Unit 2: The Cell
and Cellular
Energetics
Powerpoint for Campbell’s Biology, 9th
edition
AP Biology ~ Alamance Christian
School ~ 2011/2012
Emily Diamond
Major Topics
§  Chapters 6-10, 12 in Campbell, Biology
§  Chapter 6: A Tour of the Cell
§  Compare Prokaryotic and Eukaryotic
§  Organelles: their structure and function
§  The cytoskeleton and the ECM
§  Chapter 7: Membrane Structure and Function
§  Composition and Function
§  Transport across the membrane
Chapter 6: A Tour of the Cell
§  http://www.youtube.com/watch?v=Mszlckmc4Hw
§  Microscopes and the tools of biochemistry
§  Many types of microscopes
§  Cell fractionation
Chapter 6: A Tour of the Cell
§  The Prokaryotic Cell
§  No membrane bound compartments
§  The nucleoid
§  The Crucial Surface Area to Volume Ratio
§  The Eukaryotic Cell
§  The plasma membrane – to be discussed in
detail next chapter
§  Largely review from 10th grade
Chapter 6: A Tour of the Cell
§  The Eukaryotic Cell and it’s Organelles
§  The nucleus: chromatin storage
§  the nucleolus
Chapter 6: A Tour of the Cell
§  The Eukaryotic Cell and its Organelles
§  Ribosomes: protein synthesis
§  Free vs. bound
§  Discussed in detail later
Chapter 6: A Tour of the Cell
§  The Eukaryotic Cell and its
Organelles
§  Endoplasmic Reticulum
§  Part of the endomembrane
system
§  Continuous with the nuclear
envelope
§  Composed of
the cisternae
and the ER lumen
Chapter 6: A Tour of the Cell
§  The Eukaryotic Cell and its Organelles
§  Endoplasmic Reticulum
§  Smooth vs. Rough
§  Golgi Apparatus
§  Composed of flattened membranous sacs that
contains the lumen
§  Cis and trans face
§  Major function:
protein modification
Chapter 6: A Tour of the Cell
§  The Eukaryotic Cell and its Organelles
§  Lysosomes: digestion
Chapter 6: A Tour of the Cell
§  The Eukaryotic Cell and its Organelles
§  Vacuoles: maintenance
§  Food vacuoles are formed by phagocytosis
§  Contractile vacuoles pump excess water out
§  Central vacuoles are necessary for plant life
Chapter 6: A Tour of the Cell
§  The Eukaryotic Cell and its Organelles
§  Mitochondria: chemical energy conversion
§  HW: read about the endosymbiont hypothesis
and write an essay explaining what it is and
poking any holes you may see in the
hypothesis
§  Contain some of their own DNA and ribosomes
Chapter 6: A Tour of the Cell
§  The Eukaryotic Cell and its Organelles
§  Mitochondria: chemical energy conversion
Chapter 6: A Tour of the Cell
§  The Eukaryotic Cell and its Organelles
§  Choloroplast: Light energy capture
§  Thylakoids
§  Granum: a stack of thylakoids
§  Stroma: contains DNA and ribosomes
Chapter 6: A Tour of the Cell
§  The Eukaryotic Cell and its Organelles
§  Peroxisomes: oxidation
§  Break down fatty acids and detoxify alcohol
§  The Cytoskeleton
§  Major roles: support and motility
§  Major constituents: microtubules, intermediate
filaments, and microfilaments
Chapter 6: A Tour of the Cell
§  The Cytoskeleton
§  Microtubules
§  Constructed from tubulin
§  Major role in mitosis (separation of
chromosomes)
§  Interesting microtubules:
flagella and cilia
§  Intermediate Filaments
§  Specialized for bearing tension
§  More permanent than microtubules
§  Special function: nuclear lamina, supporting
axons
Chapter 6: A Tour of the Cell
§  The Cytoskeleton
§  Microfilaments (actin filaments)
§  Structural role: bear tension
§  Motile role: contractile apparatus
of muscle cells
§  Works with myosin to
accomplish this
§  http://highered.mcgrawhill.com/sites/0072495855/
student_view0/chapter10/
animation__myofilament_contra
ction.html
§  Also responsible for cytoplasmic
streaming
Chapter 6: A Tour of the Cell
§  The Extracellular Matrix –
read about on your own
§  Cell Junctions
§  Tight Junctions: seal
§  Desmosomes: anchor
§  Gap Junctions: connect
§  Plasmodesmata
Chapter 7: Membrane Structure
and Function
§  A Historical Perspective
§  1935 – The Sandwich Model – phospholipid
bilayer between two layers of proteins
§  1972 – The Fluid Mosaic Model
§  Demonstrated through freeze-fracture
Chapter 7: Membrane Structure
and Function
§  Membranes are fluid (consistency of salad oil)
§  Held together primarily by hydrophobic
interactions
§  Phospholipids can move and have kinks in their
tails
§  Proteins can drift, move under direction
§  Cholesterol serves as fluidity buffer
§  Affects permeability, enzymatic proteins
Chapter 7: Membrane Structure
and Function
§  Membrane Proteins and
their Functions
§  Integral proteins
§  The majority are
transmembrane
proteins
§  Can contain
hydrophilic channels
§  Peripheral proteins
§  Loosely bound to the
surface of the
membrane – often to
integral proteins
§  Figure 7.10
Chapter 7: Membrane Structure
and Function
§  Selective Permeability
§  Due to the chemical composition of
the
membrane
§  Due to transport proteins within the membrane
§  Where do these proteins come from?
