plastic trait

a trait that can change in a single individual

example: a cheetah that "trains" everyday in running will produce more enzyme to break down lactic acid in the muscle than the average cheetah

order of how animals take care of nutritional needs

nutrient needs--> feeding---->

digestive break down or fermentative break down--->

aborption--->

nutrients delivered --->

negative feedback

nutrients

chemical compounds that compose the bodies of organisms 

how important is proteins in animals? 

-about half of organic matter is protein

-muscle, enzyme proteins, structural proteins, receptors, channels, antibodies, peptide hormones, hemoglobin

protein

proteins are strings of amino acids, folded into a very specific shape

standard amino acids

20-22 required amino acids for the synthesis of proteins in all organisms 

final shape of proteins

either teritiary or quaternary 

essential amino acids

amino acids tha can not be synthesized by the animal (or fast enough) so must be consumed fully formed from food 

what parts do lipids make up?

-cell membranes, energy stores, insulation, steroid hormones, waxy cuticles 

lipid

-composed of fatty acids

unsaturated fatty acid

has double bonds between carbon atoms

saturated fatty acids

single bonds between carbon atoms

can most animals synthesize lipids with double bonds at the 3rd and 6th position? 

no, thus omega-3 and omega-6 are considered essential fatty acids 

role of carbohydrates in animals? 

-most have low amounts of carbs used for energy and storage

-other that have carb base structures have more 

--chitin exoskeletons

monosaccharides: 

simplest carbohydrates

disaccharides

two monosaccharides bonded together

polysaccharides

thousands of monosaccharides bonded together

how abundant are carbohydrates in the environement?

-one of the most abundant

-high concentrations in plants in the form of cellulose

-high concentrations in insects and crustaceans in the form of chitin

do most animals have the ability to break down carbohydrates?

no, most lack the enzymes to break down cellulose, chitin, and others

feeding

grasping and ingesting food

digestion

breakdown of food molecules

typically aerobic 

mechanical breakdown 

physical forces that increase the SA:V of food to expose more surfaces to enzymes 

enzymes

molecules that catalyze chemical reactions

typically proteins 

some feeding adaptations and where they are found? 

-baleen in the humpback whale--the strands in the mouth that allow the whale to consume krill

-beak in the blue heron

-canine teeth in the lion

-grinding teeth in the giant panda

-hinged jaw in the python

-radula in the snail

where does digestion occur? 

-occurs in two places, most animals use both 

1. intracellular digestion: uses intracellular enzymes; an example of an animal that only uses this is tube sponges

2. extracellular digestion: uses mechanical action, intraluminal enzymes (cells in the lumen), and membrane associated enzymes (cells lining digestive tract)

general parts of a digestive-abosportive body plan? 

1. headgut

2. foregut

3. midgut

4. hindgut

parts of the headgut, foregut, midgut, and hindgut

headgut: mouth, lips/beak, tongue

foregut: esophagus, crop, gizzard, stomach

midgut: small intestine

hindgut: large intestine, anus  

carnivores vs herbivores needs/traits for feeding

carnivores: need to catch prey, consume prey quickly, an digest a largely protein diet

herbivores: need to breakdown plant cell walls, and digest a largely carbohydrate diet

carnivores vs herbivores skull and teeth adapations:

carnivores: large canines, pointed premolars, minimal saliva and no enzymes in saliva (nothing to be broken down like carbohydrates)

herbivores: reduced canines, flat grinding premolars and molars, lots of saliva, and carboyhydrate enzymes (amaylse) in their saliva

--mastication: chewing animals 

parts of the foregut and functions: 

esophagus: transport food by perstalsis and segmentation

crop: store food

gizzard: breakdown food by muscular means

stomach: store food, initiate protein digestion, breadown food by muscular, acidic, and enzymatic means

do animals have a crop, gizzard, and a stomach? 

no, either have a crop and a gizzard, or a stomach 

protein digestion aspects: 

-proteins are diverse thus require a lot of different enzymes to digest and breakdown

-proteins can be large and complex, so require a sequence of enzymes to break them down 

-end products are primarily amino acids 

the steps for food breakdown and how enzymes don't break down the body 

1. protein-digesting enzymes are synthesized by stomach cells in inactive forms called proenzymes 

2. acid converts proenzymes into active intraluminal enzymes that break down proteins into peptides 

3. the stomach lining (gastric mucosa) protects the stomach from enzyme and acid

4. peptides are then passed onto the midgut for further processing 

fermentation

breadown of food by anaerobic enzymes, typically symbiotic microbes 

how do symbiotic microbes work in fermentation?

