Adaptations For Nutrition Flashcards
Nutrition definition:-
The process by which organisms obtain nutrients to provide energy to maintain life functions and matter to create and maintain structure.
Subdivisions of nutrition type:-
Autotrophs (Phototrophs and Chemoautotrophs).
Heterotrophs (Holozoic feeders, Saprotrophs and Parasites).
Auto=producers.
Hetero=consumers.
Autotroph:-
An organism that synthesises its own complex organic molecules from simpler molecules using either light or chemical energy.
Phototrophs:-
Convert CO2 and H2O into glucose using light energy from the sun during photosynthesis. Inc green plants, fungi and some bacteria.
Chemoautotrophs:-
Use energy from chemical reactions to build up organic molecules. These organisms are all prokaryotes and perform chemosynthesis which is less efficient than photosynthesis.
Heterotrophs:-
Organisms that obtain complex organic molecules produced by other organisms.
Eat either autotrophs or organisms which have eaten autotrophs.
Inc all animals, fungi, protoctista and some bacteria.
Holozoic feeders:-
Take food into body and digest it internally. Specialised digestive system. Includes most animals.
Holozoic feeder types:-
Herbivores- feed on plants.
Carnivores- feed on other animals.
Omnivores- feed on both animal and plant material.
Detritivores- feed on dead and decaying materials.
Holozoic feeder digestion summary-
Complex organic molecule into simple organic molecule:-
•carbs into glucose
•proteins into amino acids
•lipids into fatty acids and glycerol
Why do molecules monomers need to be broken down?
We can then absorb them (take into the blood stream by diffusion).
Saprotrophs:-
An organisms that derives energy and raw materials for growth from the extracellular digestion of dead or decaying material.
No specialised digestive system and secrete enzymes to digest food externally. Inc all fungi and some bacteria.
Decomposers:-
Microscopic saprotrophs. Important in decomp of leaf litter and recycling of valuable nutrients like nitrogen. E.g. the mould rhizopus found on rotting fruit.
Saprotrophic digestion:-
Enzymes secreted onto organic matter outside body. Enzymes hydrolyse the bonds in the organic matter e.g protein/carbs to make smaller soluble molecules e.g amino acids/glucose.
These smaller molecules are absorbed across the cell membrane by diffusion and active transport.
Parasites:-
Live in or on another organism (host) and obtain noirishment at the expense of that host. No digestive systems. Adapted in many ways: endoparasites live in host’s body and ectoparasites live on its surface.
Pork tapeworm(gut endoparasite):-(5)
- ribbon-like and up to 10m long. Made up of linear segments (proglottids).
- muscular head (scolex) w/hooks and suckers to attach to duodenum wall.
- 2 hosts, human and pig.
- pig infected by eating in areas contaminated by human faeces.
- humans infected by eating undercooked infected pork.
Cysticercosis:-
Adult tapeworms may cause little discomfort but long term infection may cause weight loss and abdominal discomfort.
If the person is infected directly by eating the eggs, dormant embryos can form cysts in various organs which damages the surrounding tissue.
Pork tapeworm treatment:-
Adults can be treated w/ drugs (Praziquantel). This induces severe spasm and paralysis of the worm’s muscles, preventing the hooks and suckers from holding onto to the wall of the intestine.
Precautions to prevent tapeworm infection (3):-
Making sure meat is well cooked.
Avoid spreading untreated sewage on land.
Inspection of meat and meat producing facilities (Public Health measures).
Problems for the tapeworms(7):
- only room for 1 tapeworm.
- dies if the host dies.
- need to transfer to new host.
- penetrating host.
- mode of nutrition/gas exchange
- could be dislodged by peristaltic contractions of gut wall.
- pH extremes and immune system
Tapeworm solution to host pH and immune system:-
Thick cuticle and produces inhibitory substances on its surface.
Tapeworm solution to gut wall contractions:-
Suckers and a double row of curved hooks for attachment to gut wall.
Tapeworm solution to only room to accomodate 1 tapeworm:-
Each segment contains male and female reproductive organs and 40000 eggs produced by each segment.
Tapeworm solution to host death:-
Has 2 hosts (human and pig).
Tapeworm solution to transferring to other host:-
Eggs have resistant shells so can survive outside the body until eaten by a secondary host.
Tapeworm solution to penetrating host:-
Small eggs/cysts ingested unnoticed.
Tapeworm solution to mode of nutrition and gas exchange:-
Long and thin=short diffusion pathway and large SA:vol so pre-digested food and O absorbed over body surface.
Head lice:-
Wingless insects, legs not well adapted to jumping or walking so transfer is by direct contact. Die if removed by host. Nymphs and adult feed on blood which they suck from host’s scalp.
3 stages of louse life cycle:-
Egg.
Nymph (hatches after 1-2 weeks, empty eggs called nits).
Adult-develops from nymph after about 10 days.
Unicellular organism nutrition:-
- animal like protoctista e.g amoeba use holozoic.
- obtain nutrition by diffusion, facilitates diffusion and active transport across the cell membrane.
- larger molecules taken in by endocytosis into food vacuoles which fuse with lysosomes. Contents digested by enzymes.
- products absorbed into cytoplasm and indigestible are egested by exocytosis.
Hydra (multicellular fresh water) structure:-
Cylindrical, 6 tentacles with stinging cells surrounding mouth (only body opening). Has hollow body cavity and surrounded by 2 cell layers- endoderm and ectoderm which are separated by a jelly layer containing nerve fibre network. Has adhesive foot called basal disc.
Hydra nutrition e.g Daphnia:-
Stinging cells discharfe when tentacles brushed, paralysing prey. Tentacles move prey to mouth and down through hollow body cavity. Endodermal cells secrete protease and lipase, digesting prey. Products absorbed into cells and indigestible remains are egested through mouth.
Hydra experiments:-
Experiments carried out using radioactive carbon show that tentacles contain microscopic protoctista. Protoctista photosynthesise, producing complex organic molecules (sugars) which they pass to the hydra.
Tube gut:-
Many animals have distinctive anterior (front) and posterior end + a digestive system that is a tube w/ 2 openings. Food ingested at mouth and indigestible waste egested at anus.
More complex animals have a more complex gut with diff sections carrying out diff functions.