§  Significantly increase the rate of transport
§  Passive vs. Active Transport
Chapter 7: Membrane Structure
and Function
§  Passive Transport
§  Diffusion: movement down a concentration
gradient
Chapter 7: Membrane Structure
and Function
§  Passive Transport
§  Special case: osmosis – the movement of
free
water molecules across a selectively permeable
membrane
§  The affects of
osmosis on cells without walls:
the concept of tonicity
Chapter 7: Membrane Structure
and Function
§  Affects of osmosis on cells with walls
§  Turgor pressure
§  Turgid
§  flaccid
§  plasmolysis
Chapter 7: Membrane Structure
and Function
§  Passive Transport can utilize proteins – facilitated
diffusion
§  Channel or carrier proteins
§  Example: aquaporin
Chapter 7: Membrane Structure
and Function
§  Active Transport
Chapter 7: Membrane Structure
and Function
§  Ion pumps create a membrane potential
§  Electrogenic pumps generate voltages across a
membrane
§  Concentration of
solutes and the membrane
potential combine to form the electrochemical
gradient
§  Cotransport involves coupling a substance that has
been actively transported across the membrane to
a different pump to aid in the movement of
another substance
Chapter 7: Membrane Structure
and Function
Chapter 7: Membrane Structure
and Function
Chapter 8: Intro to Metabolism
§  Metabolism: the totality of
reactions
§  Metabolic pathways
§  Catabolic
§  anabolic
an organism’s chemical
Chapter 8: Intro to Metabolism
§  Forms of energy
§  Kinetic and Potential
§  Thermal and chemical
§  Laws of
Energy
Transformation
§  First
§  Second
Chapter 8: Intro to Metabolism
§  Free Energy Change
§  Defined in 1878 by J. Willard Gibbs
§  Defined as: the portion of a system’s energy
that can perform work when temperature and
pressure are uniform throughout the system, as
in a living cell
§  Change in free energy
§  ΔG = ΔH – TΔS
§  Stability
Chapter 8: Intro to Metabolism
§  Free Energy Applied to Metabolism
§  Reactions can be exergonic or endergonic
§  Example of cellular respiration
§  C6H12O6 + 6 O2 à 6 CO2 + 6H2O
ΔG = -686 kcal/mol (-2879 kJ/mol)
Chapter 8: Intro to Metabolism
Chapter 8: Intro to Metabolism
§  Adenosine Triphosphate can be regenerated
Chapter 8: Intro to Metabolism
§  Enzyme Characteristics
§  Typicallly end in -ase
§  Substrate specific
§  Work at the active site
§  Undergo induced fit when
interacting with the
substrate
Chapter 8: Intro to Metabolism
§  Enzymes lower activation energy
Chapter 8: Intro to Metabolism
Chapter 8: Intro to Metabolism
Chapter 8: Intro to Metabolism
§  Enzymes are not invincible
§  Effected by pH and temperature
§  Enzymes do not always stand alone
§  Cofactors
§  Inhibitors
§  Competitive vs. noncompetitive
§  Allosteric regulation
§  Can be activating or inhibiting
§  Cooperativity
Chapter 8: Intro to Metabolism
Chapter 9: Cellular Respiration
and Fermentation
§  Cellular Respiration Overview
§  Glucose à glycolysis à CAC à ETC à ATP
§  Cellular Respiration Energy Overview
§  Glucose à NADH à ETC à proton-motive force
à ATP
Chapter 9: Cellular Respiration
and Fermentation
§  Concept 9.1:
Catabolic pathways yield energy by
oxidizing organic fuels
§  Organic compounds + oxygen à carbon dioxide
+ water + energy
§  C6H12O6 + 6 O2 à 6 CO2 + 6H2O
ΔG = -686 kcal/mol (-2879 kJ/mol)
§  Catabolism is linked to work by a chemical drive
shaft -- ATP
Chapter 9: Cellular Respiration
and Fermentation
§  Catabolic reactions yield energy through REDOX
reactions
§  Hydrogens move from glucose to oxygen
§  Shuttled by NAD
§  Done by dehydrogenase
Chapter 9: Cellular Respiration
and Fermentation
Chapter 9: Cellular Respiration
and Fermentation
§  NADH shuttles the electrons to the ETC
§  Stair step harvest of energy
§  NADH à O2 = free energy change of -53kcal/mol
Chapter 9: Cellular Respiration
