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Biochemistry to Cells
Chapters 2 and 3
• Anatomy
Anatomy is Structure,
Physiology is function
– Study of internal and
external structure
– i.e. structure of heart
and blood flow
• Physiology
– Study of how organisms
perform specific
functions
– i.e. how does the heart
pump blood
Levels of Organization in the Body.
Inorganic versus Organic Compounds
Inorganic
• Small molecules that
generally do not contain
carbon and hydrogen
atoms.
Organic
• Molecules composed of
carbon and hydrogen
molecules
• Larger and more complex
than inorganic molecules
Carbohydrates
Sugars and Starches
• Contain carbon, hydrogen
and oxygen in a 1:2:1 ratio
• Main source of energy for
body
• Monosaccharides
– Glucose, fructose, galactose
• Disaccharides
– Lactose, maltose, sucrose
• Polysaccharides
– Glycogen, starch, cellulose
Monosaccharides – building
blocks for all sugars
From Monomers to Polymers
Dehydration Synthesis
Hydrolysis
• Remove water to build large
molecules from smaller
ones
• i.e. making proteins from
amino acids
• Split water to break down
large molecules into small
• i.e. digestive tract
Lipids
Fats, oils and waxes
• Contain large amounts of
carbon and hydrogen in a
1:2 ratio, but very little
oxygen.
• Insoluble in water
(hydophobic), makes a great
barrier.
• Energy reserves, insulates
and cushions organs
• Composed of fatty acid
chains and glycerol
Saturated
•No double bonds, all carbon
atoms are saturated with
hydrogen
•Animal fats, are solid at
room temperature
•Large amounts in your diet
increases the risk of heart
disease
Unsaturated
•Contain at least one double
bond
• Most Plant oils, liquid at
room temperature
Triglycerides are the most
common fats in body.
Phospholipids
How is structure related to function?
•Consists of a glycerol and
two fatty acid chains linked
to a phosphate group (PO4)
•The phosphate group is
attracted to water
(hydrophilic), Why?
•The fatty acid chains are
hydrophobic.
•Make up all cell
membranes
Cell membrane composed of
phospholipids and proteins.
Function?
Structure?
Proteins
Most abundant organic
compounds in the body
• Composed of amino acids,
20 different amino acids
• Structure of an amino acid
–
–
–
–
Amino group
H
Carboxyl group
R (remaining), varies from
one amino acid to another
• Peptide bond joins two
amino acids together
Proteins
• The structure of the
R group makes the
amino acids
different from each
other.
• The R groups
between the
different amino
acids help create the
proteins shape.
• Folds and bonds
form creating
distinct protein
shapes
Shape Determines Function
Structure of a protein is determined by sequence of amino acids
• Proteins are made at the _________ and sent to the
____________ to be packaged into their specific shape.
• Small differences can have large effects… mutations
Formation of Proteins
Protein Function
• Support: provide structure to cells and organs
• Movement: contractile proteins in muscles
• Transport: carrier protein found in cell
membranes
• Metabolic Regulation: Enzymes speed up
chemical reactions
• Coordination and Control: Protein hormones
influence the chemical reactions in cells
• Defense: keratin in the skin, antibodies, clotting
proteins
Enzyme Function
Enzymes are Proteins
• Speed up chemical reactions in
a cell by reducing the activation
energy needed to start the
reaction.
• Enzymes control all life
processes.
• Enzyme shape determines
function.
• Shape of proteins can be
altered by pH, temperature, or
ion composition
Enzyme Function
• Substrate – reactant that enzyme affects
• Active site – region on enzyme that substrate attaches to.
– Lock and Key arrangement
• Each enzyme catalyzes only one type of reaction (specificity)
Nucleic Acids: DNA and RNA
Basic building block
is a nucleotide.
Structural
similarities:
Structural
differences:
Nucleus – Composed of Chromatin
(DNA)
Chromatin
DNA wrapped around 8 histone
proteins, creates a subunit called a
nucleosome.
How tightly packed the DNA is
around the nucleosome and its tails
helps determine gene expression
Two Types of Chromatin
Euchromatin
Heterochromatin
Transcription
Transcription – rewriting of DNA into
RNA; controlled by RNA polymerase
Translation- changing the message of
nucleic acids into an amino acid
chain (protein)
Which nucleic acid carries the code
for the protein?
Translation- occurs in the ribosome
Role of mRNA:
tRNA:
rRNA:
Codons:
Anticodons:
How is gene expression controlled in
Eukaryotic cells?
Heterochromatin
RNAi (RNA interference)
• Epigenetics – study of
changes in gene expression
caused by histone
modification and DNA
methylation other than
changes in the DNA
sequence (mutations)
• Regulates gene expression
w/o changing the DNA
• Changes have been shown
to be heritable.
• Double stranded RNA
molecules that inhibit gene
expression (What?)
• Small interfering RNAs
(siRNA) attach to mRNA
• The mRNA is then cut up by
a number of enzymes
(agronaute and dicer).
• Why does this affect gene
transcription?
• What advantage doe s this
give our cells?
Cells are composed of organic
compounds.
ATP – energy currency for cell
• ATP → ADP + P
• Energy is released
Mitochondria – Powerhouse of cell.
How does form relate to function?
Cell Specialization