5.9

explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality, control of intraspecific and interspecific predation, control of disease, removal of waste products, quality and frequency of feeding
and the use of selective breeding.



FISH FARMING:
they are attractive to farmers for there low fat and high protein
and also efficient in turning nutrient into fish mass.
PROS:
Fish farming allows us to control:
 quality of water (clean)
 preditors
 reduce pests
 other forms of disease
These all contribute to the yield of fish
When you have a high density of fish then transmission of disease is high
Some fish farmers have taken to using Antibiotics, which is a danger to human health
OR pesticides, which is also a concern to human health

5.8

interpret and label a diagram of an industrial fermenter and explain the need to provide suitable conditions in the fermenter, including aseptic precautions, nutrients, optimum temperature and pH, oxygenation and agitation, for the growth of microorganisms:



Industrial fermenter
The reaction vessel in which fermentation occurs:
Steel jacket (1 inside the other)
- in between the space is water "cooling jacket"
- to clean the fermenter there is a tube for steam to sterilise it.
- Heating Plate - to raise temperature (cooling jacket and heater allows us to control optimum conditions)
- Tap/Pipe to insert nutrients (food for microorganisms)
- Temperature Probe (deploy heater or cooling jacket)
- Addition of microorganisms is needed for the reaction (another tap)
- pH probe (asymetrical graph - trying to keep the optimum rate so we can get max. rate of reaction)
- Motor to stir - to adjitate the mixture, stop it clumping, spreading the microorganisms
The whole point of the fermenter is to create a reaction center of which we control the optimum growth conditions for the microorganism so it is able to produce the product that we are looking for.
- tap to drain of product 
- then goes through DOWNSTREAM PROCESSING which involves purification.

5.7

understand the role of bacteria (Lactobacillus) in the production of yoghurt:

5.6

describe a simple experiment to investigate carbon dioxide production by yeast, in different conditions:

5.5

Understand the role of yeast in the production of beer


Beer is mostly Ethanol (an alcohol molecule) which is produced from glucose.
Glucose -> Ethanol + Carbon Dioxide (anaerobic respiration)
The microorganism that does this is YEAST which supplies the enzymes to bring around this conversion
The Ethanol is flavoured by HOPS
The glucose comes from starch (converted into maltose (by amylase) -> glucose (by moltase)
The source of the starch is barly seeds/ wheat seeds (could include rice)
 Starch broken down by AMYLASE through the germination of the seed called: 'malting'

5.4b)

understand the reasons for pest control and the advantages and disadvantages of using biological control with crop plants.


Biological control of pests:
In Australia to the norther american prickly pear (Cactus) fluroished.
No natural herbivore that ate the cactus in Australia so the introduced a new species = Moth
The moth ate away at the cactus, thus removing it from the agricultural land of Australia.
PROS: There are no toxic chemicals involved
      Less impact on man/ wildlife
CONS: Not 100% effective
      Difficult to control (always a danger that introduced species will find alternative prey and will not die out once pest has been removed)
      Difficult to match a preditor to the prey

5.4a)

Understand the reasons for pest control and the advantages and disadvantages of using pesticides with crop plants.



The pesticides:
large fields of crops (all the same) = monoculture = pests
Pests will use the crop as there food source which will reduce productivity of farming = loss of food and finance
1. use pesticides- chemicals - designed to kill the pest
PROS : chemicals = easy to obtain
       easy to apply
       very effective
CONS : many of them are toxic (will kill other things/ maybe humans)
       Bio accumilation
       Mutation in the pest leads to resistance therefore more pesticide is needed and it will be more toxic or may not work

5.3

understand the use of fertiliser to increase crop yield



5.3:
want to increase growth = achieved by adding fertilisers to the soil
usually take the form of nitrates or phosphates
the compounds go to the soil, taken up by the root structure, the transpiration system takes them to the leaves
Nitrates will go on to form proteins, Phosphates are involved in DNA and membrane structure
The fertilisers = Organic OR Artificial
ORGANIC: produced from animal waste on forms eg: cow faeces -> goes through decomposition and fermentation -> forms slurry gives plants nitrate and phosphate to promote growth
ARTIFICIAL: are chemicals, synthetically produced (potassium nitrate & amonium nitrate) farmer buys them then applied to the field this also promotes growth
4.16- Eutrophication= problem that arises through use of articial and sometimes organic fertilisers.

