Advanced Cell Biology. Lecture 7
Alexey Shipunov
Minot State University
January 25, 2013
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January 25, 2013
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Outline
Questions and answers
Nucleic acids
Structure
Other nucleic acids
Macromolecules in cells
Cells and energy
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January 25, 2013
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Outline
Questions and answers
Nucleic acids
Structure
Other nucleic acids
Macromolecules in cells
Cells and energy
Shipunov (MSU)
Advanced Cell Biology. Lecture 7
January 25, 2013
2 / 43
Outline
Questions and answers
Nucleic acids
Structure
Other nucleic acids
Macromolecules in cells
Cells and energy
Shipunov (MSU)
Advanced Cell Biology. Lecture 7
January 25, 2013
2 / 43
Outline
Questions and answers
Nucleic acids
Structure
Other nucleic acids
Macromolecules in cells
Cells and energy
Shipunov (MSU)
Advanced Cell Biology. Lecture 7
January 25, 2013
2 / 43
Questions and answers
Previous final question: the answer
Write a sequence complementary to ATTGGAAGC
Is it from DNA or RNA?
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Questions and answers
Previous final question: the answer
Write a sequence complementary to ATTGGAAGC
Is it from DNA or RNA?
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TAACCTTCG
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DNA
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Questions and answers
Disulfide bonds movie
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Nucleic acids
Structure
Nucleic acids
Structure
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Nucleic acids
Structure
Hydrogen bonds in complementary strands
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Nucleic acids
Structure
Double helix
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DNA form helical structure where phosphate and sugar form
“envelope” and bases form a “core”
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Two grooves: major and minor
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Nucleic acids
Structure
DNA double helix
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Nucleic acids
Structure
DNA double helix from top
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Nucleic acids
Structure
Sequences, ends, abbreviations
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Since nucleotides are complementary, it is usually only one strand
listed
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Each strand has 3’ (–OH) and 5’ ends (phosphate)
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Nucleic acids
Structure
3’ and 5’ ends
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Nucleic acids
Structure
Abbreviations for nucleic acids components
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Nucleic acids
Structure
Abbreviations for nucleotide sequences
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Nucleic acids
Structure
Nucleotides and UV light
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Nucleic acids
Other nucleic acids
Nucleic acids
Other nucleic acids
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Nucleic acids
Other nucleic acids
ATP
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ATP (adenosine-triphosphate) is coenzyme (ferment helper),
derivative of ribose, adenine and three phosphoric acids
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Contain two highly energetic bonds
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Nucleic acids
Other nucleic acids
ATP
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Nucleic acids
Other nucleic acids
ATP movie
ATP movie
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Nucleic acids
Other nucleic acids
NADP
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NADP, nicotinamide adenine dinucleotide phosphate is a
coenzyme, derivative of adenine
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Typically, used as hydrogen carrier
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Has a medical name “vitamin B3 ”
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Nucleic acids
Other nucleic acids
NADPH
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Nucleic acids
Other nucleic acids
Other nucleotide coenzymes
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FAD, flavin adenine dinucleotide, vitamin B2
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CoA, coenzyme A, vitamin B5
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Both are extremely important for cell respiration
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Nucleic acids
Other nucleic acids
FAD
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Nucleic acids
Other nucleic acids
CoA
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Macromolecules in cells
Most frequent macromolecules
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Polymer molecules generate most of cell dry weight (30% of total
weight)
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Proteins are 15%, nucleic acids 7%, lipids and polysaccharides
2% each
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Macromolecules in cells
Noncovalent bonds, conformations and binding
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Non-covalent bonds are responsible from shaping of
macromolecules
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Almost every macromolecule has different shaping
variants—conformations
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Intermolecular binding is also due to noncovalent bonds
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Macromolecules in cells
Types of noncovalent bonds
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Hydrophobic forces
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Van der Waals attractions: due to fluctuation of electric charges
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Electrostatic, including hydrogen
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Macromolecules in cells
Binding with noncovalent (electrostatic) bonds
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Cells and energy
Metabolism
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Metabolism is the sum of all chemical reactions in living organism
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Catabolism is the part of metabolism responsible for degrading
complex molecules
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Anabolism is the opposite part
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Cells and energy
Metabolism
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Cells and energy
Second law of thermodynamics
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Thermodynamic definition (Rudolf Clausius): No process is
possible whose sole result is the transfer of heat from a body of
lower temperature to a body of higher temperature.
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Simplistic definition: In isolated system, disorder is always
increasing
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To revert initial order, energy should be spent
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Generally speaking, entropy is a measure of disorder
(better—measure of randomness)
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In strict sense, entropy is dS = δQ
T , where Q is amount of heat and
T —absolute temperature (constant)
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Cells and energy
Entropy
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Cells and energy
Triumph of entropy: “post-apocalyptic world”
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Cells and energy
Entropy explained: energy tube
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Cells and energy
Different forms of energy
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Mechanical energy: potential and kinetic
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Heat energy
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Electromagnetic energy
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All forms are inconvertible; and first law of thermodynamics
says that energy never disappears, it only changes its form
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Cells and energy
Photosynthesis
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The way of transforming light energy to energy of chemical bonds
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The schematic description is:
light energy + CO2 + H2 O → sugars + O2 + heat energy
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Part of anabolism
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Cells and energy
Cellular respiration
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Almost opposite process
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Schematic description:
sugars + O2 → CO2 + H2 O + chemical energy (ATP)
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Part of catabolism
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Cells and energy
Oxidation and electron transfer
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Cellular respiration is based on oxidation, taking electrons off
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Converse reaction is reduction; together they are redox reactions
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For organic molecules, typical oxidation sequence is:
carbohydrates → alcohols → aldehydes → organic acids → CO2
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Cells and energy
Enzymes and energy of activation
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Most of processes need the energy of activation
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Enzymes could lower activation barriers
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Cells and energy
Energy of activation
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Cells and energy
Catalysis movie
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Cells and energy
Final question (3 points)
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Cells and energy
Final question (3 points)
How are living organisms working against the second law of
thermodynamics?
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Cells and energy
Summary
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The second law of thermodynamics is about increasing entropy
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All metabolic reactions need energy
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Cells and energy
For Further Reading
A. Shipunov.
Advanced Cell Biology [Electronic resource].
2011—onwards.
Mode of access:
http://ashipunov.info/shipunov/school/biol_250
B. Alberts et al.
Essential Cell Biology. 3rd edition.
Garland Science, 2009.
Chapter 2, Chapter 3: 58–100.
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