Animals - Chapter 9 Flashcards
Nutrients
all organisms must have a way of obtaining essential nutrients
essential nutrients = basic/raw materials needed to provide energy, regulate cellular activities, and to build and repair tissues
Macromolecules
these are the essential nutrients that our bodies need
they are larger, more complex assemblies of organic molecules which contain carbon bonded to hydrogen, as well as other atoms
CHON, SP (carbon, hydrogen, oxygen, nitrogen, sulfur, phosphorus)
Carbohydrates
1 carbon : 2 hydrogens : 1 oxygen function = short term energy storage, main source of energy, structure (cell walls and exoskeleton) monomer = monosaccharides (glucose, fructose, galactose) examples = disaccharides (sucrose, lactose, maltose), polysaccharides (glycogen, chitin, cellulose) energy content = 37 kJ/g
Lipids
1 carbon : 2 hydrogens : very few oxygens function = long term energy storage, insulation, protection and cushioning of organs, cell membranes, hormones monomer = triglycerides (glycerol, fatty acid chains) examples = fats, phospholipids, steroids energy content = 17 kJ/g
Proteins
elements = CHONS (no ratio) function = structural molecules, metabolic activities, motion, hormones, can be converted to high-energy storage molecules monomer = amino acids examples = enzymes, nails, hair energy content = 17 kJ/g
Nucleic acids
elements = CHONP (no ratio) function = genetic code, heredity, cellular energy molecules monomer = nucleotide examples = DNA, RNA, ATP
Water
needed for the proper functioning of all cells and organs, ⅔ of the body mass
functions include =
transporting dissolved nutrients into the cells that line the small intestine
flushing toxins from cells
lubricating tissues and joints
forming essential body fluids, such as blood and mucus
regulating body temperatures
eliminating waste materials
Vitamins
organic molecules the body needs in small quantities
regulate cell functions, growth, and development
some are fat soluble (ADEK) some are water soluble (BC), which impacts on how they are processed and eliminated
Minerals
elements the body needs in small quantities
aid in metabolic processes and in tissue building/repair
Metabolism
chemical reactions that the body performs in order to stay alive
catabolism = the breakdown of materials (digestion)
anabolism = the building of larger molecules (growth and repair)
metabolic rate = rate of converting stored energy into working energy, varies with body size, physical activity level, sex, age, hereditary factors
basal metabolic rate = minimum amount of energy required to keep you alive
Types of digestion
intracellular digestion = digestion inside the cell, occurs through phagocytosis (cell engulfs the food)
examples = single-celled organisms
extracellular digestion = digestion outside the cells, food enters a tube and exits from another end
examples = most animals, human digestive tract
Mechanical digestion
the physical breakdown of large food particles into smaller ones
achieved through chewing, mashing, chopping
this increases the surface area of the food, allowing more enzymes to come into contact with the food
Chemical digestion
the chemical breakdown of large molecules into smaller ones
macromolecules are broken down into their monomers
food particles are broken down by enzymes, each enzyme has a pH at which it performs best
Filter feeders
use a body structure that is similar to a filter basket
siphons water into its mouth and then filters it to obtain small organisms
Fluid feeders
suck or lick fluids from live plants or animals
mouth parts are adapted to pierce or rip skin or tear tissue
Substrate feeders
live in or on their food source and eat their way through it
Bulk feeders
includes many animals, and most vertebrates
ingest fairly large pieces of food
Types of digestive systems
incomplete = one opening, nutrients absorbed by lining of the cells, digestion continues inside the cells
complete = 2 openings, one for intake one for waste, organized into specialized regions that enable breakdown and absorption, one way flow
complete digestive system allows an organism to continuously feed and have more efficient digestion
Stages of the digestive system
there are four stages to food processing
ingestion = taking in food
digestion = breaking down food into nutrients
absorption = taking in nutrients by cells
egestion = removing any leftover wastes
Egestion
fiber is made up of cellulose which cannot be digested by humans
it provides the bulk in the colon
bulk pushes against inner walls of colon to stimulate egestion
Gastrin
secreted from the stomach
stimulates the release of gastric juices into the stomach (pepsin, HCl) in order to help with digestion and protection of the stomach
CCK
secreted from the duodenum
signals the pancreas to secrete a variety of substances to control the pH of the intestine, and enzymes that are needed for digestion
signals stomach to slow down speed of digestion or small intestine can digest fats
Secretin
secreted from the duodenum
stimulates liver to make more bile
encourages pancreas to secrete lipid and protein enzymes, and bicarbonate ions to neutralize chyme
Insulin
secreted from the pancreas
binds to special receptors on cells and allows glucose the enter the cells through the membrane
Glucagon
secreted from the pancreas
stimulates the liver, muscle cells and fat cells to break down glycogen and release glucose into the bloodstream
Enzymes
molecules that speed up the rate of reaction
are usually protein based and therefore quite specific to a substrate
can function only at an optimal temperature and pH level
Carbohydrate digestion
begins with the action of the enzyme amylase in the mouth, which breaks the starch down into disaccharides
restarts in the duodenum with pancreatic amylase, which breaks down the disaccharides into monosaccharides (glucose rings)
in the small intestine, maltase breaks down maltose (disaccharide) into two glucose molecules
Protein digestion
HCl is released in the stomach and converts pepsinogen into its active form of pepsin, which breaks down proteins into shorter polypeptides
the pancreas secretes inactive trypsinogen which converts to active trypsin in the small intestine and breaks down any partially digested molecules that remain
the small intestine secretes erepsin which then digests the peptones into amino acids
Lipid digestion
occurs only in the small intestine
bile, secreted from the liver, emulsifies fats, breaking them down into micelles in order to increase their surface area
pancreatic lipase then breaks down the lipid chains into individual molecules (glycerol and fatty acid chains)
Passive transport
transport of materials (solutes, molecules, ions) that does not require extra energy from the cell
Diffusion
tendency of particles to spread out from an area of high concentration to an area of low concentration across a permeable membrane
difference in concentrations is the concentration gradient
molecules diffuse until the point of equilibrium has been reached, and there is no more concentration gradient
osmosis = diffusion of water across a selectively permeable membrane
Facilitated diffusion
the diffusion of particles across a selectively permeable membrane by way of a protein channel
molecules are still moving down the concentration gradient but are using the protein to provide a channel from one side of the membrane to the other
often larger or charged molecules are transported this way
Active transport
process whereby a solute is moved against the concentration gradient (Iow to high concentration)
due to concentration gradient, the cell must expend energy to work the pump that is moving the molecule
energy used by the cell is ATP