5.2

understand the effects on crop yield of increased carbon dioxide and increased temperature in glass houses


Rate of photosynthesis       CO2 + H20 (light (enzyme reaction)) -> C6H1206 (glucose stored as starch) + O2

Increase CO2: (substrate)

Rate of P/S will increase = higher yield up to a point

Increase Temperature:

Increase temp. = increase rate of reaction = yield increase

The peak = optimum temperature

Increase temperature = no frost damage, constant temp ALL = icnrease in Yield

5.1

Describe how glasshouses and polthene tunnels can be used to increase the yield of certain crops:

Glasshouses are also known as Greenhouses - built on a framework and is very similar to a house, but it is all glass - allowing light to get the to interior

Polythene tunnels are also a framework with polythene layed over it that allows light to penetrate through. They are associated with market gardening in less developed countries because they are cheaper and glass is easy to adjust.

How the Glasshouse works:
1. Solar radiation is initial source of energy in form of light
2. Light can penetrate through glass to internal surfaces.
3. Light is absorbed by internal surfaces.
4. Surfaces re-emit energy as heat
5. Heat warms the air, therefore raising average Kinetic Energy = Temperature increase.
6. Warm air is trapped, (cool at top, sink, re warms, back to top again

Warm air àincrease crop yield

1. Rate vs. Temp graph, = closer/ optimum temperature for enzyme reactions (photosynthesis)

2. Constant temperature throughout the year.

3. Prevention of loss of water vapour

4. Avoid frost damaged (to seedlings) in winter/spring

5. Glasshouses = burning of fossil fuels

a) increase CO2 levels inside --> increase concentration of substrate for photosynthesis

b) Ethene produced is insufficient - this stimulates the fruit ripening.

The Eye

When you read, the cilary muscel contracts, so you increase pressure in the eye ball (the jelly) SQUEEZES the whole eye, putting the eye under increase pressure when reading = tiredness
when not focusing, the cilary muscel relaxes = reducing pressure in eyeball
If you pressure is not normal, then your vision will not be normal = the need for glasses!

Reflex Arc

Ganglion = bunch of nerves (swelling)

Where is the cell body of a motor neuron? = The grey matter of the spinal cord

2.89

understand the sources, roles and effects of the following hormones: ADH, adrenaline, insulin, testosterone, progesterone and oestrogen

2.88

describe the role of the skin in temperature regulation, with reference to sweating vasoconstriction and vasodilation

There are many different types of sensors in the skin
The greatest number being on our fingertips
- protects skin  - stops germs getting in  - stops too much water loss  - lets you feel, touch, pain, temperature, pressure  - helps keep your body temperature constant

VASOCONSTRICTION:
Narrowing of blood vessels from contraction of muscular wall of the vessels. Thus, the flow of blood is contricted = retained body heat. Skin turns paler because less blood is reaching the surface, therefore reducing radiation of heat.

VASODILATION:
Widening of blood vessels  from relaxtion of vessel walls. The flow of blood increases, decreases blood pressure.

2.87

understand the function of the eye in focusing near and distant objects, and in responding to changes in light intensity

FOCUSING:

Bending of light rays is done by the curved cornea (your lens can do this slightly too)
The shape of the lens is controlled by the CILARY MUSCELS

Distant Objects:
- cilary muscels RELAX
- this tightens the suspensory ligaments
- the lens pulls into a THIS shape
- the distant object is focused on the retina

Near Objects:
- cilary muscels CONTRACT
- this slackens the suspensory ligaments
- so the elastic lens goes FATTER
- the near object is focusd on the retina.

