INTERNAL BACTERIAL STRUCTURE Flashcards
- Gram: Both gram positive (+) and gram negative (-)
- Chemical composition: DNA; RNA; Proteins
- Function: Genetic material (all essential genes)
- Remember: DNA and RNA of a prokaryotic cell (bacteria) is
not bounded by a nuclear membrane; therefore, they are
scattered in the cytoplasm (that is why there exists a
Nucleoid Region).
NUCLEOID REGION (NUCLEAR BODY/CHROMATIN BODY/
NUCLEAR REGION)
- Gram: Both gram positive (+) and gram negative (-)
- Chemical composition: DNA
- Function:
o Non-essential genetic material
o Roles in conjugation (by Sex Pili), drug
resistance, and toxin production.- Plasmids are extra-chromosomal DNA.
PLASMIDS
- Gram: Both gram positive (+) and gram negative (-)
- Chemical composition: 70s, 30s, 50s (Bacterial species)
o S stands for Svedberg (unit for Ribosomes) - Function:
o CHON Synthesis (Protein Synthesis)- In comparison, eukaryotes also have ribosomes, but it is made up of 60s, 40s, and 80s.
RIBOSOMES
- Gram: Both gram positive (+) and gram negative (-)
- Chemical composition: Glycogen, Lipids, Polyphosphate, etc.
- Function: Storage
GRANULES
MICROORGANISMS THAT POSSESS GRANULES
- Corynebacterium
- Mycobacterium
- Yersinia Pestis
Metachromatic granules (AKA Babes’-Ernest Granules) – for food storage
Corynebacterium
Much Granules
Mycobacterium
Yersinia Pestis
Volutin Granules
- Gram: Gram positive (+) only
- Chemical composition: Keratin coat, Calcium dipicolinate
- Function: Resistance to heat, chemicals, and dehydration.
* Endospores are vegetative forms of
microbes wherein they lay dormant
for years and replicate when the
desired environment is achieved.
ENDOSPORES
Two microorganisms that possess endospores
Bacillus and Clostridium.
made up of monomer building blocks called nucleotides
Nucleic acids
Adenine
Guanine
- Composed of two
carbon-nitrogen
closed rings (2
nitrogen per ring
=4) Larger
Purines
Cytosine
Thymine
Uracil
Composed of one
carbon-nitrogen
closed ring (2
nitrogen)
Smaller
Pyrimidines
always double-stranded or they are in
helical form.
Each base is complementary with one another.
o Each base is bonded by hydrogen bonds.
DNA structure
enzymes remove/destroy the hydrogen bonds so the coiled DNA will separate and undergo replication.
Helicase
- Show more variety in the nature of their genomes than do
cells - Can be DNA or RNA; never both.
- The primary way scientists categorize and classify viruses.
- Can be dsDNA, ssDNA, dsRNA, or ssRNA
- May be linear and composed of several segments or single
and circular. - It is much smaller than genomes of cells
GENETIC MATERIAL OF VIRUSES
- Replication: The process of copying DNA.
- Think of “duplication”
- Happens in all types of cells, prokaryotes and eukaryotes.
COPYING DNA
- After the genetic material is copied, the prokaryotic cell divides — a process called______ in which two
identical daughter cells arise from one parent cell.
binary fission
= After the genetic material is copied, the prokaryotic cell divides — a process called binary fission, in which two identical daughter cells arise from one parent cell
= At one-point isang bacteria na bilog. When copying of genetic material occurs, they will divide by binary fission and the
parent cell will produce 2 daughter cells
= With that division, we can compute the generation time for a
specific organism.
= For instance, E. Coli, to have a sufficient bacterial load, it needs 15-20 mins to have a million of these bacteria.
PROKARYOTE GENETICS: CELL DIVISION
- Mitosis: A single cell divides into two identical daughter cells. It is essential for growth and repair in both single-cell and
multicellular organisms - Meiosis: It produces sex cells, and its main purpose is for sexual reproduction. Daughter cells are not identical.-
EUKARYOTE GENETICS: CELL DIVISION
A single cell divides into two identical daughter cells. It is essential for growth and repair in both single-cell and
multicellular organisms
Mitosis
It produces sex cells, and its main purpose is for sexual reproduction. Daughter cells are not identical.
