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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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Presentation on theme: "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."— Presentation transcript:

1 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

2 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

3 Chapter 9 - Patterns of Inheritance AIM: Are we born this way or does the environment make us who we are? Summary of Photosynthesis EnergyFrom sunlight (solar energy) and put into glucose (chemical energy) Materials used (reactants)CO2 and H2O Materials produced (products)Glucose and O2 Time FrameWhen light is available LocationIn chloroplasts of producers (autotrophs): plant cells, algae, and some single-celled protists (Some bacteria can also do photosynthesis) ImportanceGlucose used as energy source to make ATP (cell respiration) or used to make other molecules 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 light

4 Chapter 7 - Photosynthesis: Using light to Make Food AIM: Describe the process of photosynthesis.

5 Chapter 9 - Patterns of Inheritance AIM: Are we born this way or does the environment make us who we are? Summary of Cellular Respiration EnergyFrom 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 Frame24 hours a day in ALL eukaryotes including plants LocationIn ALL living cells…within 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…

6 Chapter 9 - Patterns of Inheritance AIM: Are we born this way or does the environment make us who we are? Summary

7 Chapter 5 - Energy and the Cell AIM: Describe the structure/function of Enzymes. Enzymes

8 AIM: So what are the macromolecules? Chapter 3 - The Molecules of Cells 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 Reactants (substrates) Products Reactants are called substrates when involving enzymes (enzyme) Active site – spot on enzyme with shape that fits substrate so that substrate can bind to it and get turned into products.

9 AIM: So what are the macromolecules? Chapter 3 - The Molecules of Cells Enzymes: 1. Biological catalysts 2. Speed up chemical reactions without being used up Remember, proteins are like the people in the cell. A person doesn’t 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)

10 LOCK and KEY MODEL Chapter 5 - Energy and the Cell AIM: Describe the structure/function of Enzymes. Model for how enzymes bind their substrates… The shape of the substrate fits the shape of the enzyme’s active site

11 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

12 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.

13 AIM: So what are the macromolecules? Chapter 3 - The Molecules of Cells 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.

14 AIM: So what are the macromolecules? Chapter 3 - The Molecules of Cells 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. Every protein has a certain temperature and pH that it functions best at.

15 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.

16 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.

17 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 organism’s 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…

18 Chapter 5 - Energy and the Cell AIM: How are enzymes regulated (controlled)? Inhibiting (turning off) enzymes (This is NOT denaturing)

19 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

20 Chapter 5 - Energy and the Cell AIM: How are enzymes regulated (controlled)? Positive and negative feedback

21 Chapter 5 - Energy and the Cell AIM: How are enzymes regulated (controlled)? 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… Cells use enzyme inhibition to maintain specific levels (homeostasis) of substances in the cell… Let’s see how inhibition is used to maintain specific levels of solutes (maintain homeostasis)…

22 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 (let’s 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. Using inhibition to maintain specific solute concentrations:

23 TOO MANY!!!!!! STOOOOPPPP! This slide will not make sense unless you use it in powerpoint and watch the substrate get converted to final product. Using inhibition to maintain specific solute concentrations:

24 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 off…negative feedback. What will happen when levels of “G” decrease? “G” will fall off enzyme 3 and production will resume. Using inhibition to maintain specific solute concentrations:

25 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 again…therefore, the levels of G are constantly doing what? They are constantly fluctuating up and down over a narrow range. Using inhibition to maintain specific solute concentrations:

26 This method of inhibition where the product shuts itself is called: NEGATIVE FEEDBACK Using inhibition to maintain specific solute concentrations:

27 Negative Feedback Chapter 5 - Energy and the Cell AIM: How are enzymes regulated (controlled)? 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. Define negative feedback:

28 Negative Feedback When the output of a system inhibits its own production thereby only allowing it to ever reach a certain level Chapter 5 - Energy and the Cell AIM: How are enzymes regulated (controlled)? 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). 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.

29 Negative Feedback Chapter 5 - Energy and the Cell AIM: How are enzymes regulated (controlled)? 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.

30 Positive 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… Chapter 5 - Energy and the Cell AIM: How are enzymes regulated (controlled)? Opposite of negative feedback. Such a condition is considered unstable…

31 Positive Feedback Chapter 5 - Energy and the Cell AIM: How are enzymes regulated (controlled)? Examples: 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. 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…

32 Positive Feedback Chapter 5 - Energy and the Cell AIM: How are enzymes regulated (controlled)? 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!

33 Disease Chapter 5 - Energy and the Cell AIM: How are enzymes regulated (controlled)? - 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 2. Inherited Disorders – sickle cell anemia, cystic fibrosis, Down syndrome (all genetic) Infection by certain pathogens can be prevented using vaccines (more in a moment)

34 Disease Chapter 5 - Energy and the Cell AIM: How are enzymes regulated (controlled)? - 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

35 Disease Chapter 5 - Energy and the Cell AIM: How are enzymes regulated (controlled)? - 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.

36 Chapter 24: The Immune System NEW AIM: How does the body defend itself against MO’s? ix. Vaccines a. First vaccine - small pox Edward Jenner 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) 2. Two related diseases: cow pox and small pox

37 Chapter 24: The Immune System NEW AIM: How does the body defend itself against MO’s? ix. Vaccines b. Inject a harmless variant of the disease causing microbe 1. Body (WBC’s) responds to antigens by making antibodies 2. Some of these WBC’s remain after the “war” 3. Immune system is now primed for the “real thing” 4. That’s easy…so 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 virus…the antigens change quicker than out immune systems can keep up with. It is like a criminal that can shape-shift (change what they look like…become anyone).

38 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 cell’s machinery to make more of itself.

39 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. 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. B. Estimated 1.1 million people are HIV positive in the US. D. HIV invades and destroys white blood cells (WBC’s) leaving the person without an immune system

40 Fig 10.21A Chapter 10 - Molecular Biology of the Gene NEW: Viruses: Packaged Genes… Retroviruses HIV What disease does HIV cause? - AIDS – Acquired Immune Deficiency Syndrome Therefore, HIV/AIDS does not kill anyone directly, it is the opportunistic infection or cancer that kills the person. 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).


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