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Unit 3
Nutrients of Life
Key Questions

1. Why do organisms need/use nutrients?

2. What are organic vs. inorganic compounds?

3. What are some characteristics of certain nutrients?

4. What are enzymes and how do they function?

5. What factors affect the rate of enzyme action?

6. What reactions do nutrients undergo?
1. Why do Organisms
Need Nutrients?
1. Energy
2. Growth
3. Repair
4. Chemical
Reactions
5. Regulation
Why do Organisms Need
Nutrients?

Organisms must take in nutrients from the
environment and change them into a form that
they can use.

There are different types of nutrients – organic
and inorganic – both are found in cells and allow
them to perform reactions to maintain life.
Remember the periodic
table???
2. What are Organic vs.
Inorganic Compounds?

Inorganic compounds:
 Do not have BOTH carbon and hydrogen

Examples:
 Water
 Acids (pH is 1-6)
 Bases (pH is 8-14)
 Salts
 Minerals (ex: calcium)
Remember pH?
Inorganic Nutrients
a. Water
 Has many important functions to
maintain internal balance
 Up to 60% of our bodies are water!
 How much water should you drink a
day?
 Indicators – thirst, urine
Inorganic Nutrients
b. Minerals
 Used
in organisms to help perform certain
functions.
 Examples:
 Calcium
(bones)
 Iron (oxygen)
What are Organic vs.
Inorganic Compounds?
 Organic
compounds:
 Contain
both carbon and hydrogen.
 Types:
1.
2.
3.
4.
Carbohydrates
Lipids
Proteins
Vitamins
Focus: Organic
Compounds
1. Carbohydrates (Sugars)
Examples
Starch
Glucose
Cellulose
Building Blocks
Simple Sugars
Focus: Organic
Compounds
Uses
Energy
Elements
C, H, O
Chemical Indicators
And Results
-Starch – iodine (amber colored
and turns blue/black)
-Glucose – Benedict’s Solution
(blue turns orange with heat)
Focus: Organic
Compounds

Iodine: amber-colored but turns blue/black in
presence of starch
Negative
Positive
Focus: Organic
Compounds

Benedict’s Solution: Blue-colored and turns
orange in the presence of glucose when heated
Focus: Organic
Compounds

The sugars we eat are very complex – they need
to be broken down into simple sugars (like
glucose) so that they can fit into our cells.

Starch is a HUGE sugar, and glucose is a small
sugar!
Focus: Organic
Compounds
2. Lipids (fats)
Examples
Fats, oils, waxes
Building Blocks
3 fatty acids and 1 glycerol
Focus: Organic
Compounds
Uses
Stored energy, insulation,
cushioning
Elements
C, H, O
Chemical
Indicators
And Results
Brown paper test for
translucence
Biochemistry
Glycerol
3 Fatty Acids
Biochemistry

The cell membrane includes a lipid
bilayer:
Biochemistry
Examine
 Why
a leaf!!!
does it
feel waxy???
Focus:
OrganicCompounds
3. Proteins (polypeptides)

Carry out most of the work in a cell.

Make-up most things in your body (muscle,
blood, hair, cells)
Focus: Organic
Compounds

Protein molecules are long, folded chains made
of 20 different amino acids in a specific
sequence.

The order of the long chain of amino acids
determines the SHAPE of the protein.

The function of a protein depends on its shape
Focus: Organic
Compounds
Focus: Organic
Compounds
Proteins
Examples
Hormones, Enzymes,
Antibodies
Building Blocks
Amino Acids
Focus: Organic
Compounds
Uses
-Enzymes-Chemical
Reactions
Elements
C, H, O, N
Chemical
Indicators
And Results
Biuret’s Reagent – turns light
purple with protein
Focus: Organic
Compounds

Biuret’s Reagent - turns light purple in the
presence of protein.
Focus: Organic
Compounds

For Example:


Enzymes are protein molecules that fit with a
certain substrate.
Hormones are protein molecules that fit with a
certain membrane receptor.
Focus: Organic
Compounds
4. Vitamins
Organic compounds that your body needs in
small amounts to function properly
 Get most from daily diet
 Examples:
 Vitamin D (bones)
 Vitamin C (immune)

How do Organisms Use
Nutrients?

Many of the complex nutrients we
eat have to be broken down before
they can be used to build new
things.

Enzymes help with these reactions
of building and breaking down.
Enzymes
Enzymes

Enzymes are PROTEIN molecules

Act as biological catalysts – affect the rate of chemical
change without being changed themselves

They are necessary for ALL chemical reactions to occur
in cells!

Have a specific shape that allows it to act on a specific
molecule (substrate)
Enzymes

Some enzymes help to build large molecules by
joining substrates together

Other enzymes help to break substrates apart
Enzymes

Active Site: Where the enzymes join with the
substrate.
Thought Question

Why might enzyme action be referred to as the
‘Lock and Key Model’ for enzyme action?
Enzymes
The shape of each active site of an enzyme only fits with
certain substrates (just like a key for a door)
Enzyme Animations

http://www.kscience.co.uk/animations/anim_2.htm
Enzymes

The rate at which enzymes work can be
influenced by internal factors (inside your body)
such as pH and temperature.
Enzymes

1. Temperature

At high or low temperatures, enzymes may
denature – enzyme changes shape, so it does
not fit with the substrate

The reaction may slow down or stop
Enzymes
Temperature and Enzyme
Activity
Enzymes

The optimum (best) temperature for enzymes
depends on the organism!
Enzymes found in humans work best at 98.6
degrees F
 Those found in dogs work best at 101 degrees
F

Enzymes

2. pH

The pH an enzyme works best in is different for
each enzyme.
What are the
optimal
temperatures/p
H for:
Typical: human
enzymes:
Thermophilic
bacteria:
Pepsin:
Trypsin:
Lactose Intolerance Lab
Question – Lactose
Intolerance

A lactose intolerant student fixed himself a cup of hot
chocolate.

He added the hot chocolate mix, milk, and lactaid and
placed the mixture in the microwave for 2 minutes.

He drank the hot chocolate while watching his favorite
TV show and not soon after, he was running to the
bathroom with awful cramps.

He was so confused – what happened???
Lactose Intolerance

Interesting fact!

People with mild intolerance can usually have
yogurt because the live cultures (bacteria!)
break down much of the lactose into glucose
and galactose – simple sugars that are easier to
digest.
D. Reactions in Cells
 Chemical
reactions are occur constantly in
cells and they require enzymes!
 These
reactions allow cells to build new
molecules and break down others in order
to maintain homeostasis.
 The
major reactions are called synthesis
and hydrolysis.
Reactions

1. Synthesis



Building larger molecules from smaller ones with the
use of enzymes
When joining the pieces together, water is removed
When small nutrients enter a cell, the cell will use them
as building blocks in the synthesis of compounds
necessary for life
Biochemistry
Reactions
2.


Hydrolysis (Break Down)
Breaking down larger molecules into
smaller materials by adding water with the
use of enzymes
Occurs in digestion
Biochemistry
Biochemistry
 PRACTICE:
 Hydrolysis
or Dehydration Synthesis?
Dehydration Synthesis or
Hydrolysis?
Dehydration Synthesis or
Hydrolysis?
Dehydration Synthesis or
Hydrolysis?
Bill Nye – Nutrition
(23 min.)

http://www.schooltube.com/video/8b5b475d98ac476fbdb8/BillNye-Nutrition
Applicable NYS Standards

1.2 h, 2.1 I, 5.1 c, 5.1 f, 5.1 g