Download Chapter 3 Chemistry of Life Modern Biology Textbook Holt

Ms. Mezzetti
Lynn English High School
Science Department
Warm up:
Define biochemistry
What does “Chemistry
of Life” mean?
Objectives:
Students will be able to:
Distinguish between organic and inorganic compounds.
Explain the importance of carbon bonding in biological
molecules.
Summarize how large carbon molecules are synthesized and
broken down.
Describe how the breaking down of ATP supplies energy to drive
chemical reactions.
Carbon
Organic compounds contain carbon atoms and
are found in living things.
Therefore, all living organisms contain carbon
Most inorganic compounds do not contain
carbon atoms.
Carbon Bonding
Carbon atoms can form:
•four covalent bonds
•single, double and triple
bonds
•ring, branched or
straight chains
Carbon Compounds
Monomers: subunit of larger molecules
Polymer: 3 or more monomers
Monomers/Polymers
Monomer:
Polymer:
Monomer:
Polymer:
Condensation Reactions/Hydrolysis
Condensation Reactions
remove water and
combine monomers to
make polymers
Hydrolysis break down
polymers into smaller
macromolecules and
monomer
Energy for life
• Adenosine triphosphate (ATP) stores and releases energy
during cell processes, enabling organisms to function.
• ATP is the fuel/energy for life!
Organic Molecules
Objectives:
Students will be able to:
Identify the 6 most abundant elements of life are
C-H-N-O-P-S
Distinguish 3 types of carbohydrates-monosaccharide's,
disaccharides and polysaccharides.
Explain how enzymes are a type of protein and catalyze
chemical reactions.
Identify the monomers and polymers of carbohydrates,
proteins, lipids and nucleic acids.
Compare the nucleic acids DNA and RNA.
6 Most abundant elements in nature
Carbon
Hydrogen
Nitrogen
Oxygen
Phosphorus
Sulfur
We classify the major organic compounds into 4
groups:
Carbohydrates
Proteins
Lipids
Nucleic acids
Carbohydrates: Sugars and Starches
composed of carbon,
hydrogen, and oxygen in a
1:2:1 ratio- CH2O
Used as short term energy
End in ‘ose
Animals store energy as
glycogen
Plants store energy as starch
Plant cells made of cellulose
Fungi cell walls contain chitin
Carbohydrates
• Monosaccharide's
• The monomers of carbohydrates are called
monosaccharide's, simple sugars such as glucose,
fructose and galactose
• Disaccharides
• Two monosaccharide's join to form a double sugar
called a disaccharide such as sucrose (glucose +
fructose) and lactose
• Polysaccharides
• Three or more monosaccharide's join to form large
macromolecules such as starches, cellulose, chitin
& glycogen. These are complex carbohydrates
Proteins
• Proteins are organic compounds
composed mainly of carbon,
hydrogen, oxygen, and nitrogen.
C-H-O-N
• Proteins have many functions: -structural-such as muscle fiber
collagen & keratin, defensiveantibodies, and catalytic rolesenzymes.
• Found in
Proteins
• Amino Acids: Proteins are made up of
monomers
called amino acids.
• There are 20 different types identified by
their R group.
• Dipeptides:
Two amino acids are
joined by peptide bonds to form a
dipeptide.
• Polypeptides:
A long chain of
amino acids is called a polypeptide.
Usually 1000’s of amino acids joined
together by peptide bonds.
Amino Acids
• There are 20
different amino
acids. Each is
different depending
on it’s R group.
Structure of Proteins
4 Structures of proteins:
• Primary-single chain
of amino acids
• Secondary- chains
become folded or
helical
• Tertiary-chains bend
• Quaternary-globular
Proteins
• Enzymes:
– are globular proteins that speed
up chemical reactions and reduce
the amount of activation energy
needed for the reaction.
