1. Metabolic Rates Throughout Creation
Exploring Creation with General Science Week 25 - Mod 12 Energy and Life – part 2
March 28, 2011
Sections:
What Actually Gets Burned for Energy?
Energy Use in the Body
Calories & Food
Metabolic Rates Throughout Creation
How Combustion Works in Living Organisms
For Next Time?

2. What Actually Gets Burned for Energy?
PROTEINS: the 3rd macronutrients. The body burns these only if you have too many of them or have run out of carbs & fat. These are important to many chemical processes in your body. Like Polysaccharides, proteins are formed from smaller substances that link together. These are called Amino Acids. Nearly every chemical reaction in the body is affected by proteins. 2 2 2

3. What Actually Gets Burned for Energy?
The info stored in DNA is used to tell the cells in the body how to make protein. So the cells need 2 things – DNA and Amino Acids. If the DNA is in the nucleus, then where do the Amino Acids come from? Our cells can make only 12 of the 20 Amino Acids that they need; what about the last 8? These are called the Essential Amino Acids. To get these, we have to eat protein which contains them. 3 3 3

4. What Actually Gets Burned for Energy?
The best place for getting these 8 Amino Acids is meat, milk, fish, and eggs because animal protein contains all 8 of them. Vegetarians have a hard time getting the RIGHT proteins in their bodies because plants don’t contain these proteins. So we don’t eat proteins as a source of energy, but in fact, our cells need these proteins to make the other things that the body needs. 4 4 4

5. What Actually Gets Burned for Energy?
Children who don’t get the 8 Essential Amino Acids typically suffer severe brain damage which results in mental retardation. When we eat proteins, our bodies break them down into the amino acids that the cells need to make the correct proteins that our bodies need to function. Eat too much protein, it gets converted into carbs & fats. But if the body runs low on these items, it can burn Amino Acids for its energy. 5 5 5

6. What Actually Gets Burned for Energy?
Athletes – they need large amounts of energy in a short time – stresses the body – burn in the muscle – body is using the Amino Acids in the muscle – prior to the event, they eat lots of proteins and/or carbs – pancake breakfast for the Fox Trot. So, what we eat gives us the 3 macronutrients we need. These nutrients are used in different ways. Look at Figure 12.3, pg.307 – old books 6 6 6

7. What Actually Gets Burned for Energy?
2 points the author leaves you with: 1. Food contains many things we need – micronutrients – important – not used for energy – small quantities. 2. The process our bodies use is combustion to get energy from the food – it is a carefully controlled & regulated chemical process. On Your Own 12.6 and 12.7 7 7 7

8. Energy Use in the Body
What do we need this energy for? Remember the Involuntary Muscles? These are working all the time – energy is needed in an uninterrupted process to keep these guys going. But there is something else we need lots of energy for and never think about. Back to Exp – Products of Combustion Hypothesis??? 8 8 8

9. Energy Use in the Body
What was the 1st product you saw? In technical terms, where did it come from? What other gases do we exhaust? What happened when you breathed through the cabbage water? What gas came out? Human Beings are ENDOTHERMIC – means we use energy to regulate our internal temperature and keep it steady – we are “warm-blooded”. 9 9 9

10. Energy Use in the Body
The opposite is ECTOTHERMIC – no constant internal temperature – “cold-blooded” – whatever the surrounding temp is. These creatures require less food cause they need less energy – their bodies aren't using energy to maintain a constant temperature. Higher temps mean faster chemical processes – faster reactions usually. 10 10 10

11. Energy Use in the Body
Ever go to the zoo in the cold weather and see how sluggish the cold-blooded creatures are? How ‘bout lizards in the desert? Thus our bodies use energy to control our involuntary muscles which keeps our organs & internal processes functioning properly. And energy is used to maintain a constant internal temperature. On Your Own 12.8 11 11 11

12. Calories and Food
We’ve all heard of calories and weight loss/gain Calorie: a unit of energy measurement. Since food gives us macronutrients & macros give us energy, the best way to measures the amount of energy we take in is to count the calories of the food we eat. More macros equals more energy, but there’s some confusion in the scientific world. One food calorie = 1000 chemistry calories, but the author will always talk in FOOD calories. 12 12 12

13. Calories and Food
Since the calorie is a unit of measurement, it is used to measure the amount of macros in the food as well as the amount of energy our bodies need to live. The total energy we convert each day is called our Metabolic Rate – 2 factors – 1st is minimum amount of energy to survive –called the Basal Metabolic Rate (BMR). Your BMR depends on your height, weight, age, gender, and athletic or health condition. 13 13 13

14. Calories and Food
The 2nd factor is the amount of activity we do every day. The more work or play, the higher the BMR. Look at the general trends – table 12.1 Trends – averages – exercise Best ratio of macronutrients to calories is 70% of your calories should come from carbs, 21% from fats, & 9% from proteins. These are general numbers – no real consensus – still too many mysteries about our bodies. 14 14 14

15. Metabolic Rates Throughout Creation
And we aren't event talking about the… MICRONUTRIENTS. On Your Own 12.9 From the start of time, metabolic rates have varied – some drastically even among similar creatures. Look at Figure 12.4 – different mammals with different metabolic rates. See the trend – size vs. metabolic rates. Smaller creatures have larger metabolic rates. 15 15 15

16. How Combustion Works in Living Organisms
Going back for a moment – 1st the food is burned in our cells, so all of our energy needs originate in our cells. Ok, let’s look at how Monosaccharides are burned for energy. Amino Acids & fats can be burned for energy, but those processes are even more complicated. We’ll look at glucose specially; it is a Monosaccharide carb – figure 12.5. 16 16 16

17. How Combustion Works in Living Organisms
This combustion takes 3 steps – to make the release of energy more gentle. Step 1: Glycolysis – glucose is broken down into 2 parts – small energy release & hydrogen. 2 glucose parts are sent to particular organelles in the cell – Mitochondrion. Step 2: in the Mitochondrion, the Krebs Cycle occurs. The 2 parts of the glucose are broken down further into carbon & hydrogen. 17 17 17

18. How Combustion Works in Living Organisms
Then oxygen combines with carbon to make carbon dioxide (CO2) and a small energy release. Step 3: The hydrogen from step 1 & step 2 go to the 3rd step called the Electron Transport System. In this step, the 2 H atoms combine with the O atom to make water – H2O. And we get a large release of energy in the Mitochondrion – called the “p ”* of the cell. 18 18 18

19. How Combustion Works in Living Organisms
Overview: All the steps – take glucose (food) & oxygen – produces c d , w , and e . This is defined as Combustion. This very complicated process is a gentle way of burning simple carbs – Monosaccharides. We have simplified a very complex process. It is hard to understand & even some scientists never learn the process in depth. 19 19 19

20. How Combustion Works in Living Organisms
The 4 main things to understand are… 1. The process of combustion in living organisms is amazingly complex – it has to be so in order to provide energy in a gentle fashion. 2. The combustion process occurs within the cell. 20 20 20

21. How Combustion Works in Living Organisms
3. Two of the three steps in the combustion process occur in an organelle called the Mitochondrion. 4. Since the majority of the combustion process takes place within the Mitochondrion, it is called the “powerhouse” of the cell. On Your Own 21 21 21

22. Review Questions
If there’s time… 22 22 22

23. For Next Time
Start reading Module 13 – ½ way through. Take the test for Module 12. Write up all “On Your Owns” for Module 12. Turn in write-ups for Experiment 12.1 – “What Combustion Needs” and Experiment 12.2 – “The Products of Combustion” Have a blessed week. 23 23 23