Download 29 Cellular Respiration Biology “B”

29 Cellular Respiration
Biology “B”
Pages 145-152
Name: _____________________ Date: _________ Period: _______
Animals eat and breakdown plant products (sugar/glucose) in a process
called digestion. Human digestion requires us to internally digest food by
chewing food, swallowing, processing food in the stomach to further break it
down, and then absorb the basic parts of the food (sugars and such) into the
bloodstream through our intestine. Each movement; getting food, chewing
it, swallowing, uses energy and LOSES heat energy. It COSTS energy to
get and process food! When the sugar gets to the bloodstream it is
absorbed by individual cells that need the sugar to run the engine of the cell.
The cell has to break down sugar with a series of enzymes. (See diagrampg.2.) Enzymes are specialized protein molecules that help a reaction go
forward. An enzyme attaches to another molecule to change that molecule
in some way. Enzymes will attach to specific molecules (called substrates)
and change the substrate in some way to form a product. The reaction is
shown below:
Enzyme causes reaction to go
forward to make product(s)
The enzyme in the reaction remains UNCHANGED. The enzyme merely
helps two substrates come together in this case. Enzymes are also known to
attach to a substrate and make two or more products.
There are two parts to the breakdown of sugar once it gets inside the cell:
a.) Glycolysis- (this is from “glyco-“ referring to glucose and “-lysis”
meaning break) Glycolysis means the “break down of sugar”. The
break down of sugars occurs in the cytoplasm of the cell and
requires the enzymes to use two ATP molecules. One molecule of
glucose (C6H12O6) is converted through a series of steps to TWO
molecules of pyruvate (C3H4O3). This process produces four more
ATP than it takes to perform glycolysis! This occurs in bacteria and
yeast. So JUST breaking down glucose to pyruvate yields 4 NET
energy packets or ATPs. This is not a lot of energy compared to the
total energy stored in glucose. Glycolysis needs no oxygen it is
anaerobic (means reaction does not need oxygen).
Page 2 (Cont. #29 Bio. B)
b.) Pyruvate is then taken into the mitochondria and enters a series of
reactions, called the Krebs Cycle. This does not occur in bacteria or
yeast! That is because bacteria and yeast do NOT have mitochondria!
The products of this cycle are used in the electron transport cycle to help
produce a lot (36 of them to be exact*) of energy packets (ATP) in cells
with mitochondria.
The entire process of getting the food into the body and getting ATP is:
#1
#2
#3
#4
To get the sugar into the body, we first eat
the different macromolecules and chew them up.
The reason to chew the food is to mechanically
break down the food so enzymes can break the
macromolecules down easier (that is the enzymes
need to GET AT every single molecule). If the
molecules are stuck in a huge ball, many of the
molecules will be protected from the enzymes and
won’t be broken down (so chew food completely).
As you can see to the left, large molecules
are swallowed (see “FOOD” see “#1”) and enter
the stomach (see #2). Though some digestion (read
this as breakdown of the macromolecules) occurs
here, most of the digestion occurs just below the
stomach, in the intestine (see #3).
In the intestine, the macromolecules
(polymers) have been broken down into smaller
units and they start to get to be absorbed by the
intestinal cells (see #4). The intestinal cells send
the simple molecules into the blood stream that
makes the simple sugars and amino acids (amino
acids are building blocks of protein) available to
individual cells (see #5- below)
SO-the over-all breakdown of glucose is
shown below in a diagram form.
#5
Mitochondria
2 pyruvate
Water
Cytoplasm
Krebs Cycle
ATP and water are
final products
Page 3 (Cont. #29 Bio. Cytoplasm
or cytosol
B)
Glucose is brought into
the cell and broken
down into the
cytoplasm into two
molecules of pyruvate.
(See picture to the
right.)
Cytoplasm
2 pyruvate
1 glucose molecule in
the cytoplasm of a cell
Pyruvate then moves into the mitochondria to be
broken down further using a “cycle of enzymes” in the
Citric Acid Cycle or Krebs Cycle which eventually leads
to making energy packets (ATP) that the cell can
actually “run” on. ALL living cells run almost
exclusively on ATP. This is just like most homes use
mostly electricity to run most lights, televisions, and
machines, in your house. Cells use mostly ATP to run
MOST reactions in the cell- with the help of enzymes.
Mitochondria
Answer the following questions here and on your scan-tron!
_____1.) Glycolysis helps to:
a.) create complex high energy compounds
b.) bring together two molecules of pyruvate
c.) release the energy stored in the bonds of glucose
d.) release the energy stored in water
Page 4 (Cont. #29 Bio. B
_____ 2.) There are one-celled bacteria (NOT blue-green) and single-celled
yeast that do not have mitochondria. How do they process energy?
a.) use sun for energy b.) use glycolysis only c.) use Krebs only
_____ 3.) The definition of glycolysis is:
a.) the breakage of lipids
b.) the breakage of protein
c.) glyco- referring to glucose and -lysis, meaning to break
d.) the creation starch
_____ 4.) Glucose breaks into:
a.) 3 pyruvate b.)oxygen and water c.) 2 pyruvate d.) none of these
_____ 5.) Pyruvate is modified as it moves into the:
a.) nucleus b.) ribosomes c.) mitochondria d.) centrioles
_____ 6.) The overall process of glycolysis produces:
a.) more oxygen than carbon dioxide
b.) more NADPH than NADH
c.) more ATP than was used to initiate the reaction
d.) less ATP than was used to initiate the reaction
_____ 7.) Modified pyruvate enters the mitochondria and enters the
a.) glycolysis 2 cycle b.) Calvin cycle c.) Glycolytic cycle d.) Krebs cycle
_____ 8.) The Krebs cycle (Citric Acid Cycle) and electron transport yields
a.) Glucose and carbon dioxide
b.) Glucose and oxygen
c.) ATP and water
d.) ATP and oxygen
_____ 9.) An enzyme
a.) causes a reaction to stay the same b.) causes the reaction to go backward
c.) raises the activation energy
d.) causes the reaction to go forward
_____ 10.) Enzymes
a.) are changed by the reaction
b.) lose at least one electron during the reaction
c.) are made of lipids
d.) are usually made of proteins and are unchanged during a reaction
Date: __________________________
Lesson Plan for Handout #29 Biology B
Objective: TLWD ability to determine how enzymes do their work, trace
the macromolecules ingested from the mouth to being broken down and
absorbed, and finally broken down to make ATP when given handout #29.
Content: Ingestion of macromolecules, broken down to monomers,
absorbed into blood stream and individual cells and broken down for cellular
energy (ATP)
NJCCCS: 5.3.12.B.5, 5.3.12.B.6.
Method: Power point, notes, discussion, white board
Homework: Complete #29
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