Chapter 6 Flashcards
Nutrition
The study of chemicals that comprise the body and how animals synthesize components of their bodies from the chemicals they collect from the environment
Components and nutrients in body from biggest to smallest
proteins
lipids
minerals
nucleic acids
carbohydrates
Proteins comprise what percent of organic matter?
half
How many amino acids and what are they required for?
20
required for protein synthesis in all organisms
What vital roles do proteins play? (3)
- Enzymes to regulate reactions. speed up biochemical reactions by increasing the frequency of collisions, lowering the activation energy and properly orienting the colliding molecules.
- Required for locomotion
- Play several types of structural roles (actin and myosin)
What is an limiting element?
NItrogen. Organisms can’t use the gaseous (molecular) form N2
What are essential amino acids?
Amino acids that can’t be synthesized by animals
How are amino acids bonded togther?
peptide bonds (covalent)
How many amino acids make up a dipeptide, tripeptide,
polypeptide? How many are needed to be called a protein?
2 AA
3 AA
10 AA or more
50 or more AA
Amino acids are characterized by….? What provides their
uniqueness?
The presence of at least one amino and carboxyl group.
side groups (R)
What are the four protein structures?
Primary – linear sequence of AA composing the polypeptide chain
Secondary – twist or bend upon themselves to form a more complex structure: alpha helix or beta pleated sheets
Tertiary – 3d shape of polypeptide chain; unique for each protein
Quaternary – describes the joining of 2 or more polypeptide chains to form dimers, trimers, etc.
Animals do not_______amino acids or proteins
Nitrogen containing amino groups (-NH2) are immediately removed from excess amino acids
Store
Why are lipids needed?
Lipids are needed for all membranes and are the storage compounds of animals
Lipids are insoluble in water. Meaning they are?
hydrophobic
Common lipids (3)
Triglycerides, phospholipids and sterols
Triglycerides can be solid (fat) or liquid (oil)
Composed of glycerol and 3 fatty acids (may be different)
***Are a form of energy storage
Saturated fats
have a single covalent bond; each carbon bonds to the maximum number of hydrogen atoms; thus each fatty acid is SATURATED with H
e.g., cocoa butter, palm oil and coconut oil.
Monounsaturated fats
have 1 double covalent bond between 2 C atoms and thus are not completely saturated with H,
e.g., olive oil, peanut oil
Polyunsaturated Fats
have more than 1 double covalent bond between fatty acid carbons;
e.g., corn oil, sunflower oil, soybean oil.
Phospholipids
Modified triglycerides
The phosphate head is polar and attracts other polar or charged particles (Hydrophillic)
The hydrocarbon tail is nonpolar and only interacts with nonpolar molecule(Hydrophobic)
Amphipathic
molecules that have both polar and nonpolar regions
ex. phospholipids
Sterols
Easily made from saturated fat.
Flat molecules made of four interlocking hydrocarbon rings
e.g., cholesterol, steroid hormones, is the raw material for vit. D.
What are carbohydrates and their functions?
Are hydrated carbon chains
- Provide structural support and shape
- Chitin, cellulose, and hemicellulose
- Storage compounds
- Starch, glycogen
- Transport compounds
Examples of a monosaccharides (carbohydrates) (3)
glucose
ribose
2-deoxyribose
What is the main form of carbohydrate storage?
Glycogen
Examples of a disaccharides (carbohydrates) (2)
sucrose
lactose
Examples of a polysaccharides (carbohydrates) (2)
glycogen
chitin
What are vitamins?
- Organic compounds that must be obtained from an outside source
- Act as cofactors for enzymes
- Required in small amounts
Minerals are…?
Chemical elements required by animals
- Iodine
- Metals found in many enzymes
- Phosphorus
________of the use of a feeding apparatus is as important as the apparatus itself
Behavioral modification
- Wolf spiders
What are the 4 types of feeding methodologies?
