2.4 Nutrition

what is an autotroph

autotrophs are organisms that can synthesise complex organic molecules from simple inorganic substances

what are the two types of autotrophs and write about each of them

photoautotrophs:

-use light energy to synthesise organic molecules

-carry out photosynthesis

-carbon source: carbon dioxide

chemoautotrophs:

-use chemical energy released from oxidation reactions

-do not require light

carbon source: carbon dioxide

what is a hetrotroph

-hetrotrophs cannot synthesise their own organic molecules and must obtain nutrients by feeding on other organisms

-source: glucose and starch

what are the types of hetrotrophs

-holozoic

-saprotrophic

-mutualistic

-parasitic

what is holozoic nutrition and examples

-take food into their bodies, break it down and absorb it into body tisue

-examples: most animals (carnivores, herbivores, detrivores)

give meaning of sapratrophic nutrition and give examples

-feed on decaying matter by secreting enzymes from the hypha (tip) and is absorbed by diffusion#

-examples: some bacteria and all fungi

what is mutualistic nutrition and give examples

-two separate species derive some benefit from the relationship

-examples: digestion of cellulose by microorganisms in the gut of a herbivore

what is parasitic nutrition and give examples

-highly specified species that feed on or in other living organisms. The host always suffer harm to some degree

-examples: tapeworm, head lice

suggest one advantage of autotrophic nutrition in an ecosystem

they start off the food chain-without them there is no food chain

what are some adaptations of photosynthetic autotrophic unicellular organisms like chlorella

-chloroplasts to absorb light energy

-thin cell wall - efficient diffusion of gases

-large S/A: volume ratio

what is the heterotrophic unicellular organism we need to know and what are the steps in feeding

Amoeba (holozoic feeder)

(use phagocytosis)

1.pseudopodia surround the food particle

2..food is enclosed in a food vacuole

3.digestive enzymes break down food

4.soluble products diffuse into the cytoplasm

Paramecium (dont really need to know i think)

1.uses cilia to sweep food into oral groove

2.form food vacuole for intracellular digestion

write the digestion process of an organism with an incomplete digestive system

1.prey is captured and enters gastrovascular cavity

2.enzymes are released for extracellular digestion

3.partially digested food is absorbed by cells lining the cavity

4.further digestion occurs intracellularly

advantages of incomplete digestion

-reduces structural complexity and conserves energy

-maximise nutrient absorption