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Summary UBC BIOL 260 Cheat Sheet
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ANIMAL NUTRIENTS: why do organisms need nutrients- energy needed to combat effects of entropy, nutrients provide building blocks needed forgrowth, development, and repair Nutrients: any substance/matter needed for life & growth of living things; substance that provides nourishment for
maintenance of life & growth What are the main types of nutrients- Organic nutrients: contain carbon, derived from organisms (carb, protein, fats/
lipids, nucleic acids, vitamins) Inorganic: don’t contain carbon, except CO2 (Ca, Fe, Zn, P, N, H2O) Major types of organic nutrients: CHO->
monosaccharides-> carbs; CHNO(S) -> a.a -> proteins; CHO(N, P, S) -> fatty acids & glycerol -> lipids; CHNOP -> nucleotides -> nucleic acids Wh
do organisms get nutrients? By eating other organisms; burn some nutrients as fuel, recycle some as building blocks How do plants obtain nutrients: s
water, sun PLANTS Vs. ANIMALS: plants have chloroplasts (use light energy to make glucose) & mitochondria (break down nutrients to make AT
animals lack chloroplasts How can plants obtain building blocks for other nutrients? Can synthesize organic materials- plants capture energy from su
used to fix inorganic carbon from CO2 & create carbs, inorganic molecules taken from soil & H2O used to form other key building blocks
How are nutrients used? Oxidized & energy captured as ATP, released as heat, or used as
building blocks for new molecules How is energy extracted from nutrients? Energy in
inorganic nutrients can be captured as ATP, nutrients broken down through oxidation,
energy is transferred to ATP through addition of phosphate group to ADP Mitochondria
powerhouse- convert to smth that can be transported across long distances & in a form
easily used 2 main components: KREBS cycle: oxidizes organic molecules -> breaks do
into CO2, transfers protons to electron carriers: NADH & FADH2 ETC: takes in O2,
releasing water, making ATP; generates proton gradient (source of potential energy);
protons pumped into intermembrane space- O2 acts as terminal e- acceptor; protons flow
down conc. gradient into matric (through ATP synthase- spins to generate ATP) powers
phosphorylation of ADP to ATP; Metabolic pathways allow all nutrients to be converted to Acetyl CoA
Some a.a. can directly enter Krebs; mitochondria oxidize many types of nutrients, capture energy (ATP)
Where does metabolic heat come from? Metabolic processes inefficient: some energy transferred during
chemical rxn released as heat- not sufficient to keep body temp above enviro temp (need feathers, fat)
Thermogenic organism: specialized pathways for generating heat, allows body temp to be higher than
enviro temp (mammals, birds, fish, plants) Non-shivering thermogenesis: some tissues in species,
mitochondria have type of pore, protons leak through, biochemical work & heat production occurs wo
producing ATP Endotherms: thermogenic animals generate lots of heat internally, maintain constant
body temp when enviro temp changes, animals that can’t do this called ecotherms How do we get
building blocks needed for growth & develop? Anabolism: synthesize larger molecules from small Catabolism: break
large molecules to small (release energy)- catabolism supplies energy for anabolism ** some nutrients can’t be made
from other nutrients (essential) can only be found in diet/elements directly/indirectly involved in metabolism
DIGESTION: mouth: ingestion, mechanical & enzymatic digestion Humans: omnivores, digestive system
generalized, salivary glands: secrete salivary amylase enzyme, performs enzymatic digestion of carbs (digest glucose
polymers- starch, glycogen into disaccharides), contains water & mucus to lubricate food animals w/ specialized diet
have low salivary amylase Parasympathetic system: rest & digest, stimulates saliva production; salivary control
center in hypothalamus Sympathetic: fight or flight Homeostasis: The balance between the 2 Stomach: mechanical
digestion: muscular, grinds food enzymatic: secrete HCl and enzymes that help digest proteins; proteins digested by enzyme pepsin, active at low pH
(disrupts H bonds), bonds between a.a. are covalent Stomach lining; contains gastric pits/glands Chief cells:
produce pepsinogen (inactive form, pepsin precursor- low pH causes conformational change, attacks itself cuts
out part of protein, exposes active site in pepsin which digests proteins, pepsin can digest pepsinogen and activate
it (+) feedback) Partietal cells: produce HCl Goblet cells: produce mucus- contains bicarbonate, neutralizes acid
and mucins that make it thick H. pylori: penetrates mucus layer lining, damages goblet cells, loss of mucus =
exposes cells to stomach acids-> ulcers How is stomach acid secreted: sight, smell, taste, or thought of food,
presence of food in stomach-> causes parietal cells in stomach to secrete HCl
Carbonic anyhydrase assists w/ converting CO2 + H2O -> H2CO3 parietal cells have to move protons against
conc. Gradient, presence of food in intestine inhibits secretion; stomach acid secretion regulated by hormones
and nervous system- 3 main chemicals: acetylcholine, histamine, gastrin bind to receptors on parietal cells ECL
cells: 2 inputs acetylcholine & gastrin- enteric neurons release peptide (GRP) onto G-cells-> release
gastrin into blood Small intestine: very long, folded surafece (incr. SA) major site of absorption,
perform enzymatic & chemical digestion, secretions from pancreas & gall bladder (lipase, amylase,
protease) & bicarbonate: neutralizes stomach acid, protects lining of intestine Pancreatic amylase:
allow digestion of glucose polymers to disaccharides digestion of fats: requires pancreatic & gall
bladder secretions, bile salts from gall bladder break large fat droplets into small, pancreatic lipases
digest into glycerol and FA Large intestine: nutrients passing through colon eaten by bacteria, wate
reabsorption (colon); too much water absorbed- constipation, minimal role in digest symbiotic
relationship between bacteria and intestine, digest nutrients into forms absorbed How is cellulose
digested: large cecum (hindgut fermenters) anaerobic metabolism Foregut fermenters: specialized
pocket of stomach that houses bacteria & acts as fermentation chamber to digest cellulose (ruminant
many stomachs, bacterial waste products & dead bacteria digested in rest of intestine water movem
is passive: moves through pores
(aquaporins) & spaces between
cells, net movement driven by
relative conc. of solutes; Na +
réabsorbed by secondary active
transport
Symplastic & transmembrane: whatever gets to
vasculature gets to entire plant, built in filtering
Apoplastic: ends at endodermis, selective
filtering
Of solutes o
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