All organisms are made up of chemical compounds composed of atoms. Atoms consist of protons, neutrons, and electrons. Chemical bonds form between atoms, including covalent bonds, ionic bonds, and hydrogen bonds. Important biological molecules include water, carbohydrates, lipids, proteins, nucleic acids, and ATP. These molecules are essential for life and allow organisms to function through various chemical reactions, some of which are catalyzed by protein enzymes.
2. Organisms are chemical machines
All organisms consist of atoms
– Subatomic particles
Electron (e-) – located in electron cloud
Proton (p+) – located in the nucleus
Neutron (no) – located in the nucleus
Oxygen atom (O)
Nucleus:
8 protons (+)
8 neutrons
outermost energy
level:
6 electrons (-)
inner energy level:
2 electrons (-)
3.
4. – Differ in the number of protons in the
nucleus.
– Number of protons = Number of
electrons
Elements are neutral on the periodic table
– Atomic Number = Number of protons
– Atomic Mass = Number of protons + Number
of neutrons
http://www.privatehand.com/flash/elements.html
6. Differ in the number of neutrons they
contain in the nucleus
– Example:
Carbon 12 – 6p+, 6e-, 6no
Carbon 13 – 6p+, 6e-, 7no
Carbon 14 – 6p+, 6e-, 8no
7. Chemical Bonding – Compounds are
made of joined atoms of two or more
different elements.
Valence shell – outermost electron shell
– Atoms with a full valence shell are inert
(unreactive)
– Atoms without a full valence shell can form bonds
(reactive).
8. Name Symbol # p+ # e- #no
Oxygen
6
K
53
- Why do all isotopes of an element have the same chemical
properties? (Use your book to help you answer this)
9. The first electron shell of every atom can
hold a maximum of 2 electrons.
Each additional shell can hold a maximum
of 8 electrons.
11. Covalent bonds – atoms share
electrons
– Ex: H2, O2, CO2
covalent bonds
Oxygen atom (O) Carbon atom (C) Oxygen atom (O)
Carbon dioxide (CO2 )
12. Ionic Bonds – atoms gain or loose
electrons
– Atoms form ions
+ charge – cation
- charge – anion
Ex: NaCl
13. Hydrogen Bonds – weak chemical
attraction between polar molecules
– Water is a polar molecule because the electrons
of O and H are shared unequally.
14. Cohesion
• Surface tension
Adhesion
• Capillary action
Heat Capacity
• A large amount of heat
is required to increase
the temperature of
water
15. Water’s polarity gives it the ability to
dissolve other polar molecules as well as
ionic compounds
16. H2O H+ + OH-
The pH scale indicates the concentration
of H+ ions in a solution.
• Acids – contain more H+ ions therefore have a pH
below 7
The lower the pH the greater the acidity
• Bases – contain more OH- ions therefore have a
pH above 7
The higher the pH the more basic
• Neutral – contain equal OH- and H+ ions
17. • 70% of your body is made of water.
• The remaining 30% is made up mostly of
organic compounds (Carbon-based
molecules).
– Carbon is a unique element because it forms four
covalent bonds and can form a lot of different
structures.
18. Many carbon-based molecules are made of
many small subunits bonded together.
– Monomers are the individual subunits.
– Polymers are made of many monomers.
19. Key source of energy found in
most foods
Fruits, vegetables, and grains
Made up of single sugars called
monosaccharides.
Glucose, fructose
Disaccharides - two
monosaccharides are joined
Sucrose (table sugar)
Polysaccharides – chains of three
or more monosaccharides
Starch, cellulose, glycogen
20. Polymer (starch)
Starch is a polymer
of glucose monomers
that often has a
branched structure.
Polymer (cellulose)
Cellulose is a
polymer of glucose
monomers that has a
straight, rigid
structure
monomer
21. Nonpolar molecules not soluble in water
Fats, phospholipids (make up the cell membrane),
steroids (cholesterol), waxes
Saturated fatty acids
Solid at room temperature
Butter, lard, grease
Unsaturated fatty acids
Liquid at room temperature
Olive oil, fish oil
22.
23. Formed by chains of linked amino acids
Many functions including:
Enzymes
Structural (imbedded in the cell membrane)
Antibodies
24. Formed by chains of nucleotides
Two types :
DNA (deoxyribonucleic acid)
Double strand of nucleotides
Stores hereditary information
RNA (ribonucleic acid)
Single strand of nucleotides
Plays a key role in making proteins
Nucleotide
25.
26. Another important biological molecule
ATP (adenosine triphosphate)
– Consists of a single nucleotide with 2 extra
phosphate groups.
– ATP stores energy temporarily.
– All cells require ATP to function.
27. Chemistry allows life to function!
Everything living things do is possible due
to chemical reactions
The chemistry of
breathing
28. Activation energy is the amount of energy
that needs to be put in to start a chemical
reaction.
31. – Proteins that increases the speed of a
chemical reactions in cells
– Act as a catalyst (reduces the activation energy
needed in a reaction)
32. Any factor that changes the shape of an
enzyme can affect the enzyme’s activity.
– An enzyme’s function depends on its structure.
– Denaturing (changing the structure) the protein by
changes in temperature or pH
– Example: pepsin