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B1
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Without
causes a deficiency disease
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Calcium- In dairy
Calcium- Healthy bones and teeth
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The amount of energy we need depends on:
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Gender
o Males need more
Pregnancy
Temp
Size
o More energy is need- more cells
MR
o Varies between people – gender, age, job
o More muscle mass- higher MR- muscles needs more energy that fatty tissue- so
chemical reaction need to be tfaster to make energy
o Genetics
o Exercise- increases MR for 1 hour

Obesity

Too much energy- fat will be stored- leads to an excess amount of body fat
Obesity causes:
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Hormonal problems
Bad diet- too much fats and carbs
Lack of exercise

Obesity is a form of MALNOURISHMENT
Problems caused by obesity:
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Arthritis
Type 2 diabetes
High BP
o Too much salt- water levels cells by osmosis
o Also caused by high cholesterol levels
Heart diseaseo Build-up of cholesterol in the arteries of the heart
o Too much cholesterol is caused by too much saturated fat

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Cancer
Sleep apnea

Types of fat:
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Saturated- increase cholesterol, causes high blood pressure
Mono-unsaturated- little effect on of cholesterol
Poly-unsaturated- decrease of cholesterol levels

Losing weight:
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By cutting back on fat full foods, and exercising, to increase energy used- decreases fat
stores
Also make heart healthier
Exercising increases muscle mass, which increases metabolic rate

Lack of food:
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Malnourishment due to not enough food
o Causes slow growth, fatigue, poor resistance to infection, irregular periods
(women)
Caused by civil wars, droughts, pests (destroy crops), also in developing countries
Lack of mineral ions and vitamins causes deficiency diseases *

Obesity is measured in Body Mass Index=
Weight
Height
Cholesterol:
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Fatty substance essential for good health
Made by the liver
Found in every cell
Used for:
o Cell membranes
o Waterproofing skin
Carried by lipoproteins (fat attached to proteins) in the bloo, as it isn’t soluble

Lipoproteins

LDL- low density lipoprotein (Bad cholesterol)
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Carries cholesterol from the liver to body cells
Excess is deposited in vessels – narrowing them

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Heart disease
Atherosclerosis can occur if arteries are blocked
Heart attack- when arteries in the heart are blocked, so the blood cannot get into the
heart to be oxygenated
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Inheritance, exercise and health:

Inherited factors that affect heath:
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Metabolic rate- eg: can inherit an underactive thyroid gland- low metabolic rate
Cholesterol level- increase heart disease risk

Why exercise is healthy:
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Less likely to be overweight- using more energy
Moe muscle mass- higher low metabolic rate - less likely to be overweight and suffer the
problems associated
Increase HDL, and decreases LDL, so lowers the risk of heart disease and other
problems

B1
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These can be passed from one person to another
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A virus can get inside a cell and take over and make of copies of it
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The viruses are
then passed out in the bloodstream

Disease symptoms causes by how the body reacts to toxin
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High temp
Headaches
Rashes

How pathogens spread:
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Droplet infection (influenza)- infection passed on by droplets in in the air from
sneezing/coughing, and someone else breathing it in
Direct contact (herpes)
Straight into the bloodstream/ breaking the skin (HIV)
Via a vector- bug (malaria)
Contaminated food (salmonella)- undercooked food doesn’t kill the bacteria

Semmelweises’ work
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He noticed that more women died in childbirth with a doctor, who saw other patients,
than with a midwife, who only worked with the women
Made doctors wash their hand with chloride of lime
The death rate fell

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The bacterium on their hands was killed, so it was not transferred by the doctors, who
contracted the bacteria from other patients and passed it onto the mothers
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Antibiotics: Kill bacteria inside the body
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But they cannot kill viruses, because they reproduce inside the cells
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Growing and Investigating Bacteria:

To culture/grow microorganisms you need to give them everything they need:

Pre-inoculation:
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Petri dish is sterilised before use to kill unwanted bacteria
Inoculation loop it passed through a flame to sterilise

