I am preparing this for my biology class.
The basic molecule of obtaining energy is adenosine
triphosphate, or ATP, as we learned. Energy is released when a phosphate is
released to yield adenosine diphosphate. This happens millions of times a
second in each cell. Eventually, the ADP gains back the P04 to become ATP so the
process can start over again.
Reaction:
ATP+H2O⇋ADP+Pi+energy
We have slow twitch and fast twitch muscles in the body.
Slow twitch muscles perform better in endurance events like the Marathon we
just had in New York City. Each person differs in how much slow or fast twitch
muscle they have. All muscles have both types of muscle fibers. Some people are
better at sprinting because they have more fast twitch muscles.
These two muscle types have different processes for making
ATP. Cells in both types of muscle fiber break down glucose and use the
chemical energy to produce ATP, but slow-twitch muscle fibers do sow
aerobically – using oxygen, while fast-twitch muscle fibers do so
anaerobically.
Plants and some bacteria or algae are producers and
autotrophs; they make their own nutrients – carbohydrates, proteins, fats –
from inorganic material and the sun’s energy. Material includes nutrients from
the soil and water. Heterotrophs derive raw material for their carbohydrates,
fats and proteins from other organisms such as plants or animals. Humans are
heterotrophs.
Photosynthesis
In plants, chlorophyll in chloroplasts uses the sun’s
energy, carbon dioxide and water to form sugar. Plants also use nutrients and
nitrogen from the soil to form proteins. So, according to what vegetable we
eat, we get a different amount of grams of carbohydrates or protein.
Photosynthesis converts light energy to chemical energy.
Respiration uses oxygen, released by plants into the atmosphere, to convert
energy in chemical bonds of organic fuels to ATP, which is another source of
chemical energy.
For both plants and animals, the production of ATP during respiration
occurs in mitochondria.
Plants store energy in photosynthesis and then use respiration
themselves to harvest this energy. Photosynthesis produces fuels and respiration
burns them.
Starch in potatoes is a polysaccharide. Some engineers are
getting ethanol fuel from plants.
Aerobic Cellular
Respiration
Involves taking in oxygen and expelling carbon dioxide.
C6H12O6 + 6O2 →
6CO2 + 6H2O
glucose +
oxygen -> carbon dioxide + water
About 32 ATP
molecules are produced for each glucose molecule burned.
Oxidation =
removal of electrons
Reduction =
addition of electrons
NADH carries
electrons from glucose and other molecules and deposits them on top of the
electron transport chain. The molecule at the bottom of the chai drops the
electrons to oxygen.
Three Parts of
Cellular Respiration
A.
Glycolysis
Glycol
– sweet or sugar lysis – splitting
Glucose is split into two pyruvic acids. Two molecules of ATP
are used but after the electron transport cycle with NAD+, four ATPS are
produced, for a net of two ATP molecules per molecule of glucose.
B.
Citric
Acid Cycle or TCA or Krebs Cycle completes the breakdown of glucose.
Pyruvic
acid is changed to acetic acid. Each acetic acid is attached to coenzyme A from
B vitamin pantothenic acid. Acetyl CoA is formed. They enter into the citric
acid cycle. CoA is recycled. Acetic acid plus carbons forms citric acid. For
each acetic acid molecule, tow carbon dioxides exit. Some energy makes ATP, but
more energy from NADH and FADH2 is used to make even more ATP.
Different sugars are involved.
C.
Electron transport Chain
This
is a redox reaction: Electrons are lost. This is called oxidation. Glucose loses
electrons to oxygen and is oxidized. Energy is released. Oxygen is one of the strongest
electron grabber atoms. The electrons of the hydrogen in glucose “fall” into
their new bonds with oxygen. The path of
electrons from glucose to oxygen happens with nicotinamide adenine dinucleotide
or NAD+. NAD+ is reduced to NADH.
This
is part of the electron transport chain in mitochondria.
Figure 6.11 A concentration gradient of H+ in the inner mitochondria
is the potential energy source that drives ATP production by the enzyme ATP
synthase.
Figure 6.13 Carbohydrates enter respiration via glycolysis; glycerol
enters respiration via glycolysis from fats; fatty acids at acetyl CoA and protein
amino acids at all three.
Anaerobic Respiration
When your muscles use AATP faster than your blood can
deliver oxygen, as in intense workouts or sports, anaerobic respiration takes
over. Muscles can work anaerobically for 15 seconds. Then they use fermentation
to generate ATP. During anaerobic respiration, there is no oxygen to accept
electrons. Instead, NADH disposes of electrons by adding them to pyruvic acid
produced by glycolysis. Figure 6.4
Pyruvic acid + electrons yields lactic acid. It is
transported to the liver and converted back to pyruvic acid.
Anaerobic respiration yields just 2 ATPs.
Some microorganisms just need anaerobic respiration. Some of
these transform milk to cheese, sour cream and yogurt. Yeast uses both respiration
and fermentation. IF there is no oxygen in their environment, they resort to
anaerobic respiration. Ethyl alcohol and carbon dioxide are the waste product. Beer and wine are produced this
way. Yeast in bread yield carbon dioxide that causes dough to rise.