- Individual items- sees many types of food sources, but picks which one it wants to eat
- Suspension feeding– there is a medium (water) with food in it and the animal separates the two
- Fluid feeding- animals eating some kind of liquid (blood)
- Symbioses-(I added)
What are the 3 types of diets ?
Carnivores
Herbivores
Omnivores
Feeding methods are diverse
- Three examples
- Orcas ?
- Blue whales ?
- Reef-building corals ?
- Determined by motility
- sessile?
- predators; individual feeders
- suspension feeders
- symbioses and photosynthesis
- non-mobile
What are the steps for an individual items feeder?
Food must be:
- Located
- Identified
- Subdued
- Ingested
Related animals exhibit ______ that allows them to eat different things. (birds and beaks)
Snails (invertebrates) have a scraping organ called?
- Specializations
- The radular apparatus.
- Cartilaginous rod surrounded by connective tissue embedded with chitinous teeth
- Teeth are highly specialized
- chainsaw looking
What is suspension feeding? What is a benefit?
- Feeding on much smaller items suspended in water
- It allows animals to feed lower on the food chain and obtain more energy in the same amount of time
ex. whale
- Use baleen plates to collect food
- Made of keratin
- Hang from upper jaw
- 100’s of meter-long plates
- Water enters mouth and is forced through keratin fibers
- Small food items are trapped
- Called filter feeding
What do fish use for suspension feeding?
Gill rakers- trap and move the food into the mouth but not true a filter feeder.
What are the two methods of fluid feeding?
- Piercing and sucking:
- Mosquito, platyhelminths, nematodes, annelids (leeches), and arthropods
- Suck blood from animals or sap from plants
- Cutting and licking:
* Vampire bats, hagfish, lampreys
What are the 3 categories of microbes that occur with symbioses?
- Photosynthetic autotrophs
- Autotrophs can make organic molecules from inorganic precursors
- AKA: photoautotrophs
- Chemosynthetic autotrophs
- Make organic molecules from inorganic molecules using energy-releasing inorganic chemical reactions
- AKA: chemoautotrophs
- Heterotrophs
* Must ingest organic molecules and break them down to get energy
Feeding methods of symbioses using photoautotrphs:
- Animals obtain organic molecules from internal populations of algae (photoautotrophs)
- Most algae are dinoflagellates
- All of these types of animals have additional feeding methods
- Reef-building corals
- Algae supply food energy and help make the calcareous skeleton
- Stress can cause symbionts to leave
Feeding methods of symbioses using chemoautotrphs:
First discovered in….?
What are the key to this realationship?
What area is home to the key?
- Hydrothermal-vent communities (Riftia pachyptila)
- Sulfur-oxidizing bacteria
- Trophosome
Feeding methods of symbioses using heterotrophs:
Organic compounds required from?
What provides metabolic capabilities that animals lack?
Often found where?
They are ____ and sometimes called _____microbes.
What microbes can be utilized?
- external sources
- Microbes
- specialized regions of the gut, even humans
- anaerobic and fermenting
- Bacteria, Protists, Yeasts, Fungi
ex. foregut fermenters: ruminants (cows)
Feeding methods of symbioses using heterotrophs:
Other vertebrate foregut fermenters?
3 functional categories of microbes?
kangaroos, hippos, colobus monkeys, sloths
- Fermentative breakdown of chemicals the animal can’t digest
- Cellulase converts cellulose into short chain fatty acids that are absorbed by the animal
- Other products include CO2 and methane
- Synthetic
* Microbes synthesize B vitamins & essential amino acids - Nitrogen recycling
* The animals nitrogen wastes are recycled into new proteins the animal can use
Feeding methods of symbioses using heterotrophs: foregut fermenters
Digastric (ruminant) stomach:
What are the four chambers?
- Rumen & reticulum
- Fermentation vats
- Rely on bacteria and protozoans
- Convert carbohydrates into butyrate, lactate, acetate, propionate, CO2, nd methane
- Omasum
* Mixing - Abomasum
* Only part that secretes digestive enzymes - Eructation: burping
Feeding methods of symbioses using heterotrophs: hind and mindgut fermenters
In hindgut fermenters where does fermentation take place?
