INTRODUCTION TO BACTERIA Flashcards
LIFE DOMAINS?
PROKARYOTES (BACTERIA AND ARCHAEA) AND EUKARYOTES
DIFFERENCES BETWEEN EUKARYOTES AND PROKARYOTES?
PRO ARE SINGLE CELL ORGANISMS, HAVE NO NUCLEI, ARE USUALLY SMALLER AND HAVE NO MEMBRANE BOUND ORGANELLES
PROK. AND EUKARYOTES COMMON FEATURES?
- DNA
- PLASMA MEMBRANE
- CYTOPLASM
- RIBOSOMES
APPROX HOW MANY TYPES OF BACTERIA EXIST IN THE HUMAN BODY?
500-1000
2 MAIN BACTERIAL CELL SHAPES?
COCCI (ROUND)
BACILLI (RODS)
STREPTOCOCCI/STREPTOBACCILI ARE ARRANGED IN A?
LINE
DESCRIBE STAPHLYOCOCCI STRUCTURE?
GRAPE LIKE
WHAT IS A BACTERIAL COLONY?
A GROUP OF BACTERIA DERIVED FROM THE SAME MOTHER CELL (GENETICALLY IDENTICAL CELLS)
ELECTRIC NOSES?
COULD BE A TOOL IN DISEASE DIAGNOSTIC IN THE FUTURE BY DISTINGUISHING BACTERIA TYPE BASED ON ITS UNIQUE SMELL
WHO DISCOVERED BACTERIA COULD BE GRAM POSITIVE OR GRAM NEGATIVE AND WHEN?
H. GRAM, 1884
COLOR OF G+ VS G- BACTERIA AFTER GRAM STAINING?
G+ ARE VIOLET/PURPLISH
G- ARE RED/PINKISH
WHY DO G+ BACTERIA HAVE VIOLET COLOURING (COMPARED TO PALER, RED/PINKISH COLOURING) OG G- BACTERIA AFTER GRAM STAINING?
BECAUSE THEY HAVE A THICKER PEPTIDOGLYCAN LAYER THAT CAN RETAIN THE DYE
DO G+ OR G- BACTERIA HAVE AN OUTER LIPID MEMBRANE?
G-
TEICHOIC AND LIPOTEICHOIC ACIDS ARE PRESENT ON G+ OR G- BACTERIA?
G+
ARE O-SPECIFIC SIDE CHAINS PRESENT ON G+ OR G- BACTERIA?
G-
G- BACTERIA INCLUDE:
- ENTEROCOCCI
- SALMONELLA SPECIES
- PSEUDOMONAS SPECIES
G+ BACTERIA INCLUDE:
- STAPHYLOCOCCI
- ALL STREPTOCOCCI
- SOME LISTERIA SPECIES
NAME FOR BACTERIA THAT USE LIGHT AS THEIR ENERGY SOURCE?
PHOTOTROPHS
NAME FOR BACTERIA THAT HAVE CHEMICAL ENERGY SOURCE?
CHEMOTROPHS
BACTERIA TYPES BY OXYGEN REQUIREMENTS?
- OBLIGATE AEROBES
- OBLIGATE ANAEROBES
- FACULTATIVE ANAEROBES
- AEROTOLERANT ANAEROBES (INDIFFERENT TO O2 PRESENCE)
- MICROAEROPHILES (REQUIRE OXYGEN, BUT AT A LEVEL LOWER THAN IN THE ATMOSPHERE, I.E. 1-10% COMPARED TO REGULAR 21%)
BACTERIA TYPES BASED ON TEMPERATURE PREFERENCE?
- PSYCHROPHILES (<15)
- MESOPHILES
- THERMOPHILES
- HYPERTHERMOPHILES (60+, OPTIMAL OFTEN ABOVE 80)
BACTERIA TYPES BASED ON pH PREFERENCE:
- ACIDOPHILE
- NEUTROPHILE
- ALKALIPHILE
PRIMARY METHOD OF BACTERIAL REPRODUCTION?
BINARY FISSION (ASEXUAL, OFFSPRING IDENTICAL TO THE MOTHER CELL)
PHASES OF BINARY FISSION:
1) LAG PHASE (NO INCREASE IN NUMBER OF LIVING BACTERIAL CELLS)
2) LOG PHASE (EXPONENTIAL INCREASE IN NUMBER OF LIVING BACTERIAL CELLS)
3) STATIONARY PHASE (PLATEAU IN NUMBER OF LIVING BACTERIAL CELLS, RATE OF CELL DIVISION AND DEATH ROUGHLY EQUAL)
4) DEATH OR DECLINE PHASE (EXPONENTIAL DECREASE IN NUMBER OF LIVING BACTERIAL CELLS; NUTRIENTS EXHAUSTED)
WHAT ARE NUCLEOIDS?