and Fermentation
§  Concept 9.2:
Glycolysis harvests chemical energy
by oxidizing glucose to pyruvate
§  The big idea: Glucose à pyruvate
§  Characteristics
§  Invests energy
§  Gains energy
§  Ten steps
§  Occurs with or without oxygen
Chapter 9: Cellular Respiration
and Fermentation
Chapter 9: Cellular Respiration
and Fermentation
§  Concept 9.3:
the Citric Acid Cycle completes the
oxidation of glucose begun in glycolysis
§  Aka Tricarboxylic Acid Cycle or the Krebs Cycle
§  This cycle alone generates one ATP per turn
Chapter 9: Cellular Respiration
and Fermentation
§  Step One:
Pyruvate à Acetyl CoA
Chapter 9: Cellular Respiration
and Fermentation
Chapter 9: Cellular Respiration
and Fermentation
§  The Electron Transport Chain
§  a stepwise fall from high energy to low
NADH
50
Free energy (G) relative to O2 (kcl/mol)
FADH2
ure 9.13
40
FMN
I
Fe•S
Fe•S II
O
§  prosthetic groups
III
Cyt b
30
energy
§  composed of proteins
Multiprotein
complexes
FAD
Fe•S
Cyt c1
IV
Cyt c
Cyt a
Cyt a3
20
10
0
2 H + + 1⁄2
O2
H2O
§  Requires electron carriers
§  Ubiquinone
§  Cytochromes
§  Terminal electron acceptor:
Oxygen
Chapter 9: Cellular Respiration
and Fermentation
§  Chemiosmosis
§  Powered with a hydrogen ion gradient
Chapter 9: Cellular Respiration
and Fermentation
§  Some accounting
§  Glucose à NADH à ETC à proton motive
force à ATP
Chapter 9: Cellular Respiration
and Fermentation
§  Concept 9.5:
respiration.
Fermentation and Anaerobix
§  Read on your own
§  Concept 9.6
§  Cellular Respiration is not an isolated process
§  It can be regulated
Chapter 9: Cellular Respiration
and Fermentation
§  Concept 9.4:
Chemiosmosis couples electron
transport to ATP synthesis during oxidative
phosphorylation
§  Occurs in the inner mitochondrial membrane
Chapter 10: Photosynthesis
§  Outline of the Chapter
§  General Principles of Photosynthesis (10.1)
§  The Light Reactions of Photosynthesis
§  The Calvin Cycle
Chapter 10: Photosynthesis
§  General Principles of Photosynthesis
§  Occurs in the chloroplasts
§  Double membrane organelle
§  Stroma
§  Thylakoids
§  Thylakoid space
§  Grana
§  Chlorophyll: found in the membrane of
thylakoid
the
Chapter 10: Photosynthesis
Chapter 10: Photosynthesis
§  General Principles of Photosynthesis
§  It shuffles atoms
§  Overall equation
§  6 CO2 + 12 H2O + light energy à C6H1206 +
6 O2 + 6 H20
§  Oxygen is given off
dioxide
from water, not carbon
§  Historically was thought to be opposite
§  Challenged by Van Niel
Chapter 10: Photosynthesis
§  The logic of
Van Niel
§  Proved later through radioactive isotope labeling –
used Carbon-18
Chapter 10: Photosynthesis
§  General Principles
§  It is the reverse of cellular respiration
§  Reverses direction of electron flow
§  Endergonic
§  Occurs as a two step process
§  The light reactions - thylakoid
§  The Calvin Cycle – stroma
Chapter 10: Photosynthesis
Chapter 10: Photosynthesis
§  The Light Reactions
§  Some things to understand
§  Chlorophyll
§  Photosystems
§  The flow of electrons
§  Linear and cyclic
Chapter 10: Photosynthesis
§  Chlorophyll
§  Absorbs photons of light
§  A and b
§  Accessory pigments: cartenoids:
photoprotection
provide
Chapter 10: Photosynthesis
§  Photosystems
§  Composed of
a reaction center complex
surrounded by several light-harvesting
complexes
§  light harvesting complexes contain
pigment molecules to absorb light
§  Reaction center contains a primary
electron acceptor
§  Two types of photosystems involved in
photosynthesis
§  Produce energy through linear
electron flow
Chapter 10: Photosynthesis
§  Linear Electron Flow
Chapter 10: Photosynthesis
§  Cyclic Electron Flow
§  Special cases
§  Does not produce NADPH or release oxygen
§  Does produce ATP
Chapter 10: Photosynthesis
§  Chemiosmosis: Chloroplasts vs Mitochondria
§  Many Similarities.
