Consists of carbohydrates
(energy, sugar and starch),
proteins (amino acids,
growth and repair, make up
enzymes which denature at
40C), Fibre (aids digestion),
water (all chemical
reactions take part in it.
Fats (fatty acids and
glycerol, storage of energy,
insulators, steroid production),
vitamins (keeps us healthy,
Vit C - immune system, Vit D
- bones), minerals (e.g. irons -
carries oxygen to red blood
cells, calcium + magnesium,
salt - muscle contractions)
Weight Problems
If you take in
more energy
than you use,
you will store
excess fat.
Obesity can
cause arthritis,
type 2 diabetes,
high blood
pressure and
heart disease.
Lose weight by
reducing energy
intake and doing
more exercise.
People who do
not eat enough
can suffer from
deficiency
diseases (not
enough vitamins
or minerals)
Metabolic Rate
The rate at which someone
digests food, the rate of
chemical reactions differ
between different people.
Affected by proportion of
muscle to fat and how
much exercise one does.
THe metabolic rate can
also be inherited.
Cholesterol
For making vital
hormones and for the
cell membranes.
Risk of heart disease
if good and bad
cholesterol levels are
unbalanced.
Made by liver, eating high fatty foods
affects levels, can be inherited, doing
regular exercise lowers it.
Pathogens & Disease
Infectious diseases:
when microorganisms
enter and attack the body.
Symptoms:
high temp,
headaches,
rashes.
Can become infected by:
droplet infection - influenza,
direct contact - conjunctivitis,
contaminated food and drink
- cholera, through a break in
the skin - hepatitis.
Bacteria & Viruses
Viruses(e.g. rabies,
hepatitis) are smaller and
regularly shaped, some
bacterium are good for
the body. Viruses enter
the cell though bacteria
(e.g. leprosy, cholera)
attack from the outside
Viruses do not produce
toxins, but they take over
the body. Bacterium split
in two to reproduce
(binary fission).
Pathogens make you feel ill
as they can produce toxins and
reproduce rapidly. They
damage your tissues.
1st Line Defence
Mechanisms: Skin -
sebum (water proof
oil), forms scabs, dead
skin on outer layer
Ears - wax: antiseptic
Eyes - tears: clear
dirt, antiseptic: alkali
Lungs - mucus:
traps pathogens
Mouth -
saliva:
alkali,
stomach
acids
Nostrils - cilia hairs, mucus
2nd Line Defence:
the white
blood cell
Ingesting - eats
pathogen
Produces antibodies
that connect to and
defeat the pathogen, a
different one needs to
be made each time,
though they can be
created easily the next
time similar pathogen
enters the body.
Antitoxin - creates
antitoxins that
counteract the
toxin from the
pathogen.
Antibiotics
Painkillers do
not treat illness,
they cure
symptoms. e.g.
paracetamol,
aspirin.
Antibiotics kills
the bacteria
Only treat Bacteria as
viruses reproduce
inside the cell. Cannot
develop medicine that
is not dangerous
when killing viruses
Penicillin - Discovered
by Alexander Fleming
In 1928: growing
bacteria on agar plates
The lids were off, clear
rings of something had
grown around and
killed the bacteria.
He gave up on
penicillin as he
couldn't make it
survive by 1934
Ernst Chain and Howard Florey
used it on people ten years later.
They kept working on it and brought
it to an industrial scale.
It was used to
supply the
demands of WW1
Successful with Blood infections and
Septic Wounds
Growing Bacteria
One needs a culture
medium (usually
agar jelly) to provide
carbohydrates,
minerals and rich
nutrients as an
energy source.
Need warmth
and oxygen to
grow
We culture (grow)
micro-organisms to
help us learn about
them, medical and
scientific research.
Petri-dish, inoculating
loop (thing you use to
transfer bacteria) and
agar must be sterilised.
Avoid contamination
= accurate results
and no dangers.
A mutation of the
bacteria, in hot
temperatures they
reproduce very
quickly. Carbon
dioxide builds up as
a waste product.
Dip loop into
suspension
of thing you
want to grow.
Seal dish to prevent
growth of unwanted
micro-organsims or
escape of culture.
Oxygen still needs to
get to the culture. The
petri dish it turned
upside down so
condensation that forms
will fall onto the culture.
Incubate at 25C (in
schools) to allow
culture to grow. In
labs it is a much
higher temperature
as it speeds growth.
Changing
Pathogens
Bacteria can mutate and become
resistant to anit-biotics which can lead
to a new strain of disease.
95% bacteria is
killed by Antibiotic
1. 5% left
reproduce, 95%
are killed by
antibiotic 2.
Process continues:
the third colony of
bacteria is resistant
to Antibiotic 1&2
Caused by over use of antibiotics when they
are not needed. Doctors prescribe when it is
viral, people do not finish course of meds.
MRSA:
Antibiotic
resistant
bacteria spread
from patient to
patient around
the hospitals
Mutations cause new
diseases which spread
easily as people are not
immune to them and there
is no effective treatment yet.
Immunity
Dead or inactive
pathogen injected
This causes white
blood cell to create
antigen or antibody
to defeat pathogen
The pathogen cannot harm you
The next time the pathogen
(virus or bacteria) enters
body the white blood cells
will be prepared as they
have created antibodies
before of the same type to
match the pathogen.
MMR vaccine: measles,
mumps and rubella.
Small pox has been
wiped out
Then Vaccine
Debate - Small risk
of side effects, can
have a biased view
by doctor
(vaccination targets
set by government)
though
vaccinations
protect you from
infectious
diseases.