Meiosis
It is the process by which the DNA directs the synthesis of hnRNA/mRNA molecules that carry the coded information needed for protein synthesis.
Transcription
It is the process by which mRNA codons are deciphered and a particular protein molecule is synthesized.
Translation
- Our chromosomes are similar, but the only difference is the protein because →
the protein holds our genetic material
WHAT BASE DOES RNA HAVE THAT DNA DOESN’T HAVE?
Uracil
WHAR BASE DOES DNA HAVE THAT RNA DOESN’T HAVE?
Thymine
- Replication: The process of copying DNA
- To make RNA, the DNA will undergo the process of Transcription
o It is a process by which a DNA
sequence is copied to produce a
complementary RNA. - In other words, it is the transfer of genetic information from
DNA into RNA. - Like replication, but we are making RNA
- Beginning of the process that ultimately leads to the translation of the genetic code (via mRNA) into a peptide or
protein
PROTEIN SYNTHESIS
o It is like a blueprint, it is the copy of information in DNA that is brought to the ribosome where the information is translated into a protein.
Messenger (mRNA)
It is like a factory. It is the protein factories of the cells.
Ribosomal (rRNA)
o It is like a delivery truck. It brings the amino acids to the ribosome
Transfer (tRNA)
- Next thing to do in making a protein is to use the instructions delivered by RNA to make a protein molecule.
- Ribosomes make proteins from the messages encoded in mRNA.
TRANSLATION
WHERE DOES TRANSLATION OCCUR?
Prokaryotes:
Cytoplasm
WHERE DOES TRANSLATION OCCUR?
Eukaryotes:
Outside the nucleus in the cytoplasm
Many strains of Staphylococcus are now resistant to_______
- Gene for beta-lactamase is only expressed (turned on) in the
presence of__________
When the bacteria is not exposed to _____ that gene is turned off and no beta-lactamase is made
penicillin
One bacterial protein that confers penicillin resistance is called _____ → It is an enzyme that cuts up and deactivates penicillin.
Understanding how ______ is turned on/off can help us to design a drug to disable that gene expression (turn off
the gene), making penicillin-resistant strains of Staph vulnerable to penicillin.
beta-lactamase
When a recipient cell takes up DNA from the environment (such as DNA released from a dead organism)
TRANSFORMATION
- In 1928, Frederick Griffith discovered this process while trying to develop a vaccine for pneumonia caused by_____
Streptococcus pneumoniae
_____ had a protective capsule and caused deadly pneumonia when injected into mice.
S strain
_____ were mutants that could not make the protective capsule and did not cause deadly disease (because the white
blood cells of the mice could easily destroy R strain cells).
R strain
Griffith worked on two strains
Streptococcus Strain and
Rough strain.
_____ may capsule kaya smooth while
Rough strain kasi walang nakapaligid sa kanya (walang capsule)
Streptococcus
Nag-inject siya ng rough strain sa daga (nonvirulent). As expected, the mouse is alive.
Rough Strain
Then, in-inject niya sa another daga yung
smooth strain. Since, mataas virulence ng smooth strain, the
mouse is dead.
Smooth Strain
Now, he tried to deactivate the smooth strain by heating. The smooth strain was successfully deactivated and when this is injected to the mouse, the mouse is alive.
Heat-killed Smooth Strain
Because of the desire to create a vaccine, he combined the rough strain and
heat-killed smooth strain kasi pareho sila nagcause ng pagkabuhay ng daga.
Rough Strain & Heat-killed Smooth Strain
- Transfer of DNA from one cell to another via a replicating virus (bacteriophage).
- Can occur between prokaryotic cells or between eukaryotic cells
TRANSDUCTION
through sex pili. You have chromosomal
DNA and extra-chromosomal DNA (Plasmid).
