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Cellular Chemistry
I. Where can I find chemicals in my body?
A. A chemical is a substance that is made up of
elements/molecules and used in a chemical
reaction. Chemicals made up of more than
one type of element are called compounds.
I. Where can I find chemicals in
my body?

B. Living things are
composed of two main types
of chemical compounds:

Inorganic: compounds that
do not contain carbon,
oxygen, and hydrogen.
Water (made of the elements
hydrogen and oxygen) is the
most important inorganic
compound for life:
I. Where can I find chemicals in my body?
i.
ii.
Water is the most abundant
compound in a cell (and
organism). Most organisms
are 60-90% water by weight
Most chemical reactions
occur in water because it
provides an optimum
environment
Ex. transport of molecules in
the cell
Fill It In ….

Chemical formula of water:

Inorganic because …
I. Where can I find chemicals in my body?
2.
Organic:
compounds
that DO
contain
carbon,
oxygen, and
hydrogen
I. Where can I find chemicals in my body?
a.
Carbohydrates
(carbon, hydrogen,
oxygen)
Ex. Provide energy
source for
respiration (glucose)
I. Where can I find chemicals in my body?
b.
Lipids (carbon,
hydrogen, oxygen)
Ex. Insulate and
protect organs in the
body (fats)
I. Where can I find chemicals in my body?
c.
Nucleic Acids
(carbon, hydrogen,
oxygen, nitrogen and
phosphorus)
Ex. Allow traits to be
passed from parent
to child (DNA)
I. Where can I find chemicals in my body?
d.
Proteins (carbon,
hydrogen, oxygen,
nitrogen, sulfur,
phosphorus)
Ex. Provide
specifically shaped
molecules that can
carry other
molecules
(hemoglobin carries
oxygen)
Fill It In …
The “Core Four” organic compounds:
 1.
 2.
 3.
 4.

I. Where can I find chemicals in
my body?


Scientists can test for
the presence of the
different chemicals,
such as carbohydrates,
using indicators.
For example, iodine
changes to a blueblack color in the
presence of starches
I. Where can I find chemicals in my body?
D. The six essential elements (CHNOPS) are
essential to life because they help maintain
homeostasis.
I. Where can I find chemicals in my body?
a. The elements make up essential organic
and inorganic compounds. Each type of
molecule performs specific jobs in
organisms (see examples above).
I. Where can I find chemicals in my body?
Hydrogen is also
important in the
regulation of pH
More H+ = acid
Less H+ = base
Chemical Reactions- MYP
CO2+H20
 H2CO3

H2CO3 in the blood
CO2+H20 in the lungs
pH ScaleAcid: form H+ ions in a solution
pH range 0-6.9
Base: Form OH- ions in a solution
pH range 8-14
BrainpopAcid and
Base
pH DEMO
Substance Water
Prediction
Color
Change
pH Level
Vinegar
Sprite
Soda
Baking
Soda
Soap
Lemon
Juice
I. Where can I find chemicals in my body?

Foods you eat and
chemical reactions in
your body increase or
decrease your pH
I. Where can I find chemicals in my body?

b. Hydrogen is also
donated or accepted by
weak acid-base pairs to
regulate the pH of a
system like cells and
blood. These weak acidbase pairs are called
buffers.
I. Where can I find chemicals in my body?
 i.
When a cell’s pH drops
(becomes more acidic), the
buffers in the cell “accept”
the hydrogen ions which
reverses the pH change
 ii. When a cell’s pH rises
(becomes more basic), the
buffers in the cell “donate”
hydrogen ions
I. Where can I find chemicals in my body?
 iii.
In a cell, acid is
being produced as the
cell respires. To
maintain the pH, a cell
must use buffers to
counteract the acid
 iv. Different cells or
areas of the organism
need different pH
levels to perform.
Buffers help keep that
pH level constant
Buffers Regulate pH
Not enough
hydrogen?
Here’s
another H
atom!
Buffers can
donate hydrogen
Too much
hydrogen?
I’ll hold a
hydrogen
atom!
Ahhhhh – just the right
pH!
Buffers can
accept hydrogen.
Fill It In …

HOW does a buffer help maintain
homeostasis?
Check Yourself



What are the six essential elements?
What is the most important inorganic compound
to life?
What are the four major organic compounds?

How are the six essential elements important to
homeostasis?

What is a buffer?
Check Yourself



What are the six essential elements? CHNOPS
What is the most important inorganic compound
to life?
What are the four major organic compounds?

How are the six essential elements important to
homeostasis?

What is a buffer?
Check Yourself



What are the six essential elements? CHNOPS
What is the most important inorganic compound
to life? WATER
What are the four major organic compounds?

How are the six essential elements important to
homeostasis?

What is a buffer?
Check Yourself



What are the six essential elements? CHNOPS
What is the most important inorganic compound
to life? WATER
What are the four major organic compounds?
CARBOHYDRATES, LIPIDS, NUCLEIC ACIDS, PROTEINS

How are the six essential elements important to
homeostasis?

What is a buffer?
Check Yourself



What are the six essential elements? CHNOPS
What is the most important inorganic compound
to life? WATER
What are the four major organic compounds?
CARBOHYDRATES, LIPIDS, NUCLEIC ACIDS, PROTEINS


How are the six essential elements important to
homeostasis?
1. MAKE UP ESSENTIAL COMPOUNDS
2. CREATE BUFFERS
What is a buffer?
Check Yourself



What are the six essential elements? CHNOPS
What is the most important inorganic compound
to life? WATER
What are the four major organic compounds?
CARBOHYDRATES, LIPIDS, NUCLEIC ACIDS, PROTEINS


How are the six essential elements important to
homeostasis?
1. MAKE UP ESSENTIAL COMPOUNDS
2. CREATE BUFFERS
What is a buffer? COMPOUND THAT ACCEPTS OR DONATES H+