Chapter 9 - Patterns of Inheritance

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Chapter 9 - Patterns of Inheritance
AIM Are we born this way or does the environment
make us who we are?
TOPIC 2
Homeostasis in Organisms
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Chapter 7 - Photosynthesis Using light to Make
Food
AIM Describe the process of photosynthesis.
Photosynthesis
Fig. 7.5
Occurs in the chloroplasts of plants, algae and
other protists
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Chapter 9 - Patterns of Inheritance
AIM Are we born this way or does the environment
make us who we are?
Summary of Photosynthesis
light
C6H12O6 6O2
6CO2 6H2O
Energy From sunlight (solar energy) and put into glucose (chemical energy)
Materials used (reactants) CO2 and H2O
Materials produced (products) Glucose and O2
Time Frame When light is available
Location In chloroplasts of producers (autotrophs) plant cells, algae, and some single-celled protists (Some bacteria can also do photosynthesis)
Importance Glucose used as energy source to make ATP (cell respiration) or used to make other molecules
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Chapter 7 - Photosynthesis Using light to Make
Food
AIM Describe the process of photosynthesis.
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Chapter 9 - Patterns of Inheritance
AIM Are we born this way or does the environment
make us who we are?
Summary of Cellular Respiration
Energy From chemical energy of glucose and put into ATP to be used by proteins.
Materials used (reactants) Glucose and O2 (made by producers)
Materials produced (products) CO2, H2O and ATP
Time Frame 24 hours a day in ALL eukaryotes including plants
Location In ALL living cellswithin mitochondria in eukaryotes.
Importance ATP is needed to fuel proteins so they can work so you can move, think, maintain homeostasis, do mitosis/meiosis, etc
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Chapter 9 - Patterns of Inheritance
AIM Are we born this way or does the environment
make us who we are?
Summary
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Chapter 5 - Energy and the Cell
AIM Describe the structure/function of Enzymes.
Enzymes
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Chapter 3 - The Molecules of Cells
AIM So what are the macromolecules?
Enzymes
1. Biological catalysts
2. Speed up chemical reactions without being used
up
Example reaction that occurs in small intestines
(digestion) Sucrose H2O ? glucose
fructose
(enzyme)
Reactants (substrates)
Products
Reactants are called substrates when involving
enzymes
Active site spot on enzyme with shape that fits
substrate so that substrate can bind to it and
get turned into products.
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Chapter 3 - The Molecules of Cells
AIM So what are the macromolecules?
Enzymes
1. Biological catalysts
2. Speed up chemical reactions without being used
up
Remember, proteins are like the people in the
cell. A person doesnt get used up with they do
something. The reaction might be to tear a piece
of paper in half. What is the substrate? What is
the product? Did I get used up?
Enzymes can work at a rate up to 600,000
reactions per second (try tearing 600,000 pieces
of paper per second)
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Chapter 5 - Energy and the Cell
AIM Describe the structure/function of Enzymes.
Model for how enzymes bind their substrates
LOCK and KEY MODEL
The shape of the substrate fits the shape of the
enzymes active site
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Chapter 5 - Energy and the Cell
AIM Describe the structure/function of Enzymes.
Enzymatic Reaction Rates
What affects the number of reactions an enzyme
can perform per second?
The same thing that affect the shape of the
enzyme
Temperature and pH
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Chapter 5 - Energy and the Cell
AIM Describe the structure/function of Enzymes.
pH reminder
A aqueous solutions (solutions with water as the
solvent) have a pH, which is a measure of the
concentration of protons (H) in the solution.
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Chapter 3 - The Molecules of Cells
AIM So what are the macromolecules?
Proteins are very sensitive to environmental
changes, which is why organisms can only survive
in a narrow range of environmental parameters
like pH and temperature and therefore must
maintain homeostasis.
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Chapter 3 - The Molecules of Cells
AIM So what are the macromolecules?
Every protein has a certain temperature and pH
that it functions best at.
Every protein has a certain temperature and pH
that it functions best according to where it has
evolved. For example, hydrolytic enzymes in your
stomach function best at a pH 2 and temperature
of 98.6F, while those in your blood function best
at pH 6.8 and a similar temperature. Bacteria
that lives in ice have proteins that function
best near freezing and those that live in
hydrothermal vents have proteins that work best
at near boiling temperatures.
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Chapter 5 - Energy and the Cell
AIM Describe the structure/function of Enzymes.
You are studying an enzyme in the lab and
determine the rate of reaction at various
temperature and pH values. Your data is below.
What do you conclude?
The enzymes you are studying works best at around
37 degrees C at a pH of 8.
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Chapter 5 - Energy and the Cell
AIM Describe the structure/function of Enzymes.