-microbes typically occur in mixed communities 

-microbes are usually in areas devoid of O2 and thus ferment rather than digest

-microbes have their own species-specific enzymes they use in the fermenation process

-microbes require specific conditions to thrive (not acidic, not attacked by host enzymes) 

two types of stomachs: 

1. mongastric stomach

2. ruminant stomach 

monogastric stomach: 

-one compartment

-varies in size by species

-specailizes in protein digestion

-mostly carnivores and omnivores have this 

ruminant stomach 

-multiple compartments

-compartments help separate symbiotic microbes (that ferment carboyhyrates) from acids and enzyme (that digest proteins)

-mostly herbivores, especially fermenters 

--have bigger stomachs because plants are lower quality food vs meat so the bigger the stomach the longer the food can be in there to more nutrients 

small intestine function and what part is it? 

-part of the midgut

-site of continuing protein digestion

-major site of lipid digestion

-site of some carbohydrat digestion

-major site of nutrient absoprtion 

after the foregut how does the midgut continue food digestion/fermentation

-intraluminal enzymes secreted by the pancrease reduce peptides to shorter chains called oligopeptides 

-then membrane-associated enzymes and intracellular enzymes in the midgut epithelium breakdown oligopeptides into amino acids 

how are lipids and carbohydrates broken down in the midgut

-lipds are not water soluble, so they need to be emulsified (broken down into small droplets) by bile salts secreted by the liver

-intraluminal enzyme secreted by the pancrease breakdown lipids primarily into fatty acids, and carbohydrates into monosaccharides and disaccharides 

what are bile salts and intraluminal enzymes secreted by? 

liver-bile salts

pancreas-intraluminal enzymes 

order of nutrient absoprtion in the midgut? 

lumen through the brush border to the epithilial cells to the villus interior 

how is fructose, glucose, and galactose transported through the brush border?

fructose: GLUT5 transporter 

glucose/galactose: co-transportation uses sodium deficit to move large molecule in, with the SGLT1 transporter 

how do fatty acids pass through the brush border?

-fatty acids bind to bile salts = micelle 

-this allows the fatty acids to get close and then simple diffuse into the cell 

fructose, glucose, and galactose pass into the villus interior?

-either by GLUT2

or

-for glucose and galactose go through sodium-potassium pump (active transport) 
--atp is used and turned into adp

--sodium goes out of the cell and potassium goes in leaving the deficit in the cell of sodium  

how does fatty acid travel into the vilus interior from the cell

-the fatty acid goes through a series of transformations: 

fatty acid-->triacylglycerols-->glycerol-->chylomicrons (protein)-->then...

-the golgi appartus packages the fatty acids into vesciles allowing them to be water soluble and can pass through the membrane 

large intestine function and where is it located?

-the hindgut

-symbiotic microbes largely ferment structural carbohydrates into short-chain fatty acids (SCFAs)

-parts: cecum, colon

-aborption of fat soluble SCFAs and major site of water absorption 

behavioral food selection 

-animals are often driven to seek foods that are high in required nutrients 

how does hormonal feedback effect feeding and digestion

Cholecystokinin (CCK)

-peptide hormone released into the blood by small intestine to aid in digestion

-levels are elevated after onset of feeding

-acts as a satiety signal for food

-if injected, decreases feeding

-does not likely cross blood brain barrier but signals brain via vagus nerve 

protein digestion order 

1. intraluminal enzymes (digests proteins, carbohydrates, and lipids)

2. membrane-associated enzymes

3. intracellular enzymes

what does CCK (cholecystokinin) activate in brain? 

-vagus nerve that acts on satiety center in the brain stem

the role of insulin and glucagon in hormonal feedback in digestion? 

insulin: causes cells in the liver and skeletal muscle to synthesize glycogen; insulin binds glucose together to make glycogen (glycogen acts as a storage) 

glucagon: causes cells in the liver and skeletal muscle to catabolize glycogen; glucagon seperates glycogen back into glucose--to use as energy 

three major hormones released in hormonal feedback in digestion and where they are secreted from? 

1. CCK (cholecystokinin)-small intestine

2. insulin-pancreas

3. glucagon-pancreas

insulin

-peptide hormone secreted by pancreas

-triggers glucose uptake by cells, causes blood glucose levels to decrease

-is the only hormone known to trigger energy storage (glycogen)

-increased insulin in brain cerebrospinal flud (CSF) decreases food intake

what part of the brain is known as the major place to find insulin receptors? 

-arcuate nucleus in the hypothalamus 

arcuate nucleus: 

-key region of the brain involved in feeding regulation

-has insulin receptors 

where does cellular energy come from?

-ATP (adenosine triphosphate)

ATP characteristics in the cell(s)

-not transported between cells--each cell must have it's own ATP

-not stored in significant amounts--rate of cell work is limited by the rate of ATP synthesis 

how is ATP produced (two categorie)

1. aerobic catabolism (requires O2)

2. anaerobic catbolism (does not require O2)

why is catabolic pathways in the production of ATP efficeint? 

