5.3 Fertilisers

5.3 understand the used of fertilizer to increase crop Yield



Aim: To increase growth in plant

Growth is achieved by the application of fertilisers to the soil and these normally take the form of nitrates of phosphates (sometimes both)

These compounds go into the soil and into the root structure, then moved in the transpiration stream to the leaf and used in the leaf.



In leaf:
- Nitrates will form proteins
- Phosphates are involved in DNA and membrane structure

The fertilisers can be divided into two groups:

1. The organic fertilisers
- Produced from animal waste from farm (cow faeces) – through a process of decomposition and fermentation and forms a substance known as slurry. Slurry is supplied to the field giving them a supply of Nitrate and Phosphate to promote growth.

2. Artificial fertilisers
- Form of synthetically produced chemicals (i.e Potassium nitrate and Ammonium nitrate), which can be bought by the farmer and placed in a solution and applied to the farm. These will release the nitrates, which will promote growth.

5.2 Crop Yield

5.2 Understand the effects on crop yield of increases carbon dioxide and increased temperature in glasshouses.




Rate of photosynthesis -combination of co2 + water -----light/enzyme=me-→ glucose (starch – stored by plant) + o2

Increasing the concentration of co2 = substrate



The rate of photosynthesis will increase which will mean there will be a higher yield up to a certain point when we increase the co2 level.

Increase the temperature:


As we increase the temp there is an increase in the rate of reaction increasing the yield - until it hits a peak that is the optimum temperature.

The both an increase in the yield but both have limits

Increasing temp also
- Helps avoid frost damage
- Provides constant temperatures.

5.1 Glasshouses

5.1 describe how glasshouses and polythene tunnels can be used to increase the yield of certain crops



Glasshouses are sometimes know as greenhouses.
Constructed on a framework (like a house) where all surfaces are made of glass, which allows light to penetrate though to the interior.

Polythene tunnels are a framework with polythene over the surface that allows light to penetrate through. Associated with market gardening, also used in less developed countries since its cheaper with glass and easier adjustable.

How does the glasshouse work:
- Solar radiation – initial source of energy in the form of light.
- Light is able to penetrate though the glass into the interior surfaces.
- The light is absorbed by surfaces inside the glasshouse (soil, wooden surfaces, plants)
- The surfaces will readmit the energy as heat.
- The heat warms the air – raising its average kinetic energy = temp increase
- The warm air is trapped, sending it back down to bottom of glasshouse
- protects from stop winds and heavy rain

Warm air in glasshouse ---→ increase in crop yield

- High temps in the class house lead to closer/optimum temp for enzyme reactions (photosynthesis)
- Provides constant tem throughout year. Which = constant production.
- Prevention of loss of water vapour – crops don’t dry out because they have a constant supply of water vapour
- Avoid frost damage – particularly to seedlings in springtime.
- Glasshouses are often warmed by the burning of fossil fuels, which leads to an increase in the CO2 levels in the glasshouse. This increases the concentration of the substrate for photosynthesis causing more product and growth. Inefficient burning of fossil fuel ethane, this gas stimulates fruit ripening(tomato)

2.89 Hormones

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


HORMONE----- ENDOCRINE GLAND------TARGET TISSUE--------EFFECT
Oestrogen ------Ovary/Follicle------------Uterus-----------Increase thickness
Testosterone----Testis--------------------Testis------------Matures sperm
Progesterone---Corpus Luteum --------Uterus---------Maintains Thickness
Adrenaline-------Kidney--------------- Heard/blood -----Increase Heart Rate
Insulin-------------Pancreas---------------Liver------------Glucose → Glycogen which is stored as Liver Glucose
Glucagon --------Pancreas -------------Liver -----------Opposite of Insulin

2.87 near and distant objects

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

Rays of light from distant objects are almost parallel when they enter the eye. They require less bending and the cornea can manage most of it without help from the lens. Muscles in the ciliary body relax and the lens is pulled into a thinner shape by the suspensory ligaments. This provides the correct focusing power.

Rays of light from near object are already diverging when they enter the eye. They need much more powerful refraction to bend them to a focus on the retina. Muscles in the ciliary body contract and the lens swells to a more rounded shape This makes it more powerful and the rays are bent more to achieve a focused image on the retina.

2.86 Eye as a receptor

2.86 describe the structure and function of the eye as a receptor

Information is collected by receptor cells, which are usually grouped together in sense organs, also know as receptors.

Each type of receptor is sensitive to a different find of change or stimulus.

The eye is a receptor that detects light.

The iris (right shaped, coloured part of the eye) controls the amount of light entering the eye by controlling the size of the hole in the centre, the pupil. The iris contains circular and radial muscles. In bright light the circular muscles contract and the radial muscles relax, making the pupil smaller. This reverses the amount of light entering the eye, as too much could to damage. The reverse happens in delight, when the eye has to collect as much light as possible to see clearly.

The thick clear cornea bends light rays as they enter the eye in order to bring them to a focus on the retina. The lens provides fine focus to sharpen the image.

ADH

2J ON MR. burrell’s Posterous bio blog
ADH – Anti-Diuretic Hormone
Stimulus: Concentration/composition of blood
Receptor: Brain – Hypothalamus
(Receptor to Coordinator = ‘Nerve’)
Coordinator: Pituitary Gland
(Coordinator to Effector = ADH)
Effector: collecting duct/ collecting tubule
Response: opening/closes of permiable (how much stuff going in and out) Collecting duct. Removal/reabsorption of water

The pituitary gland is where the ADH is created, in the Anterior lope in the Pituitary gland.

ADH is a chemical that travels through the blood. ADH in blood is called a hormone. The hormone is made in the Endocrine gland. Aim to reach the Target Gland or Target issue

Hormonal system = Endocrine system (just other name)

Endocrine gland >>>>(Hormone in blood) >>>> Target tissue or target gland.
Pituitary gland >>>>>>>>>>>>>>>>>>>>>>>>> Collecting tubualbe

In humans, hormones travel through blood

Hormone Endocrine gland Target tissue Effect
Oestrogen Ovary/Follicle The Uterus Increase thickness
Testosterone Testis Testis Matures sperm
Progesterone Corpus Luteum Uterus Maintains Thickness
Adrenaline Adrenal glands (kidneys) Heard/blood Increase Heart Rate
Insulin Pancreas Liver Glucose → Glycogen which is stored as Liver Glucose
Glucagon Pancreas Liver Opposite of Insulin