PHGY 170 EXAM QUESTIONS AND ANSWERS
100% SOLVED
Cellular metabolism - ANSWER summation of all of the different reactions that take place in
cell
Catabolism - ANSWER Breakdown of cellular macromolecules and releases the energy stored
within them. Released energy is transferred to other molecules and is stored as ATP
Anabolism - ANSWER Production of cellular macromolecules. Consume ATP and build
macromolecules that the cell needs
Energy molecules (ATP, GTP, NAD+. FAD) - ANSWER o ATP= adenosine triphosphate
Composed of adenosine molecule, ribose sugar, and chain of 3 phosphates
§
Phosphates are important-store a lot of energy b/w the 2nd and 3rd phosphates
§
o GTP= guanosine triphosphate, identical to ATP, except adenosine is replaced with
guanosine. GTP is another primary cellular energy source and can considered to be the same
as ATP
o NAD+ (nicotinamide adenine dinucleotide): NAD+ is changed to its high energy form by
addition of an H+ ions and 2 electrons, producing NADH
o FAD (flavin adenine, dinucleotide): FADH is changed to its higher energy from by the
addition of two H+ ions and two electrons, production FADH2
,Function of the mitochondria - ANSWER Organelles that take large macromolecules and
break them down to produce the energy in the form of ATP, that cells need
Structure of the mitochondria - ANSWER Double layered membrane
§
Inner membrane= folded on itself to form structures called cristae
§
Inside of the mitochondria= matrix; where the macromolecules are converted into small,
§
high-energy compounds such as NADH
Cellular respiration - ANSWER o Cellular respiration: ATP production and comprises the
catabolic reactions and processes that convert organic macromolecules into ATP. 2 stages
o Stage 1: stripping of high-energy electrons off of these macromolecules and storing them in
high energy electron carriers
o Stage 2: Combining of these electrons with protons and molecular oxygen to water. In these
processes, energy is stored as a proton gradient across the mitochondrial inner membrane
and this gradient is then used to generate ATP
Sources of glucose for cellular metabolism - ANSWER Monosaccharides: Glucose: most
§
commonly consumed in the form of glucose
Disaccharides: Lactose: consist of two monosaccharides bonded by an alpha or beta-1,4
§
glycosidic linkage
Polysaccharides: glycogen: longer chains of monosaccharides. Act as energy storage
§
molecules that must be broken down before being used to produce cell energy.
How does glucose get into cells? - ANSWER Glucose first enters the blood from ingested
§
,foods, de novo synthesis (formation of complex molecules in the body from simpler
molecules) or from the breakdown of glycogen stores.
Once in the blood, glucose circulates and is available for cells to use
§
Most common way to get glucose into cells is by glucose transporters (GLUT) found in
§
most mammalian cells
Why are there 10 steps of glycolysis - ANSWER · Catabolic reactions are exothermic, meaning
they give off heat. Glucose has a lot of energy stored within it and if all the energy was stored
at the same time, it will likely kill the cell
· 10 step process allows the energy stored in glucose to be released a little at a time so that it
can be efficiently transferred to other molecules with only a small amount lost as heat
What are the stages of glycolysis (3) - ANSWER Stage 1: one glucose molecule is
§
converted into 2 glyceraldehyde-3-phosphate molecules (G3P) molecules. Uses 2 ATP
Stage 2: Each G3P is converted to a molecule called 3-phosphoglycerate. Each G3P
§
produces one ATP and one NADH Net ATP is 0 and net NADH is 2
Stage 3: 3-phosphoglycerate is converted to pyruvate. Each 3-phosphoglycerate at this
§
stage produces one pyruvate and one ATP. Therefore one glucose has been converted 2
pyruvate and produced 2 ATP and 2 NADH
What are the anaerobic metabolism pathways? - ANSWER In plant cells and yeast:
§
pyruvate undergoes fermentation and is converted into ethanol in a process oxidizing the
high energy molecule NADH into NAD+
In most animal cells and bacteria, pyruvate is reduced so that NADH can be oxidized to
§
NAD+ and lactate (lactic acid) is formed.
