Download Science 1.11

Welcome to Level 1 Science:
Biology
Science 1.11
Biology 1.5
http://nhscience.lonestar.edu/bi
ol/bio1int.htm#photo
Vrisus resoruces at bottom
HIV
• HIV Life Cycle
http://www.sumanasinc.com/webcontent/ani
mations/content/lifecyclehiv.html
Science 1.11 Bugs & Us
“Interactions Between Humans
& Micro-Organisms”
AS 90950
Credits: 4 Internal
Photo: Escherichia coli
Making Yoghurt
Equipment
• 250mL milk
• 20g milk powder
• 1T fresh yoghurt
• Heating apparatus
• Incubator
Instructions
1. Place 250mL of milk into a large, clean beaker or jar
2. Heat milk until hot (do not allow it to burn)
3. Remove from heat. Add 20g milk powder. Mix. Chill until milk is lukewarm
(about body temperature)
4. Add 1T yoghurt to milk. Mix gently.
5. Incubate at 30ºC for 24 hours.
Yogurt Bacteria
Lactobacillus Bulgaricus
Lactobacillus acidophilus
+ Bifidobacterium (a
group with many species)
Arrangement
paired = diplo
chained = strepto
clusters = staphylo
Shape
round = coccus
rod = bacillus
spiral = spirillus
Streptococcus thermophilus
Yr11, T1, 2012 (yogurt bacteria)
Yr11, T2, 2012 (yoghurt bacteria)
(digital microscope)
Bacteria – In General
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•
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Size
# of species
Unicellular
Prokaryotes
Most are consumers
– Parasites
– Pathogens
– Saprotrophs
Generalised Bacterial Structure
Bacteria: Functions of the Parts
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•
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•
•
•
Capsule
Cell wall
Cell membrane
Cytoplasm
Chromosome
Flagella
Bacterial MRS GREN
(copy the below and add to it using pg 4 – you should
include a diagram of binary fission (reproduction) and
extra cellular digestion (nutrition).
• Move – using flagella (protein based “motor”)
• Respire – chemical reaction (react food with oxygen to
produce energy add to this )
• Sensitivity – can detect chemicals in environment
• Growth – cell can grow larger
• Reproduction – by binary fission, when get to a certain
size
• Excretion – wastes (give an example) diffuse across cell
membrane
• Nutrition – feed by extra cellular digestion
Bacteria: Binary Fission
Bacteria: Extracellular Digestion
Bacterial Respiration
Fungi Clip
• Reproduction, digestion – clickview Ch4
Fungi Questions (pg5)
1) Define the following:
a)
b)
c)
d)
Saprophyte
Hyphae
Spores
sporangia
2) How do fungi feed?
3) How do fungi reproduce? Sketch this.
4) How do fungi respire?
5) How do fungi excrete waste?
Viral MRS GREN
Make your own notes using the following as prompts.
M – Do they move on their own? How do they use hosts
to move?
R – Do they need to respire? Why not?
S – Are they sensitive? How so?
G – Do they grow / stay same size?
R – Do they reproduce on their own? How do they
replicate? Include labelled diagrams.
E – do they excrete wastes?
N – Do they require nutrition? Why not? Link to other
processes
• 1. Open up your PowerPoint presentation. Select the page into
which you want to insert the animation into
2. Go to View - Toolbars - Control Toolbox (figure 1) and click on the
icon which looks like a little hammer
3. Select "Shockwave Flash Object" (figure 2) from the list
4. Drag a square onto the place where you want the Mix-FX file to
appear
5. After you have done this, right-click on the box, choose
properties, and the properties menu will pop up
6. To add the Mix-FX file you must click on "Custom", and select the
"Build" icon (the three dots at the end of the line)
7. Now enter the Movie URL (make sure that you enter the correct
path!) and tick the "Embed Movie" box as well
8. Finally, save and run your slide show in presentation view
Viral Replication
1. Yeast
• Questions (Use “Living World” Pg4)
1) What did Leeuwenhoek find out and when?
2) What did Pasteur find out and when?
3) What is fermentation?
