Nutrition

• Biology
• 12th Grade

NUTRITION

Nutrition,
What do you know?

The students, might need some help to get started. If so, mention Autotrophic, Photosynthesis, or carbohydrates to get them started

PLANTS

Autotrophic

Autotrophic nutrition is a process in which the organism produces their food from the simple inorganic materials such as water, carbon dioxide and mineral salts in the presence of sunlight. 

All the green parts of the plants
have an autotrophic mode of nutrition.

Which gas is used by plants during photosynthesis?

1. carbon dioxide
2. oxygen
3. nitrogen
4. phosphorus

Explain the structure of the leaf to its function in photosynthesis

The main function of a leaf is to produce food for the plant by photosynthesis. Chlorophyll, the substance that gives plants their characteristic green colour, absorbs light energy.

Explain how environmental factors affect the rate of photosynthesis

Light intensity is one factor that affects photosynthesis. Without the energy from light, the chemical reaction cannot happen. If plants have less light, they photosynthesize more slowly. The speed of photosynthesis increases with greater light intensity, though it ultimately levels off once the plant has as much light as it needs.

Carbon dioxide concentration is another factor that affects photosynthesis. Generally, there is plenty of carbon dioxide in the air so there is little impact on photosynthesis in different environments. It's still a requirement, however, and if we deprive plants of carbon dioxide in the lab, we find a similar relationship to that of light: the rate of photosynthesis increases with carbon dioxide concentration until the plant has enough or more carbon dioxide than it needs; at that point, the rate doesn't increase much further.

Temperature is also a major factor that affects photosynthesis, although this one works differently. There is an optimum temperature for the reaction to happen at the highest possible rate. This is true of a lot of chemical reactions, especially biological ones. If the temperature is too cold or too hot, plants struggle to photosynthesize. However, plants can be adapted to different climates and handle different temperatures.

Extra info Light intensity

Light intensity is one factor that affects photosynthesis. Without the energy from light, the chemical reaction cannot happen. If plants have less light, they photosynthesize more slowly. The speed of photosynthesis increases with greater light intensity, though it ultimately levels off once the plant has as much light as it needs.

Extra info CO2

Carbon dioxide concentration is another factor that affects photosynthesis. Generally, there is plenty of carbon dioxide in the air so there is little impact on photosynthesis in different environments. It's still a requirement, however, and if we deprive plants of carbon dioxide in the lab, we find a similar relationship to that of light: the rate of photosynthesis increases with carbon dioxide concentration until the plant has enough or more carbon dioxide than it needs; at that point, the rate doesn't increase much further.

Extra info: Temperature

Temperature is also a major factor that affects photosynthesis, although this one works differently. There is an optimum temperature for the reaction to happen at the highest possible rate. This is true of a lot of chemical reactions, especially biological ones. If the temperature is too cold or too hot, plants struggle to photosynthesize. However, plants can be adapted to different climates and handle different temperatures.

Minerals in Plant Development

• Magnesium is an important component of chlorophyll (required for photosynthesis)
  
• Potassium is an inorganic salt found within the sap of a plant (maintains water potential)
  
• Calcium is important for plant root and shoot elongation

Checklist:

Are you able to...

2.2 describe the process of photosynthesis in green plants?

2.3 relate the structure of the leaf of a flowering plant to its function in photosynthesis?

2.4 explain how environmental factors affect the rate of photosynthesis?

2.5 discuss the importance of minerals in plant nutrition using nitrogen and magnesium as examples?

To do options:
1. Practice with exam questions
2. Extra instruction about plant nutrition
3. Higherlvl_Photosynthesis

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ANIMALS
(inc. HUMANS)

Heterotrophic

Heterotrophic nutrition is a mode of nutrition in which organisms depend upon other organisms for food to survive. 

herbivores

carnivores

omnivores

Saprophytic

In saprophytic nutrition the organisms obtain their food from dead and decaying organic matter of dead plants, dead animals and other decomposing organic matter.

Option: Use the video-review_PDF

Explain the role and importance of enzymes

Group assignment Anagrams:
WHAT DO WE NEED?

• hatband sorcery
• nope stir
• fast
  
• nativism
  
• neil arms
• we art
• gear hugo

The class can all work together, or work in two or three teams.

What do we need in our food?

• Carbonhydrates
  
• Proteins
  
• Fats
  
• Vitamins
  
• Minerals
  
• Water
  
• Roughage
  

Malnutrition

Malnutrition is a health condition caused by a deficiency, imbalance or excess of nutrients in the diet.

- It can be caused by an improper dietary intake of nutrients.  e.g. overnutrition (too much) or undernutrition (not enough)

- It can be caused by the inadequate use of nutrients by the body. e.g. due to illness or disease

Digestion:

The main purpose of the digestive system is to break large molecules down into smaller subunits due to the fact that:

  

• Large molecules are typically chemically inert and need to be broken down and reassembled into usable products

• Large molecules are typically insoluble and cannot be easily absorbed into cells, whereas smaller subunits are soluble 

Alimentary Canal (directly transfers food)

• Oesophagus – Food tract from mouth to stomach

• Stomach – Storage tank with low pH (protein digestion)

• Small intestine – Site of nutrient absorption

• Large intestine – Absorbs water and dissolved minerals 

Accessory Organs (supports digestive processes)

• Salivary glands – Moistens food bolus (starch digestion)

• Pancreas – Secretes key enzymes into small intestine

• Liver – Metabolises absorbed nutrients (produces bile)

• Gall bladder – Stores and secretes bile (emulsifies fats)

Checklist:

Are you able to:

2.1 distinguish among heterotrophic, autotrophic and saprophytic nutrition;
2.7 relate the structures of the human alimentary canal to their functions;

2.8 explain the role and importance of enzymes;

2.10 describe what happens to the products of digestion after their absorption;

2.11 discuss the importance of a balanced diet in human

To do options:
1. Practice with exam questions
2. Extra instruction about Human nutrition
3. Higherlvl_Enzymes
4. Higherlvl_DigestionAbsorption

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In which topic do you want extra practice
before the EOYT?

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