1. The Chemical Context of Life
Image by Riedell
KEY CONCEPTS:
2.1 Matter consists of chemical elements in pure form and in combinations called compounds.
2.2 An elements properties depend on the structure of its atoms
2.3 The formation and function of molecules depend on chemical bonding between atoms
2.4 Chemical reactions make and break chemical bonds.

2. Click the image to play the video segment.
Atomic Structure 2A
Click the image to play the video segment.
Video 1

3. Atoms are the ________________:
basic unit of MATTER
PROTONS (+)
______________
are found ______________
___________________ in ____________________
NEUTRONS
in NUCLEUS
ELECTRONS (-)
orbit outside nucleus
energy levels
Animation from:

4. Atoms differ in __________ of _______, ________,& _______
NUMBERS
PROTONS
NEUTRONS
ELECTRONS
Image from:

5. Atoms that have _________________ have an _____________ and are called __________
They are written with a + or – next to their symbol
gained or lost electrons +
electric charge Na
IONS - Cl

6. Atoms/ions important for living things
Used to make bigger molecules
Ions = electrically charged atoms
____________
Carbon - C
____________
Oxygen - O
Sodium – Na+
Chloride – Cl-
Hydrogen - H
Potassium – K+
Nitrogen - N
Calcium – Ca++
Sulfur - S
Hydrogen – H+
Phosphorus - P

7. Hydrogen Ions (H+) H+ acidic More H+ = more acidic
The number of ____ ions determines how _______ a solution will be. H+
acidic
More H+ = more acidic

8. ATOMS CAN ______TOGETHER TO _____________________
JOIN
MAKE MOLECULES
Ex:
Joining 2 HYDROGEN atoms with 1 OXYGEN atom makes one ______ molecule.
WATER
what kind
chemical formula
A _______________ tells _________ of and __________ atoms are in a molecule
EX: ________
how many
H2O

9. VERY, VERY LARGE MOLECULES MACROMOLECULES = ____________________
EXAMPLE:
Insulin =
C254 H377 N65 O76 S6
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10. MOLECULES CAN BE SHOWN IN DIFFERENT WAYS
Water molecule:
H2O
Other Images by: Riedell

11. - + Polar Molecules electric charge Because of the location of
Image from:
Because of the location of
electrons in molecules,
some molecules have an
_________ pattern of
____________________
More ___ on one side;
More ___ on the other
EX: water
UNEVEN
electric charge + -
More about this in Chapter 7

12. The same molecule can have both POLAR and NON-POLAR parts
EX: PHOSPHOLIPIDS
The same molecule can have both POLAR and NON-POLAR parts
Polar head
NON-polar tails
More about this in Chapter 7
Image by Riedell

13. WHAT HOLDS MOLECULES TOGETHER?
Molecules are _____________by the
________ between ______________
regions of nearby molecules = _____________________
held together
attraction
oppositely charged
van der Waals forces

14. HYDROGEN BONDS positively
Bonds that form between the _________ charged _____________
in one molecule and a
__________ charged _________
in a nearby molecule are called
_____________________
positively
HYDROGEN atom
negatively
atom
HYDROGEN BONDS
EX: water molecules
are held together
by Hydrogen bonds
Hydrogen bond animation
Images from:

15. _________ is the most important atom found in living things CARBON
four
It can join to _______
other atoms at same time
chains
It can form ______ or _____
so it can make lots of
different kinds of molecules.
rings
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16. __________ molecules are found __________ and _____________ atoms
__________ molecules are found __________ and _____________ atoms
ORGANIC
in living things
contain CARBON

17. “Like dissolves like” HYDROPHILIC
____________________ means “water loving”
_________ groups/molecules try to _________ and touch water or ______________ molecules
POLAR
be near
other polar
Water makes a great solvent in
living things because so many
molecules found in living things
are polar or have a charge.

18. “Like dissolves like” HYDROPHOBIC NON-polar
“Like dissolves like”
HYDROPHOBIC
_________________ means “water fearing”
___________ groups/molecules try to _________ other __________ molecules and __________ ________ molecules
NON-polar
be near
NON-polar
away from
polar
Oil based paints dissolve
in solvents such as
turpentine
. . . not water.

19. “Like dissolves like” SOAP
“Like
dissolves
like”
SOAP
______ works because it has a _____________ that dissolves _______ and a __________ that dissolves in _____ to wash away oily dirt.
NON-polar end
grease
Polar end
water

20. A chemical equation tells what happens in a chemical reaction
when molecules interact.
NaOH + HCl → NaCl + H20
_______________ ________________
Molecules that react Molecules that are
produced →
REACTANTS
PRODUCTS
Image by RIedell

21. REMEMBER: ALL the chemical reactions that happen in cells = _____________
METABOLISM
join
Chemical reactions can _____
molecules together.
Chemical reactions can ______
molecules apart.
break

22. One way to join molecules to make a bigger molecule is by ________
a _______ molecule to make a bond.
= ____________________ reaction
removing
WATER
dehydration synthesis
See an animation

23. DEHYDRATION SYNTHESIS “dehydration” “synthesis”
=_____________ _____________
water loss
put parts together

24. POLYMERIZATION kind of synthesis small subunits similar
_________________ is a
________________ reaction in which many _____________ that are ________ join to make
a bigger molecule
These small units are called ______________
The big molecule they make is called a
_____________
kind of synthesis
small subunits
similar
MONOMERS
POLYMER
Image by RIedell

25. EXAMPLE: DNA _________ subunits (A,T,G,C) join together to make
a _____ molecule
Nucleotide
DNA

26. Chemical reactions can also ________ molecules apart.
______________ = kind of chemical reaction in which a molecule is broken apart by adding a________ molecule.
“_____” = water “_____” = break apart
break
HYDROLYSIS
WATER
hydro
lysis
See an animation

27. opposite HYDROLYSIS is the _________ of DEHYDRATION SYNTHESIS.
Adding a water molecule breaks the bond.

28. More on this is Chapters 7, 8,& 9
ATP is the energy
molecule used by
all cells.
Breaking a bond
using hydrolysis is
the way ENERGY
is released.
More on this is Chapters 7, 8,& 9

29. Living things _______ of these kinds of _______ (and MORE) to get the _______they need.
use BOTH
reactions
materials

30. WATER is important for all living things
Average person ~~ 60-70% water
Babies ~~ 78%
Human brain ~~ 90%
Image from:

31. WHY Water is important to cells:
POLAR
DISSOLVE
1. It’s __________ so it can ____________ lots of different substances.
2. It can _________ lots of ______
_______________________________ very much (That helps with _________________)
3. ____________________ form between water
molecules so they stick together.
4.Water is an important ___________________
in many CHEMICAL REACTIONS.
absorb
HEAT
WITHOUT changing temperature
HOMEOSTASIS
HYDROGEN BONDS
REACTANT/PRODUCT