Describe How Humans Use And Are Affected By Micro-Organisms
A.S.90168 2 credits
This is a small but interesting standard.The subject matter is part of our everyday
life.HOW?
The type of answers expected in this standard involve a lot of written
explanations that must have the correct scientific terms.
Mega Spelling list
You need to know how to spell these words and what they mean.
inoculate extra cellular digestion enzyme pathogen
respiration saprophyte aerobic
nutrition anaerobic hyphae
excretion binary fission spores
growth reproduction toxin
parasite capsule sporangium
flagella disinfectant
Bacteria Shapes
Bacteria Structure
• You need to be able to label the following parts of a typical bacteria:
• Capsule• Cell wall and membrane• DNA or nuclear material (no nucleus)• Flagella• Cytoplasm
TaskDraw a typical bacteria and label it
from the following the next slide
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Bacterial Cell structure
You must be able to draw a basic bacteria
capsule
flagellum
cell membrane
nuclear material
cell walla
b
c
d
e
fcytoplasm
A Typical Bacteria
Typical Bacteria Drawings
A Typical Bacteria
Reproduction of Micro organisms
A bacteria can reproduce every 20 minutes in ideal conditions.
The process is called binary fission Binary fission involves a unicellular
organism (like bacteria) dividing in half after the genetic material has duplicated and separated.
Graphical image of pop vs. time
Making Flash Cards (to help you learn the definitions)
• Come and get 22 flash cards
• Write the 22 important microbe words on one side of each card
• Use the NCEA biology text to write definitions for each word on the other side of that word
• Now you have a set of 22 cards (keep them in a safe place!)
Flash Card list
inoculate extra cellular digestion enzyme pathogen
respiration saprophyte aerobic
nutrition anaerobic hyphae
excretion binary fission spores
growth reproduction toxin
parasite capsule sporangium
flagella disinfectant
cytoplasm
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Cellular organism copies it’s genetic information then splits into two identical daughter cells
Starter
• Bacteria grow then reproduce by _______ in two a______. This process is called __________ . In
ideal conditions bacteria can double their numbers every ___ minutes.
splittingsexually
binary
binary fission
20
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Bacteria grow and divide by a process called Binary fission
What conditions allow bacteria to divide so quickly?
1.Warmth
2.Food
3.Space
4.moisture
Ecoli.mov
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Bacteria growth in ideal conditions
Why the numbers of bacteria vary in each section?
A
B
C
D
Flash card activity
• Each student writes a neat table in their book
Three columns with headings
1. Word 2. Definition correct 3. Revision
Flash Card Activity
• Get into pairs
• One person picks 5 cards at a time from the other persons 20
• Each person is to ask the other a definition from each of their 5 flask cards (the person asking writes the word down in the table)
• If the person answers incorrectly the student asking replies – eg - Saprophyte is a micro-organism that lives off dead or decaying matter
• The other student then repeats the definition back in exactly the same manner
• If they get it right they get a cross by their name in the definition column and the card goes to the bottom of the pile of 5
• If the student got it right first time then the card goes on another pile of revision cards and the student gets a tick in the revision column
Flash Card Activity
• Go through the 5 cards until they are answered correctly and are all on the revision list
• Then the pair reverse roles and repeat the activity
• This goes on until each person has the 22 cards in the revision pile
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Bacteria Feeding
Bacteria feed by a process called extracellular digestion
What does this mean?
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Food Safety
Cut out the boxes from the sheet and place (not glue) at the temperature you think they should go
Read pages 30 – 31 in living world text
Then glue the box by the correct temperature and glue the sheet into your book
How many did you get right?
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Handling Food to minimize microbe growth
Under the headings: Buying food Storing food Preparing food Cooking food
Make brief neat notes on how to minimize microbe growth on food (you must say why the process reduces microbe growth) from pages 30 and 31 you have 10 minutes
Bacteria Uses - sewage
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Bacteria Uses - sewage
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These are the aeration trickle towers at Bromley- bacteria operate in aerobic conditions to break down waste
Cheese Making
• Read page 34 in the living world text• Then for your favourite cheese draw a flow
diagram of the process from the picture on page 35
Bacteria Uses – sewage treatmentAeration tank or trickle filter:Here liquid waste is aerated using air bubbles or trickled over corrugated plastic sheet (to increase the surface area for bacteria to breakdown organic material)
Primary settlement tank solids are removed to the anaerobic digester
Secondary settlement tank- activated sludge returned to aeration tank
Anaerobic digestion –methane is removed and used to generate electricityThe sludge is removed and used as fertiliser
Effluent removed for discharge to ponds before discharge to estuary
Bacteria Uses – cheese and yogurt
Certain bacteria produce cheese and yoghurtFor example the bacteria lactobacillus use the
lactose in milk as food to produce lactic acid.This lactic acid allows a chemical called renin to
curdle the protein in the milk to make curds.The curds be kept with the milk to form yoghurtIf the curds are removed from the whey and dried
they make cheeseDifferent bacteria create different flavouredcheeses.
Starter
Draw a labeled fungi diagram
draw a labeled bacteria diagram
capsule
flagellum
cell membrane
nuclear material
cell walla
b
c
d
e
fcytoplasm
What is pasteurisation?
Starter-thinking question
Antibiotics are not effective at destroying ______infections.
If this is the case why is it that doctors will often prescribe antibiotics when you have the flu?
