Revise B2 in 15 Mins

8/3/2019 Revise B2 in 15 Mins

1/20

START REVISING HERE


2/20

Microorganisms are Very Small

Biggest Smallest

When millions of

them grow in one

place then you

can see them

Colonies of Bacteria

and Fungi growing

in an agar plate.

Agar jelly is their

food.

FUNGI VIRUSESBACTERIA

(On a needle)


3/20

Some microorganisms are Pathogenic

Pathogenic means they cause diseases

Athletes foot, Thrush Fungal Smallpox , Flu Viral Tuberculosis, Cholera Bacterial

If you are infected with one ofthese you will show symptoms:

E.g. runny nose, high temp,

spots, sneezing etc.

Some diseases are caused by the things we do:Over eating, cigarettes, alcohol, drugs

These are called LIFESTYLE diseases:

Obesity, Heart disease, lung cancer.

Remember: YOU can change your lifestyle


4/20

How do bacteria Grow?

Real Fast !!!

Rapid growth

Lots of food,

water, warmth

and space

Growth rate = death rate(running out of food or too muchexcretory products)

More dying

than growing

Just give them: WARMTH FOOD WATER (Not O2)

Getting used to

their Petri dish

food supply

1 cell 2 4 8 16 32 64 128 256 512 - In just 3 Hrs

------------ And it looks like this -------------

Time


5/20

So why dont we get i l l al l the time? Skin stops them getting into our

bodies and makes antibacterialchemicals

Tears also kill them

Stomach acid kills them

And if that doesnt stop them WBCs will:

BURP!

Thats me, the white

one


6/20

The Immune System

Its me your friendly neighbourhood

white blood cell again. This is how wekill microbes

1. We find them, surround them and

digest them, BURP! (phagocytosis)

2. Some of us make chemicals

called antibodies that stick on to

the outside of microbes. Each

microbe has a different covering or

antigens. Different antibodies

recognises the shape of each

different antigen. Death follows

AND

Foreign blood cell

being attacked

Arghhh


7/20

OK, but what if Im too sick and my immune

system isnt stopping them?

If its a bacteria take a course of antibiotics And dont stop just because you feel better

And you might experience side effects, even death!!

And, they might kill all your good Microbes.SO WHAT

If its a fungus it will have as much food, space

and water as it wants. And what next?

-- Itch Itch Scratch Scratch --

And this arrow is NOT

pointing at your feet

Better get the bio

yoghurt out

Ahh, thats better


8/20

Antibiotic Resistant Bacteria Superbugs MRSA

These are all the exactly the same thing,

NASTY bacteria that cannot be killed by Antibiotics

click for video

Final resistant

population

Why are they so common?

People take ABs for colds & flu

People dont finish the course

Its just normal variation and natural selection

ALMOST FORGOT: Antibiotics dont kill VIRUSES

I h d hi k h I h i i ?
http://www.sumanasinc.com/scienceinfocus/antibiotics/antibiotics_fla.htmlhttp://www.sumanasinc.com/scienceinfocus/antibiotics/antibiotics_fla.html


9/20

Ive had chickenpox, why cant I catch it again?

Because your now immune to it silly

How does that happen?

WBC make

antibodies

Antibodies attach to nasty

microbes & kill them I think Imdying!

Once killed, the WBCs

become memory cells

which remember themicrobes antigens

1. First Infection

2. If there is a second Infection

Me

again

Yeh and I

remember

you cos Im

a memory

cellZap BangWallop!The differences between 1 & 2 are:

1. Antibodies are made slowly and you mayfeel ill before all the MOs are all killed2. Antibodies are made really fast and you

dont get ill at all. You are IMMUNE

Im dead!


10/20

This is what an Immune Response looks like

Antibody

numbers

Second

encounter with

pathogen

First encounter

with pathogen

Memory cells

become activePathogen

rapidlydestroyed

Memory cells

created here


11/20

Vaccines & Vaccinations

A vaccination make you immune from a disease A vaccine contains either:

A dead MO, parts of a MO, or a weakened MO

WHY?

They ALL contain the MOs antigens/markers

They all lead to memory cells being made

Some Problem Microbes Flu Virus mutates rapidly (changes its antigens) HIV virus Attacks the immune system

and also mutates rapidlyNASTY

Original antigens New antigens

MO MO


12/20

Can you describe what's happening in the picture?

