The Digestive System:

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The Digestive System Why we eat, what we
eat, and all the nitty-gritty biochemistry!
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Our end goal?...to understand what all this means
and WHY it is necessary to keep us alive!
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Digestion
The breakdown of food macromolecules
(carbohydrates, lipids, proteins, and nucleic
acids) using enzymes.
WHY?
So our bodies can absorb the building blocks
needed to keep our body running (to gain energy,
build new molecules that make up your body, etc.)
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A little science process vocab to keep in
mind for your exit slip
Quantitative observation
An observation involving numbers/quantity. Ex
The dog had a mass of 15.6 kg.
Qualitative observation
An observation involving a verbal, non-number
description. Ex The dog was very small.
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Alimentary Canal The tube that runs from mouth
to anus.
Accessory Organs Organs that assist in
digestion, but are not part of the alimentary
canal.
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Can you match? Why are liver, gall bladder, and
pancreas in green font?
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Mmm!
Can you ID the structures 1-6?
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Physical Digestion
Also referred to as mechanical digestion.
Breaking food into smaller particles, not
changing the chemical/molecule makeup of the
food. Ex Chewing a hamburger into smaller
hamburger pieces to swallow.
Chemical Digestion
Using molecules your body makes called ENZYMES,
large food molecules are broken down into smaller
molecules that can be absorbed by your body for
use. Ex Salivary amylase breaks down starch
into maltose. Maltase will then break down
maltose into two glucose molecules that can be
absorbed by your bodyto use as energy! What are
the orange words?
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SALIVARY AMYLASE
MALTASE
ABSORBED BY SMALL INTESTIVE
E!
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Functions of the digestive organs
Organ and P(physical) or C (chemical) digestion Function
Teeth (P) Mastication of food (physical)
Salivary glands/saliva (P and C) Dissolve food, ease swallowing, salivary amylase digests starch to maltose
Esophagus (P) Smooth muscle tube that contracts to move food to stomach
Stomach (P and C) Churns and mixes food into chyme. Mixes in hydrochloric acid (HCl) to kill bacteria and activate the enzyme pepsin to digest large proteins into smaller protein chains
Liver (P) Produces bile
Gall bladder (P) Stores bile that emulsifies fat (breaks large fat blobs into smaller fat droplets)
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Organ Function
Pancreas (C) Produces digestive enzymes Pancreatic amylase Starch into maltose Pancreatic lipase Digests lipids (fats) into glycerol and fatty acids Trypsin Digests proteins into amino acids These enzymes enter the small intestine to do their work!
Small Intestine (C) First part of the small intestine is for digestion using enzymes from pancreas as well as enzymes made by the small intestine Peptidase (proteins into amino acids), carbohydrases (like maltase and lactase to digest maltose and lactose), and lipase. Second part of the small intestine is for absorption of these nutrients.
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Organ Function
Large Intestine (no digestion) Absorption of WATER and vitamins. Bacteria that live in your small intestine actually provide you with some of your vitamins!
Rectum (no digestion) Where the undigested food material is stored until defecation. What CANT we digest? Think corn! We dont have an enzyme to digest the plant cell-wall material called cellulose. You have probably hard cellulose called FIBER.
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More about these molecules we call
FOOD INTRODUCTION TO BIOCHEMISTRY!
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From the beginning
Molecule (this is glucose)
Atom What are the subatomic particles of an
atom?
Macromolecule (this is starch)
NOT the butter, that would be a lipid!
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http//www.scaleofuniverse.com
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Biological macromolecules
Macromolecule (Polymer) Building block(s) (Monomer) Elements present Examples Some Functions
CARBOHYDRATES Monosaccharides C, H, O Glucose Lactose Starch Quick energy
LIPIDS Glycerol Fatty Acids C, H, O Fats Energy storage, Insulation, Protection
PROTEINS Amino Acids C, H, O, N (sometimes S) Hemoglobin Enzymes Keratin Transport Increase rate of reaction Structure protection
NUCLEIC ACIDS Nucleotides (Phosphate group, sugar, nitrogen base) C, H, O, N, P DNA, RNA Contain the code to build proteins
Well dive into these guys more when we do DNA!
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If you want to survive, you need to take in these
macromolecules and DIGEST them down to their
monomers so you can absorb and USE them!
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Who are we?
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Who are these guys?
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Notice anything about these molecules? They are
all ORGANIC.
Organic molecules
Molecules made of more than one type of element
and that are made by and used by LIVING
ORGANISMS. Contain carbon-hydrogen bonds. The
atoms and building blocks (monomers) are joined
with COVALENT BONDS (meaning each atom shares
electrons with the one its connected to). Most
common elements in living things C, H, O, N, P,
S!
inOrganic molecules
Molecules that do not fit the description above!
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Organic or inorganic?
H2O
C6H12O6 (glucose)
CO2 (carbon dioxide)
C2H6 (ethane)
O2 (oxygen)
Sodium biocarbonate
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Lets focus on Carbohydrates
Carbohydrates Paper-Lab Analysis Questions
Read the directions STEP-BY-STEPor you will
regret it. Trust bee.
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The epic battle of
VS.
NUT
CHEERIO
ANYONE WITH NUT ALLERGIES?
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Crash Course Biology (a YouTube channel!)
Super-helpful short tutorials to bookmark for
extra help in other areas of this class!
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55 120 lbs
56 250 lbs
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Lipids
All lipids are nonpolar, so they will NOT
dissolve in water (hydrophobic). Three main
lipid types 1. Fats/oils/waxes 2. Sterols
(Cholesterol and hormones) 3. Phospholipids
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• Fats/oils/waxes
• - Long term energy storage
• - Lubrication
• - Trap debris/waterproof
• Saturated vs. Unsaturated

