Adaptations for nutrition. Flashcards
Autotrophic definition.
Produces own food
complex compounds from simpler organic compounds.
Photoautotrophic-photosynthesis
Chemoautotrophic-from chem reactions(inorganic molecules).
Heterotrophic definition.
Cannot make own food
Feeds on organic compounds from other organisms.
Sapotrophs-feeds by extracellular digestion(fungi).
Holozoic-internally digests food
Sapotroph digestion.
Enzymes released on surface to break down plant/animal matter
absorb products of digestion.
Holozoic nutrition stages.
Ingestion, digestion, absorption, assimilation, egestion.
Assimilation definition.
synthesis of biological compounds from absorbed simpler molecules.
How unicellular organisms obtain nutrients.
ingestion,phagocytosis
Intracellular digestion
Diffusion and active transport to cytoplasm
waste via exocytosis.
Hydra digestion.
single, sac-like gut
hydrolytic enzymes
extracellular digestion
partly digested food moved via phagocytosis to endodermal cells
intracellulkar digestion
waste egested via enteron(singl opening).
Layers in the human gut/ description.
lumen
epithelium-single cell layer, line gut wall
Mucosa-mucous membrane, glands that secrete enzymes, mucus, acid/alkaline(op pH0, lines gut wall.
Submucosa-connective tissue, blood and lymph vessels(transport), glands secrete alkaline.
Muscle(circular then longitudinal)-circular contract behind bolus, long relax in front of food=peristalsis
Serosa-tough, outer protective layer.
Buccal cavity digestion and pH.
Mechanical
Chemical(starch)
6.5-7.5
Function of parts of digestive system.
Salivary glands-secrete amylase, mineral ions and mucus into buccal
Oesophagus-carries food from buccal to stomach(peristalsis)
Stomach-mech,chem, gastric glands, pH 2
Liver-secretes bile into small intestine via gallbladder and bile duct.
Pancreas-secretes enzymes, alkaline fluid into duodenum via pancreatic duct.
Colon(large)-reabsorbs water, minerals from waste material.
Gastric glands function.
Secretes endopeptidases
HCL
alkaline mucus in stomach.
Bile function.
Bile salts, alkaline fluid
Neutralises stomach acid=ideal lipase pH.
Small intestine.
Duodenum-first section, proteins and lipids hydrolysed
ileum-2nd section, main absorption site
pH 7-8.
Carbohydrate digestion.
Amylase(saliva, pancreatic juices)-starch to maltose, pH 8
Maltase, sucrase, lactase on membrane of epithelial cells of small intestine.
Mlatase-maltose to alpha glucose
Sucrase-sucrose to glucose and fructose
Lactase-lactose to glucose and galactose.
Protein digestion.
Endopeptidases-non-terminal peptide bonds to smaller peptides, trypsin, pepsin.
Exopeptidases-hydrolyse terminal peptide bonds to dipeptides and amino acids
Trypsin.
Secreted by pancreas as inactive trypsinogen
Enterokinase coverts inactive trypsinogen into active trypsin in duodenum.
Pepsin.
Secreted from gastric glands
Inactive pepsinogen converted into pepsin by HCL in gastric lumen/stomach.
Lipids digestion.
In small intestine
Emulsified by bile salts from liver
Large–>small soluble(micelles)
Lipases(in pancreatic juice) hydrolyse lipids into monoglycerides, fatty acids and glycerol .
Absorption.
In the ileum
Fats absorbed by simple diffusion(non-polar)
Once in cells, reformed into triglycerides
Absorbed into the lacteals
Transported via lymphatic system into blood
Amino acids via act trans to epithelial cells then fac diff to blood
Glucose+monosaccs=co-trans from lumen to cytoplasm of epithelial cells
To bloodstream via fac diff.
Sodium ions in co-transport.
Act transported out cell to lumen
=diff grad
Nutrients taken into cells w/ Na ions.
Herbivores adaptations to cellulose diet.
Long gut
Loose articulation of lower jaw
Horny pad on upper jaw
Small, flat incisors(lower jaw)=cut grass
Diastema(gap)=enable food movement by tongue
Premolars and molars= large SA and sharply bridged surfaces for grinding plants.
Ruminants.
mammals digest slowly in 4 chamber stomach
Regurgitate to chew again
Breaks down fibre well
Rumen, reticulum, omasum, abomasum.
Descriptions of ruminant stomach.
Rumen-mutualistic bacteria, hydrolyse cellulose to glucose
Reticulum-regurgitated from here and rumen to mouth to be re chewed
Omasum-re chewed cud swallowed and enters, water absorption
Abomasum-protein digestion
Small intestine-products of digestion absorbed into blood.
Carnivores adaptations.
Short gut, powerful jaw muscles
Sharp incisors-remove meat from bones
Pointed canines-grip and kill prey
Sharp carnassials-slice and shear meat
Molars-crush bones(sharp, flat edges).
Ectoparasites.
Louse
lay eggs
jump between hosts
suck scalp for blood.
Endoparasites.
Pork tapeworm
Adult(primary host) in human gut
Larval form(secondary host) in pigs
Absorbs pre-digested nutrients through cuticle
Thick cuticle
Secretes anti-enzymes prevents being digested
Scolex w/ strong suckers and hooks to attach to gut wall
Long, thin body=large surface area to Vol ratio for absorption.
