Download Chapter 10 .1 The Function of Digestion MACROMOLECULES AND

Chapter 10 .1 The Function of Digestion
MACROMOLECULES AND LIVING SYSTEMS
- 3 main fluid compartments of the body
 Cytoplasm inside cells
 Fluid between the cells (interstitial fluid)
 Fluid in the blood
- Fluids are mostly water, makes up 60% of the body
- Compartments contain and are composed of thousands of different kinds of molecules and
ions
- Inorganic (non- living) matter: water, phosphate, hydrogen ions and sodium ions
- Organic molecules: carbon bonded to hydrogen, oxygen, sulfur, and nitrogen
Shows distribution of body fluids in adults. Fluids move freely in and out of the cell in both
directions (osmosis and diffusion)
MACROMOLECULES: large molecule made up of smaller molecules that are linked together,
known as nutrients
- These nutrients are raw molecules that bodies need to provide energy to regulate cellular
activities, build and repair tissue
- Regardless of size or complexity, all organisms require nutrients to perform life functions and
obtain energy for survival
- Macromolecules grouped into 4 major categories:
 Carbohydrates
 Lipids (fats)
 Proteins
 Nucleic acids
- Energy released from these macromolecules, and matter supplied by them, is used to
maintain the body’s metabolism – all the chemical processes carried out by cells to maintain
life
METABOLISM – the sum total of all of the chemical reactions that occur in an organism
- Four major categories of macromolecules known as essential nutrients
ESSENTIAL NUTRIENTS – a nutrient that cannot be made by the body, therefore must be
obtained from food
Macromolecule
Carbohydrates
Lipids (fats)
Proteins
Nucleic Acids
Main Functions
- Provide materials to build
cell membrane
- Provide quick energy for
use by cells
- Store energy reserves for
later use by cells
- Cushion and insulate
internal organs
- Provide materials to build
cell membranes
- Provide structure and
support for blood cells,
body tissues and muscles
- Aid in muscle movement
(ex. Contraction)
- Act as catalyst to speed up
chemical reactions in the
cells
- Provide immunity against
infection and disease
- Transport ions in cell
membranes
- Contain the organism’s
genetic information
- Direct the organism’s
growth
Examples
Glucose, fructose, lactose,
maltose, starch, glycogen,
cellulose
Fats, oils, waxes
Insulin, hemoglobin collagen,
antibodies, enzymes
Deoxyribonucleic acid (DNA),
ribonucleic acid (RNA)
CARBOHYDRATES
- Macromolecules that always contain carbon, hydrogen and oxygen, almost always in the
same proportion: two atoms of hydrogen and one atom of oxygen for every atom of
carbon
- Carbohydrates provide short term or long term energy storage for organisms
- Two main types of carbohydrates: simple sugars and polysaccharides:
MONOSACCHARIDES (Simple Sugars)
- Mono means one, sacchar means sugar
MONOSACCHARIDES – a simple sugar with 3 to 7 carbon atoms (and corresponding number
of hydrogen and oxygen atoms)
Examples of monosaccharides: Glucose (sugar found in the blood) fructose (sugar found in fruit)
DISACCHARIDES – double sugars, a sugar made up of two monosaccharides molecules, make
up of two simple sugars
Examples of disaccharides: sucrose (table sugar), maltose (sugar in germinating grain), lactose
(sugar in dairy products)
POLYSACCHARIDES
POLYSACCHARIDES – large molecule made up of many linked monosaccharides molecules,
complex carbohydrates that consist of many linked simple sugars, poly means many
Examples: starch, cellulose, glycogen
GLYCOGEN - a polysaccharide made up of glucose subunits
- Starch performs the important function of storing energy in plants
-
Glycogen performs the same function in animals
LIPIDS
LIPIDS – a macromolecule/ an organic compound that does not dissolve in water, such as fat
and oil
- Basic structure of lipids is a molecule of glycerol (an alcohol) consisting of three carbon
atoms, each attached to a fatty acid chain (an acid with a long tail of carbon and hydrogen
atoms)
- Lipids store 2.25 times more energy per gram than other biological molecules
- Some lipids function as energy storage molecules
- Other lipids, called phospholipids, form the membrane that separates a cell from its
external environment
Examples of lipids: butter, lard, oils (olive and safflower)
PROTEINS
- Proteins are assembled from small subunits are known as amino acids
AMINO ACIDS – a building block of protein
- Most protein molecules are made up of hundreds of amino aids joined together by peptide
bonds into one of more chains
PEPTIDE BONDS - a bond that holds together the amino acids in a protein
- Chains are called polypeptides
POLYPEPTIDES – a linear chain of several amino acids linked by peptide bonds
- Most enzymes and antibodies (combat disease) are proteins
- Proteins help build and repair muscles and cell membranes
NUCELIC ACIDS
- Nucleic acids direct growth and development of all organisms using a chemical code
- Two types of nucleic acids:
 Ribonucleic acid (RNA)
 Deoxyribonucleic acid (DNA)
BREAKING DOWN MACROMOLECULES: ENZYMES
- Carbohydrates, lipids and proteins must be chemically broken down into smaller molecules
(small enough to be absorbed by the by the cells lining the small intestines) before the body
can use them
- This chemical breakdown process called hydrolysis (Hydro, Greek for water, lysis means to
loosen)
HYDROLYSIS – a chemical reaction in which water breaks apart macromolecules into smaller
molecules
- During hydrolysis, water molecules is added to the macromolecule (carbohydrate, protein or
lipid)
- This breaks the chemical bonds that hold together the smaller molecules from which the