Solid at room temp Bad Lard, butter
Liquid at room temp Good Oils
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A Triglyceride
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2. Sterols - Cholesterol (structural support to
cell membranes) - Hormones (chemical messengers)
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• Phospholipids
• - Compose the cell membrane
• - Hydrophobic tails and hydrophilic heads create
  the double-layered membrane

Yeah, these look crazy complicated, but well
come back to them when we get into the cell
membrane stuff!
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Some good lipid tutorials!
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PROTEINS!
Wiggle your finger. Feel your heart beat. Take
a deep breath. Allow glucose to enter your
cells. Run your fingers through your
hair. Scratch your nose with your
fingernail. Digest your lunch so you can use the
nutrients (and build more of these proteins
yourself!) Fight infection. Spin a web (if
youre a spider).
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PROTEINS!
Wiggle your finger. Actin and myosin! Feel
your heart beat. Actin and myosin! Take a deep
breath. Hemoglobin! Allow glucose to enter
your cells. Insulin! Run your fingers through
your hair. Keratin! Scratch your nose with your
fingernail. Keratin! Digest your lunch so you
can use the nutrients (and build more of these
proteins yourself!) All those digestive
enzymes! Fight infection. Antibodies! Spin a
web (if youre a spider). Spidroins!
The most diverse macromolecule group!
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PROTEINS!
Building block (MONOMER) of proteins is the AMINO
ACID
i amino group ii R-group (different for each
amino acid) iii carboxyl group
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20 different amino acids that can be assembled
into a myriad of proteins! Our bodies make most
of them (called nonessential amino acids)but we
have to get 10 of them (essential amino acids)
from our diet b/c our bodies cant make them.
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How to build a protein? Dehydration synthesis
like always!
2 amino acids joined together
More than 2!
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Proteins assume their primary shape based on the
code they are given from DNAand then they fold
into unique shapes. The SHAPE determines what
the protein will do and how it will FUNCTION.
BEADS AND FOLDING MANIPULATIVE!
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Enzyme animation tutorial and notes
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A little intro to the pH scale (since pH can
affect enzyme action)
7 neutral (equal OH- and H) Above 7 Basic
(lots of OH-) Below 7 Acidic (lots of H)
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How do you make really good sweet tea? - Sucrose
(table sugar aka glucose covalently bonded to
fructose) - HEAT! BOILING! - Why boil? Ever
been to a restaurant that doesnt serve sweet
tea? Boo! You add packets of sugar to cold tea
and its just not the same. Why? Butif you had
the enzyme ___________, you would be set
(assuming it could work at what?)
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Which line on the graph represents a reaction
catalyzed by an enzyme? Relate back to sweet
tea example! Explain yourself!
Enzymes _____ the activation energy of a reaction.
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Properties of Enzymes Lab
Hello again, liver! This time we dont care
about your glycogen, but a particular enzyme
thats made by your cells.
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Greatest rate of increased enzyme
activity? Denatured? Optimal temperature? Optim
al temp of most human enzymes?
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An interesting thing happened one time when we
did an extension of this lab
A student was investigating the effect that
temperature had on enzyme activity. He heated
the hydrogen peroxide up until it was almost
boiling and then added liver to the solution.
I told him there was a serious flaw in his
logic. What was the flaw???
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a) Which enzyme is most likely found in the
mouth? b) Which enzymes if most likely found in
the stomach? c) Which enzyme is probably not an
enzyme found in the digestive system?
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One morewhat does this graph suggest about
increasing the amount of substrate? What has
happened once the graph levels out?
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Lets tie it back to DIGESTION
Chalkboard enzymes, digestion, and organs drawing!
Animation!
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The Big Digestion lab!
Time to apply everything youve learned to a lab
based on whats happening in your bodyusing the
real-deal enzymes!