§  Differences
§  Electrons in photosynthesis are from water
§  Thylakoid membrane pumps protons from the
stroma into the thylakoid space
§  ATP forms as protons diffuse from the
thylakoid space into the stroma
Chapter 10: Photosynthesis
§  Summary of the Light Reactions
§  Electrons pushed from water (low potential) to
NADPH (high potential)
§  Light driven electron current generates ATP
Chapter 10: Photosynthesis
§  The Calvin Cycle
§  Carbon Dioxide à Sugar
§  Spends ATP and consumes NADPH
§  Three Phases
§  Carbon fixation
§  Reduction
§  Regeneration of RuBP
Chapter 10: Photosynthesis
§  Carbon fixation
§  One carbon dioxide at a time
§  Catalyzed by rubisco
§  Produces 6 carbon intermediate: immediately
splits in half
§  Reduction
§  Production of G3P (the sugar)
§  For every three molecules of carbon dioxide, six
molecules of G3P are formed
Chapter 10: Photosynthesis
§  Calvin Cycle Summary
§  Consumes 9 molecules of ATP
§  Consumes 6 molecules of NADPH
§  G3P is the starting point for many metabolic
synthesizing pathways
§  Read 10.4.
thought J
Not talking about in class. Important
§  Photosynthesis summary:
makes the sugar
necessary for cell to survive. (see summary at end
of chapter)
§  Chapter 11: Covered in project
Chapter 12: The Cell Cycle
Figure 12.3 Chromosome duplication and distribution during mitosis
Chapter 12: The Cell Cycle
§  Key Terms
§  Genome
§  Chromosome
§  Chromatin
§  Somatic
§  Gamete
§  Sister Chromatid
§  Centromere
§  arm
Chapter 12: The Cell Cycle
§  Phases
§  Interphase and M
Phase
§  Phases of
Interphase
§  G1, S, and G2
§  Phases of M Phase
§  Pro-, ProMeta-
Meta-, Ana-, Telo-
Chapter 12: The Cell Cycle
Chapter 12: The Cell Cycle
Chapter 12: The Cell Cycle
Chapter 12: The Cell Cycle
§  The Cell Cycle Control
System
§  Overview
§  The Molecules of
the
System
§  Internal and External
Checkpoints
§  The Molecules of the System
§  Protein Kinases and Cyclins
§  Cyclin-dependent kinases (Cdks)
§  Activity rises and falls based
on conc of cyclin partner
Chapter 12: The Cell Cycle
§  The Internal and External Signals
§  Internal:
§  Kinetochore attachments
§  Density-dependent inhibition
§  Anchorage dependence
§  External
§  Growth factors
Chapter 12: The Cell Cycle
§  Cell Cycle Control System: Cancer
§  What’s different about cancer cells?
§  If they stop dividing, they do so at random
times (not at normal check points)
§  Often divide indefinitely
§  HeLa cells
§  Can evade apoptosis triggers
§  How do cancer cells arise?
§  Transformation
§  Proliferation = tumor
§  Metastasis
§  Treatment: Radiation and Chemotherapy
Chapter 12: The Cell Cycle
Chapter 12: The Cell Cycle
Chapter 12: The Cell Cycle