Transcript Unit 2 - shscience.net

With the person next to you, answer the
following questions, which are based on
your homework:
1.
What types of nutrients are found in
foods?
1.
What makes a food ‘nutritious?’
1.
What is your definition of a ‘nutrient?’
What are nutrients???
 Definition:
 Nutrients
are the components in foods that
organisms use to survive and grow.
Unit 2
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?
Why do Organisms Need
Nutrients?

Organisms must take in (ingest) essential
nutrients from the environment and change them
into a form that they can use.

Research has shown that good nutrition can help
lower people’s risk for many chronic diseases
(heart disease, stroke, diabetes) -according to the
CDC
1. Why do Organisms
Need Nutrients?
1. Energy
2. Growth
3. Repair
4. Chemical
Reactions
5. Regulation
 There
are different types of nutrients –
organic and inorganic – both are found in
cells and allow them to perform reactions
to maintain life.
Nutrition Song (4:02)!!!

https://www.youtube.com/watch?v=6fhSGWdbm9g
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)
pH
What are Organic vs.
Inorganic Compounds?
 Organic
compounds:
 Contain
both carbon and hydrogen.
 Types:
 1.
Carbohydrates
 2. Lipids
 3. Proteins
 4. Nucleic Acids, and Vitamins
Focus: Organic
Compounds
a. 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
b. Lipids (fats)
Examples
Fats, oils, waxes
Building Blocks
3 fatty acids and 1 glycerol
Biochemistry
Glycerol
3 Fatty Acids
Biochemistry
Examine
 Why
a leaf!!!
does it
feel waxy???
Focus: Organic
Compounds
Uses
Stored energy, insulation,
cushioning
Elements
C, H, O
Chemical
Indicators
And Results
Brown paper test for
translucence
Brown Paper Test
Biochemistry

Remember: The cell membrane
includes a lipid bilayer:
Biochemistry

FYI – Cholesterol
 Soft, waxy substance made by our bodies in the liver
and from the animal foods that we eat (plant foods do
not contain cholesterol)
 Transported in the blood and used for body functions
(production of hormones and vitamin D)
 Combines with protein and fatty acids to form HDL –
remove cholesterol from cells of body and LDL – ‘bad
cholesterol (can stick together to form plaque on walls
of blood vessels)
Biochemistry

‘Good fats’ are necessary as an energy source (calories),
healthy hair and skin, reduce heart disease risk
(unsaturated fats- liquid at room temp like vegetable oils
and fish-Omega-3-fatty acids)

‘Bad fats’ – (saturated fats) increase risk for various
diseases including heart disease – solid at room temp like
butter and cheese

‘Trans fats’ hydrogenated – boost bad cholesterol levels in
blood (liquid oils turn solid to increase shelf life)
Focus:
OrganicCompounds

c. Proteins (polypeptides)

Carry out most of the work in a cell.

Protein molecules are long, folded chains
made of 20 different amino acids in a specific
sequence (code in our DNA!)
Focus: Organic
Compounds

The order of the amino acids determines the
SHAPE of the protein.

As a polypeptide chain forms, it naturally twists
and bends.
Focus: Organic
Compounds
 The
function of a protein depends on its
SHAPE!
Focus: Organic
Compounds
c. 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.
Proteins !!!

http://publications.nigms.nih.gov/structlife/chapter1.html
Enzymes
C. 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
Activity
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?
Applicable NYS Standards

1.2 h, 2.1 I, 5.1 c, 5.1 f, 5.1 g