Transcript the Unit 2 power point with videos.

Unit 2
Cells
Watching Youtube Videos
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Once you’ve viewed the video you must click
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History
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1660’s
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Microscopes developed
Allowed for the observation of cells for the first time
Robert Hooke examined cork under the microscope
Saw a honeycomb – called them cellulae (latin for small
rooms)
1830’s
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Matthias Schleiden and Theodor Schwann examined plant
and animal tissues under the microscope
From this OBSERVATION, came up with the
HYPOTHESIS that all living organisms are made up of
cells
Cell Properties
1. Import Raw materials
2. Ability to produce energy
3. Synthesize macromolecules (carbohydrates,
proteins, lipids)
4. Organized pattern of growth
5. Respond to stimuli
6. Communication
7. Reproduction
Prokayrotic Cells
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Single celled organisms
Bacteria
No membrane bound
nucleus
Cell wall on outside of
cell membrane
Most primitive of cell
types
Eukaryotic Cells
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Membrane bound organelles
DNA located in membrane bound nucleus
Possess subcellular organelles
Animal Cell
Plant Cell
Web links
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http://www.cellsalive.com/cells/3dcell.htm
Here’s an interactive animation to learn the
parts of cells
http://www.wiley.com/legacy/college/boyer/04
70003790/animations/cell_structure/cell_stru
cture.htm
Plasma Membrane
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All cells are surrounded by
a semi permeable plasma
membrane
Membrane is composed of
a phospholipid bilayer
Hydrophillic on the outside
and hydrophobic on the
inside
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Phosphate group is
hydrophillic
Lipid tails are hydrophobic
Subcellular Organelles
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Nucleus
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Command center
Surrounded by nuclear membrane
Nuclear ores in this membrane allow
for transport between nucleus and
cytoplasm of cell
Chromosomes located here
Nucleolus
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Darker staining region of nucleus
High concentration of RNA
Ribosome RNA subunits synthesized
here
Subunits transported to cytoplasm
via pores
Subunits combined to form
ribosomes in the cytoplasm
Subcellular Organelles
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Ribosomes
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Protein synthesis for cell
Consist of a large and a small
subunit
Located throughout the cell as
free ribosomes or are bound to
the Endoplasmic Reticulum
Endoplasmic Reticulum
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Series of channels and
interconnected tubules within
the cytoplasm
Surface of E.R. is the site for
carbohydrate and lipid
synthesis
Rough Endoplasmic Reticulum
has ribosomes attached for
synthesis of those proteins for
export
Subcellular Organelles
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Golgi Apparatus (body)
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Flattened sacks
Collection, packaging and
distribution of materials throughout
cell
Receive materials from the ER
Modify these contents by adding
carbohydrate groups if warranted
Often located near the nucleus
Cisternae are special folds at the
ends of golgi bodies
Vesicles are formed by pinching off
at the cisternae
Vesicles will go to different areas of
the cell or to the plasma membrane
for extracellular transport
Vesicles can fuse with the plasma
membrane to dump their contents to
the outside of the cell
Subcellular Organelles
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Lysosomes
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Vesicles which contain
enzymes that break down
macromolecules
Fuse with endocytotic vesicles
to break down what the cell
engulfs
Peroxisomes
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Smaller vessicles than
lysosomes
Eukaryotic cell detoxification
organelles
Enzymes are received directly
from free ribosomes
Enzymes here also convert
fats into carbohydrates
Subcellular Organelles
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Mitochondria
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Energy production for the cell
Oxidative metabolism occurs
here
ATP produced here
Double membrane organelle –
has both an outer membrane
and an inner folded membrane
Contains its own DNA
separate from the nucleus
Folded internal membrane
called CRISTAE
Cristae provide additional
