UNIT II A- BAFPAVH Flashcards
(68 cards)
1
Q
Proposed by Carl Woese
A
Phylogenetic relationship
2
Q
Phylogenetic relationship
A
Provides information on shared ancestry but
not necessarily on how organisms are similar
or different
3
Q
evolutionary history and relationship of an
organism or group of an organisms
A
phylogeny
4
Q
phylogeny
A
another such as which organisms thought to
have evolved from which species it is closely
related to
5
Q
bacteria
A
single-celled organisms
- lack organelles, such as chloroplast and
mitochondria
- do not have true nucleus found in eukaryotic
cells
- a double stranded DNA that is continuous
and circular is located in a nucleoid
6
Q
an irregular-shaped region that
does not have a nuclear membrane
A
Nucleoid
7
Q
Bacterial cell membrane and cell wall is made
of
A
peptidoglycan
8
Q
cell membrane+ cell wall
A
cell envelope
9
Q
Binary fission
A
-bacterial reproduction
splitting of a bacterial cell after
reaching a certain size
10
Q
bacterial reproduction. sexual/ asexual?
A
reproduce asexually hence the two
daughter cells, result from the binary fission,
have the same DNA as the parent cell
11
Q
horizontal gene transfer or
transformation, conjugation and
transduction
A
bacterial exchange of genetic
material among one another
12
Q
bacterial shape: Coccus: define and examples.
A
- spherical/ovoid in shape
- some remain attached after binary fission
even forming separate cells
examples: Streptococci – cocci in chains - Staphylococci – clusters of multiple
cocci - Tetrads – square arrangements of
four cocci - Sarcinae – cubes of eight cocci
13
Q
bacterial shape: bacillus: define and examples.
A
-Rod-shaped bacteria
- Can be solitary or arranged together
Example:
o Diplobacilli – 2 bacilli arranged next
to each other
o Streptobacilli – chains of bacilli
14
Q
bacterial shape: spiral: define and examples.
A
Spiral in shape Example: o Spirillum - thick, tough spirals o Spirochetes – thin, flexible spirals o Vibrious – comma-shaped rods with a small twist
15
Q
State other bacterial shape.
A
- Filamentous – long and thin
- Square
- Star
- Stalk
16
Q
what makes gram staining of bacteria possible?
A
cell wall
17
Q
define gram staining
A
- A method of staining bacteria involving
crystal violet dye, iodine, and the
counterstain safranine - Used for general identification of bacteria or
detect the presence of certain bacteria - Cannot be used to identify bacteria in the
species level - Can be used for grouping bacteria, gram-positive or gram-negative
18
Q
Appearance of gram-positive bacteria and why?
A
Violet – due to the thick
cell wall that trapped the crystal violet iodine
complex
19
Q
Appearance of gram-negative bacteria and why?
A
appear red due to the thin cell wall not holding the violet iodine complex but can hold safranine
20
Q
Selectively permeable barrier, mechanical boundary of cell, nutrient and waste transport, location of many metabolic processes (respiration, photosynthesis), detection of environmental cues for chemotaxis
A
Plasma
membrane
21
Q
Gas
vacuole
A
An inclusion that provides
buoyancy for floating in aquatic
environments
22
Q
Ribosomes
A
Protein synthesis
23
Q
Storage of carbon, phosphate,
and other substances
A
Inclusions
24
Q
Localization of genetic material
DNA
A
Nucleoid
25
```
In typical gram-negative
bacteria, contains hydrolytic
enzymes and binding proteins for
nutrient processing and uptake
In typical gram-positive bacteria,
may be smaller or absent
```
Periplasmic
| space
26
Cell wall
Protection from osmotic stress,
| helps maintain cell shape
27
Capsules
and slime
layers
Resistance to phagocytosis,
| adherence to surfaces
28
Fimbriae
| and pili
Attachment to surfaces, bacterial
conjugation and transformation,
twitching and gliding motility
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Swimming and swarming motility
Flagella
30
Endospore
Survival under harsh
| environmental conditions
31
Archaea
```
delineated from Eukarya,
Eubacteria.
-Lack a nucleus and consist of the
extremophiles or ‘ancient’ bacteria (e.g.
methanogens, thermophiles, halophiles)
```
32
arkhaios
primitive
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Examples of members of archaea
```
• Pyrolobus fumarii - holds the upper
temperature limit for life at 113 °C and
found living in hydrothermal vents
• Picrophillus – isolated from acidic soils
in Japan; most acid-tolerant organisms;
known capable of growth at around pH 0
• Methanogens – produce methane gas
as a metabolic by-product and found in
anaerobic environment such as in
marshes, hot springs, and animal guts
```
34
Common Characteristics of Archaea
• Presence of tRNA and rRNA
• Absence of peptidoglycan cell walls;
replacement by largely proteinaceous coat
• Occurrence of ether-linked lipids built from
phytanyl chains in extreme environments
(Bacteria has esther-linked lipids)
35
Fungi
- eukaryotic, non-vascular, non-motile and
heterotrophic organisms
- may be unicellular or filamentous
- reproduce by means of spores
- exhibit the phenomenon of alternation of
generation
- lack chlorophyll and hence cannot perform
photosynthesis
- store their food in the form of starch
- Biosynthesis of chitin occurs in fungi.