2.86

describe the structure and function of the eye as a receptor

YOUR EYES:
Eye is in a socket in the skull, it is moved by 3 pairs of eye muscels.
At the front of the eye is a transparent cornea where light enters
It then passes through the pupil, this is surrounded by the coloured iris.
At the front of the cornea is the conjunctiva (delicate, transparent layer)
It is kept moist by the tear glands (wash your eyes when you blink)

SEEING THINGS:
light enters through the cornea, it passes through the lens and is focused on the retina.
In the retina there are cells which are sensitive to light called RODS AND CONES
When light stimulates them they send impulses to the brain along the optic nerve.
Your brain interprets the impluses and turns them into a picture.

Actually, the image on the retina is inverted, but your brain has learned to turn the picture the right way up.
Rod cells respond to dim light
cone cells respond to colour and details.

2.85

describe the structure and functioning of a simple reflex arc illustrated by the withdrawalof a finger from a hot object

Many reflexes protect you.
they happen very quickly so you dont harm yourself.
the pathway of the impulse along the neurons is called a reflex arc

Stimulus = hot flame
Receptor = heat sensor in the skin.

- The impulse travels to the spinal cord along the sensory neurone.
- In the spinal cord the impulse is passes on to the relay neurone.
- This passes the impulse on to the motor neurone.

Effector = Arm muscles. The motor neuron carries the impulse to the muscle in the arm

Response = Muscles contract to remove the hand from the hot object

2.84

understand that stimulation of receptors in the sense organs sends electrical impulses along nerves into and out of the central nervous system, resulting in rapid responses
Neurons:
Nerve cells are different from other cells, they do have a cell membrane, cytoplasm and nucleus, but they are different shape.
Part of the cell is stretched out to form the axon.
The axon can be over a metre long.

How the messages are carried:
The messages that nerves carry are called nerve impulses
They are electrical signals.
They pass very quickly along the axon of the neurone.

Each impulse is separate from the next, one after the other
some axons have a fatty sheath around them.
this insulated the axon and makes the impulse travel faster.

2.83

Brain and Spinal Cord = Central Nervous System

Brain is protected by the skull
Spinal Cord is protected by the back bone

The central nervous system is connected to difference parts of the body.
 Each nerve is made up of lots of nerve cells or neurons.

2.82

1. motor nerve
orange - in the spine
end- effector (muscel)
electrical/nerve impulse is inside the nerve from the cell body to the synaptic knob.
long structure = axon
in mamals it is surrounded by the schwann cell (contains fat) increases speed of nerve conduction
this links receptor to effector.
2. Endocrine system
endocrine gland contains hormone (protein or steroid)
eg: Adrenal glad
hormone secreated into blood (adrenaline)
then it will arrive at organ that it will have an effect on = target tissue.
they can have multiple targets and multiple effects
Nerves= fast Hormones= slow

2.77b

Controlled body temperature

Negative feedback loop – method of control – maintains constant conditions.

Humans= 37-38 degrees = co-ordinator

All internal conditions

We have receptors = hypothalamus in the brain

Responds to stimulus in the body – temp. eg: blood

Effector = skin

The response = increase / decrease in body temperature

Then this would FEEDBACK to hypothalamus

Eg:

Skin – sweat glands capillary network – blood to move closer or surface away from surface of the skin

In diagram = x = time y axis = regulation point

Body temp increase. = responses in the skin =cooling

On a hot day = blood vessels dilate

On cool day – body temp decrease – connects to hypothalamus

2.77a - Thermoregulation

Homeostasis ‘same’ ‘fixed/constant’

Homeothermic – ‘temperature’ same temp.

Eg: mamals = body temp (y) environment temp (x)

Homeothermic = thermo regulation

Eg: mammals = temp change then body temp. stays the same = Homeothermic Organism à Thermoregulation

OR some organisms have a body temperature that could vary in different environments.

Looking at 2.9:                  

Rate of reaction = optimum temp for that enzyme.

Optimum temp for the enzyme nearly the same temp of mammal body temp.

2.76

Changes = Light, Temperature, Pressure, Chemical
Organisms need RECEPTORS to indentify to these changes
and then they need EFFECTORS to respond to the changes (eg: muscel, glands)

The RESPONSE shows that the organisms can survive through changes in the environment.