They usually have enlarged____?
ex. ?
In midgut fermenters where does fermentation take place?
ex.?
- large intestine and cecum
- cecum/colon
- Rabbits, horses, zebras, rhinos, ostriches, geese, grouses, and herbivorous lizards and turtles
- small intestine
- Tilapia, carp, catfish
Feeding methods of symbioses using heterotrophs: invertebrates
Termites require microbes to digest cellulose. They are what kind of fermenter?
Scarabid beetles use microbes to produce ___?
- Ex: Leeches, Tsetse flies, ticks, sucking lice
- Blood sucking animals have universal requirement for symbionts
- Help digest blood and make antibiotics that prevent blood decay
- Hindgut
- Short chain fatty acids
What is digestion?
The breakdown of food into smaller molecules that can be distributed to tissues within the body
What are the types of digestion?
- Mechanical- chewing or grinding of food
- Chemical- breaking of chemical bonds
* protease, carbohydrase, lipase - Extracellular – occurs outside of cells
* Principal mode of vertebrates and arthropods - Intracellular – occurs inside cells
* Primarily in sponges, coelenterates, flatworms, and some molluscs
What is absorption?
The actual bringing of nutrients into the tissues of the body
Generally how does absorption take place in humans?
Transfer from lumen of GI tract to the blood or lymph.
Carbohydrates and proteins absorbed into the blood. Lipids into the lymph and it brings it into the blood.
What are the three basic plans of digestion and absorption that can be studied?
- Vertebrates
- Arthropods
- Molluscs
Vertebrates have what kind of structure?
How many parts is it broken into?
What are those parts?
1. Tubular
2. 4
3.
- Headgut: Parts in head and neck (mouth)
- Foregut: Everything between headgut and intestine
- Midgut: Small intestines
- Hindgut: Large intestines
Vertebrates: What is the headgut, what is it comprised of, and what is its function?
- Headgut is parts in head and neck
- Lips, buccal cavity, tongue, pharynx
- Capture and engulf food and prepare it for digestion
Vertebrates: What is the foregut, what is it comprised of, and what is its function?
- Foregut: everything between headgut and intestine
- Esophagus, crop, gizzard, stomach
- Conducts, stores, & digests ingested material
Vertebrates: What is the midgut and what is its function?
- Small intestines
- Digests and absorbs nutrients
midgut is the site of protein, carbohydrate and lipid digestion/absorption. Also see vitamin and mineral absorption
Vertebrates: What is the hindgut and what is its function?
- Large intestines
- Absorbs water & stores waste
In humans, large and small intestines are differentiated based upon____?
In many other vertebrates, the diameters are____? So have to be differentiated by function
- diameter
- equal
What four processes are seen in “tube”?
Motility- movement of food thought GI tract from mouth to anus and the mixing of the food with the secretions
Secretion- seen throughout entire tube. Saliva, gastric juice, and mucus
Digestion- Happens from foregut- midgut
Absorption- Midgut (small intestine)
What are the two accessory structures?
- Pancreas
- exocrin and endocrine funtions
- secrete digestive enzymes / insulin and glucagon
- Biliary system (contains liver)
* gallbladder- just store bile
Vertebrate: Headgut
____ lubricates headgut & assists in swallowing.
It may contain ____ and ___? What kind?
May have valve directing food to alimentary canal and gas to trachea. What is this valve and where is it?
Saliva
digestive enzymes and anti-coagulants (bats)
amylase- breaks down carbohydrates
epiglottis and larynx
What is a startch?
Polysaccharide storage in plants
What is glycogen?
Polysaccharide storage in animals
What structures make up the vertebrate foregut?
- Esophagus
- Crop (birds)
- Stomach
Vertebrate Foregut: what does the esophagus do?
conducts a food bolus using peristalsis and gravity in the case of human
Vertebrate Foregut: What is the crop?
