Food Chains, Dietary Energy and Cellular Respiration, Week 6

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Energy Transfer within a Trophic SYstem

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This week is for review since we have been taking about energy transfer and trophic cycles.

Etymology of the word trophic:

late 19th century: from Greek trophikos, from trophē ‘nourishment’, from trephein ‘nourish’.

trophic means to nourish

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Eating gives us energy

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If we eat too much then we store the energy and gain weight.  In the United States, 36.5 percent of adults are obese. Another 32.5 percent of American adults are overweight
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https://www.cdc.gov/obesity/data/adult.html

https://www.healthline.com/health/obesity-facts#2

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calories in/ Calories out

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Food Intake

1 glazed donut  200 calories

1 Starbucks Grande frappucino with Whipped Cream 380 calories

1 McDonald's Big Mac 540 calories

1 Burger King Whopper 670 calories

Exercise Calorie Burning/HR

Walking 3 mph 280 calories

Jogging 5 mph 500 calories


Biking 450 calories

Hiking 500 calories 

​So if you eat  a burger it take an hour of high energy exercise to burn the calories, otherwise you will store some of the energy

A full meal is over 1,000 calories.
A McDonald's meal with a shake has
1,680 calories and 74 grams of fat

Nutrition Info:

http://www.center4research.org/fast-food-facts-calories-and-fat/

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Vocabulary

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calorie:
the amount of energy required to raise the temperature of 1 gram of water by 1 degree Celsius 
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CALORIE
1,000 calories or  kilocalorie (Kcal); a capital C in Calorie means "kilocalorie", the Calorie is what we see in food labels
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Carbohydrates give us calories

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​We need some, in moderation

The Glycemic Index (GI) is a relative ranking of carbohydrate in foods according to how they affect blood glucose levels. Carbohydrates with a low GI value (55 or less) are more slowly digested, absorbed and metabolised and cause a lower and slower rise in blood glucose and, therefore usually, insulin levels.

​https://www.gisymbol.com/
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Food that we eat gets broken down into subunits

Glycogen
a complex animal carbohydrate, made up of liked chains of glucose molecules, that store energy for short-term use

Triglyceride
a type of lipid found in fat cells that stores excess energy for long term use

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Energy is extracted from food by mitochondria

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​The process is called aerobic respiration

Aerobic Respiration
A series of reactions that occur in the presence of oxygen and converts energy stored in food into ATP

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There are many parts to the process:

Glycolysis
a series of reactions that breaks down sugar into smaller units; glycolysis takes place in the cytoplasm and is the first step of both aerobic respiration and fermentation.

Citric Acid Cycle
a set of reactions that takes place in mitochondria and helps extract energy (in the form of high-energy electrons) from food; the second step in aerobic respiration

Electron Transport Chain
a process that takes place in mitochondria and produces the bulk of ATP during aerobic respiration; the third step in aerobic respiration

Oxidative Phosphorylation
a process involving a flow of electrons through the electron transport chain

Mitochondria 
Where ATP is made, membrane bound organelles in the cell that float around the cell, they have their own DNA, they produce ATP using sugar and oxygen and our cells can use that ATP for cell work.

Each step in the process of building a protein takes energy, the energy is called ATP.

ATP synthase is an enzyme that creates the energy storage molecule adenosine triphosphate (ATP), forming it from adenosine diphosphate (ADP) and inorganic phosphate (Pi).

​https://en.wikipedia.org/wiki/ATP_synthase#

​ATP
Adenosine Triphosphate
The molecule that cells use to power energy-requiring functions, the cells "currency"

Fermentation
a series of chemical reactions that takes place in the absence of oxygen and converts some of the energy stored in food into ATP.  Fermentation produces far less ATP than aerobic respiration.
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