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