Structure and Function of Bacterial Cell L1 Flashcards
Microorganisms are either?
Normal flora In healthy human body without causing disease
Some species are harmful to human(pathogens) cause infection diseases
Does Prokaryotes have plasmids or not?
Yes
Extrachromosomal, present as small circular self-replicating
DNA
Plasmids
Transcription and translation can be carried out simultaneously where
In prokaryotes
Formation of messenger RNA (mRNA) and movement
of mRNA out of the nucleus into the cytoplasm
Transcription in euk
Translation takes place on ?
ribosomes
Does prokaryotes have chromosomes?
No
double-stranded (ds), circular, tightly coiled ‘nucleoid’
Any bacterial cell is composed of the following structures
• Cell wall
• Cytoplasmic membrane
• Cytoplasm
• Nuclear body
is a rigid structure that surrounds the bacterial cell just outside of the plasma membrane
The cell wall
The main structural component of the cell wall is?
peptidoglycan
Bacteria are classified according to their cell wall as?
Gram positive or Gram negative
Peptidoglycan is formed of ?
carbohydrate + protein
It consists of long polysaccharide chains that are cross-linked by amino acid bridges
Peptidoglycan
bacteria the peptidoglycan forms a thick layer external to the cell membrane in which gram?
In Gram-positive
Cell wall of gram …… bacteria also contain Teichoic acid
molecules
positive
In ……… bacteria, the peptidoglycan layer is thin and is overlaid by an outer membrane
Gram-negative
The space between the plasma membrane and the outer
membranes is called the ?
periplasmic space
The outer membrane of Gram Negative Cell Wall contains
lipopolysaccharide (LPS)
LPS is?
is toxic (endotoxin)
Gram stain is? Consists of?
Differential stain: consists of two or
more dyes.
What is most commonly used in staining procedure
The gram stain
It separates bacteria into two classifications according to the ?
composition of their cell walls
Gram positive take ……
Gram negative take ……
blue or violet color
pink or red color
Function of the cell wall
Determines the shape of the bacterial cell
Protection of bacterial cell against osmotic lysis
Responsible for staining properties of bacteria
The cytoplasmic membrane is a ?
bilayer of phospholipids
Functions of Cell Membrane
• Selective permeability selectively allows particular ions and molecules to pass through the membrane, while preventing the movement of others
• Active transport (using energy) of ions and molecules to the inside of cells
• Excretion
Cell Membrane Excretion such as?
hydrolytic exoenzymes
Define cytoplasm
A homogeneous soft gel mass inside the cell
The cytoplasm of prokaryotes has no membrane bound organelles, it contains:
• Nuclear body
• Plasmids
• Ribosomes
• Enzymes
• Storage granules
The Nuclear Body (Nucleoid) Consists of?
Consists of single circular DNA molecule coiled to form a mass
What carries all essential genetic information of the cell in rrok?
The Nuclear Body (Nucleoid)