Recap Organisms have evolved to occupy very
different environments and therefore enzymes
occupy different environments. Most of out
enzymes function at 98.6F (37C) and a pH of
around 7.2. The enzymes in our lysosomes,
however, function at a pH of 4 to 5. The enzymes
in our stomach like pepsin function at a pH of 2.
Different enzymes have evolved to function in
different conditions and therefore enzymes have
different optimal conditions. If one moves away
from those optimal conditions the enzyme will
likely lose activity.
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Chapter 5 - Energy and the Cell
AIM Describe the structure/function of Enzymes.
You discover a new bacterium in a hot spring at
Yellowstone National Park. The temperature of the
spring is 78 degrees Celcius (172F) and a pH of
5. Hypothesize the optimal temperature and pH of
this organisms enzymes assuming the cytosol of
the organism is similar to the spring.
They would likely work best at pH 5 and a temp of
78
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Chapter 5 - Energy and the Cell
AIM How are enzymes regulated (controlled)?
Inhibiting (turning off) enzymes
(This is NOT denaturing)
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Chapter 5 - Energy and the Cell
AIM How are enzymes regulated (controlled)?
Inhibitors tend to have SIMILAR SHAPE as the
substrates and compete against the substrates for
the active site.
Many of our medicines are inhibitors of bacterial
or viral enzymes
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Chapter 5 - Energy and the Cell
AIM How are enzymes regulated (controlled)?
Positive and negative feedback
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Chapter 5 - Energy and the Cell
AIM How are enzymes regulated (controlled)?
Cells use enzyme inhibition to maintain specific
levels (homeostasis) of substances in the cell
For example, the level of ATP must be maintained
in the cell. Making too much ATP would be
wasteful. Making too little ATP would also be a
problem as the cell could not power reactions
like moving vesicles around, active transport,
etc
Lets see how inhibition is used to maintain
specific levels of solutes (maintain homeostasis)
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Using inhibition to maintain specific solute
concentrations
1
2
5
6
4
3
In this example, a series of enzymes will convert
substrate A into end product G using six
reactions (six enzymes). Remember, this is like a
factory line where each worker (enzyme) makes a
small change to the substrate to get the end
product.
The cell must regulate the concentration of G
(lets say it is an amino acid like glycine).
Right now there is too little G. Therefore, what
will these enzymes do?
They will be active and make more.
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Using inhibition to maintain specific solute
concentrations
1
2
This slide will not make sense unless you use it
in powerpoint and watch the substrate get
converted to final product.
5
6
4
3
TOO MANY!!!!!! STOOOOPPPP!
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Using inhibition to maintain specific solute
concentrations
1
2
5
6
4
3
When the concentration of the product G gets
too high, it will bind to enzyme 3 and shut it
off. G will no longer be made. It shut itself
offnegative feedback. What will happen when
levels of G decrease?
G will fall off enzyme 3 and production will
resume.
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Using inhibition to maintain specific solute
concentrations
1
2
5
6
4
3
This is how you regulate the concentration of G.
If G is too high, it will shut its own production
off, if it stop inhibiting and be made
againtherefore, the levels of G are constantly
doing what?
They are constantly fluctuating up and down over
a narrow range.
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Using inhibition to maintain specific solute
concentrations
1
2
5
6
4
3
This method of inhibition where the product shuts
itself is called
NEGATIVE FEEDBACK
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Chapter 5 - Energy and the Cell
AIM How are enzymes regulated (controlled)?
Negative Feedback
Define negative feedback
When the output of a system goes back (feeds
back) and inhibits or turns down (in the negative
direction) its own production when it gets too
high thereby maintaining a specific
concentration.
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Chapter 5 - Energy and the Cell
AIM How are enzymes regulated (controlled)?
Negative Feedback
When the output of a system inhibits its own
production thereby only allowing it to ever reach
a certain level
Ex. Think about the thermostat in your house that
controls heating. If there is too much heat, the
heat turn the thermostat off. The house will cool
and when there is too little heat, the thermostat
kicks on again until the heat turns it off again.
Ex. The product of an enzyme or series of enzymes
when reaching a certain concentration inhibits
one of the enzymes thereby shutting its own
production off until the concentration falls
during which the product will no longer inhibit
the enzyme and it will be made again (homeostatic
level is maintained stable).
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Chapter 5 - Energy and the Cell
AIM How are enzymes regulated (controlled)?
Negative Feedback
Ex. Glucose/insulin example glucose levels are
high in the blood (you drank grape juice).
Insulin (hormone) is secreted into blood and
binds to insulin receptors on liver and muscle
cells causing them to take up glucose. Low
glucose then shuts off insulin production.
Output insulin, shut itself off.
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Chapter 5 - Energy and the Cell
AIM How are enzymes regulated (controlled)?
Positive Feedback
Opposite of negative feedback.