-dividing the process into stages, chemical bond energy is efficeintly channeled into ATP

-different fuels (like glucose and fatty acids) are reduced to common intermediates that can share common metabolic pathways 

-fuel molecules contain enough bond energy to generate many ATP molecules 

what are the three stages of glucose catabolism? 

1. glycolysis

2. the krebs cycle 

3. electron-transport chain and oxidative phosphorylation 

where does glycolysis happen? 

in the cytosol

after pyruvic acid is produced that goes into the mitochondria for use in the krebs cycle 

Glycolysis shorthand (input and output) 

-input: 1 glucose, 2 ATP, 4 ADP, 2 NAD

-output: 2 pyruvic acid, 4 ATP, 2 NADH2, 2 H2O

Glycolysis shorthand (input and output) 

-input: 1 glucose, 2 ATP, 4 ADP, 2 NAD

-output: 2 pyruvic acid, 4 ATP, 2 NADH2, 2 H2O

function of glycolysis

-to take glucose and turn into 2 pyruvic acid's 

krebs cycle shorthand (input and output) 

-input: 1 pyruvic acid, 4 NAD, 1 FAD. 1 ADP, 1 GDP

-output: 1 ATP, 4 NADH2, 1 FADH2, 3 CO2

where does the krebs cycle occur? 

in the mitochondria 

for more active creatures how would mitochondria play a role in producing more energy? 

-more mitochondria in cells

-more mitochondria enzymes

where in the mitochondria does the krebs cycle happen? 

-inside of the inner membrane (matrix of the mitochondria)

how many times does the krebs cycle happen with one glucose starting glycolysis

twice for two pyruvic acids produced per one glucose

shorthand of glycolsis and krebs cycle together (input and output)

-input: 1 glucose, 10 NAD, 2 FAD

-output: 4 ATP, 10 NADH2, 2 FADH2, 6CO2, 2 H2O

three places that energy is stored chemically in cell? 

-ATP, NADH2, FADH2

where does the electron-transport chain and oxidative phsophorylation happen? 

-intermembrane space (between inner and outer membrane) of the mitochondria 

electron-transport chain: 

-comprised of a series of membrane proteins in the mitochondrial inner membrane that each play a role in the movement of protons

-pumping protons from the matrix to the intermembrane space 

relationship between the electron-transport chain and the oxidative phosphorylation? 

-electron-transport chain pushes protons from the matrix into the intermembrane space and oxidative phosphorylation back diffuses protons to make ATP 

what does the electron-transport chain make? 

-electrochemical gradient

oxidative phosphorylation:

-restores the electrical balance and generates ATP 

shorthand of the electron-transport chain and oxidative phosphorylation (input and ouput)

-input: many NADH2, many FADH2, many O2

-output: many NAD, many FAD, many H2O, many ATP (about 30)

what are the uses of absorbed chemical enery in animals and whats the biggest by product? 

-uses: biosynthesis (growth phase), maintance of the animal, generation of external work (movement)

by-product: heat

metabolic rate

-rate at which an animal converts chemical energy to heat and external work (measured in calories or joules per unit time) 

basal metabolic rate (BMR): 

-a standardized measure applied to endotherms when fasting, resting, and at a neutral temperature 

standard metabolic rate (SMR): 

-standarized measure applied to ectotherms when fasting and resting (different values for different body temperatures) 

how it metabolism measured? 

1. direct measurements, measure heat production

2. indirect measurements, measure O2 consumption and CO2 production 

what does eating affect in metabolism? 

specific dynamic action 

--heat produced per O2 consumed 

--after eating and during eating O2 consumption is high and then gradually declines 

how do large animals and small animals vary in metabolic scaling? 

-larger animals have a higher overall metabolic rate, but have a lower metabolism per individual cell; not directly proportioned and the bigger the animal the more efficient the metabolism is 

-smaller animals have more metabolism because they have more surface area and have to keep eating and metabolizing to stay warm 

thermoregulation: 

-maintenance of a relatively constant body temperature

-some animals thermoregulate by physiological means

-some animals thermoregulate by behavioral means

-some animals do not thermoregulate 

endotherms: 

-an animal that derives most body temperature (T_b) from internal heat production 

-all thermoregulate physiologically

-some thermoregulate behaviorally 

ectotherms: 

-an animal that derives most T_b from an external heat source

-some thermoregulate behaviorally 

where does physiological heat come from? 

-breaking chemical bonds

-phosphorylation of ADP to ATP produces heat--only 42%  of the energy released from fuel is captured in ATP. the rest becomes heat

-when a muscle contracts, some of the ATP energy is converted into heat rather than mechanical work 

-friction with in the body generates heat 

poikilotherm 

-an animal that has variable T_b

homeotherm: 

-an animal that maintains a stable T_b regardless of external influence 

heterotherm: 

-an animal with heterogeneous thermal relations 

are poikilotherms, heterotherms, and homeotherms, ectotherms or endotherms? 

