Biology - Digestion Flashcards
(50 cards)
what are heterotrophs?
organisms that cannot make their own food
where does external digestion take place?
in a lumen or tract
where does internal digestion take place?
in a membrane-bound vesicle
how do unicellular organisms ingest food?
phagocytosis
where is food stored in unicellular organisms like amoeba?
food vacuoles
what are lysosomes?
they contain digestive enzymes and fuse with food vacuoles to digest nutrients
what is the “mouth” of the paramecium called?
cytopharynx
where do the needed nutrients diffuse to in paramecium and amoeba?
the cytoplasm
does the molecular composition of food change in the mouth when it is being chewed?
no….the surface area is increased
what kind of digestion do cnidarians (hydra) use?
both internal and external
what releases digestive enzymes in cnidarians?
endodermal cells lining the cavity
where is digestion completed in cnidarians?
intracellularly once food it engulfed by the gastrodermal cells
where is undigested food expelled in cnidarians?
the mouth
what digestive system do annelids have?
a one-way digestive tract
what is the crop of an annelids?
stores food
what is the gizzard of an annelids?
grinds the food
where is the dorsal fold of the annelids? what does it do?
in the intestine; it provides more SA; called the typholosole
what happens to soluble nutrients in annelids?
they diffuse into the blood from the small intestine
what do arthropods have in their digestive system that annelids don’t have?
jaw for chewing and salivary glands
trace the human digestive tract.
oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, anus
what happens in the oral cavity during digestion?
mechanical and chemical digestion of food
when is saliva secreted?
in response to a nervous reflex triggered by the presence of food
what enzyme in the mouth hydrolyzes starch to maltose?
salivary amylase
how is food moved through the esophagus?
peristalsis