Found in some animals (birds)
Temporary storage site
Can be used for fermentation/digestion
Crop milk
Vertebrate Foregut: What does the stomach do?
- Initiates protein digestion
- Secretes pepsinogen (zymogen)
- Secretes HCl that converts pepsinogen to pepsin and denatures proteins in meal. (unfold them)
- Pepsin is a protease that chops up primary structure of proteins
- Muscle contractions mix food, saliva, and stomach secretions (3 layers of smoothe muscle)
- Liquid mixture is called chyme
- Two basic types of stomach: monogastric (carnivores/omnivores) & digastric (herbivores)
- Insects have gastric ceca
- Birds have proventriculus (gastric juice) and gizzard
Vertebrate Foregut:
Parietal cells secrete ____?
Chief cells secrete _____?
Goblet cells secrete____?
Enteroendocrine cells do what?
- HCl
- pepsinogen
- mucus
- makes the hormone gastrin and secrete hormones in the blood that control motility and secretion in the stomach
Vertebrate Midgut (small intestines)
What are the three segments that make up the midgut?
- Duodenum: first segment
- Jejunum: second segment
- Ileum: third segment
Vertebrate Midgut: What is the duodenum and what does it do?
The first segment
- Secretes mucus and fluids
- Receives secretions from liver (bile: emulsifies fats and neutralizes stomach acids)
- Receives secretions from pancreas (proteases, lipases, and carbohydrases & neutralizes stomach acids)
Vertebrate Midgut: what is the jejunum?
The second segment
- Secretes fluid
- Site of digestion and absorption
Vertebrate Midgut: what is the ileum?
The third segment
•Absorbs nutrients
Vertebrate Midgut Anatomy
Serosa: outermost layer
Longitudinal muscle layer
Circular muscle layer
(stomach has oblique layer)
Submucosa: fibrous connective tissue
Mucosa: mucous membrane, has many circular folds
Vertebrate Midgut Anatomy: villi
- Villi line the circular folds and are 1 mm tall
- Crypts of Lieberkuhn are between the villi
- plicae circulares
- Each villus contains aterioles, capillaries, venules–> portal vein, and lacteals
- nutrient rich blood: carbs and amino acids
- lipids go to lymph
Vertebrate Midgut Anatomy: microvilli
greater surface area greater rate oif diffusion and more enzymes in contact with chyme.
lumen,villi, and microvilli
Midgut Anatomy
The ____ are the major site of bacterial digestion in herbivorous birds, reptiles, and most mammals
These animals are considered what kind of fermenters?
ceca
hindgut
- What influences all aspects of digestive activity?
- Enteric nervous system is composed of what two structures?
- What is responsible for alimentary motility in most vertebrates?
- Skeletal muscle is responsible for motility in ____?
- ______ is responsible for motility in annelids, bivalve mollusks, tunicates and cephalochordates.
- Intrinsic nerve plexuses
- myenteric plexus and submucosal plexus
- Smooth muscle
- arthropods
- Ciliary activity
Vertebrate Control of Motility
What are the two modes of motility and how do they work?
Both are controlled by ____?
Regurgitation is____?
- Perstalsis: wave of constriction, circular muscle constriction & relaxation, pushes luminal contents through GI tract
- Segmentation: rhythmic contractions of circular muscle, contractions are asynchronous, does not involve longitudinal muscle, just mixes and packs luminal contents
- medulla oblongata
- reverse peristalsis (not the same as vomit)
Vertebrate Control of Motility
What are the two types of control?
Intrinsic Control:
- Smooth muscle contraction can be myogenic (basic electrical rhythm)
- Pacemakers are coupled with smooth muscle cells
- Slow waves
- AP production causes contraction
Extrinsic Control: increase or decrease the pace
- Modulation of intrinsic slow waves
- Chemical stimulants found in chyme
- Innervation by autonomic nervous system
- NE (sympathetic) inhibits APs (decrease)
- Ach (parasympathetic) stimulates APs (increase)
Different parts of the GI tract have different patterns electrical activity which gives you_____
different patterns of contraction
Arthropod Digestion and Absorption
Arthropods include____?
