IMMUNOLOGY
BMI2601
@sciencera. Learntothink
QUESTION 1 [16]
Identify characteristics for each of the following types of microbes that
distinguishes them from each other: bacteria, archaea, protists, fungi,
viruses, viroids, and prions. (16)
Bacteria • Prokaryotic microorganisms that are
unicellular, tiny, and lack a genuine
nucleus.
• Peptidoglycan makes up their cell wall.
They have a flagellum that helps them
move about.
• "Bacteria are classified into many
categories based on their forms and sizes."
Cocci are spherical-shaped bacteria; bacilli
are rod-shaped bacteria; spiral-shaped
bacteria are spirilla
• They reproduce via binary fission, and
genetic material is transferred via
transformation, transduction, and
conjugation, as well as sporulation.
• "Nitrogen fixation is carried out by a few
numbers of microorganisms, such as
Rhizobium."
• Antibiotics are also made from them. And
can also be used in agriculture as
biopesticides
• They can grow on non-living surfaces
Archaea • These are unicellular prokaryotic organisms
, with bacterial-like structures.
• "Their cell wall differs from bacteria in that
it has unique lipids that allow them to live
in harsh environments." ("What Are
Microbes? - Microorganism Definition,
Types, and Examples")
• They are also found in the intestines and
skin of humans.
Protists • "These are minuscule, unicellular
organisms that are neither plants nor
animals," says the researcher.
• They can be either autotrophic or
heterotrophic in nature.
• They mostly reproduce by binary fission or
budding.
• Plant-like protists like diatoms and
dinoflagellates, animal-like protists like
amoeba, and fungus-like protists like slime
molds are all members of this group.
"Protists supply us with oxygen and recycle
critical nutrients to make it available to
other life forms."
Fungi • "They can be unicellular or multicellular,
using chitin as the cell wall."
• These organisms are heterotrophic,
meaning they cannot produce their own
food.
• Organelles that are membrane-bound
make up this group.
• Fungi include yeasts, molds, and
mushrooms, to name a few.
• As they decompose dead plants and
animals, they collect nutrients.
• A few fungi are toxic and can cause
ringworm and other fungal illnesses. The
rest are used in the production of
antibiotics such as penicillin.
, • In the baking industry, as well as in the
beer and wine industries, fungi such as
yeast are used.
• Fungi are typically non-motile creatures.
• Budding, fragmentation, asexual, and
sexual spore generation are all examples of
spore reproduction.
• Fungi may survive on their own.
Viruses • Viruses serve as a link between living and
non-living organisms.
• "They are protein, nucleic acids, and lipid-
based non-cellular microbes."
• "They are measured in nanometers, with
diameters ranging from 20 to 250
nanometers, and can only be seen with an
electron microscope." nucleotide core
surrounded by a protein sheath that might
infect living cells.
• They live inside host cells and replicate by
infecting living cells inside them.
• They are self-sufficient.
Viroids • Viroids are made up entirely of RNA.
• These are smaller in size and exclusively
infect plants, according to reports.
• These are some of the tiniest known
infectious disease agents.
• Viroids are nucleic acid species having a
distinct structure and a low molecular
weight.
• They replicate within the host cell, which
they damage and create changes in, leading
to death.
• Viroids are divided into two families:
Pospiviroidae, which includes nuclear
viroids, and Avsunviroidae, which includes
chloroplastic viroids.
• Viroids are thought to migrate
, intracellularly, cell to cell via the
plasmodesmata, and long-distance via the
phloem.
Prions • These organisms are obligatory parasites
that have been shown to live in the
environment for up to two years.
• Prions are self-perpetuating proteins
without any genetic material.
• Various diseases, such as bovine
spongiform encephalopathy (BSE) and
Creutzfeldt-Jakob disease, have been linked
to these organisms (CJD).
• Prions can spread for years in a person's
brain without causing any symptoms.
• They can degrade nucleic acids yet are
responsive to proteins that are denatured.
• On the cell membrane, prion proteins play
a vital function in cell signaling and cell
adhesion.
QUESTION 2 [12]
2.1. What are the main functions of the sensory-somatic nervous
system? (4)
• Sensory and motor neurons coexist in the sensory-somatic
nervous system, which is made up of cranial and spinal nerves.
• The skin, skeletal muscle, and sensory organs send sensory
information to the CNS via sensory neurons.
• The CNS sends messages to the muscles, instructing them to
contract, via motor neurons.
• An animal would be unable to process any information about its
surroundings (what it sees, feels, hears) and govern motor
actions without its sensory-somatic nervous system.
• Unlike the autonomic nervous system, which contains two
synapses between the CNS and the target organ, sensory and
motor neurons only have one synapse, with one neuron ending
at the organ and the other immediately contacting a CNS cell.