- nuclei are very small.
- fungi have no embryonic stage; develop
from the spores
- mode of reproduction is sexual or asexual
- fungi are parasitic and can infect the host
- produce a chemical called pheromone
which leads to sexual reproduction in fungi
36
Examples of fungi
mushrooms, moulds, yeast
37
Alternation of
| Generations/Metagenesis/Heterogenesis
- important characteristic of fungi
- asexual phase of the life of an organism
- has 2 generations which are often
morphologically or chromosomally distinct
38
Fungi classification: Mode of Nutrition: Saprophytic
feeding on dead organic
substances
Examples: Rhizopus, Penicillium
and Aspergillus
39
Fungi classification: Mode of Nutrition: Parasitic
```
living on other living organisms
(plants or animals); absorb
nutrients from their host
Examples: Taphrina and
Puccinia
```
40
Fungi classification: Mode of Nutrition: Symbiotic
```
interdependent relationship
association with other species in
which both are mutually benefited
Examples: Lichens (algae
synthesize carbs & fungi provides
shelter) and mycorrhiza
```
41
Fungi classification: Spore formation: Zygomycetes
```
formed by the fusion of two
different cells
sexual spores – zygospores
asexual spores –
sporangiospores
The hyphae are without the
septa
```
42
Fungi classification: Spore formation: Ascomycetes
```
sac fungi; coprophilous (live
on dung), decomposers,
parasitic or saprophytic
sexual spores - ascospores
Asexual reproduction –
conidiospores
Example: Saccharomyces
```
43
Fungi classification: Spore formation: Basidiomycetes
```
Mushrooms are the most
commonly found
basidiomycetes and mostly
live
as parasites
Sexual reproduction occurs
by basidiospores
Asexual reproduction
occurs by conidia, budding or
fragmentation
Example: Agaricus
```
44
Fungi classification: Spore formation: Deuteromycetes
```
imperfect fungi-do not follow
the regular reproduction
cycle
do not reproduce sexually
Asexual reproduction by
conidia
Example: Trichoderma.
```
45
Fungi classification: Reproduction:
| Vegetative
By budding, fission and
| fragmentation
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Fungi classification: Reproduction:
| Asexual
-Anamorph
-This takes place with the help of
spores called conidia or
zoospores or
sporangiospores
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Fungi classification: Reproduction:
| Sexual
-Teleomorph
-ascospores, basidiospores, and
oospores
48
Protozoa
- eukaryotic, unicellular microorganisms
which lack cell wall
- do not have cell wall but some possess a
flexible layer called pellicle, a rigid shell of
inorganic materials outside the cell
membrane
- move by locomotor organelles or by a
gliding mechanism
- have heterotrophic mode of nutrition
49
Protozoan forms
Free-living forms - ingest particulates, such as
bacteria, yeast and algae
Parasitic forms - body fluids of their hosts
- reproduce primarily by asexual means,
although in some groups sexual modes also
occur
50
Protozoa classification: Sarcodina
```
Motility: streaming of
ectoplasm, producing
protoplasmic projections called
pseudopodia (false feet)
Examples: Free-living form like
Amoeba proteus* and parasitic
form like Entamoeba histolytica*
```
51
Protozoa classification: Mastigophora
```
Locomotion: one or more
whip-like, thin structures called
flagella
Examples:
Free-living forms like Euglena
viridis*, Cercomonas
longicauda*, Heteronema acus*
Parasitic forms like
Trichomonas vaginalis,
Trypanosoma gambiense*,
Giardia lamblia*
```
52
Protozoa classification: Ciliophora
```
Locomotion: cilia, short
hairlike projections whose
synchronous beating propels
the organism
Examples:
Free-living forms like
Paramecium caudatum*,Stentor polymorpha*, Vorticella
campanula*
Parasitic form like Balantidium
coli*
```
53
Protozoa classification: Sporozoa
```
do not have locomotor
organelles in their mature stage
however, in immature form, they
exhibit some type of movement;
All the members of this group
are parasites.
Examples: Plasmodium, the
malarial parasites of animals
and human beings.
