welcome to level 1 science: biology

Welcome to Level 1 Science:Biology

Science 1.11Biology 1.5

http://nhscience.lonestar.edu/biol/bio1int.htm#photo

Vrisus resoruces at bottom

HIV

• HIV Life Cycle http://www.sumanasinc.com/webcontent/animations/content/lifecyclehiv.html

Science 1.11 Bugs & Us“Interactions Between Humans

& Micro-Organisms”AS 90950 Credits: 4 Internal

Photo: Escherichia coli

Making YoghurtEquipment• 250mL milk• 20g milk powder• 1T fresh yoghurt• Heating apparatus• Incubator

Instructions1. Place 250mL of milk into a large, clean beaker or jar2. 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 acidophilus

Lactobacillus Bulgaricus

Streptococcus thermophilus

+ Bifidobacterium (a group with many species)

Arrangementpaired = diplo chained = strepto clusters = staphylo Shaperound = coccus rod = bacillus spiral = spirillus

Yr11, T1, 2012 (yogurt bacteria)

Yr11, T2, 2012 (yoghurt bacteria)(digital microscope)

Bacteria – In General

• Size• # of species• Unicellular• Prokaryotes• Most are consumers– Parasites– Pathogens– Saprotrophs

Generalised Bacterial Structure

Bacteria: Functions of the Parts

• 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) Saprophyteb) Hyphaec) Sporesd) 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 GRENMake 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 into2. Go to View - Toolbars - Control Toolbox (figure 1) and click on the icon which looks like a little hammer3. Select "Shockwave Flash Object" (figure 2) from the list4. Drag a square onto the place where you want the Mix-FX file to appear5. After you have done this, right-click on the box, choose properties, and the properties menu will pop up6. 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 micro-

organisms to give resistance to a disease• Antibody: proteins produced by the immune

system against a disease organism or its toxins

Yeast Suspension Recipe1) In a boiling tube, in this order:Add 0.5g dried yeast1 teaspoon sugar30mL warm waterMix (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 MicroscopyLook 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 24-251) Describe what happens the first time you are infected with a pathogen2) 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 Bugsnb: 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

Yeasts (over 1500 known species). Some good (Saccharomyces cerevisiae converts carbohydrates to carbon dioxide and alcohols), some bad (Candida albicans causes thrush)

Saccharomyces cerevisiaeCandida albicans

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

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

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.

Disease: Syphilus Pathogen: Treponema pallidum

Type: Bacterial

An STD, ulcer forms at point of contact (90 days), usually cervix, penis. ID50% = 57 organisms, mortality rate of 8%-58%

Electron micrograph of Treponema pallidum

Reddish papules and nodules over much of the body due to secondary syphilis (“big pox”)

Primary chancre (ulcer) of syphilis on the hand

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