2.32 describe an experiment to investigate the energy content in a food sample.

Energy in food experiment:

1.      Set up clamp stand with a boiling tube at a fixed height from the lab bench

2.      Add 20ml of water to the boiling tube and record the temperature of water

3.      Being careful not to break the food item apart, mount of piece of food item to test onto the pin

4.      Using a Bunsen burner flame light the food on fire by tilting the cork toward flame

5.      When alight, rest the cork onto heat proof mat, underneath boiling tube

2.31 describe the structure of a villus and explain how this helps absorption of the products of digestion in the small intestine

Structure and adaptions of a Villus:

·         Close proximity to capillaries to cell layer allows absorbed nutrients to immediately enter the bloodstream

·         Microvilli: increase surface area to volume ratio and helps to deliver nutrients to villus surface

·         One cell layer: allows nutrients to diffuse easily from small intestine to the blood supply

2.30 understand that bile is produced by the liver and stored in the gall bladder, and understand the role of bile in neutralising stomach acid and emulsifying lipids

Bile is made in the liver and stored in the gall bladder:

Functions:

1.      Emulsification: Helps digestion by breaking down fats into fatty acids, which can be taken into the body by the digestive track

.

2.      Neutralization: IS alkaline and act as to neutralize the stomach acid in the small intestine, providing a more optimal environment for the pancreatic enzymes.

2.29 understand the role of digestive enzymes, to include the digestion of starch to glucose by amylase and maltase, the digestion of proteins to amino acids by proteases and the digestion of lipids to fatty acids and glycerol by lipases

Digestive enzymes: important to break down macromolecules into their soluble and absorbably monomers which the body can use for functions such as cell respiration.

Enzyme groups:

Carbohydrase:

Examples

·         Amylase: breaks down starch into maltose

·         Maltase: breaks down maltose into glucose

Protease:

Examples

·         Pepsin: breaks down protein into polypeptides

·         Peptidase: breaks down polypeptide into amino acids

Lipase:

·         Lipase: breaks down fats (lipids) into fatty acids and glycerol

2.28 explain how and why food is moved through the gut by peristalsis

Peristalsis: A series of coordinated, rhythmic muscle, that occurs automatically to move food through the digestive track.

How:

·         Two muscles in esophagus circular (inner) and longitudinal (outer)

·         Muscles work antagonistically

·         When circular contracts the canal gets narrower

·         When longitudinal contracts the canal gets shorter

·         Moves food down in inchworm type motion

2.27 understand the processes of ingestion, digestion, absorption, assimilation and egestion

Ingestion: food is taken into the gut

Digestion: large insoluble particles broken down to smaller soluble particles

Absorbtion: small molecules and water absorbed into blood

Egestion: food that cannot be digested or absorbed is removed

Assimilation: the absorbed food particles are used to build chemicals in our bodies

2.26 describe the structures of the human alimentary canal and describe the functions of the mouth, oesophagus, stomach, small intestine, large intestine and pancreas

Mouth: responsible for adding saliva (responsible for providing enzymes) and crushing the food to make it easier to digest and be taken down the esophagus.

Esophagus: carries the food from mouth to stomach using peristalsis

Stomach: breaks down food further into its monomers (amino acids, glycerol, glucose, fatty acids etc)

Small intestine: absorbsion of all nutrients into the blood stream

Large intestine: absorbsion of all the liquid

Rectum: all the solid left over stays here until removed via the anus

2.25 understand that energy requirements vary with activity levels, age and pregnancy

Energy requirements vary with activity levels, age and pregnancy.

The body will behave differently with these different factors thus affecting their energy requirements.