4) Describe how yeast is commercially grown
8. Life History of an Epidemic
• Epidemic: the spread of a disease on a large scale
• Endemic: a disease present persistently at low
levels in a population
• Pandemic: the spread of a disease on a global
scale
• Vaccination: injection of modified microorganisms to give resistance to a disease
• Antibody: proteins produced by the immune
system against a disease organism or its toxins
Yeast Suspension Recipe
1) In a boiling tube, in this
order:
Add 0.5g dried yeast
1 teaspoon sugar
30mL warm water
Mix (if needed)
2) Name. Place in a test tube
rack on window sill.
Saccharomyces cerevisiae
Yeast Microscopy
• Stain: Congo Red
Live yeast in congo red
Yeast Microscopy
Look for:
living cells (clear)
dead cells (blue)
cells budding
Culturing / Binary Fission (recap)
• http://www.youtube.com/watch?v=5Xi2Nc1UicQ
Subculturing
• What?
– Taking an agar plate with mixed species on it and
producing a plate with pure colonies of only one
species
• Why?
– A useful first step in bacterial identification
– The size, shape, colour (etc) of the colonies may
be useful in deciding which species is on the agar
plate.
Pathogen Identification
Koch’s Postulates
Gram Stains
(a useful first step in identifying a bacterial species)
• Some bacteria: thick
peptidoglycan cell wall
• They retain stain
(purple)when given gram
stain procedure = gram
positive
• Some bacteria: thin
peptidoglycan cell wall
• They lose stain (look
pink)when given gram stain
procedure = gram negative
How does gram staining work?
• Gram-positive bacteria have a thick mesh-like cell wall made of
peptidoglycan (50-90% of cell envelope), which are stained purple by
crystal violet, whereas Gram-negative bacteria have a thinner layer (10%
of cell envelope), which are stained pink by the counter-stain.
There are four basic steps of the Gram stain:
• applying a primary stain (crystal violet (purple) to a heat-fixed smear of a
bacterial culture. Heat fixing kills some bacteria but is mostly used to affix
the bacteria to the slide so that they don't rinse out during the staining
procedure.
• the addition of a mordant, which binds to crystal violet and traps it in the
cell (Gram's iodine)
• rapid decolorization with alcohol or acetone, and
• counterstaining with safranin; carbol fuchsin (pink) is sometimes
substituted for safranin since it will more intensely stain anaerobic
bacteria but it is much less commonly employed as a counterstain.
http://en.wikipedia.org/wiki/Gram_staining#Staining_mechanism
Importance
• The Gram stain is almost always the first step in
the identification of a bacterial organism, and is
the default stain performed by laboratories over
a sample when no specific culture is referred.
• While Gram staining is a valuable diagnostic tool
in both clinical and research settings, not all
bacteria can be definitively classified by this
technique, thus forming Gram-variable and
Gram-indeterminate groups as well.
Second line of defence
• White Blood Cells (aka leukocytes) try to stop any pathogens
that have entered the body.
• Leukocytes are made in the bone marrow of long bones (eg
femur)
Types:
• Phagocytes (attack & engulf pathogens)
• Granulocyte – fast moving, attack foreign matter
• Macrophage – swallow dead / foreign matter
• Lymphocytes (produce chemicals)
• B-lymphocyte cells – produce antibody (a Y shaped protein which
recognises antigens (proteins) on a pathogen and inactivates or
kills them.
• T-lymphocyte cells – mature in the thymus gland, can kill infected
body cells.
Vaccination
• Questions, after reading page 24-25
1) Describe what happens the first time you are infected with a
pathogen
2) What is different the second time you are infected with the
same pathogen?
3) How is the immune system able to work much more
effectively the second time?
4) How were you protected from disease as a baby and before
you were born?
5) What is meant by passive immunity?
6) Why is passive immunity not permanent?
7) What is vaccination?
8) What is active artificial immunity?
9) Explain the limits on the success of vaccination.
How do Antibiotics work?
Good & Bad Bugs
nb: pathogen = a bacterium, virus, or other
microorganism that can cause disease
Pathogens…
• pathogen
– Greek: πάθος pathos, "suffering, passion"
– γενής genēs (-gen) "producer of")
– infectious agent — in colloquial terms, a germ —
is a microorganism such as a virus, bacterium,
prion, or fungus, that causes disease in its animal
or plant host
• pathology....
Helicobacter pylori
H. Pylori, a bad guy. Uses multiple flagella to
swim through mucus lining the stomach wall, it
causes stomach ulcers.
