Diversity of Organisms
Contents
The five kingdom classification
system
Monera – cell diagram– types
Spore formation
Reproduction
Two types of nutrition
Factors affecting growth rate
Beneficial & Harmful Bacteria
Antibiotics
Antibiotic resistant strains of
bacteria
Growth curve of bacteria
Continuous flow production
Batch flow production
Fungi
Types of fungi
Rhizopus – Structure
Reproduction – asexual – sexual
Beneficial & harmful fungi
Yeast structure – reproduction –
economic importance
Asepsis
Protista – Amoeba
Plant & animal kingdoms
Prokaryotic nature of bacteria
Eukaryotic nature of fungi 2
The five
kingdom
classification
system
3
What is in each kingdom?
(1/2)
Prokaryote (Monera )kingdom: simple singlecelled organisms that feed by a number of
different methods.
Protista (Protoctist) kingdom: complex singlecelled organisms and all of the algae (including
multicellular algae) that feed by a number of
different methods.
4
What is in each kingdom?
(2/2)
Fungus kingdom: multicellular organisms with
little cellular differentiation that feed
heterotrophically by absorption.
Plant kingdom: multicellular organisms that feed
by photosynthesis.
Animal kingdom: multicellular organisms that feed
heterotrophically by ingestion.
5
Monera
Bacteria
Bacterial cell - Diagram
Cell wall
Cell or plasma
membrane
Cytoplasm
Nuclear or genetic
material
Plasmid
Capsule
Flagellum
7
Types of bacterial cell
Cocci – single, chains, pairs, clusters
Rods – single, chains, with or without flagella
Spirals – often have flagella
8
Bacterial shapes
9
Mixed bacteria showing shapes
10
Spore formation
Occurs during unfavourable conditions
Contents of cell shrinks
Tough outer coat formed within the cell
This is the endospore
11
Endospore
Resists desiccation
Resists high temperatures – hard to kill
When favourable conditions return
Endospore absorbs water
Expands
Breaks tough outer wall
Divides by binary fission
12
Bacterial endospore
13
Reproduction
Usual method of asexual reproduction is known as
binary fission
DNA replicates
Cell grows to full size
Cell divided across the centre
Forms two cells same size each with their own
DNA
14
Mutations and bacteria
Favourable mutations are rare
Bacteria have a short life cycle – can reproduce
about every 20 minutes in favourable conditions
Numerous generations can be produced in a
very short time – approx 72 in 24 hours
Favourable mutations will become the norm very
quickly
Can give rise to resistant strains of bacteria
15
Two types of Nutrition
Autotrophic bacteria – make their own food by
Photosynthesis or
Chemosynthesis e.g. nitrifying bacteria in soil
Heterotrophic bacteria – eat food already made –
can be aerobes or anaerobes
Saprophytes – free-living
Symbiotes – three types : –
Mutualism, Commensalism, Parasitism
16
Bacterial nutrition summary
17
Factors affecting growth rate
1.
2.
Temperature – each has their own optimum
Presence or absence of oxygen
Facultative anaerobes
Obligate anaerobes e.g. Clostridium botulinum
Obligate aerobes
3.
4.
5.
pH – each has their own optimum
External solute concentration – osmosis, jams,
Dead Sea bacteria
Pressure – some found exclusively at sea
depths
18
Beneficial & Harmful Bacteria
Beneficial Bacteria
Produce
Streptomyces sp. (species)
Lactobacillus sp.
Escherichia coli
Antibiotics
Yoghurt or cheese
Vitimin K in the colon
Harmful Bacteria
Causes
Salmonella typhi
Typhoid
Vibrio cholerae
Cholera
Mycobacterium tuberculosis Pulmonary TB
19
Pathogen
A pathogen is an organism that causes a disease.
They are parasitic bacteria that are capable of
causing a disease in their host e.g. diphtheria,
whooping cough and tetanus (3 in 1) are
diseases caused by bacteria.
20
Antibiotics
(1/3)
Are chemicals produced by micro-organisms
(m/os) that are toxic to bacteria.
antibiotic: substance produced by living microorganisms (e.g. Penicillium notatum) which
destroy or inhibit the growth of other microorganisms especially bacteria or fungi e.g.
penicillin, streptomycin, tetracycline, etc. – has
no effect on viruses.
