11. Chapter 41: Animal Nutrition Flashcards
Basic animal nutrition
All animals eat other organisms. Most animals are also opportunistic. (will eat a variety of things depending on what is available)
Three dietary categories
- Herbivores eat mainly autotrophs (gorillas, cows, and many invertebrates. 2. Carnivores eat other animals (sharks, spiders and snakes). 3. Omnivores consume animal and plant matter (cockroaches, bears, and humans).
What are the five main groups of the mechanisms by which animals ingest food?
- Many aquatic animals are suspension-feeders – sift small food particles from the water. (e.g. baleen whales) 2. Deposit-feeders, like earthworms, eat their way through sediments and extract organic material 3. Substrate-feeders live in or on their food source, eating their way through the food (e.g. maggots into animal carcasses and leaf miners through leaves) 4. Fluid-feeders make their living sucking nutrient-rich fluids from a living host. (E.g. Mosquitoes/ leeches suck bllod, Aphids tap plant saps, hummingbird/beed obtain nectar) 5. Most animals are bulk-feeders that eat relatively large pieces of food. (i.e. Their adaptations include tentacles, pincers, poisonous fangs, and jaws with teeth.)
Define Homeostasis
the steady state physiological condition of the body.
Define Negative-feedback. Example?
: a change in the variable being monitored triggers a response that counteracts the initial fluctuation. (primary mechanism of homeostasis, prevent small changes from becoming large) (E.g. Our body temperature is kept close to 37oC by the cooperation of several negative-feedback circuits)
Glucose regulation (negative-feedback)
- When blood glucose levels rise above a set point, 2.the pancreas secretes insulin into the blood. 3. Insulin stimulates liver and muscle cells to make glycogen, dropping blood glucose levels. 4. When glucose levels drop below a set point, 5. the pancreas secretes glucagon into the blood. 6. Glucagon promotes the breakdown of glycogen and the release of glucose into the blood. (The pancreas signals distant cells to regulate levels in the blood = endocrine function.)
Define Positive-feedback. Give two examples.
a change in some variable triggers mechanisms that amplify the change. 1. During childbirth, pressure of the baby’s head against sensors near the opening of the uterus stimulates uterine contractions. 2. Global warming (climate change)
What three things does a nutritionally adequate diet supply?
- Fuel (chemical energy) for all cellular work 2. Organic raw materials for biosynthesis 3. Essential nutrients, substances that the animals cannot make for itself from any raw material.
What do most of the calories you consume do?
ATP recycling accounts for the largest fraction by far of the energy budget of most animals. (Powers most cellular activity.)
Where is ATP derived from?
oxidation of organic fuel molecules in cellular respiration. (The monomers of carbohydrates, proteins, and fats (2x calories) can be used as fuel.)
When an animal takes in more calories than it needs to produce ATP, what can the excess be used for?
Biosynthesis: growth and reproduction.
In humans, what does that the liver and muscle cells store energy as?
Glycogen: Polymer made up of many glucose units. If glycogen stores are full, the excess is stored as fat.
What happens when fewer calories are taken in than are expended?
Fuel is oxidized: human body generally expends liver glycogen first, then muscle glycogen, and finally fat (Most healthy people have enough stored fat to sustain them through several weeks of starvation - Energy needs can be fueled by the oxidation of only 0.3kg of fat per day.)
What are the two severe problems that can occur if the energy budget remain out of balance for long periods?
- Undernourished: caloric intake is 90% of the recommended level. 2. Severely undernourished: if caloric intake is less than 80% of recommended level.
What happens when glycogen and fat are used up?
The body breaks down its own proteins for fuel: 1. Muscles decreases in size, brain becomes protein-deficient 2. If energy intake remains less than energy expenditure, death results
Over nourishment (obesity)
- now a common problem 2. Fat hoarding provided a fitness advantage for our hunting/ gathering ancestor 3. Genetic and environmental component to obesity
Animal diets must supply essential nutrients, source of carbon (sugars) and nitrogen (proteins) in order to fabricate organic molecules (cannot be fabricated from raw material) What is an example so specie specific essential for primates?
ascorbic acid (vitamin C)
Define Malnourishment.
An animal whose diet is missing one or more essential nutrients is said to be. (Much more common than undernourishment - not enough caloric intake, possible to be over nourished yet malnourished)
Malnutrition at a personal scale.
Malnutrition at a national scale.
How many amino acids are required to make proteins (most animals can synthesize half of these)
- 20 amino acids (essential amino acids must be obtained by food) 2. 8 essential AA in adult human (proteins in animal products are complete, plant proteins are incomplete and would result in protein deficiency diets)
How can protein deficiency be avoided?
By eating plant food that complement each other. (i.e. Beans supply lysine, corn provides methionine)
What are vitamins?
organic molecules required in the in small quantities. 1. serve primarily as coenzymes 2. required in small amounts 3. deficiency can lead to serious problems (overdose too)
How many vitamins have been identified to being essential to humans?
13: water-soluble and fat-soluble. A balanced diet will prevent deficiency (RDA for vitamin C = 60mg but Linus Pauling advocated 25,00mg)
What are minerals?
simple inorganic nutrients, required in small amounts. 1. humans require large quantities of Ca and P for bone construction 2. Iron in hemoglobin (oxygen binding protein of RBC) 3. Na and Cl influence osmotic balance b/w cells and interstitial fluids (Cdn eat 20 time more than require, too much = high blood pressure)
What is the four main stages of food processing?
- ingestion (first stage) 2. digestion (breaking down into smaller molecules) 3. absorption 4. elimination
Can animals directly use macromolecules in their polymer state?
No, Macromolecules required are not identical to those consumed. Plus, polymers are too large. However, all organisms use common monomers (e.g. the same 20 amino acids).
In digestion, what are macromolecules cleaved into? and what is it used for?
cleaved into monomers –used in biosynthesis or as fuel for ATP production.
In digestion, what are polysaccharides split into?
monosaccharides
In digestion, what are proteins broken down into?
Amino acids
In digestion. what are fats digested to?
glycerol and fatty acids
What type of digestion occurs before chemical digestion? Why is it important>
Mechanical fragmentation of the food; Increases the surface area exposed to digestive enzymes; a variety of hydrolytic enzymes catalyze digestion.
Where do the animal’s cells absorb the small molecules after digestion?
digestive compartment
What happens during elimination?
undigested material passes out of the digestive compartment
What are the simplest digestive compartments? What is it termed?
food vacuoles, organelles in which hydrolytic enzymes break down food (Termed intracellular digestion.)
In most animals, at least some hydrolysis occurs by?
Extracellular digestion: much larger prey can be ingested than by phagocytosis.