-poikilotherms: ectotherms

-heterotherms and homeotherms: endotherms 

two types of heterotherms: 

1. temportal heterothermy

2. regional heterothermy 

temporal heterothermy: 

- thermal relations that change over time 

regional heterthermy

-thermal relations differ between body parts

temperature vs heat: 

-temperature is an average measure of the insensity of random molecular movements 

-heat is the energy a substance possese by virtue of its molecular movements 

-larger animals have more heat; smaller animals can have higher temperature due to fever, etc

principles of heat transfer: 

-heat moves by conduction or convection from high temp to low temp

--the driving force for dry heat transfer between objects 1 and 2 when in contact = absolute value T_1-T_2

-heat transfer raises the temp of the object receiving heat and lowers the temp of the object losing heat

-two objects in contact are at thermal equilibrium (net movement of heat) when they have the same temperature 

convection: 

rate of driving force of heat transfer is increasing due to wind speed (cooler air constantly coming in)

conduction:

heat moving between two still objects-moves heat in relation to temp

radiation: 

heat is transfered by electromagnetic waves

thermal radiation aspects: 

-absorbed, reflected, or transmitted (can pass through)

-absorbed thermal radiation is converted to heat that the object surface

-darker colors absorb more, lighter colors reflect more 

evaporation: 

-chemical process that is liquid vaporization that occurs from the surface of a liquid 

-evaporation is an endothermic process (heat is absorbed) and is often the most efficient means of heat transfer 

how does SA:V affect exchange rates 

-smaller the animal the faster they exchange heat with environment 

what roles does body tissue temp play involing molecular, cellular, and tissue function 

-rates of diffusion

-rates of osmosis

-rates of enzymatic reactions

-viscosity
-membane fluidity (particularily lipids) 

consequences of the body being cold? 

-metabolic rates are increased exponentially wtih T_b

--at low T_b, ATP is produced at a low rate and physiological processes and behavior are slowed 

possible consequences of cold: 

-enzymes and other protein will become less efficient

-lipids (including membranes) become less fluid

-intracellular freezing kills cells--frostbite 

possible consequences of heat: 

-metabolic rate are increased exponentially with T_b

-at high temps heart rates and breathing rates increase

--oxygen can become limiting

-proteins can denature 

thermoregulation in ectotherms: 

-behavioral thermoregulation

-metabolic acclimation/climatization

-tissue thermal specialization

-freezing prevention mechanisms

-freezing tolerance 

acclimation: 

-plastically adjusting to a single variable; typically a lab setting

climatization: 

-plastic response to multiple variables; animals moved to a different environment 

critical temperature: 

temp at which the animal starts to struggle 

behavioral thermoregulation in ectotherms: 

-takes advantage of radiation, conduction, convection, and evaporation 

tissue thermal specialization in ectotherms: 

-an adaptation

-skeletal muscles of polar fish can generate more power at polar temperatures than muscles of temperate-zone fish 

--more mitochondria and mitochondria enzymes

-protein function is often thermally specialized

--temp influences conformation and flexibility 

how are crystallin proteins effected by different temperatures

-cristallin protein are used in the lens of the eye; keeps the structure while remaining clear

-when it gets colder the lens will become dark causing poor eye sight. 

--for subzero artic fish the opposite happens but less affected 

enzyme affinity depends on temperature: 

-affinity: attraction or bonding force 

-too much affinity slows rxns

-ideal affinity for max rxns

-not enough affinity slows rxns 

-certain temperatures are the best for certain species to have the best ATP synthesis as ATP synthesis in anaerobic glycolysis 

in polar species how does tissue thermal specialization work? 

-membranes with more double-bonds in the phospholipid fatty acid tails than temperate-zone species 

three types of freezing prevention mechanisms:

1. antifreeze compounds

a. colligative antifreezes
b. noncolligative antifreezes

2. supercooling  

colligative antifreeze: 

-lower the freezing point of body fluids by increasing the concentration of solutes 

-solutes are typically sugars and salts

-solutes cause the liquid to be at a lower temp to freeze 

noncolligative antifreezes: 

-allows an animal to cool below the freezing point without freezing by binding to ice crystals to prevent them from growing 

-noncolligative antifreeze (proteins) bind to the start of the crystal and not allowing the freezing process to continue 

supercooling: 

-allows an animal to cool below the freezing point without freezing by reducing the number of ice-nucleating agents

freezing tolerance in ectotherms: 

-extracellular freezing can prevent intracellular freezing

-animals with freezing tolerance often have increased concentrations of ice-nucleating agents

-cell shrinks causing it to be concentrated so high that it can't freeze only outside of cell is freezing 

what chemical are freezing tolerant species high in? 

glucose