When the output of a system goes back (feeds
back) and further enhances its own production (in
the positive direction) leading to more output
and in turn more enhancement and even more
output, etc
Such a condition is considered unstable
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Chapter 5 - Energy and the Cell
AIM How are enzymes regulated (controlled)?
Positive Feedback
Examples
1. Hypothetical if your house thermostat worked
based on positive feedback, the output (heat)
would further activate the thermostat, which
would instruct the release of more heat, which
would even further activate thermostat, etc
2. Child Birth contractions the hormone
oxytocin stimulates contration of the uterus.
This will cause the baby to press up against the
uterus, which causes more oxytocin release, more
contractions, more pushing of the baby, more
oxytocin, even harder contractions, etc until
baby and placenta are out and oxytocin is cleared
from blood.
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Chapter 5 - Energy and the Cell
AIM How are enzymes regulated (controlled)?
Positive Feedback
Examples
3. Sneezing
- You initially have to somewhat sneeze, which
causes you to feel more like you have to sneeze,
and then more, and more, and aaaaaaahhhhhhh
choooooooooooooo!
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Chapter 5 - Energy and the Cell
AIM How are enzymes regulated (controlled)?
Disease
- Body fails to maintain homeostasis
- causes
1. Pathogens disease causing organisms like
certain viruses, fungi, bacteria and other
parasites (tapeworm, etc)
Treat bacteria with ANTIBIOTICS
Treat fungi with fungicides
Infection by certain pathogens can be prevented
using vaccines (more in a moment)
2. Inherited Disorders sickle cell anemia,
cystic fibrosis, Down syndrome (all genetic)
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Chapter 5 - Energy and the Cell
AIM How are enzymes regulated (controlled)?
Disease
- Body fails to maintain homeostasis
- causes
3. Exposure to toxins lead poisoning, radiation
poisoning
4. Organ Malfunction heart attack, diabetes
5. Poor Nutrition scurvy (vitamin C
deficiency), goiter (iodine deficiency)
6. High Risk Behaviors lung cancer due to
smoking
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Chapter 5 - Energy and the Cell
AIM How are enzymes regulated (controlled)?
Disease
- Body fails to maintain homeostasis
- causes
7. Cancer
- When one of your cells goes rogue and starts
undergoing mitosis uncontrollably and moves
around the body (metastasizes). The result is
clumps of cells in organs called tumors.
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Chapter 24 The Immune System
NEW AIM How does the body defend itself against
MOs?
ix. Vaccines
a. First vaccine - small pox - 1797
1. Edward Jenner
2. Two related diseases cow pox and small pox
3. Took pus from cowpox pustule and inserted it
into an incision on a boy
4. Boy could not get small pox (he was immune)
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Chapter 24 The Immune System
NEW AIM How does the body defend itself against
MOs?
ix. Vaccines
b. Inject a harmless variant of the disease
causing microbe
1. Body (WBCs) responds to antigens by making
antibodies
2. Some of these WBCs remain after the war
3. Immune system is now primed for the real
thing
4. Thats easyso where is the HIV vaccine?
HIV is a retrovirus. Viral particles that use
reverse transcriptase and prone to making more
errors in their DNA that a virus using DNA
polymerase. This results in a quickly changing
virusthe antigens change quicker than out immune
systems can keep up with. It is like a criminal
that can shape-shift (change what they look
likebecome anyone).
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Chapter 10 - Molecular Biology of the Gene
NEW Viruses Packaged Genes
Viruses
-Small molecular machines with their own nucleic
acid that need a host cell to make more of itself.
- They bind cell surface receptors to get into
the cell and hijack it, using the cells
machinery to make more of itself.
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Chapter 10 - Molecular Biology of the Gene
NEW Viruses Packaged Genes
HIV
How is HIV transmitted?
The virus is transmitted through contact of a
bodily fluid containing HIV like blood, semen,
vaginal fluid, and breast milk with a mucous
membrane or the bloodstream.
A. 33 million people are HIV positive in the
world.
B. Estimated 1.1 million people are HIV positive
in the US.
C. 2.2 million people, 330,000 of which were
children, died as a result of the virus last year
75 of deaths occurred in Sub-Saharan Africa.
D. HIV invades and destroys white blood cells
(WBCs) leaving the person without an immune
system
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Chapter 10 - Molecular Biology of the Gene
NEW Viruses Packaged Genes
Retroviruses
Fig 10.21A
HIV
What disease does HIV cause?
- AIDS Acquired Immune Deficiency Syndrome
Immune system gradually declines leaving the
individual susceptible to opportunistic
infections like tuberculosis (5 10 of
Americans test positive for the bacterium that
causes tuberculosis, but the immune system keeps
it in check and the person is fine)and tumors
(many cells that would have caused cancer are
destroyed by the immune system).
Therefore, HIV/AIDS does not kill anyone
directly, it is the opportunistic infection or
cancer that kills the person.