2.24 identify sources and describe functions of carbohydrate, protein, lipid (fats and oils), vitamins A, C and D, and the mineral ions calcium and iron, water and dietary fibre as components of the diet

Functions and sources of:

Carbohydrate: Main fuel for providing cells with energy (source: bread)

Protein: Need for growth and repair of tissues. All cells contain protein (source: Meat)

Lipid: Form an essential part of cellular structure. Fat is deposited in parts of body as long term storage of energy (source: Milk)

Vitamin A: Makes a chemical in the retina and protects surface of eye (source: Carrot)

Vitamin C: Sticks together cells lining surfaces such as the mouth (source: fresh fruit)

Vitamin D: Helps bones absorb calcium and phosphate (source: fish oils, liver)

Calcium: Making teeth and bones strong (source: vegetable)

Iron: part of hemoglobin in red blood cells (souce: red meat)

Water: essential for many bodily processes including cell respiration and hydration

Fiber: keeps digestive system healthy (source: vegetables)

2.23 understand that a balanced diet should include appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre

A balanced diet for a human should include appropriate portions of:

·         Lipids

·         Carbohydrates

·         Protein

·         Vitamins

·         Minerals

·         Water

Dietary fiber

2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll

Testing plant for presence of starch:

1.      Place leaf in boiling water for 1 minute to soften it

2.      Turn off the Bunsen burner and Place leaf into test tube half full of ethanol and lace the test tube in the hot water for 10 minutes

3.      Spread the leaf out on a Petri dish and cover it with iodine

4.      Return the leaf to the hot water for about a minute

5.      If starch is present the leaf will turn black and blue

Experiments to test the limiting factors:

1.      Light intensity:

·         Move the light bulb to a measured distance away from water plant

·         Measure the volume of oxygen released by the plant in set period of time

·         Move the light bulb to a different distance to vary the intensity

2.      Carbon dioxide:

·         Add a concentration of sodium hydroxide carbonate (eg 0.1%) to the plant’s water

·         Measure the volume of oxygen over set amount of time

·         Add a different concentration of oxygen each time

3.      Temperature:

·         Change the temperature of the plant’s water

·         Measure the volume of oxygen produced over set period of time

2.21 understand that plants require mineral ions for growth and that magnesium ions are needed for chlorophyll and nitrate ions are needed for amino acids

Necessary Minerals for Plants:

1.      Nitrate: making amino acids (used to make proteins

If Nitrate deficient plant will suffer stunted growth

2.      Magnesium: making chlorophyll (absorbs light)

If Mg deficient leaves will turn yellow

2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis

Adaptions of the leave for photosynthesis:

Leaf stalk:

·         Supports the blade

·         Can grow to angle blade towards sun

Main vein

·         Carries the products of photosynthesis to rest of the plant

·         Easy access to all the leaf as it is placed in the center

Leaf blade:

·         Angled to receive the maximum amount of sunlight

·         Large surface area to volume ratio

·         Thin, flat, broad

Branching veins:

·         Allow quick transportation of the products of photosynthesis to rest of plant

·         More efficient than diffusion to main vein

2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis

Factors affecting the rate of Photosynthesis (Limiting factors of photosynthesis)

1.      Light intensity: As the light intensity increases so does the rate until a plateau is reached.

2.      CO₂ Concentration: As the concentration increases so does the rate until a plateau is reached

3.      Temperature: As the temperature increases so does the rate. However, after an optimal temperature for enzyme activity, they begin to denature causing the rate to decrease.

2.18 write the word equation and the balanced chemical symbol equation for photosynthesis

Photosynthesis Equation:

Carbon dioxide + water à(light energy) Glucose + oxygen

6CO₂ + 6H₂O à (light energy) C₆H₁₂O₆ + 6O₂

2.17 describe the process of photosynthesis and understand its importance in the conversion of light energy to chemical energy

Photosynthesis: The process by which plants use light energy to power the reaction that results in glucose production.

It converts the light energy into chemical energy

The raw materials of Photosynthesis:

Carbon dioxide: absorbed by the leaves through the stomata

Water: absorbed by the roots

The products of photosynthesis:

Oxygen: used in cell respiration and given off when too much is made

Glucose: which is used for the fuel in cell respiration and any excess is stored as starch

Photosynthesis makes the materials necessary for cell respiration to occur which provides the plants with energy