What similarities do they have with vertebrates?
- Insects and crustaceans (crayfish, crabs, shrimp)
- Extracellular digestion and motility through muscular contraction
Arthropod Digestion and Absorption: Foregut
Foregut is extention of the cuticle: a thin, chitinous exoskeleton and comes from the ectoderm
What are the 2 characteristics of an insects foregut?
What are the characteristics of an crustaceans foregut?
- Most have a crop and some may have proventricularis or gizzard
- SAT-P
- Tubular esophagus
- Sac-like stomach (proventricularis) that contains acid, but not as acidic as humans
- Anterior (cardiac) chamber:
- A muscular gastric mill
- Digestive enzymes come from midgut (hepatopancreas)
- Posterior (pyloric) chamber:
- Smaller
- Setae keep particles from leaving until they are small enough
Arthropod Digestion and Absorption: Midgut
- Embryonic origin is the___?
- Primary site of _____ and _____?
May have ceca
- Insects have _____ carrying urine empty into the junction of mid- and hindgut.
Crustaceans have large variations in complexity from simple tubes to complex arrays of ceca.
- Hepatopancreas characteristic?
- endoderm
- digestion and absorption
- Malpighian tubules
- Hepatopancreas
- Not that similar to the vertebrate pancreas
- Secretes digestive enzymes that go to stomach via retrograde flow
- Food particles also enter hepatopancreas to be digested and absorbed
- Stores lipids and glycogen
- Sequesters toxins
- Principal site of digestion and absorption!!
Arthropod Digestion and Absorption: Hindgut
Hindgut
Also has cuticle (from ectoderm)
Crucial in adjusting urine composition in insects
Some nutrient absorption
Bivalve Mollusc Digestion and Absorption:General
3 examples of bivalve mollusc are?
Motility is a result of_____?
Most digestion is___?
Tract consists of what 4 parts?
- Clams, mussels, oysters an relatives
- ciliary action
- intracellular
- Tract consists of:
- Esophagus
- Stomach
- Intestine
- Rectum
Bivalve Mollusc Digestion and Absorption: Complex function of the stomach
What is the crystalline style and its 3 characteristics?
- A long, thin gelatinous rod
- Clear and colorless
- Made by style sac
- Protruding end is degraded during digestion
Bivalve Mollusc Digestion and Absorption: Crystalline style
How does it function?
What is the function of the ciliary fields?
1.
- Pull mucus with trapped food from the mouth to the stomach by winding up the mucus strands
- Grinds up food against the chitinous gastric shield
- Releases digestive enzymes, especially amylase, into the stomach (breask down carbs)
- Perform extracellular digestion
- Sort and direct food particles into the digestive diverticula
Bivalve Mollusc Digestion and Absorption: Digestive diverticula
What are they and their function?
- Branching, dead ended tubules
- Critical for digestion-absorption
- Store lipids
- Food particles brought into cells using phagocytosis andpinocytosis
- Intracellular digestive enzymes break down food particles
- Products are thought to be passed on to hemolymph
Bivalve Mollusc Digestion and Absorption
Midgut
- Functions in digestion and absorption in some molluscs
Hindgut
- Passes through the heart as it goes to the anus
Enzymatic Digestion
Most enzymes are____?
What are the 3 spatial contexts in which enzymes operate
What are the 3 major groups?
- hydrolytic- adds water to the molecule to break it apart
- Intraluminal enzymes (float around inside lumen) Membrane-associated enzymes,** Intracellular enzymes** (mollusc use)
- proteases, carbohydrases, and lipases
Digestive Enzymes: Proteases
Two types of proteases?
Endopeptidases:break peptide bonds from within amino acid chains
Exopeptidases: break peptide bonds only from the ends
- Stomach: pepsinogen
- Pancreas: trypsinogen, chymotrypsinogen, procarboxypeptidases, aminopeptidases
- Small intestine: enterokinase, peptidases
Digestive Enzymes: Carbohydrases
What are the 2 types?
