Area: Natural science Subject: Biology Grade: 6

Date: Term: II Nº Hours: 3 Week:

Topic: Nutrition in fungi and plants

Goal Indicator:

To identify the forms of nutrition for fungi and plants

Exploration: • How do the fungi and plants feed? Which mode of nutrition do the green plants carry out?

Contextualization

Look at the following video about plants and Fungi http://www.youtube.com/watch?feature=player_detailpage&v=rNTt-pdtNDU

• The morphology of multicellular fungi enhances their ability to absorb nutrients • Fungi consist of mycelia, networks of branched hyphae adapted for absorption • Most fungi have cell walls made of chitin • Fungi are efficient decomposers • They perform essential recycling of chemical elements between the living and nonliving world • Fungi form mutualistic relationships with plants, algae, cyanobacteria, and animals • All of these relationships have profound ecological effects

Mycorrhizae: are modified roots consisting of mutualistic associations of fungi and roots The fungus benefits from a steady supply of sugar donated by the host plant In return, the fungus increases the surface area of water uptake and mineral absorption and

supplies water and minerals to the host plant

Conceptualization

NUTRITION IN FUNGI

Fungi are heterotrophic organisms. They need oxygen, water, carbohydrates and other organic and inorganic compounds, like phosphorus, nitrogen and potassium, etc.

According to the food and the way they get it, fungi can be classified into two groups: saprophytic and symbiotic.

SAPROPHYTIC FUNGI

Saprophytic fungi feed on dead bodies, remaining of living things and organic debris. Fungi, just like bacteria, cannot ingest the food because of their cell wall, so they have extracellular digestion.

Fungi cell’s vacuoles put enzymes on food, breaking it down into simpler substances which are absorb through the cell membrane basically by diffusion. The substances then, pass from cell to cell.

Many simple substances the fungi cannot absorb stay into the environment, and then, can be used by other living things. That is why fungi and bacteria are necessary for maintaining the equilibrium in ecosystems.

SYMBIOTIC FUNGI

Micorrhiza: fungi growing in roots of plants, as orchid and soy. Those fungi form a mutualistic symbiotic relationship with plants. They benefit to the plants because decompose the organic matter from the soil and release nutrients plants need to produce their food. By the other hand,

plant’s roots give sugar, amino acid and other substances the micorrizha need to feed.

Lichens: mutualistic symbiotic relationship between fungi and algae or cyanobacteria. Fungi provide shelter to the algae or cyanobacteria; algae and cyanobacteria use the sunlight to produce food by photosynthesis. This food is also taken by the fungi.

Parasitic fungi: fungi can also establish parasitic relationships with plants, for example, the coffee rust, a basidiomycota fungus that attacks coffee farms in our country; or with humans, producing diseases, for example, on feet and nails, that are treated with medicines.

Coffee plant leaf attacked by coffee rust.

Parasitic fungus on human foot

Lichen

Micorrhiza

NUTRITION IN PLANTS

Plants produce their food by photosynthesis. Thus, they are autotrophic, or producer organisms of organic matter and oxygen.

Photosynthesis: The process by which sunlight is converted into chemical energy and then is used to make carbohydrates from inorganic molecules (water and carbon dioxide). The chemical bonds of the sugar (carbohydrate) retain chemical energy which can be used by the cell to do its different functions. The carbohydrate produced is glucose. The equation for photosynthesis is:

6CO2 + 6H20 Sunlight C6H12O6 + 6O2

Carbon dioxide water glucose oxygen

Photosynthesis take place in specialized organelles called chloroplasts, which are found in green tissues, basically in leaves.

The stem of the plant transport the raw sap (water and mineral salts) through the xylem from the root to the leaves, and the elaborated sap (water and glucose) through the phloem from the leaves to all parts of the plant.

Use the following link to explore more vocabulary about plant nutrition: http://quizlet.com/24992376/nutrition-in-plants-flash-cards/

Production

Make in your portfolio a mental map about plant and fungi nutrition, use colors, draws and show it to your teacher.

Quiz