Inoculation
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The loop is used to spread bacteria onto the hot agar jelly containing carbs as an energy
source and various minerals and other chemical
Also provides warmth and oxygen
The lid of the petri dish is opened as little a possible to prevent microbes from entering

Post- inoculation
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Sealed with adhesive tape, to prevent microbes from entering through the air, and from
getting out
Incubated for several days at 25* to allow growth of bacteria, but not too warm, that
harmful bacteria can grow- incubation increase speed of growth

Antibiotic experiment:

Bacterial growth:
1- lag phases- slow progressive growth as
bacteria doesn’t have enough numbers to
multiply quickly, as it takes time to take in
nutrients

2- Log phase- rapid growth- has enough energy
and numbers to reproduce rapidly into a
large population
3
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Stationary phase- region of population stability, as there Is completion for nutrients and
space

Changing pathogens

Some bacteria can mutate so they become resistant to antibiotics, as a result of natural selection
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Some have bad side effects- swelling, fever,
seizures
Although these are rare

The more that are vaccinated the less likely the Persons right to decide
people who can’t will get it
The chance of falling ill or dying from the
disease may be far greater than the chance a
serious side-effect
Epidemics are prevented if a large population
are vaccinated

B1
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This enables humans to react to their
surroundings and coordinate their behaviour
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Nerves
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A part of the NS
Made up of 100s/1000s of neurons

What happens next?
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Receptor detects a stimulus (eg- hot pan is a stimulus), then the information is sent as an
electrical impulse along sensory neurons
This impulses travels along the neuron until it reaches the CNS
This signal is then transferred to the relay neurone which sends it to the brain or the
motor neurone

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Your brain gets the info and coordinates it and sends impulses along motor neurons
that carry info from the CNS to the rest of the body
They carry impulses to make the effector organs respond
Muscles respond to the impulses by contracting, and the gland respond by secreting
chemical substance

Effectors
Any part of the body that produces a response (a muscle/gland
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Reflexes
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Rapid automatic response of the NS that does not involve conscious thought

The difference between a conscious reaction and a reflex action is that in a reflex action the
coordinator is a relay neuron in the spinal cord/unconscious areas of the brain
Help humans avoid danger, and help basic body functions (breathing)
How they work:
1
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3
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5
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This why the movement is
involuntary

Synapse
Is the junction between 2 neurones where electrical signals pass
Presynaptic cell
Neurotransmitter

Neurotransmitter receptors

Presynaptic cell

The electrical impulse arriving at the end of 1 neurone causes neurotransmitters to be released
into the gap
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2
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4
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6
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8
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Oestrogen inhibits FSH production and stimulates LH from the pituitary gland
A peek in LH on day 14 causes ovulation
After ovulation the follicle becomes the corpus luteum which produces progesterone
Progesterone maintains the thickness of the lining and inhibits oestrogen production
If pregnancy doesn’t occur the corpus luteum breaks down so progesterone levels drop so
the lining cannot be maintained so the lining breaks down

Implantation
If the egg is fertilized then pregnancy may take place
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The woman is given FHS and LH to make eggs mature and to stimulate ovulation
(superovulation) to produce more eggs
2
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The sperm is then mixed with the eggs (Intracytoplasmic sperm injection)- fertilization
4
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Embryos are injected back into the uterus, with hope of implantation
6
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And the shoot must go up to the light for photosynthesis
A condition that affects plant growth= stimulus:
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Light
Water
Gravity

They are able to tell the difference because the roots and shoots are sensitive to gravity and
water/light:
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The roots grow down towards moisture and the direction of the force is gravity
The shoots grow up towards the light and against the force of gravity

This mechanism allows plants to be able to land any way up

Plant responses
Plants respond to a stimulus by growing to/away from them
Growth movement in response to a stimulus= a tropism

1
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Response to water
 Hydrotropism
 By root= positive hydrotropism
Plant grows towards from a
stimulus = positive tropism
3
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A cutting does not have roots and so has no supply of water or minerals
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Killing weeds
Weeds are unwelcome plants that compete with the plants being grown
High doses of auxin makes an effective weed killer
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There is less chance of unripe fruit being damaged when transported
Plant hormones can be sprayed onto unripe fruit during transportation
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Controlling conditions