macromolecule is made
- Breakdown of chemical bonds involves a special class of protein molecules called enzymes
ENZYMES – a protein molecule that helps speed up important chemicals reactions in the body
- Enzymes are secreted by cells n the digestive tract
- Enzymes act as catalysts, substances that increase the rate of chemical reactions without
being used up in reactions
- Three main types of digestive enzymes, each breaks down one type of macromolecule
Type of Enzyme
Macromolecule it
breaks down
Product of
breakdown
Carbohydrase
Carbohydrate
Simple sugars
Lipase
Lipid
Glycerol (alcohol) and
fatty acids
Protease
Protein
Amino Acids
Nuclease
Nucleic acid
Nucleotides
Digestive enzymes help speed up the process of hydrolysis:
Example of
Enzyme, where it
functions
Amylase: produced in
salivary glands,
functions in the mouth
Pancreatic lipase:
produced in the
pancreas, functions in
small intestines
Pepsin: produced by
stomach glands and
functions in the
stomach
Pancreatic nuclease:
produced in the
pancreas and
functions in the small
intestines
THE VITAL ROLES OF MINERALS AND VITAMINS
- Vitamins and minerals are inorganic and organic substances that enable chemical reactions to
occur and air in tissue development, growth, and immunity
ROLES OF WATER IN THE BODY
- Body is composed of two thirds water
- Water needed to:
 Transport dissolved nutrients into cells that line the small intestines
 Flush toxins from cells
 Lubricate tissues and joints
 Form essential body fluids (Ex. Blood and mucus)
 Regulate body temperature (sweating)
 Eliminate waste materials (Urine and sweat
- Water is vital for maintaining the body’s fluid balance
FLUID BALANCE – condition in which the amount of fluid lost from the body equals the amount
of fluid taken in
- Constant supply of water is needed to replenish the fluids lost to normal, daily body functions
- Average adult pees 1.5L (6.3 cups) of urine a day, loses 1L of water through breath,
perspiration, urine and poop
HOW ANIMALS OBTAIN THEIR FOOD
- Autotrophs obtain energy by making their own food (usually sunlight)
- Heterotrophs must consume other organism to obtain energy-yielding food
-
All animals obtain their food through one of four means/feeding mechanisms: filter feeding,
substrate feeding, fluid feeding and bulk feeding
Description
- Aquatic animals
- Use of body structure similar to a filter
basket to gather organisms like protists,
bacteria, larvae of many aquatic animals
suspended in water
- Siphons water into mouth then filters to
obtains small organisms to digest
- Live in/or their food source and eat their
way through
- Caterpillars eat their way through green
tissues of leaves
- Earthworms eat their way through soil,
ingesting soil particles containing partially
decayed organic materials
- Sick or lick nutrient rich fluids from live
plants or animals
- Have mouth parts that are adapted to
pierce or rip skin/leaf tissue
- Suck/lick blood or sap
- Most vertebrates
- Ingest fairly large pieces of food or
swallow food whole
- Use of tentacles, pincers, claws, fangs,
jaws and teeth to kill prey or tear
meat/vegetation
- Take in mouthfuls of plant or animal food
-
Example
Tube Sponge
Flamingo
Tube worm
Clam
Barnacle
Baleen Whales
Caterpillar
Earthworm
Butterfly
Mosquitoes, Ticks, Aphids
Spiders, bees
Vampire bats
Hummingbirds
Great Blue Heron
Human
THE FOUR STAGES OF FOOD PROCESSING
Nutrients in the food must get into the individual cells of the animal’s body in a usable form
Essential function of an animal’s digestive system is to break food down into small, soluble
units that can pass through cell membranes
Digestive system breaks down food into useful substances that can be absorbed into the
circulatory system
Circulatory system transports these substances to the individual cells of the body
1. Ingestion – taking in or eating the food
2. Digestion – breakdown of food by mechanical and chemical processes into molecules
small enough for cells of the body to absorb
3. Absorption – transport of products of digestion from the digestive system into the
circulatory system, which distributes them to the rest of the body
4. Elimination – removal of undigested solid waste matter from the body
DIGESTION AND THE ALIMENTARY CANAL
ALIMENTARY CANAL – tube through which food is processed, beginning at the mouth and
ending in the anus; also known as the digestive tract, long open tube
- As food moves along this tube, different organs of the digestive system process the food
similar to a production line
-
In more complex animals, food enters the mouth and is physically broken apart (chemical)
into smaller pieces by the teeth
- Food further broken apart as it moves along the digestive tract by the muscular contractions
of the tube itself
MECHANICAL DIGESTION – physical breakdown of large pieces of food into smaller pieces in
the mouth by teeth or similar structures, contractions and churning motions in the stomach
- Fluid releasing glands in the mouth and further along the digestive tract add liquid and
enzymes that help break down macromolecules in food into smaller molecules
- This is chemical digestion
CHEMICAL DIGESTION – chemical breakdown of nutrient molecules into smaller molecules by
enzyme action
LENGTH OF THE DIGESTIVE TRACT
- Herbivores and omnivores
(humans) have longer
digestive tracts relative to
their body size than
carnivores
- Cellulose walls in plant
tissues are more difficult to
digest than animal tissues,
herbivores have relatively
longer digestive tracts,
which allow extra time for
digestion