```
54
algae
belongs to Protista
- a group of predominantly aquatic,
photosynthetic organisms of the kingdom
Protista
can photosynthesize like plants
- possess specialized structures and cell
organelles like centrioles and flagella, found
only in animals
either unicellular or multicellular organisms
- lack a well-defined body; structures like
roots, stems or leaves are absent
- found where there is adequate moisture
- Reproduction: asexual and sexual forms
- Asexual reproduction: spore formation
- free-living; some can form a symbiotic
relationship with other organisms
55
Types of Algae:
| Red Algae
-Rhodophyta
-Distinctive species found in
marine and freshwater
ecosystems; has chlorophyll a
but lack chlorophyll b or beta-carotene
-Pigments responsible for red
coloration: phycocyanin and
phycoerythrin
56
Types of Algae:
| Green Algae
```
Large informal grouping of
algae having the primary
photosynthetic pigments,
chlorophyll a and b, and
auxiliary pigments like betacarotene; can have symbiotic
relationships with other
organisms; members are
uni/multicellular, colonial, and
flagellates
Example: Spirogyra, Ulothrix, &
Volvox
```
57
Why are Blue-green Algae/Cyanobacteria not algae?
- they are prokaryotes hence not an algae
- lives in moist or aquatic environments
- obtains energy through photosynthesis
- fixes nitrogen in the soil
Example: Nostoc, and Anabaena
58
Viruses
- Infectious, acellular pathogens
- Obligate intracellular parasites with host and
cell-type specificity
- DNA or RNA genome (never both)
- Genome is surrounded by a protein capsid
and, in some cases, a phospholipid
membrane studded with viral glycoproteins
- Lack genes for many products needed for
successful reproduction, requiring
exploitation of host-cell genomes to
reproduce
- Have living (can mutate) and non-living
characteristics (acellular – no cellular
organelles)
- Don’t grow and divide; new viral
components are synthesized within the
infected host cell
- Vast majority of viruses have RNA genomes
DNA virus – has DNA
RNA virus – has RNA
Plant viruses – have single-strand RNA
genome
Bacteriophages – have double-stranded DNA
genome
Example:
• Coronavirus
• Bacteriophage – a virus that infects a
bacteria; bacteria-eater
59
Viral Replication Process
- Begins when a virus infects its host
- Touching to the host cell, penetrating the
cell wall/membrane
- The virus genome is uncoated from the
protein and injected into the host
- The viral genome hijacks the host cells’
machinery forcing it to replicate the viral
genome and produce viral proteins to make
new capsids
- the viral particles are assembled into new
viruses
- New viruses burst out of the cell in the host
cell during the process of lysis which kills the
host cells
- Some viruses take a portion of the host
membrane during the lysis process to form
an envelope around the capsid
60
Helminths
```
Not a group of microorganisms but are
included in studying microbiology
- Parasitic worms that feed on a living host to
gain nourishment and protection while
causing poor nutrient absorption
- Cause weakness and disease to the host
- These worms and larvae live in the small
bowel and are referred to as intestinal
parasites
- Nematodes or roundworms
- Trematodes, which includes flukes or
flatworms
- Cestodes or tapeworms
- Monogenans, also members of the flatworm
phylum
- Share similar morphology
- Multicellular organisms that are visible to the
naked eye
The worms are usually caught when
treading on contaminated soil in warm,
humid countries that have poor sanitation
and hygiene
- Can grow up to 13ml in length
- Can penetrate human skin
```
61
Features of Helminths:
Trematodes /
flatworms
flat, leaf-shaped and
| unsegmented; hermaphroditic
62
Features of Helminths:
| Nematodes
cylindrical and have lips, teeth
and dentary plates; either male
or female
63
Features of Helminths:
Cestodes or
tapeworm
segmented and hermaphroditic;
have a sucker and a projecting,
hooked rostellum
64
Diseases caused by Helminths: Hookworm
| disease
```
common worm infestation in
the developing countries
Cause: Ancylostoma
duodenale or Necator
americanus
Illness lead to anemia and
malnutrition
```
65
Diseases caused by Helminths: Dracunculiasis
```
Cause: ginny worm,
Dracunculus medinensis
transmitted through
contaminated water; lies
burrowed within skin causes
severe inflammatory
reactions
```
66
Diseases caused by Helminths: Loiasis or
African eye
worm disease
```
Cause: filaria Loa loa worm
contracted through Deer fly or
Mango fly bites and the adult
worms move through
subcutaneous tissue towards
the subconjunctiva of the eye
Illness: red, itchy swelling in
the skin “Calabar swelling”
```
67
Diseases caused by Helminths: Cysticercosis
```
Cause: tapeworm Taenia
solium
Symptoms are not present for
a year but painless bumps
develop in the skin and
muscles or cause
neurological problems
```
68
Diseases caused by Helminths: Echinococcosis
```
Cause: Echinococcus tapeworms
liver is usually affected first,
followed by the lungs and
brain; liver disease may
cause abdominal pain and
jaundice; lung disease leads
to breathlessness and
coughing
```
