2.50 understand the need for a transport system in multicellular organisms

Multicellular cells have large volume to surface area ration so diffusion happens too slowly for organism to sustain itself. Therefore, they have created transport systems to make diffusion happen quicker so the organism can sustain itself.  

2.49 understand why simple, unicellular organisms can rely on diffusion for movement of substances in and out of the cell

Unicellular cells have a small volume to surface area ratio making diffusion an effective way to get the substances they require.

2.48 describe experiments to investigate the effect of exercise on breathing in humans.

Experiment to investigate the effect of exercise on breathing in humans:

1)      Have someone do jumping jacks for a certain amount of time

2)      Count their breaths before during a after exercise

3)      Their breaths should increase while exercises because the body needs oxygen for cell respiration. After the exercise they will continue to breathe heavily due to oxygen debt.

2.47 understand the biological consequences of smoking in relation to the lungs and the circulatory system, including coronary heart disease

Consequences of smoking:

·         Blood clots

·         Cancer

·         Coronary artery disease

·         Decreased ability to taste or smell

·         Delayed wound healing

·         High blood pressure

·         Lung problems eg chronic bronchitis

·         Tooth and gum disease

·         The carbon monoxide combines with the hemoglobin in red blood cells to decrease the bloods ability to carry and transport oxygen

2.46 explain how alveoli are adapted for gas exchange by diffusion between air in the lungs and blood in capillaries

Alveoli adaptations:

·         Made of one cell layer: easy for gases to diffuse in and out

·         Spherical: more surface area

·         Good blood supply: easy access for gases to blood

Oxygen and carbon dioxide dissolve in mucus to be dissolved easier

2.45 understand the role of the intercostal muscles and the diaphragm in ventilation

Intercostal muscles:

Inspiration:

·         The external intercostal muscles contract

·         Causes the rib cage to be lifted up and out

·         This increases the thoracic volume and causes air to rush in filling the space

Expiration:

·         The internal intercostal muscles contract

·         Causes the ribs the be pulled down and in

·         This reduces the thoracic volume causing air to rush out

2.44 describe the structure of the thorax, including the ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli and pleural membrane

The Thorax:

·         Is incased by the rib cage which has intercostal muscles in between the ribs and the diaphragm underneath

·         Inside the ribcage are two lungs

·         The air is brought through the trachea to the bronchi

·         The air travels to the bronchioles until it reaches the alveoli where the capillaries in the pleural membrane exchange the carbon dioxide with oxygen to use for cell respiration

2.43 describe experiments to investigate the effect of light on net gas exchange from a leaf, using hydrogen-carbonate indicator

1)      Fill four test tubes with hydrogen carbonate indicator

2)      Place in a separate test tube:

·         A plant (test tube A)

·         A snail (Test tube B)

·         A plant and a snail (test tube C)

·         A plant and a snail (test tube D) 

3)      Place Test tubes B and D in a dark place and Test tubes A and C in a place with light

4)      Record the color of the indicator after a period of time

5)      You should find that Test tube B and D were all yellow and Test tube A and C was orange ( the lighter the color the more CO₂ present)

6)      This shows that gas exchange is till occurring in the night, however, photosynthesis does not occur so the carbon dioxide levels when the snail and plant are together at dark are  much higher than during at light because at light the plant takes in the CO₂ to use for photosynthesis

2.42 describe the role of stomata in gas exchange

The stomata allow carbon dioxide to diffuse into the leaf and are the only way that the gas can exchange as the carbon dioxide comes in and the excess oxygen and water vapor go out.

2.41 explain how the structure of the leaf is adapted for gas exchange

Leaf stalk:

·         Supports the blade

·         Can grow to angle blade towards sun

Main vein

·         Carries the oxygen and carbon dioxide to the rest of the plant to use for photosynthesis and respiration

·         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

·         Short distance for carbon dioxide to diffuse

Branching veins:

·         Allow quick transportation of carbon dioxide and oxygen to rest of plant

·         More efficient than diffusion to main vein

2.40 understand that respiration continues during the day and night, but that the net exchange of carbon dioxide and oxygen depends on the intensity of light

Respiration continues during the day and night but the net exchange of carbon dioxide and oxygen depends on the intensity of light. As the Intensity of light increases the net exchange of carbon dioxide and oxygen increases

2.39 understand gas exchange (of carbon dioxide and oxygen) in relation to respiration and photosynthesis

Gas exchange is necessary for respiration and photosynthesis because carbon dioxide is needed for photosynthesis and plants to make food. Oxygen is needed for cell respiration for the cells to provide energy for the plant.

2.38 understand the role of diffusion in gas exchange

Diffusion in gas exchange:

Diffusion plays an important role in the gas exchange as it is how the oxygen gets from the alveoli to the blood stream so it can be carried by the red blood cells.

2.37 describe experiments to investigate the evolution of carbon dioxide and heat from respiring seeds or other suitable living organisms.

Experiments demonstrating the evolution of carbon dioxide and heat:

Germinating Peas:

1)      Soak some peas in water for 24 hours so they start to germinate.

2)      Boil some another batch to kill them.

3)      Disinfect both batches and place them in a vacuum flask around a thermometer

4)      Record the temperatures of both peas

5)      You will find that the temperature in the dead peas’ flask will be 21C and the germinating peas’ will be 24C

6)      This is because the peas are still alive and respiring so this shows that respiration gives off heat. 

2.36 write the word equation for anaerobic respiration in plants and in animals

Anaerobic: (in animals)

Glucose à Lactic acid (lactate) + ATP

Anaerobic: (in plants)

Glucose à Carbon dioxide + Ethanol + ATP

ATP =Adenosine Tri-Phosphate (the chemical energy)

2.35 write the word equation and the balanced chemical symbol equation for aerobic respiration in living organisms

Aerobic:

Glucose + Oxygen à Carbon Dioxide + water + ATP

ATP =Adenosine Tri-Phosphate (the chemical energy)

C₆H₁₂O₆ + 6O₂ à 6CO₂ + 6H₂O + ATP

2.34 describe the differences between aerobic and anaerobic respiration

Types of Respiration:

1)      Aerobic: with oxygen; produces lots of energy

2)      Anaerobic: without oxygen; only some energy produced

2.33 understand that the process of respiration releases energy in living organisms

Respiration: the process of converting oxygen and/or glucose into energy

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