CONJUGATION
The recipient only has a chromosomal DNA hence; the donor will attach to the recipient and with the help of DNA polymerase there will be a conjugation.
CONJUGATION Recipient
There will be a relaxosome (donor) and transfersome will go to the recipient cell. Yung isang part ng kanyang plasmid will go to the recipient and later on magkakaroon na siya ng sarili niyang plasmid and replication will happen.
CONJUGATION Donor
For an organism/microbe to be cultivated, it needs to be placed on a particular medium to promote reproduction or
growth.
BACTERIAL GROWTH AND NUTRITION
- To obtain definitive identification and characterization.
- Grow and isolate all bacteria present in an infection.
- Determine which bacteria is most likely causing the infection.
- Determine which bacteria is likely to contaminate or colonize
(not always infection-causing)
WHY CULTIVATE BACTERIA
Obtain sufficient growth of clinically relevant bacteria to:
o Test antimicrobial susceptibility
o Measure response to treatment
o Characterize the agent
o Bank strain for future use including vaccine
development
Sometimes in an infection site, there are a lot of microorganisms and we wanted to know which one among the many causing the infection manifested by a certain patient or animal.
Grow and isolate all bacteria present
- Able to utilize simple inorganic compounds
o CO2 as carbon source
o Ammonium salts as a nitrogen
source - Include phototrophs (Photosynthesis) and chemolithotrophs
(Oxidation of inorganic compounds)
AUTOTROPHS/LITHOTROPHS
NUTRITIONAL GROWTH CHARACTERISTICS
AUTOTROPHS/LITHOTROPHS
HETEROTROPHS
are autotrophs that use light (photosynthesis).
Phototrophs
If the microbes use chemicals, we call them
Chemolithotrophs
- Bacteria found in the human body
- Unable to synthesize their own metabolism
- Depend on preformed organic compounds
- Nutritional needs are variable
- Since these microbes (heterotrophs) cannot synthesize their
own metabolism, they depend on the metabolism of humans.
HETEROTROPHS
- Physical
- Temperature
- pH
- Osmotic Pressure
- MOISTURE & DESICCATION
- Chemical
- Carbon
- Anaerobic growth
- Capnophiles
GROWTH REQUIREMENTS
- Temperature
- pH
- Osmotic pressure
- Moisture& Desiccation
Physical
- Psychrophiles (cold loving)
- Mesophiles (Midrange)
- Thermophiles (Heat-loving)
- Hyperthermophiles
TEMPERATURE
o True psychrophiles: Optimum growth at 15 degrees Celsius and lower.
- Psychrotrophs: Optimum growth at 20-30 degrees celcius
- ____ are microbes or bacteria that are said to grow in cold temperatures (cold-loving)_Under psychrophiles there are true psychrophiles and psychrotophs
Psychrophiles (Cold-loving)
- Moderate temperature loving - Optimum growth at 25 − 37. 𝑜�
- Most clinically important microbes cause
infection to humans. - The midrange or middle one is the Mesophiles. Their temperature ranges around 25-37 degrees Celsius. They are the most clinically important microbes that cause infection to
humans.
Mesophiles (Midrange)
When the temperature increases, that is your thermophiles. Thermophiles survive in very high temperatures and can be seen in hot springs and even on lava
Thermophiles (Heat-loving)
o Tolerate extreme temperatures
o Can be seen in hot springs or lava
o If microbes are found in volcanic lava/magma they are called hyperthermophiles.
An example is Bacillus infernus
→most common organism
tolerating extremely high temperatures.
Hyperthermophiles
- Most medically important bacteria grow at neutral or slightly alkaline pH (7.2 to 7.6).
- Very few bacteria grow below pH 4.
- Lactobacilli grows in acidic pH; Cholera vibrio grows in alkaline pH.
- Growth media includes chemical buffer to prevent acid production
- Foods are preserved by acids produced by bacterial
fermentation - Acidophiles
- Alkaliphiles
- Neutrophiles
pH
When the microorganism can tolerate at lower than 7 pH for growth (Acidophilic Microorganism).
