biochem in cell Flashcards
“everything that living
things do can be
understood in terms of
the jigglings and
wigglings of atoms”
Richard Feynman
- Sperm fertilizing an
egg.
“Living things are composed of lifeless molecules”
Albert Lehninger
“Chemistry is the logic of biological phenomena”
Garrett and Grisham
complicated and highly organized
Living Organisms
serve functional purposes
Biological structures
actively engaged in energy
transformations
Living systems
have a remarkable capacity for self-
replication
Living systems
flows from photosynthetic organisms through
food chains to herbivores and on to carnivores at the apex of
the food pyramid
Solar energy
1st primary Producers
photosynthesis
1st primary Consumers
herbivores
2nd primary Consumers
Carnivores
Organisms capture energy in the form of special
energized molecules
ATP, NADPH
ATP structure draw
drawing
NADPH structure draw
drawing
Two complementary
polynucleotide chains running in opposite directions can pair
through hydrogen bonding between their nitrogenous bases.
Their complementary nucleotide sequences give rise to
structural complementarity.
DNA double helix
DNA double helix
5’ top
3’ bottom
Covalent bond
formation by e- pair sharing
makes _____ appropriate
for the support of life
H, O, C and N
make up 99+% of atoms in the human body
H, O, C and N
63% atoms in the human body
Hydrogen
25.5% atoms in the human body
Oxygen
9.5% atoms in the human body
Carbon
1.4% atoms in the human body
Nitrogen
What property unites H, O, C and N and renders
these atoms so appropriate to the chemistry of life?
ability to form covalent bonds by
electron-pair sharing
H-H bond
436 kJ/mol
C-H bond
414 kJ/mol
C-C bond
343 kJ/mol
C-O bond
351 kJ/mol
formation by e-
pair sharing
Covalent bond
the Units for
Building Complex Structures
Simple Molecules
example of linear aliphatic
stearic acid
example of cyclic
cholesterol
example of branched
B-carotene
example of planar
chlorophyll a
inorganic precursors: (16-64 daltons)
carbon dioxide
metabolites: (50-520 daltons)
pyruvate
building blocks: (100-350 daltons)
alanine (amino acid)
macromolecules: (10^3 - 10^9 daltons)
protein
have a
“sense” or directionality
Macromolecules and their building blocks
informational
Macromolecules
have characteristic three-dimensional
architecture
Biomolecules
maintain biological structure and
determine biomolecular interactions
weak forces
build proteins
Amino acids
are built by joining sugars
together
Polysaccharides
polymers of nucleotides
Nucleic acids
hold atoms together so that
molecules are formed
Covalent bonds
profoundly influence the structures
and behaviors of all biological molecules
Weak forces
create interactions that are constantly
forming and breaking under physiological
conditions
Weak forces
Energies of weak forces range from
0.4 to 30 kJ/mol
weak forces include
- van der Waals interactions
- Hydrogen bonds
- ionic interactions
Van der Waals Interactions
0.4-4.0 kJ/mol
Hydrogen Bonds
12-30 kJ/mol
Ionic Interactions
20 kJ/mol
Hydrophobic Interactions
<40 kJ/mol
mediated by weak
chemical forces
Biomolecular recognition
restrict organisms to a narrow range of
environmental conditions
weak forces
contribute to
the stability of
proteins
Ionic bonds
the principle that guides the
biomolecular interactions that characterize the
living state.
Molecular Recognition Through Structural
Complementarity
- A single (plasma) membrane
- No nucleus or organelles
Prokaryotic cells
- Much larger in size than prokaryotes
- 103-104 times larger!
- Nucleus plus many organelles
- ER, Golgi, mitochondria, etc.
Eukaryotic cells
a member of the
coliform group of bacteria that colonize the intestinal tract of
humans.
Escherichia coli or Ecoli
genetic elements enclosed in a protein
coat.
viruses
not free-living organisms and can reproduce
only within cells.
viruses
how an almost absolute specificity
for their particular host cells, infecting and multiplying only
within those cells.
viruses
known for virtually every kind of cell.
viruses
mobile bits of
genetic information encapsulated in a protein coat.
viruses