Pathogenic Bacteria
• Some bacteria harm the body by killing the cells they attack
• Some of the most deadly bacteria cause disease by producing poisonous substances or toxins
• read pages 183 – 186 Micro organisms and disease for homework biology and Human biology complete Q 2 page 187 checked Wed
(very important) you may need to read whole chapter for answers
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Crustose
Foliose
Fruticose
Typical Fungi• Draw and
label the
Sporangia
Spores
hyphae
Fungi Reproduction
• Fungi reproduction involve the release of spores
• These spores grow into fungi
• Fungi reproduce and grow in warm, moist conditions in aerobic or anaerobic conditions
Fungi Feed by extra cellular digestion
Beneficial Fungi• The enzyme zymase from the fungi yeast produces
alcohol from glucose in the fermentation process (anaerobic respiration)
glucose ethanol + carbon dioxide CO2 from this process is used in bread making and
beer production The ethanol produced in fermentation is the alcohol
produced in the brewing of beer and wine making Fermentation is an example of anaerobic respiration.
Read page 8 of living world
• Copy the 2 boxes (aerobic respiration and anaerobic respiration) neatly into your book
Relative Sizes of Microbes
Fungi and bacteria are small – but viruses are a lot smaller than bacteria and fungi
Covered in class
Specific learning objectives (SLO)
1 Recognise that micro-organisms are very tiny and found almost everywhere on Earth and in and on living things.
2 Appreciate the relative sizes of bacteria, fungi and viruses.
3 Describe the structure and life processes of bacteria.
4 Describe the structure and life processes of fungi.
5 Describe the structure and “life processes” of viruses.
6 Safely culture bacteria and fungi.
7 Understand the factors that affect the life processes of micro-organisms. The factors are water, temperature, oxygen availability, presence of suitable nutrients, host species, competitors, disinfectants and antibiotics.
8 Know something about how humans use/benefit from micro-organisms eg helpful micro-organisms in the body, in industry, in medicine, in the environment and in food.
9 Describe how humans are affected by micro-organisms ie disease.
10 Have some basic ideas on how humans defend themselves against micro-organisms.
11 Understand how micro-organisms can become resistant to antibiotics.
12 Be familiar with, and able to use, these terms (as well as those in bold above);nutrition growth respiration flagella capsule hyphae Toxin spores reproduction excretion enzyme sporangiuminoculate binary fission aerobic anaerobic parasiteextracellular digestion pathogen saprophyte
Viruses
Human Immunodeficiency Virus (HIV)
Acquired Immuno Deficiency Syndrome (AIDS)
In the US, there is better than a 1/1000 chance of contracting HIV during unprotected sex
A person can be contagious for more than 10 years before any sign of the disease is
apparentHIV becomes AIDS when the number of
immune cells drops below a predetermined number
No one dies from HIV or AIDS; people die from secondary infections (ranging from the
common cold to cancer)More than 3 million people (size of Chicago) die
each yearThere are approx. 14,000 new cases of HIV
worldwide every day
Think about it…
All viruses are……….
PATHOGENIC
VirusesViruses
You must also be able to draw and label a virus
Viruses are very simple forms of life it is even debatable whether they are alive!
Structure
Viruses are very small (much smaller than bacteria)
They are made of two parts
1. A piece of genetic material DNA or RNA
2. A protein case
What is a virus?A virus is a non-cellular, non living
particle made up of genetic material and protein coat that can invade living cells to make copies.
Important Virus Information
Viruses do not feed on nutrients this means they can not be grown on agar plates
They can only reproduce using the DNA of a living cell
This reproduction process destroys the host cell
Virus StructureGenetic Material
Protein coat
Viruses enter bacterial cells by punching a hole in the cells wall and injecting its
DNA
Viruses Enter Living Cells
Simplified virus reproduction
Virus Reproduction
reprogram
The test on microbes will be next Wed
Virus life cycle
Viruses are pathogenic, are they useful?
Yes – calicivirus to control rabbits
What do antibiotics do?
Antibiotics kill bacteria by affecting cellular processes of the bacterium or by
preventing the formation of a cell wall. (without affecting human cells)
Virus StructureViruses have many different shapes.
photosynthesis
decomposers
combustion
respiration
denitrifyingbacteria
animal waste
decomposers bacteria/fungi
Nitrogen in atmosphere
Fixation by nitrogen fixing bacteria from air (legume root nodules)
atmospheric fixation
Nitrogen fixation Nitrogen fixation
(biological)Nitrogen fixation(industry)
decay
Nitrification
Denitrification
Activity • Turn to page 181 in Blue NCEA Level 1 Bio
book
Under the heading Antibiotics write notes to explain
• what antibiotics are
• What microbes aren’t antibiotics effective against? and why
• Why do bacteria become resistant to antibiotics
Homework for this week.Check out the NZQA web site and
do the 2005 or 2006 examTest in 7 days
Hard Question?
• An enzyme is a p_____ mo_____that speeds up r_______ in nature ie acts as a c_______
• A spore is a s____ c___ involved in the r_________ of f____
rotein leculeeactions
ingle elleproduction ungi
atalyst
Food Preservation
Food usually goes off/bad because of micro-organism activity.
How does pickling preserve food? ……………………………..dehydration? ………………………………salting? ………………………………preservatives? ………………………………bottling/canning? Why is freezing not a totally sound
defence against bacteria and fungi? So the ideal conditions for micro-organism
growth are ________, ________, _______.
What is fermentation?
A form of anaerobic respiration.A process where sugar is converted into carbon dioxide and alcohol by yeast. Why?
Antiseptic/disinfectant difference?
One kills micro-organisms in a wound to prevent infection
A disinfectant kills micro-organisms anywhere.
Take all the Medicine
Why? A tiny amount of micro-organisms mutate
and can be resistant to medicine. Your body is helped by medicines to
overcome a pathogen. When you feel better there may still be
significant numbers of pathogens remaining.
One of these pathogens could be a resistant strain and if not killed then it can start a strain of the pathogen that is resistant to current medicines.
Text ReferenceUnits 1 and 2
Homework for 2 weeksQuestions from units 1 and 2
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