- TYPICALLY SINGLE, CIRCULAR CHROMOSOMES
- NOT MEMBRANE BOUND
- SUPERCOILED
- PACKAGED WITH AID OF HISTONE-LIKE PROTEINS
- CONTAINS ALL OR MOST OF BACTERIAL GENETIC MATERIAL
WHAT ARE PLASMIDS?
- DNA THAT ISN’T A PART OF THE CHROMOSOME (NUCLEOID)
- SMALL, TYPICALLY CIRCULAR, DOUBLE STRANDED DNA MOLECULES
- MULTIPLE COPIES
- REPLICATE INDEPENDENTLY OF THE CHROMOSOME
- OFTEN CARRY GENES THAT CONFER ADVANTAGEOUS TRAITS (E.G. ANTIBIOTIC RESISTANCE)
RIBOSOMES IN BACTERIA?
- RESPONSIBLE FOR PROTEIN SYNTHESIS
- 2 SUBUNITS (SMALL= 30S, LARGE= 50S, TOTAL RIBOSOME=70S)
WHAT ARE INCLUSIONS?
- ONLY SOME BACTERIA HAVE THEM
- STORAGE OF EXCESS NUTRIENTS TO USE WHEN ENVIRONMENT IS UNFAVORABLE
- CAN STORE GLYCOGEN, STARCH, POLYMERISED INORGANIC PHOSPHATE ETC
WHAT ARE ENDOSPORES?
- ONLY PRESENT IN SOME BACTERIA
- STRUCTURES THAT PROTECT THE BACTERIAL GENOME IN A DORMANT STATE WHEN THE ENVIRONMENT IS UNFAVORABLE
- CAN SURVIVE WITHOUT NUTRIENTS AND WATER
- SURVIVE VERY HIGH TEMP
- HARD TO KILL
TRANSFORMATION PROCESS IN WHICH BACTERIAL GENETIC MATERIAL BECOMES ENDOSPORE IS CALLED?
SPORULATION
EXAMPLES OF ILLNESS CAUSED BY BACTERIA THAT HAVE THE ABILITY TO CREATE ENDOSPORES?
- TETANUS
- ANTHRAX
- GANGRENE
- BOTULISM
FIMBRIAE VS PILI, WHICH ARE LONGER AND LESS NUMEROUS?
PILI
FIMBRIAE AND PILI ROLES:
- ALLOW BACTERIA TO INTERACT WITH THEIR ENVIRONMENT
- ATTACH TO OTHER CELLS (ADHESION)
- TRANSFER DNA (CONJUGATION)
- PROVIDE MOVEMENT (TWITCHING)
FLAGELLA ARE USED BY BACTERIA TO MOVE ESP IN WHAT KIND OF ENVIRONMENT?
AQUEOUS
TYPES OF BACTERIA BASED ON THE NUMBER OF FLAGELLUM (PL: FLAGELLA) THEY HAVE?
- MONOTRICHOUS
- AMPHITRICHOUS (HAVE A SINGLE FLAGELLUM ON EACH OF TWO OPPOSITE ENDS)
- LOPHOTRICHOUS (HAVE MULTIPLE FLAGELLA AT THE SAME PLACE ON THE CELL SURFACE)
- PERITRICHOUS (HAVE FLAGELLA PROJECTING IN ALL DIRECTIONS ALL OVER THE CELL BODY)
WHAT KIND OF SIGNALS CAN TRIGGER FLAGELLA MOTION?
- CHEMICAL GRADIENTS (CHEMOTAXIS)
- LIGHT (PHOTOTAXIS)
- MAGNETIC FIELDS (MAGNETOTAXIS)
HOW IS DIRECTIONAL MOVEMENT OF FLAGELLA CONTROLLED?
THROUGH TUMBLING AND RUNNING BEHAVIOURS
ARE PLASMIDS ESSENTIAL FOR NORMAL BACTERIAL GROWTH?
