Midterm 1 study Q's Flashcards
True or false: Microorganisms have adapted to every environment on earth.
True!
Hyperthermophiles can live in near _____ temperatures.
Hyperthermophiles can live in near boiling temperatures.
When the equilibrium falls between symbiotic communities, we can it ______.
When one species takes over the community, it can result in _______.
When the equilibrium falls between symbiotic communities, we can it dysbiosis.
When one species takes over the community, it can result in pathogenesis.
about how big is a bacteria?
1 μm
Viron vs Prion?
A virion is a complete virus particle that consists of genetic material, either DNA or RNA, surrounded by a protective protein coat called a capsid, and sometimes an outer lipid envelope. It is capable of infecting host cells to replicate and spread.
In contrast, a prion is an infectious agent made solely of misfolded protein without any genetic material. Prions cause diseases by inducing normal proteins in the host to misfold, leading to neurodegenerative conditions. While virions contain nucleic acids and can replicate, prions rely solely on protein misfolding to propagate.
1: How do bacteria know what shape they have to be?
2: What moulds their shape?
1: They know what shape they have to be due to their genetics, including the shape of their cell wall. Some bacteria can change their shape according to environmental stressors.
2:The shape of bacteria is primarily moulded by their cell wall, which is composed of peptidoglycan—a mesh-like structure that provides rigidity. The arrangement and cross-linking of peptidoglycan layers determine the overall shape, whether it be rod-like (bacilli), spherical (cocci), or spiral (spirilla).
True or false: all bacteria have a flagella
False. Not all bacteria have flagella. Flagella are specialized structures that some bacteria possess to aid in movement, but many bacteria lack flagella entirely. Bacteria can move in various ways, including through other means like pili or by using diffusion.
the cytoskeleton is composed of what macromolecule?
Proteins.
True or false: a standard bacteria contains ribosomes
True
true or false: the lipid bilayer has fluidity?
True. The lipid bilayer has fluidity, allowing its components (such as proteins and lipids) to move laterally within the membrane.
integral vs peripheral protein?
integral are embedded in the membrane, peripheral are attached to the membrane’s surface.
1: Phosphatidylglycerol structure?
2: Phosphatidyethalolamine structure?
1: Phosphatidylglycerol is made of glycerol ester linked to 2 fatty acids, and on its other side, a phosphoryl group linked to a terminal glyceride.
2: Phosphatidyethalolamine contains glycerol linked to 2 fatty acids, and a phosphoryl group with a terminal ethanolamine.
Identify the main shapes of bacteria
-A Coccus is a single circular bacterium.
–> Diplococcus (two)
–> Tetrad (four)
–>Streptococcus (chain)
–> Staphylcoccus (cluster)
-A single rod bacteria is a Bacillus
–> a chain is streptobaccillus.
Which of the following statements is true? Pay attention to the capitalized terms and their definition.
The PROPHAGE excised itself from the plant cell’s genome.
The uncoated virus, or VIRION, hijacked its host’s machinery.
This animal cell is a known host of fourteen different PHAGES.
The eukaryote could not eliminate its integrated PROVIRUS.
Answer: The eukaryote could not eliminate its integrated PROVIRUS.
Prophage refers to viral DNA integrated into a bacterial genome, not a plant cell’s genome. The statement about the prophage in a plant cell is incorrect.
Virion refers to the complete virus particle outside the host cell, not after uncoating and hijacking the host’s machinery. The use of “virion” here is incorrect.
Phages infect bacteria, not animal cells. The statement about an animal cell being a host of different phages is incorrect.
Provirus is the correct term for viral DNA integrated into a eukaryotic host genome, as in this case with a eukaryotic cell.
What are hopanoids?
are they just for bacteria?
they stick into the cell membrane and stabilize it.
Usually but not exclusively found in bacteria.
Describe the structure and function of the glycocalyx (capsule/slime layer)
Structure: Made of polysaccharide layers that may differ in rigidity and flexibility.
–>Two parts to it: the capsule layer and the smile layer.
–>Capsule layer is tightly attached, a tight matrix, visible if treated with India ink.
–>The slime layer is loosely attached and easily deformed.
FUNCTION:
–>helps attach to surfaces.
–>Protects against phagocytosis
–>prevents dehydration.
What does S-Layer do, what is it?
- Additional protective layer found in gram-positive bacteria, gram negative baceria, and archaea.
- It’s a crystalline layer of thick subunits consisting of protein or glycoprotein.
- Helps Protect from OSMOTIC STRESS and may contribute to cell shape.
Fimbriae?
- helps organism stick to surfaces
Pili?
Pili are hair-like appendages found on the surface of many bacteria. They are primarily involved in functions such as attachment to surfaces, motility, and gene transfer between bacteria (conjugation). Unlike flagella, pili are usually shorter and more rigid, and they can help bacteria adhere to host tissues or exchange genetic material through a process called bacterial conjugation.
How does the peptidoglycan layer differ between gram-negative and gram-positive bacteria?
Gram-negative: no actual molecules that link the two amino acid tetramers together.
Gram-positive: the amino acid tetramers are linked by a pentaglycine bridge (5 glycine molecules).
What are NAM and NAG?
the two sugars that make up peptidoglycan (peptidoglycan layer) in BACTERIA.
(bound together by Beta-1-4 linkages).
What enzyme can destroy the NAM and NAG sugar bonds in the peptidoglycan layer?
a lysozyme.
Why are bacteria excellent targets for antibiotics such as Penicillin and Vancomycin?
Because both of those antibiotics target the peptidoglycan layer of the bacteria, and that layer is unique to bacteria, so it would not affect our own cells.
Is the peptidoglycan layer the cell wall of the bacteria?
Yes, the peptidoglycan layer is the main component of the cell wall in most bacteria.
(it provides structural strength, maintains the cell’s shape, and protects it from osmotic pressure).
True or false: different bacteria synthesize their peptidoglycan cell walls from different locations depending on the bacteria.
TRUE!
The cell wall can have growth from different areas, depending on the bacteria.
what is a bacteriophage?
A bacteriophage (often called a phage) is a virus that infects and replicates within bacteria. They are highly specific to their bacterial hosts and are found in many environments, including soil, water, and even within living organisms.
Gram positive vs Gram negative bacteria?
Gram-Positive:
-S-layer
-Thick peptidoglycan layer
-cell membrane
Gram negative:
-Outer membrane
-Peptidoglycan
-inner membrane
do gram positive bacteria still have membrane proteins, even though their membrane is on the inside of the peptidoglycan layer?
Yes, Gram-positive bacteria still have membrane proteins in their cell membrane, even though it is located beneath the thick peptidoglycan layer.