surface area for reactions to
take place
Filled with a fluid matrix
Subcellular Organelles
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Centrioles
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Each cell contains a
single pair
These direct the
assembly of microtubules
which provide structural
support for the cell
Involved in cell division
Subcellular Organelles
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Chloroplasts
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Found in plants and algae
Capture energy from the sun
Larger than mitochondira
Inner membrane folded to form
closed vesicles called Thylakoids
Photosynthesis occurs in the
thylakoids
Thylakoids are stacked to form
granna
Fluid stroma fills the chloroplast
Have their own DNA separate from
the nucleus
Subcellular Organelles
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Cell Mobility / Motility
Cilia and Flagella
A single cell will NOT have
both
Organization of microtubules
for locomotion
Cilia are short and numerous
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Create movement by beating
in a coordinated manner
Flagella are long and few in
number
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Create movement by whipping
action
Subcellular Organelles – Plants Only
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Central Vacuole
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Filled with water and other
molecules
Functions as storage and
controls surface to volume
ratio of cell
Can increase the surface
area by filling the central
vacuole with fluid
Cell Wall
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Protection and support of
plant cell
Made of fibers and cellulose
Strong and rigid
Transport Mechanisms Overview
http://www.youtube.com/watch?v=1ZFqOvxXg9M
Click on the image for the animation
Solutes and Solvents
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A solute is dissolved
into a solvent
In a solution there will
be more solvent
molecules than solute
molecules
Example – salt water;
Solute is Salt, Solvent
is Water
Diffusion
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Molecules by random motion will move from an area of
higher concentration to an area of lower concentration
Passive process – requires no expenditure of energy
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Channels in the cell membrane function as gate keepers by their
size
Allow only molecules smaller than the pore size to pass through
Molecules will travel down their concentration gradient ie from
high concentration to lower concentration
http://www.youtube.com/watch?v=H7QsDs8ZRMI&feature=related
Diffusion
http://www.youtube.com/watch?v=H7QsDs8ZRMI&feature=related
Click on the image for the animation
Diffusion
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Facilitated diffusion
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Relies upon a carrier protein to bind to the
molecule to help it cross the membrane
Molecule still traveling down its concentration
gradient
Still NO energy required
http://www.youtube.com/watch?v=s0p1ztrbXPY
Diffusion
Click on the image for the animation
http://www.youtube.com/watch?v=s0p1ztrbXPY
Osmosis
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Specifically the diffusion of water through a
semi-permeable membrane
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Semipermeable Membrane
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Cell wants to keep some things in and keep other
things out
Water will move from an area of high water
concentration to an area of low water
concentration
http://www.youtube.com/watch?v=sdiJtDRJQEc
Osmosis
Click on the image for the animation
http://www.youtube.com/watch?v=sdiJtDRJQEc
Active Transport
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Requires the expenditure of energy
Often transporting molecules against their concentration
gradient
Channels are opened or closed in response to cellular
signals
Example – Na / K pump
Cell pumps Na out of the cell while pumping K into the
cell
Creates a concentration gradient which is used by the
cell to bring other molecules into the cell
http://www.youtube.com/watch?v=STzOiRqzzL4&playnext_from=TL&videos=d3eXoGV9IOA
Active Transport
http://www.youtube.com/watch?v=STzOiRqzzL4&playnext_from=TL&videos=d3eXoGV9IOA
Active Transport
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Endocytosis
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Infolding of the membrane to create a membrane
bound vesicle containing the target
Phagocytosis – cell eating – large invagination
Pinocytosis – cell drinking – small invagination
Exocytosis
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Extracellular transportation
Vesicle fuses with the membrane and releases