Polysaccharidases: break glycosidic bonds of long chain carbohydrates (cellulose, glycogen, starch) (in lumen)
Glycosidases: break disaccharides down into monosaccharides (in membrane)
Digestive Enzymes: Lipases
What do lipases do?
Convert lipids into fatty acids, monoglycerides, and diglycerides
major form of lipids are triglycerides and they break them done
What is considered the largest exocrine & endocrine gland?
What are 5 types of exocrine secretions:
What is the difference bewteen exocrine and endocrine?
- GI tract
- Saliva, HCl, mucus, pancreatic juice, bile
- exocrine glands have ducts and secretes outside of the body and endocrine glands secrete into the interstitial space and into the blood
Bile and Bile Salts
Are secreted by the_____?
Essential for ____?
Is acid or basic?
Contains water, cholesterol, lecethin, inorganic salts, and bile salts
Bile pigments that are byproducts of ___?
Bile is transported to _____ for storage and water reabsorption (to make more concentrated)
- liver
- fat digestion
- basic
- bile salts: disperse fats into microscopic droplets so they can be easily digested. Are recycled & disperse lipid soluble vitamins (emulsifies them)
- hemoglobin breakdown (bilirubin)
- gall bladder
Gastric Phase
Food stimulates gastric chemo- & mechanoreceptors (chyme & distension)
Gastrin & histamine are secreted
Gastrin increases gastric motility, HCl (strong) and pepsinogen (moderate) secretion
Histamine increases HCl secretion
Intestinal Phase
Gastrin: entry of partially digested proteins induces secretion. Acts upon stomach (excitory)
Secretin & VIP: stimulated by chyme entry. Causes pancreatic juice secretion (inhibitory phase)
GIP: triggered by fat & sugar entry into duodenum.
CCK: secreted in response to fatty acids & aminoacids
Gastrin
Stimulated by entry of chyme into stomach, especially when it contains partially digested proteins
What are its 4 effects?
- Secretion of HCl and pepsinogen
- Increases gastric and ileal motility
- Relaxes ileocecal sphincter & induces mass movement
- Stimulates growth and development of stomach and intestine
Secretin
Stimulated by presence of acid in duodenum
What are its 4 effects?
- Inhibits gastric emptying until acid is neutralized
- Reduces acid secretion in stomach
- Increases NaHCO3 secretion into pancreatic juice
- Stimulates growth and development of pancreas (w/CCK)
Cholecystokinin (CCK)
Stimulated by presence of nutrients, especially fat, in duodenum.
What are its 6 effects?
- Inhibits gastric motility & secretion
- Stimulates pancreatic juice secretion, especially lipase
- Contracts gall bladder
- Long-term pancreatic changes
- Role in satiety
- Stimulates growth and development of pancreas
Gastric Inhibitory Peptide or glucose-dependent insulinotrophic peptide (GIP)
Stimulated by presence of meal in digestive tract
May be released in anticipation of meal (feed-forward)
What are its 3 effects?
- Promotes metabolic processing of absorbed nutrients
- Minor inhibitor of gastric motility and secretion
- Stimulates insulin release from pancreas
3 is the mechanism for doing number 1
Nutrient Absorption: Passive diffusion
Through the membrane: fatty acids, monoglycerides, cholesterol, and other fat-soluble substances
Through water-filled pores: water, some sugars, alcohol
Nutrient Absorption
Facilitated diffusion: Some monosaccharides and amino acids: hydrophilic and large
Active Transport: Na+-driven movement of amino acids
Endocytosis:Transport of oligopeptides. Seen in transport of immunoglobulins
Lipid Absorption
Carbohydrate Absorption
Protein Absorption
Facilitated diffusion: amino acids
Active Transport: Na+-driven movement of amino acids
Endocytosis: Transport of oligopeptides. Seen in transport of immunoglobulins