Campylobacter jejuni
SEM of C. jejuni, a bad guy. Causes food poisoning or
campylobacteriosis (a notifiable disease) symptoms:
abdominal pain, diarrhoea, fever, and malaise. Incorrectly
prepared meat and poultry normally the source of infection.
Source: ODT
The rainbow bracket fungus (Trametes versicolor) is common on dead wood in forests and urban
gardens. It grows to about 5–10 centimetres in diameter and has a velvety appearance, with
distinct brown and white zones on its upper surface. Its lower surface contains thousands of
pores, the ends of tubes in which spores are produced and released into the air.
Yeast
Saccharomyces cerevisiae
Candida albicans
Yeasts (over 1500 known species). Some good
(Saccharomyces cerevisiae converts carbohydrates to
carbon dioxide and alcohols), some bad (Candida
albicans causes thrush)
A man with an atrophied leg due to
poliomyelitis
A TEM micrograph of poliovirus
Poliomyelitis is an acute, viral, infectious disease spread from person to person, primarily via the
fecal-oral route. A low percentage of patients get meningitis or paralysis.
Smallpox
AKA Variola vera (latin spotted, pimple) The term "smallpox" was first used in
Europe in the 15th century to distinguish variola from the "great pox” or syphyllis.
30-35% fatality rate, killed 400,000 per annum in Europe (end of 18th C). 1967: 2
million dead, 15 million with disease. Eradicated 1979. One of only two diseases to
be eradicated.
Yersinia pestis (a bad bacterium)
the cause of bubonic plague
Oriental rat flea (Xenopsylla cheopis) infected
with the Yersinia pestis bacterium which
appears as a dark mass in the gut. The foregut
of this flea is blocked by Y. pestis; when the
flea attempts to feed on an uninfected host Y.
pestis from the foregut is regurgitated into the
wound, causing infection.
An inguinal bubo on the upper thigh
of person infected with bubonic
plague. Swollen lymph glands
(buboes) often occur in the neck,
armpit and knee (inguinal) regions of
plague victims
Disease: Syphilus
Pathogen: Treponema pallidum
Type: Bacterial
Reddish papules and
nodules over much of
the body due to
secondary syphilis
(“big pox”)
Primary chancre (ulcer) of syphilis
on the hand
Electron micrograph of
Treponema pallidum
An STD, ulcer forms at point of contact (90 days),
usually cervix, penis. ID50% = 57 organisms, mortality
rate of 8%-58%
Rinderpest aka “cattle plague”
• Was an infectious viral disease of
cattle, domestic buffalo, and some
other species of even-toed
ungulates
• Last case in 2001 (after a global
eradication programme), declared
extinct in 2011
• Death rates as high as 100%
• Spread by direct contact and by drinking contaminated
water, and by air
• Symptoms include fever, loss of appetite, diarrhoea,
constipation, death after 6-12 days
Bacillus anthracis
• Causes anthrax ( a disease of livestock and humans)
• Type of anthrax depends on where it gets in:
– Cutaneous, the most common form (95%), causes a localized,
inflammatory, black, necrotic lesion (eschar).
– Pulmonary, the highly fatal form, is characterized by sudden,
massive chest edema followed by cardiovascular shock.
– Gastrointestinal, a rare but also fatal (causes death to 25%) type,
results from ingestion of spores
• There is a vaccine and antibiotics are effective
• Used as a biological weapon
Giardia
Practice Writing
Invent a Human Pathogen
•
Give it a name. Decide if it is a Bacterium, virus or fungus. Give the disease it
causes a name
•
Draw it and label the structures
•
Explain how the pathogen carries out MRS GREN
•
Explain how factors such as heat, nutrients, moisture affect the MRS GREN
processes
•
Explain how the pathogen is transmitted
•
Give a list of symptoms of the disease and how they are treated.
•
Explain how the disease is diagnosed
•
Explain how people are trying to prevent the pathogen being transmitted
•
Explain how the disease is cured
Yeast Writing #1
• Using the resources provided, in your own
words, discuss the ways in which people
utilise yeast.
– The Living World pg4
– Pathfinder Science pg4
– Wikipedia “Yeast”
Yeast – A Real Fun Guy
• Write no more than two paragraphs to discuss
the ways in which humans benefit from yeast.
Yeast Writing #2
• Using the resources provided, in your own
words, discuss how yeast carry out one
biological process.
– Anaerobic respiration
– Reproduction
– Feeding