contents to the extracellular space
http://www.youtube.com/watch?v=4gLtk8Yc1Zc&feature=related
Endo and Exo Cytosis
Click on the image for the animation
http://www.youtube.com/watch?v=4gLtk8Yc1Zc&feature=related
ATP: The Energy Currency of Cells
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Energy currency of all cells
Used for all active processes
Energy stored in the bonds
between the phosphate
molecules
Break the bond between P2
and P3 releases the most
energy
Couple the hydrolysis of ATP
with energy requiring reactions
Utilize the energy released by
ATP hydrolysis to ‘run’ the
energy requiring reactions
ATP  ADP + Pi + Energy
Cellular Metabolism: The Reactants
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Glucose
ADP – adenosine –di-phosphate
P – free phosphate
Electron Carriers
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NAD+
FAD
O2 - oxygen
Cellular Metabolism: The Products
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ATP – adenosine –tri-phosphate
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The energy currency of all cells
CO2 – carbon dioxide
H2O - water
Cellular Metabolism: Overview
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Glycolysis
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Krebs Cycle
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Occurs in the cytoplasm
Occurs in the mitochondrial matrix
Electron Transport Chain
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Occurs on the cristae of the mitochondria
Glycolysis
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Occurs in the cytoplasm
Splits glucose into 2 pyruvate molecules
Requires 2 ATP to get started
Generates 4 ATP and 1 NADH
Net ATP Gained = 2
http://www.youtube.com/watch?v=x-stLxqPt6E&playnext_from=TL&videos=VTW65Eh7thQ
Glycolysis
Click on the image for the animation
http://www.youtube.com/watch?v=x-stLxqPt6E&playnext_from=TL&videos=VTW65Eh7thQ
Glycolysis
Energy Investing Steps
Energy Harvesting Steps
The Krebs Cycle
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Pyruvate is transported into the matrix of the
mitochondria
The Krebs cycle is a series of chemical reactions
which sequentially strip electrons from the pyruvate
Electrons are given to the electron carriers NAD and
FAD
Electrons will be taken to the Electron Transport
Chain
For each original glucose molecule 2 ATP are
produced here
Carbon dioxide is also produced here
http://www.youtube.com/watch?v=aCypoN3X7KQ&feature=related
The Krebs Cycle
Click on the image for the animation
http://www.youtube.com/watch?v=aCypoN3X7KQ&feature=related
Krebs Cycle
The Electron Transport Chain
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Located on the Cristae of the mitochondria
NADH and FADH2 bring electrons here from
the Krebs cycle
Electrons travel down the chain of special
proteins releasing their energy along the way
Oxygen is the final electron acceptor
This cellular metabolism of the krebs cycle
and the electron transport chain is why we
need O2 and produce CO2.
http://www.youtube.com/watch?v=Idy2XAlZIVA&feature=related
The Electron Transport Chain
Click on the image for the animation
http://www.youtube.com/watch?v=Idy2XAlZIVA&feature=related
Electron Transport Chain
Photosynthesis: The Players
Reactants:
Products:
Light Energy
H2O (for electrons)
CO2
NADP+
Specialized pigments
Glucose
O2
ATP
Photosynthesis: Overview
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Light reactions
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Occur on the thylakoid membranes of chloroplasts
Dark reactions
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Occur in the fluid stroma of the chloroplast
Photosynthesis:
Light Reactions
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Require light and water
Produce ATP and O2
Take place on the thylakoid membranes of the
chloroplast
Light energy is used to make ATP
Light Reactions … How is Light energy absorbed??
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Special Pigments!
Chloroplasts contain special molecules
called pigments
Pigments have electrons which can use
light energy to jump to a higher orbit
Energy is released when the electron falls
back to its original orbit
Each pigment has a specific wavelength of
light its electrons respond to
White light is made up of light wavelengths
ranging from 400-740 nanometers
Chlorophyll absorbs all wavelengths
EXCEPT 500-600
Chlorophyll reflects wavelengths 500-600
nm
Our eyes see the reflected light which is
green
Carotenoids absorb 500-600 nm but reflect
all others
The Light Reactions
Click on the image for the animation
http://www.youtube.com/watch?v=v590JJV96lc&feature=related
Light Reactions
Wow this looks a lot like the Electron Transport Chain in mitochondria!
