3.3 - adaptations for nutrition Flashcards
define autotrophic
- organisms that produces its own food
- manufactures complex organic compounds from simpler inorganic molecules such as water + CO2
name the 2 types of autotrophic organisms
- photoautotrphic
- heteroautotrphic
what’s a photoautotrophic organism
organisms that obtains nutrition through photosynthesis
what’s a chemoautotrophic organism
organism that obtains nutrition through inorganic molecules, such as sulfur, in absence of light
define heterotrophic
organism that can’t produce its own food
obtains energy by feeding on organic compounds produced by other organims
what’s a saprotroph
organism that feeds by extracellular digestion
e.g: fungi
describe extracellular digestion by saprotrophs
- release enzymes that catalyse breakdown of dead plant + animal material into simper organic matter
- absorbs products of digestion
what’s meant by the term holozoic
describes a heterotrophic organism that internally digests food substances
what processes does holozoic nutrition involve
- ingestion
- digestion
- absorption
- assimilation
- egestion
define ingestion
process by which organisms take food into their bodies
define digestion
process by which large, insoluble molecules broken down into smaller, soluble molecules that can be absorbed across cell membranes
name the 2 types of digestion
- mechanical digestion
- chemical digestion
what’s mechanical digestion
- type of digestion that involves physically breaking down food into smaller features
- increases total SA for chemical digestion
what’s chemical digestion
type of digestion that involves breaking down large, insoluble molecules into smaller, soluble molecules using enzymes
what’s assimilation
synthesis of biological compounds from absorbed simpler molecules
define absorption
movement of useful substances into bloodstream
define egestion
removal of undigested waste material from body
describe how unicellular organisms obtain nutrients
- ingestion via phagocytosis
- intracellular digestion (using hydrolytic enzymes) breaks down large, insoluble molecules into smaller, soluble molecules
- products of digestion pass into cytoplasm by diffusion + active transport
- undigested material removed by exocytosis
what’s a hydra
small, multicellular, freshwater organism of phylum Cnidaria
describe the structure of hydra
- basic, undifferentiated sac-like gut
- single opening, surrounded by tentacles, that serves as mouth + anus
- single gut cavity (enteron)
outline process of digestion in hydra
- hydrolytic enzymes secreted into enteron by endodermis
- extracellular digestion partially digests food molecules
- partially digested food transported, via phagocytosis, into endodermal cells where intracellular digestion takes place
- undigested material egested from enteron via single opening
describe shape of gut in more complex organisms
tube like w/ 2 openings
mouth for ingestion
anus for egestion
what type of diet is human hut adapted to
omnivorous diet consisting of plant + animal material
state the names of the different layers of the gut wall
- epithelium
- mucosa
- submucosa
- muscle layer
- serosa
what’s the epithelium
single layer of cells that line gut wall
describe the structure of the mucosa layer of the gut wall
- mucous membrane lining gut wall
- contains glands that secret digestive enzymes, mucus, + acid/alkaline liquid that provides optimum pH
describe the structure of the sub-mucosa layer of the gut wall
- layer of connective tissue below mucous membrane
- contains blood vessels + lymph for transport of digestion product + glands that secret an alkaline fluid
describe the muscle layer of the gut
layer of circular + longitudinal muscles beneath the submucosa
explain the action of circular + longitudinal muscles in peristalsis
contraction of circular muscle behind bolus of food + relaxation of longitudinal muscle in front forces food down gut
what’s the serosa
tough, protective layer that surrounds gut
what’s the buccal cavity
oral cavity through which food enter the body
which types of digestion take place in the buccal cavity
mechanical digestion + chemical digestion of starch
what’s the normal pH range of the buccal cavity
pH 6.5 to 7.5
what’s the function of teeth
crush + grind food into smaller pieces, increasing SA
what’s the tongue
muscular organ in buccal cavity that’s vital in chewing + swallowing of food
describe the function of salivary glands
secret amylase, mineral ions + mucus into buccal cavity