Controlling conditions inside the body is known as its internal environment
Aims to keep everything as constant as possible- this balancing is called homeostasis
It involves the nervous system, your endocrine system and any organs

Controlling water and ions
Water can move in and out of the cells, and how it moves depends on the concentration of
mineral ions (salt) and the amount of water
If too much water moves in/out of the cells they can be damaged or destroyed
You take in water and minerals as you eat and drink
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You lose water as you breathe out, sweat, and in urine
You lose minerals in your sweat and in urine

Urine is made in the kidney- which can change the amount of salt and water lost, depending of
the conditions of the body
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Helping control the balance of water and mineral ions in the body
The concentration of urine produced by the kidneys is controlled by hormones and
nerves
Eg: if you drink a lot of water the kidneys will remove the extra water from the blood,
making your urine very pale

Controlling temp
Core body temp= 37
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Best temp for enzymes

Your body can control your temp:
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Sweat= cools you down
Shiver= warms you up

The nervous system is important in coordinating the way your body responds to changes in
temp

Controlling bloods sugar
In digestion a lot of glucose passes into the blood

Left alone your blood sugars would constantly change, cause health risks
The concentration of glucose in the blood is controlled:
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By hormones in the pancreas- insulin
So that the cells are supplied with a constant supply of glucose for respiration

B1
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Used in bacteria, some plants, mitosis

Sexual:
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2 parents
Fusion of gametes- 23 chromosomes in each is inherited
Form a new indevidual
Variation- from meisos (ramdom assortment of genes in each gemete) and from sexual
reproduction (random gametes) and mutation (changes in DNA)
Gametes in plants= pollen, ovules
Gametes in animals= sperm, eggs
Riskey- relies on sex cells from 2 indeviduals

Varation- makes sure species ssurvve (survival of the fittest) in a change of condition- such a
disease, climate change, introduction og a new predetor
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Cuttings: a bit of the plant is cut off and planted somewhere else
 Produced quickly and cheaply
 Forms a clone
2
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Embryo cloning
A top cow is giving fertility hormones to produce more eggs, these are fertilized by a top bull
inside a cow or in a laboratory to form a cluster of cells
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Adult cell cloning

PROS

CONS

Large numbers of good cloned animals
provides good services and products

Might progress to cloning humans for infertile
parents
But could go on to be abused
Unethical

Preserves endangered species

Stops variety as their a fewer alleles, so a
species would be less likely to survive in
environmental change

Brings back animals

Stops evolution

Can also be used to clone GM cows

Expensive and skilled

Genetic Engineering

Involves changing he DNA of an organism
Take the DNA from 1 organism and transfer it to the DNA of another
Insulin is made from genetic engineering to treat diabetes, whereas before animal insulin was
used, which is less pure and doesn’t treat diabetes as well
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7- EVOLUTION
Theories
Lamarck’s:
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All animals evolved from worms
Individual organisms can change over their life time to become better adapted to their
environment
They lose characteristics they don’t use, and develop characteristics that are useful
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This new feature would then be
passed on to the giraffe’s offspring
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Darwin’s:
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All organisms have evolved from simpler forms over millions of years

Survival of the Fittest/ Natural Selection:
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Animals always produce more offspring that the environment can support
In the population there is lots of variation due to sexual reproduction (inherited different
genes from two parents)
And random mutations occur in the DNA of individuals, creating a changes in alleles, that
may produce an adaptation, making the organism better suited to its environment
Predation, disease and competition
create a struggle for survival
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Over generations ‘ inheritance of successful adaptations’ leads to evolution as the
favourable
Adaptation/allele (different forms of the same gene) becomes more common in the
population
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Due to variation (mutation/sexual
reproduction) some giraffes are better
suit to their environment- some have
the allele that codes for a longer neck,
so can reach the higher branches to get
food

Those without the allele for
the long neck die of
starvation, while the others
are more likely to survive

They therefore are able to
reproduce and pass on their genes
(and adaptations) to their
offspring

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