili and sex pili

Question 44

which play a role in the adherence of bacteria to host cells.

Answer 44

Ordinary pili

Question 45

which are responsible for the attachment of donor and recipient cells in bacterial conjugation.

Answer 45

Sex pili

Question 46

The spore is a resting cell, highly resistant to desiccation, heat, and chemical agents; when returned to favorable nutritional conditions and activated, the spore germinates to produce a single vegetative cell.

Answer 46

Endospores

Question 47

is an aggregate of interactive bacteria attached to a solid surface or to each other and encased in an exopolysaccharide matrix.

Answer 47

biofilm

Question 48

Appendages

Answer 48

Pili and flagella

Question 49

Are surrounded by complex envelope layers that differ in composition among the major groups.

Answer 49

Prokaryotic cells

Question 50

It is a double layer of phospholipids with numerous protein integrated in its structure

Answer 50

Cytoplasmic membrane

Question 51

Active transport of nutrients from outside to inside againsts a concentration gradient.

Answer 51

Permeases

Question 52

Internal structures

Answer 52

-nucleoid -ribosomes -storage granules -endospore

Question 53

Surface structure

Answer 53

1. Capsule 2. Cell wall 3. Cell membrane 4. Cytoplasm 5. Plasma membrane