The Dark Reactions
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Also called the Calvin
Cycle
Does not require light
Occur in the stroma of
the chloroplast
Use the ATP produced
during the light
reactions to make
glucose from CO2
Cell Cycle
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All cells have a life cycle
Checkpoints throughout the
cell cycle ensure the cell
divides in an appropriate
manner
Gap 1 - Resting cell
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Synthesis phase when DNA is
duplicated (synthesized)
Gap 2 – Make more organelles
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G1 Check point decides if cell
should divide
G2 Check point DNA duplication
assessed
Mitosis Check point assesses
the success of cell division
Cell Cycle
Click on the image for the animation
http://www.youtube.com/watch?v=O3_PNiLWBjY&feature=related
Cell Cycle and Cancer
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Protein p53 “The guardian angel”
Monitors the integrity of DNA
Signals repair enzymes to address damaged
DNA
Tags cells for destruction if their DNA is
damaged beyond repair
Without this protein, damaged cells could
proliferate leading to cancer
DNA Synthesis
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DNA is a double stranded helix
Each strand is said to be complimentary to the other
The 4 bases pair in specific couples
Complimentary Base Pairing
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Adenine (A) only pairs with Thymine (T)
Guanine (G) only pairs with Cytosine (C)
DNA Polymerase enzyme synthesizes DNA
Replication is semi conservative - Each daughter double
helix will consist of one original and one new strand of
DNA
http://www.youtube.com/watch?v=zdDkiRw1PdU&playnext_from=TL&videos=Oiq5czvIcSc
DNA Synthesis
Click on the image for the animation
http://www.youtube.com/watch?v=zdDkiRw1PdU&playnext_from=TL&videos=Oiq5czvIcSc
Mitosis
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Cell Division
Make two EXACT daughter cells from one
parental cell
Divided into 4 separate stages
DNA is already duplicated when mitosis
begins
http://www.youtube.com/watch?v=3kpR5RSJ7SA&feature=related
Mitosis
Click on the image for the animation
http://www.youtube.com/watch?v=3kpR5RSJ7SA&feature=related
Prophase, Metaphase
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Prophase
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Nuclear membrane breaks down
Chromosomes condense and coil tightly around histone
proteins
Centrioles duplicate and form the spindle apparatus of
microtubules
Metaphase
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Chromosomes aligned at the midline of the cell by the
spindle apparatus
Duplicated chromosome pairs now duplicate their
centromeres
Anaphase, Telophase,
Cytokenisis
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Anaphase
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Telophase
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Chromosome pairs pulled apart toward opposite poles
of cell by their centromeres
Chromosomes begin to unwind as the nuclear
membrane is reformed
Cytokinesis
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Cytoplasm is divided into the two cells by the pinching
of the cell membrane to create two separate cells
Mitosis Recap
Meiosis
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For GAMETE (sex cell) production ONLY
Most organisms live as diploid creatures
meaning they possess two copies of each
chromosome
In order to maintain proper chromosome
number, the DNA must be reduced by 50% in
the gametes
Meiosis produces 4 genetically unique Haploid
cells for reproduction (eggs and sperm)
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Haploid cells have one copy of each chromosome
http://www.youtube.com/v/jdQeKjEsj0U&playnext_from=TL&videos=TM9fPRqQye0
Meiosis
Click on the image for the animation
http://www.youtube.com/v/jdQeKjEsj0U&playnext_from=TL&videos=TM9fPRqQye0
Meiosis 1
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Prophase I
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Metaphase I
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Pairs of duplicated chromosomes line up at midline
Anaphase I
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Cross over between homologous pairs of chromosomes
Centrioles duplicate
Spindle apparatus forms
Individual pairs of duplicated chromosomes pulled to
opposite poles of cell
Telophase I
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Cleavage furrow separates cell into two
Meiosis 2
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Prophase II
 Centrioles duplicate
 Spindle apparatus reforms
Metaphase II
 Chromosome pairs line up at midline
Anaphase II
 Sister chromatids now separated and pulled toward opposite
poles of cell
 At this point DNA is reduced by 50%
Telophase II
 Cleavage furrow forms
 Results in a total of 4 haploid daughter cells from 1 parental cell
 Each one is genetically unique due to crossing over in Prophase I
Meiosis Recap
Meiosis I
Meiosis II