21
Antibiotics
(2/3)
They are naturally occurring chemicals produced
by one m/o to prevent the growth of another m/o
and thus reduce competition for food, minerals,
etc.
Consequently there are m/os that can grow in
the presence of these antibiotics i.e. they are
resistant to the antibiotic.
22
Antibiotics
(3/3)
The gene for this resistance is carried on the
plasmids in the bacteria
These plasmids can be passed from one
bacterium to the next
And from one species to another
This leads to the development of antibiotic
resistant strains of bacteria
23
How antibiotic resistant strains
of bacteria may develop
(1/2)
Person given an antibiotic
All bacteria (good and bad) killed
If there is an antibiotic resistant strain of bacteria
present
Have no competition
Can increase in numbers rapidly
Colonise the person
24
How antibiotic resistant strains
of bacteria may develop
(2/2)
If a pathogen arrives it can get the antibiotic
resistance from the resident bacteria
Antibiotics will now not affect it
Effectiveness of antibiotics is being reduced
because of this e.g. multiple drug-resistant
tuberculosis.
25
Antibiotic Resistance in Bacteria
Intensive farming often involves the addition of
small amounts of antibiotics to the food
Healthier animals that grow quicker produced
Facilitates the development of resistant strains of
bacteria
Residues of antibiotics in meat consumed by
humans
Assists the development of more antibiotic
26
resistant bacteria
Growth Curve of bacteria
4
3
1
2
Go to next slide
27
Explanation of graph
(1/2)
Lag phase: bacteria are settling in, adjusting to
their new environment, and beginning to produce
the correct enzymes to digest the new food.
Back to Graph
Exponential (Log or Logarithmic) phase: a
period of rapid growth – numbers double every
time it replicates, due to abundance of
resources. Back to Graph
28
Explanation of graph
(2/2)
Stationary phase: birth rate = death rate due to
competition for food, space and the build-up of
toxic wastes. Back to Graph
Death (Decline) phase: numbers decline due to
increased competition for food, space and the
build-up of toxic wastes. Back to Graph
29
Continuous flow production
Some microbes are eaten as a protein substitute
(animal feed) – single cell protein (SCP)
Made in a fermenter
Production kept at the exponential phase to
produce the maximum quantity
Fresh nutrients added to the top and SCP drawn
off from the bottom
Fermenter cleaned after six months – build up of
toxic by-products, etc.
30
Simple
diagram of
continuous
flow method
of microbe
production
31
Batch flow production
Usually used when microbes are producing a
product that is required e.g. penicillin
Fermenter filled with nutrients and culture
Stirred and temperature controlled
Liquid removed and culture removed by filtration
Penicillin crystallised from remaining fluid
32
Diagram
showing
batch
production
of
penicillin
33
Fungi
Types of Fungi
Parasites – on people and crops e.g. athlete’s
foot, Dutch Elm disease, etc.
Saprophytes – important in decomposition e.g.
Dry rot in timber, mildew on clothes, etc.
Fruiting bodies of many saprophytic fungi are
edible e.g. mushrooms, but some are highly
poisonous or fatal e.g. Death cap.
35
Mushroom (Agaricus) close up
36
Mushroom – showing gills
37
Gill of mushroom showing spores
38
Rhizopus – bread mould
Saprophytic
Multicellular
Aseptate = no crosswalls dividing the cytoplasm
into separate cells - no cells, has nucleii.
39
Rhizopus – types of hyphae
3 types of hyphae.
Stolons: Grow horizontally on surface of substrate
Rhizoids: Grow downwards into substrate anchorage and absorption of food.
Sporangiophores: Grow upwards away from
substrate - function in reproduction.
The three types of hyphae that make up the fungus
are collectively called the Mycelium
40
Structure of Rhizopus
To Asexual Reproduction
41
Rhizopus - nutrition
Saprophyte - hyphae secrete enzymes onto the
substrate on which they are growing –
digestion is external (e.g. starch to sugar, lipids to
?, proteins to ?) –
hyphae then absorb soluble products of digestion
by diffusion.