– There are 2200 different types of
enzymes that catalyze 2200
specific types of reactions
– End in ‘ase: catalase, amylase,
lipase are examples
– Enzymes are affected by pH,
temperature and salinity
Enzyme Activity
Lipids
• Fatty Acids-building blocks of
lipids (monomers)
– they have a hydrophilic
(water loving) end and a
hydrophobic (water
fearing) end.
• Triglycerides
– Triglycerides consist of
three fatty acids and one
molecule of glycerol.
Lipids
Lipids are:
•nonpolar molecules that
store long term energy
•are an important part of cell
membranes.
Fats are a type of lipid:
Carbons are full
•saturated (animal
Single bonded
fat/solids/lard)
•unsaturated (fats from
Carbons not full
plants-oils/liquid)
Double bonded
Lipids
• Phospholipids: make up cell
membranes; have a polar head and
nonpolar tail
• Waxes: A wax is made of one long fatty
acid chain joined to one long alcohol.
Protect animal ears and plant leaves.
• Steroids: A steroid is a lipid composed
of four fused carbon rings that help
regulate body functions-testerone and
estrogen Cholesterol is a steroid found
in cell membranes that contributes to
its permeability (letting things in and
out)
Nucleic Acids
• A nucleic acid is a large and
complex organic molecule
that stores and transports
information.
• The monomers
,
building blocks of nucleic
acids are nucleotides.
• Nucleotides contain a 5carbon sugar, nitrogenous
base and a phosphate
group
Nucleotide
Nucleic Acids - DNA
• DNA- deoxyribonucleic acid
(DNA)
• Stores genetic information
for cell activities.
• Is double stranded (helix)
• Has nitrogenous bases
• adenine,
• thymine,
• guanine
• cytoseine
•RNA- ribonucleic acid
•Important for protein
synthesis.
•Is single stranded
•It’s nitrogenous bases
•adenine,
•uracil
•guanine
•cytoseine
Multiple Choice
1. Which of the following is not a function of
polysaccharides?
A. energy source
B. energy storage
C. structural support
D. storage of genetic information
Multiple Choice, continued
2. Which of the following statements is false?
F. A wax is a lipid.
G. Starch is a lipid.
H. Saturated fats are solid at room temperature.
J. Unsaturated fats are liquid at room
temperature.
Multiple Choice, continued
3. Which of the following molecules stores
hereditary information?
A. ATP
B. DNA
C. protein
D. carbohydrates
Multiple Choice, continued
4. What is the name of the molecule in plants that
stores sugars?
A. starch
B. protein
C. cellulose
D. glycogen
Multiple Choice, continued
The figure below illustrates
the basic structure of a cell
membrane. Use the
figure to answer the questions
that follow.
5. Which of the following
molecules make up the basic
structure of a cell
membrane?
A. waxes
B. steroids
C. fatty acids
D. phospholipids
Multiple Choice, continued
The figure below illustrates
the basic structure of a cell
membrane. Use the
figure to answer the questions
that follow.
6. The “tails” of the molecules in
the figure orient away from
water. Which of the following
describes the tail’s movement
away from water?
F. polar
G. adhesive
H. hydrophilic
J. hydrophobic
Multiple Choice, continued
7. simple sugars : carbohydrates :: amino acids :
A. lipids
B. proteins
C. nucleic acids
D. amino acids
Short Response, continued
Proteins are affected by environmental conditions such as
heat and pH.
Explain why the process of cooking an egg cannot be
reversed.
Answer:
The heat that is added to the egg changes the bonds in
the proteins and other molecules that make up the egg to
such a large extent that the original protein shape can no
longer be distinguished.
Open Response
Enzymes are essential for the functioning of all cells.
Part A Explain what enzymes do that is essential for cell
function.
Part B Explain the induced fit model of enzyme
action.
Answer:
Part A Enzymes catalyze chemical reactions that are involved
in important cell processes.
Part B Bonding of the substrates to enzymes causes a slight
change in the enzyme’s shape, thereby weakening some of
the bonds and lowering activation energy.