MODES OF NUTRITION

Question 1

autotrophic

Answer 1

make their own food from simple inorganic raw materials (i.e water and co2)

Question 2

types of autotrophs (2)

Answer 2

• photoautotrophic

- chemoautotrophic

Question 3

photoautotrophic (3)

Answer 3

• use light as energy source for photosynthesis
• green plants, some protoctista/bacteria
• holophytic

Question 4

chemoautotrophic (3)

Answer 4

• use energy from chemical reactions
• prokaryotes performing chemosynthesis
• less efficient than photosynthesis

Question 5

heterotrophic (3)

Answer 5

• cannot make food, consume products made by autotrophs
• consumers
• animals, some fungi/protoctista/bacteria

Question 6

saphrotrophic/saphrobiontic (4)

Answer 6

• all fungi, some bacteria
• feed on decaying matter (detritis)
• secrete enzymes (e.g proteases, amylases, lipases) onto food for extracellular digestion
• absorb soluble products via diffusion/active transport

Question 7

decomposers

Answer 7

• microscopic saphrotrophs

Question 8

parasite (3)

Answer 8

• obtain nutrition from host
• endoparasites inside, ectoparasites on surface
• host always suffers harm/death

Question 9

holozoic

Answer 9

• used by most animals

- ingest, digest, egest indigestible remains

Question 10

carnivore

Answer 10

• feed on other animals

Question 11

herbivore

Answer 11

• feed on plant matter

Question 12

omnivore

Answer 12

• feed on plants and animals

Question 13

detrivore

Answer 13

• dead/decaying material

Question 14

unicellular digestion (amoeba) (5)

Answer 14

• animal-like protoctista use holozoic digestion
• single celled w/ large SA/V ratio
• obtain nutrients via diffusion/facilitated diffusion/active trans.
• take in larger molecules/microbes by endocytosis into food vacuoles to fuse with lysosomes
• products absorbed into cytoplasm, remains egested by exocytosis

Question 15

multicellular digestion (hydra) (5)

Answer 15

• two cell layers, ectoderm and endoderm, seperated by jelly network of nerve fibres
• cylindrical shape w/ tentacles surrounding mouth (only opening)
• lives in fresh water attached to leaves/twigs by basal disc
• extends tentacles and sting/paralyse small organisms that brush them
• tentacles move prey into mouth where endodermal cells secrete enzymes (not amylase) and digested extracellularly
• products absorbed, remains egested

Question 16

tube gut (3)

Answer 16

• many animals have tube digestive system w/ two openings
• anterior (mouth)/posterior (anus)
• ingested at mouth/egested at anus