Acidophiles
When the microorganism can tolerate at higher than 7 pH for growth (Alkalophilic Microorganism)
Alkaliphiles
If they can tolerate at the middle pH (pH 7).
Neutrophiles
- Hypertonic (High osmotic pressure)
- Hypotonic (Low osmotic pressure)
- Isotonic (Midrange)
OSMOTIC PRESSURE
removes water causing plasmolysis inhibits → growth (i.e., salts as
preservatives; shrinks)
Hypertonic (High osmotic pressure)
causes water to enter
and can cause lysis → causes swelling.
Hypotonic (Low osmotic pressure)
has an equal coming in and out
amount of water in the cell.
Isotonic (Midrange)
all the water is extruded out the cell
making the cell shrink.
hypertonic solution,
the fluid or water is going into the cell
resulting in high retention causing the cell to swell.
hypotonic solution
there is an equal entry and exit of
water in the cell. If water comes out there should always be
water going in.
an isotonic solution
Most organisms can resist hypotonic solutions because of their____
rigid cell wall.
Freeze dry process that protects bacteria for up to years or so
Lyophilization
which is the cause of syphilis and
gonococcus which is the cause of gonorrhea. Drying of this
organism can cause death and destruction of their cell wall
or the bacterial cell itself
Treponema Pallidum
are very tolerant to moisture and
desiccation and drying so they can survive for many years because the spores lay dormant and later on when they have
a desirable nutrition, they will flourish.
Bacterial spores
- Reducing media containing thioglycolate to deplete oxygen; cooked meat broth.
- Anaerobic jar, anaerobic chamber, anaerobic bags/pouch.
- Microbes have oxygen requirements. Some of them are said to be anaerobic and some are aerobic
_____ oxygen is not required for growth and with oxygen the organism may die. For us to inhibit oxygen, reducing media are used (thioglycolate and cooked meat
broth etc.).
ANAEROBIC GROWTH
require high concentration of CO
= are organisms that can tolerate high carbon dioxide for growth. An organism can be supplied with carbon dioxide by the use of a direct tank to incubate carbon dioxide gas or by using a candle jar
CAPNOPHILES
relatively complex growth needs
are relatively complex bacteria because
it is difficult to grow. If you don’t give them what they need they will not grow. They need an x or b factor for them to
grow.
Fastidious bacteria
relatively basic and straightforward
growth needs.
Non-fastidious bacteria
The two most common fastidious bacteria are:
o Haemophilus
o Neisseria gonorrhoeae
can grow easily without giving
them specific things for them to grow. Straightforward growth.
Non-Fastidious bacteria
Adjustment phase
- this is where the organism
is acclimatizing to its new environment. There are few or no cells in this phase.
Lag Phase
Exponential phase/Growth phase
- After exposing them to suitable environments or culture/liquid
medium they will now reproduce or replicate.
- This is where bacteria multiplies when it reaches its suitable environment. Moreover, this is also where the living cells are more than the dead cells
Log Phase
It is a phase where
there are equal dying and living cells
Plateau Phase (Stationary phase)
Decline phase
After certain times, there will
be a decline in cells.
- called Decline phase wherein there are more cells dying than surviving because nauubos na yung nutrients na kailangan nila kaya unti-unti na silang
namamatay.
Death Phase
are made up of 2-3% agar. They solidify at
less than 40 . 𝑜�
Solid mediums
made up of 1% agar. The consistency is like a jelly-ace.
Semi-solid
does not have agar in it. Fully liquid
Liquid medium
contains broth and an agar medium, it has a liquid and solid medium
Biphasic medium
has an agar inside. Meron yang swab and merong container na merong agar sa ilalim. Yung swab itutusok mo siya sa agar sa loob ng agar, at doon siya tutubo kasi walang oxygen doon sa loob ng agar
Anaerobic transport medium
It allows the growth of specific organisms
Selective
This medium differentiates one organism from another.
Differential
Both selective and differential medium
MacConkey Agar