42
Reproduction
Two types
Asexual (sporulation) - does not involve the
manufacture or union of sex cells or gametes involves only one parent and all the offspring are
genetically identical
Sexual - involves the union of sex cells or
gametes,
two parents and results in genetically different
offspring
43
Asexual reproduction
(1/2)
usual method in suitable conditions i.e. supply of
food, water and a suitable temperature
Tip of sporangiophore develops a swelling
(sporangium)
Diagram
Separated from rest of sporangiophore by
crosswall (columella) Diagram
44
Asexual reproduction
(2/2)
Spores produced within sporangium by mitosis
Sporangium bursts when ripe - spores released
in dry conditions and carried by the wind
Germinate into new hypha and mycelium
45
Sexual reproduction
(1/2)
plus and minus strains of hyphae growing close
together (structurally similar, chemically different
- no male or female)
short side branches (progametangia) grow
towards each other
tips swell (gametangia) and produce a haploid
(n) gamete
tips meet each other – gametes fuse to form a
diploid zygote (2n) – develops into the
zygospore (2n)
46
Sexual reproduction
(2/2)
resistant to adverse conditions
after a time of dormancy
meiosis - germination
produces one sporangium – forms spores
bursts when ripe – spores released
germinate into new hypha
47
Sexual
reproduction
in Rhizopus
48
Beneficial & Harmful Fungi
49
Yeast – structure
Saccharomyces
Unicellular fungus – (e.g. on fruit skins - apple and
grape)
ovoid or spherical cells found singly or in groups
thin cell wall,
granular cytoplasm,
nucleus and
large storage vacuoles
50
Yeast – reproduction
(1/2)
Asexually by budding – usual method
modified mitotic division
bulge (bud) forms on side of cell
Enlarges and fills with cytoplasm
51
Yeast – reproduction
(2/2)
nucleus divides in two by mitosis and one goes
into the bud
the bud may remain attached to the parent and
undergo further budding to form a colony
or separate from the parent and form a new
colony itself
52
Economic importance
Brewing industry - yeast respire anaerobically
producing ethanol + carbon dioxide
C6H12O6 Energy + 2C2H5OH + 2CO2
Baking industry - the CO2 produced by yeast
causes the dough to rise - the heat evaporates
the ethanol
C6H12O6 Energy + 2C2H5OH + 2CO2
53
Precautions when working with
micro-organisms
Assume that all are
hazardous until
otherwise proven.
54
Asepsis
or aseptic techniques – methods used to prevent
microbes entering an area. These include: Sterilisation of working area, all equipment,
instruments and materials – before and after use
Flaming of containers, needles and loops during
use
Containment methods and safe disposal of
unwanted materials after use
55
Containment methods
Work in laboratories with negative pressure
outside – microbes drawn back into lab
Use laminar airflow cabinets – microbes kept
behind a flow of filtered air
Use of protective clothing and masks
All materials are sterilised before disposal or re-use
56
Sterile
This refers to a substance that is free from all types
of microbes – the substance may have been
treated to kill all the microbes.
Sterilising is the killing of all microbes e.g. by moist
heat (120°C for 20 minutes) using an autoclave.
57
Protista
Amoeba
Protista e.g. Amoeba
Cell membrane
Ectoplasm
Cytoplasm
Endoplasm
Mitochondrion
Ribosome
59
Plant and Animal Kingdoms
Plant Kingdom Vs Animal Kingdom
Multicellular
Photosynthetic
Cells with cell walls
Include a large number
of phyla e.g.
Bryophyta,
Pteridophyta,
Spermatophyta
Multicellular
Heterotrophic
Cells without cell walls
Include a large number
of phyla e.g.
Porifera, Cnidaria,
Platyhelminthes,
Annelida, Mollusca,
Arthropoda
61
Prokaryotic nature of bacteria
(1/2)
No membrane-bound nucleus or organelles
Circular piece of DNA (the chromosome)
attached to cell membrane known as the
nucleoid
This chromosome does not contain proteins
Ribosomes, food storage granules and enzymes
found in cytoplasm
62
Prokaryotic nature of bacteria
(2/2)
Cytoplasm surrounded by plasma or cell
membrane
Cell membrane surrounded by cell wall made of
peptoglycan
Cell wall may be surrounded by a capsule
Some may have flagella
63
A diagram
of a
bacterium
64
Eukaryotic nature of fungi
More advanced cellular structure
Contain many membrane-bound cellular
organelles, including a nucleus
May have developed as a result of a number of
prokaryotic cells coming together
Chloroplasts and mitochondria contain their own
DNA
65
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