When you have written your 5 descriptions, check your

answers on the next slide. No peeking!

1.

3

2

4

5. what about memory cells?


13/20

No Peeking until you have completed the first slide

1. Vaccine containing weakened,

dead pathogen or parts of it.Each of these has the pathogens

antigens (markers). All induce an

immune response

2. Sometimes there

are side effects

5. Special types of White Blood Cells called memory cells

are produced so when you come in contact with the real

pathogen they REMEMBER IT and produce antibodies

SO FAST you dont get sick; this is immunity.

4. Antibodies attach to

the pathogens antigens

(markers). They neutralise

the pathogen or attract

phagocytotic WB Cells

3.White Blood cells

produce antigens whichmatch the pathogens

antigens (markers)


14/20

Drug Safety Taking any drug involves some risk.

Side effects can be minor, severe or even cause death

Vaccinations have the same risks but the risk to the individual isoutweighed by the benefits to the rest of the population.

If 95% of the public are vaccinated it stops a disease from

spreading and can lead to its eradication (disappearance)

Smallpox has been completely eradicated over the whole world


15/20

Testing Drugs

Drugs are tested for safety (side effects) and effectiveness (if it works)

Testing involves 3 stages: On human cells (relatively cheap & quick and may indicate how safe it is) On animals (gives more information on safety and effectiveness) On people in a clinical trial (gives even more data & information)

Issues with Drug Tests

Can take 10 years to get a new drug to market

VERY expensive: staff & clinical trials, salaries,

looking after animals, hospital & lab costs, security

Ethical issues with using live animals

Ethical issues with testing it on humans,

especially if a placebo is involved.

Must be approved & licensed by the government


16/20

Clinical (Human) Trials

Trials have to be designed scientifically to be fair & reliable tests

Participants put in to two groups

Participants chosen randomly (increases reliability)

One group gets the drug the other no drug, (the control group)

A control group allows the groups/drugs effect to be compared

If its a totally new drug the control group has a placebo

A placebo looks exactly like the real drug but contains no drug

Placebos raise ethical issues; if the new drug may cure a serious

disease and does work, people in the control group may die


17/20

The Circulatory System

Veins transport blood into the heart

Arteries transport blood away from the heart

Coronary arteries supply heart cells with blood

The heart is made of muscle cells.

Every cell needs oxygen and glucose to make energy (respiration)

The blood transports oxygen and glucose to every cell

Blood leaves the heart under high pressure and returns under low pressure


18/20

Why Do Arteries and Veins Look Different?

thin outer

wall

thick layer of

muscle and

elastic fibres

thick outer layer

thin layer of

muscle andelastic fibres

ARTERY

VEIN

Arteries carry blood at high

pressure, thick wallsprevent them bursting,

elastic fibres allow them to

stretch and go back to their

normal shape

Veins carry blood at low

pressure so only need

thin walls. They also

have valves which

prevent blood movingbackwards

AND FINALLY, THE LAST SLIDE


19/20

Bad Lifestyle = Increased Risk of a Heart Attack

Risk factors: Smoking, lack of exercise, high salt/fat diet & family history

A heart attack animation

4. Cells now

starved of oxygen

1. Bad

lifestyle

2. Build up of

fat in artery

5. Heart musclecells begin to die

3. Blood flow is now

reduced to the heart

muscle cells

6. Heart attack

takes place

The End

heart attack - simple version
http://www.medindia.net/animation/heart_attack.asphttp://www.youtube.com/watch?v=7_OQWfGvanQhttp://www.youtube.com/watch?v=7_OQWfGvanQhttp://www.medindia.net/animation/heart_attack.asp


20/20

AND

Dont forget to do as many past

papers as you can.

Check your answers using the

mark schemes

Good Luck
http://www.youtube.com/watch?v=7_OQWfGvanQhttp://www.youtube.com/watch?v=7_OQWfGvanQhttp://www.youtube.com/watch?v=7_OQWfGvanQhttp://www.youtube.com/watch?v=7_OQWfGvanQhttp://www.youtube.com/watch?v=7_OQWfGvanQhttp://www.youtube.com/watch?v=7_OQWfGvanQ

Documents

Revise B2 in 15 Mins