NO
4 MAIN MUTATION TYPES?
- SILENT
- MISSENSE
- NONSENSE
- DELETION/INSERTION (CAUSES FRAME SHIFT CHANGES)
HORIZONTAL GENE TRANSFER IN BACTERIA?
Horizontal gene transfer enables bacteria to respond and adapt to their environment much more rapidly by acquiring large DNA sequences from another bacterium in a single transfer. Horizontal gene transfer is a process in which an organism transfers genetic material to another organism that is not its offspring.
(PLASMIDS CAN BE EXCHANGED BY BACTERIA IN THIS WAY)
GENOME DEFINITION
COMPLETE SET (ENTIRETY) OF GENETIC MATERIAL OF AN ORGANISM
GENOTYPE DEFINITION:
FULL COLLECTION OF GENES IN GENOME
PHENOTYPE DEFINITION:
OBSERVABLE CHARACTERISTICS (DEFINED BY THE SET OF GENES EXPRESSED AT ANY ONE TIME)
CONSTITUTIVE GENES DEFINITION:
GENES THAT ARE ALWAYS EXPRESSED
HOUSEKEEPING GENES?
GENES NECESSARY FOR THE BASIC FUNCTIONS OF THE CELL
STRUCTURAL GENES?
GENES THAT ENCODE PRODUCTS THAT SERVE AS CELLULAR STRUCTURES OR ENZYMES
REGULATORY GENES?
ENCODE PRODUCTS THAT REGULATE GENE EXPRESSION
SMALL RNAs?
50-400 NUCLEOTIDES LONG
TRANSCRIBED BUT NOT TRANSLATED
WHAT IS A PROMOTER?
- A DNA SEQUENCE UPSTREAM OF A GENE (OR A SET OF GENES) WHERE TRANSCRIPTION MACHINERY (RNA POLYMERASE) BINDS AND INITIATES TRANSCRIPTION
WHAT IS A CONSENSUS SEQUENCE?
a sequence of DNA, RNA, or protein that represents aligned, related sequences
WHAT IS A SIGMA FACTOR?
a protein needed for initiation of transcription in bacteria; It is a bacterial transcription initiation factor that enables specific binding of RNA polymerase (RNAP) to gene promoters
- SIGMA FACTORS BIND TO CONSENSUS SEQUENCES AND RECRUIT RNAP
REPRESSORS VS ACTIVATORS VS INDUCERS?
R: SUPPRESS TRANSCRIPTION KEEPING A GENE ‘OFF’
A: INCREASE TRANSCRIPTION OF A GENE KEEPING IT ON
I: SMALL MOLECULES THAT CAN HELP REGULATE TRANSCRIPTION BY BINDING TO EITHER REPRESSORS OR ACTIVATORS
WHAT ARE OPERONS?
FUNCTIONING UNITS OF DNA CONTAINING A CLUSTER OF GENES UNDER THE SIMULTANEOUS CONTROL OF A SINGLE PROMOTER
- TRANSCRIBED TOGETHER
- ALL NEEDED OR NONE NEEDED
WHAT ARE REGULONS?
GROUPS OF SEVERAL GENES OR OPERONS THAT ARE TURNED ON OR OFF IN RESPONSE TO THE SAME SIGNAL BY THE SAME REGULATORY PROTEIN
- THE MEMBERS OF A REGULON HAVE SEPARATE PROMOTERS AND ARE WIDELY SEPARATED ON THE CHROMOSOME
SIGNAL TRANSDUCTION PATHWAYS MOVE SIGNAL IN WHICH DIRECTION?
FROM CELL’S EXTERIOR TO ITS INTERIOR
WHAT IS CONJUGATION?
TRANSFER OF DNA THROUGH DIRECT CONTACT USING A CONJUGATION PILUS
WHAT IS TRANSDUCTION?
MECHANISM OF HORIZONTAL GENE TRANSFER IN BACTERIA IN WHICH GENES ARE TRANSFERRED THROUGH VIRAL INFECTION
WHAT IS TRANSFORMATION?
MECHANISM OF HORIZONTAL GENE TRANSFER IN WHICH NAKED ENVIRONMENTAL DNA IS TAKEN UP BY A BACTERIAL CELL
WHAT IS TRANSPOSITION?
PROCESS WHEREBY DNA INDEPENDENTLY EXCISES FROM ONE LOCATION IN A DNA MOLECULE AND INTEGRATES ELSEWHERE
PENICILIN WORKS ON G+ OR G- BACTERIA?
ONLY G+