, § In either case, the NADH produced during glycolysis is consumed resulting in a net yield of
2 ATP per glucose molecule
What are the stages of aerobic respiration? - ANSWER -Glycolysis
-Conversion of pyruvate to acetyl-CoA
-Krebs Cycle
-ETC
-Formation of ATP by ATPsynthase
Conversion of pyruvate into acetyl CoA - ANSWER · Pyruvate in the cytosol of the cell is
transported to the mitochondria, the site of ATP production
· A carrier molecule on the inner mitochondrial membrane brings pyruvate into the matrix
· Pyruvate is decarboxylated (removal of a carbon) by the pyruvate dehydrogenase complex.
· Complex takes pyruvate, NAD+ and CoA and converts it to acetyl-coA, NADH and CO2.
· Acetyl-CoA can then enter the Krebs Cycle
· Glucose yielded 2 pyruvate so net energy production at this stage is 2 NADH
Krebs cycle - ANSWER Acetyl CoA combines with oxaloacetate (OAA) to form citrate (a 6C
§
molecule). CoA is released and can be recycled to produce more acetyl-CoA
Citrate is broken down by several chemical reactions to remove two of the carbons and
§
create succinate. Removal of carbons transfers energy to two NAD+ to form two NADH
releases the carbon in the form of two CO2. A GTP is also produced
100% SOLVED
Cellular metabolism - ANSWER summation of all of the different reactions that take place in
cell
Catabolism - ANSWER Breakdown of cellular macromolecules and releases the energy stored
within them. Released energy is transferred to other molecules and is stored as ATP
Anabolism - ANSWER Production of cellular macromolecules. Consume ATP and build
macromolecules that the cell needs
Energy molecules (ATP, GTP, NAD+. FAD) - ANSWER o ATP= adenosine triphosphate
Composed of adenosine molecule, ribose sugar, and chain of 3 phosphates
§
Phosphates are important-store a lot of energy b/w the 2nd and 3rd phosphates
§
o GTP= guanosine triphosphate, identical to ATP, except adenosine is replaced with
guanosine. GTP is another primary cellular energy source and can considered to be the same
as ATP
o NAD+ (nicotinamide adenine dinucleotide): NAD+ is changed to its high energy form by
addition of an H+ ions and 2 electrons, producing NADH
o FAD (flavin adenine, dinucleotide): FADH is changed to its higher energy from by the
addition of two H+ ions and two electrons, production FADH2
,Function of the mitochondria - ANSWER Organelles that take large macromolecules and
break them down to produce the energy in the form of ATP, that cells need
Structure of the mitochondria - ANSWER Double layered membrane
§
Inner membrane= folded on itself to form structures called cristae
§
Inside of the mitochondria= matrix; where the macromolecules are converted into small,
§
high-energy compounds such as NADH
Cellular respiration - ANSWER o Cellular respiration: ATP production and comprises the
catabolic reactions and processes that convert organic macromolecules into ATP. 2 stages
o Stage 1: stripping of high-energy electrons off of these macromolecules and storing them in
high energy electron carriers
o Stage 2: Combining of these electrons with protons and molecular oxygen to water. In these
processes, energy is stored as a proton gradient across the mitochondrial inner membrane
and this gradient is then used to generate ATP
Sources of glucose for cellular metabolism - ANSWER Monosaccharides: Glucose: most
§
commonly consumed in the form of glucose
Disaccharides: Lactose: consist of two monosaccharides bonded by an alpha or beta-1,4
§
glycosidic linkage
Polysaccharides: glycogen: longer chains of monosaccharides. Act as energy storage
§
molecules that must be broken down before being used to produce cell energy.
How does glucose get into cells? - ANSWER Glucose first enters the blood from ingested
§
,foods, de novo synthesis (formation of complex molecules in the body from simpler
molecules) or from the breakdown of glycogen stores.
Once in the blood, glucose circulates and is available for cells to use
§
Most common way to get glucose into cells is by glucose transporters (GLUT) found in
§
most mammalian cells
Why are there 10 steps of glycolysis - ANSWER · Catabolic reactions are exothermic, meaning
they give off heat. Glucose has a lot of energy stored within it and if all the energy was stored
at the same time, it will likely kill the cell
· 10 step process allows the energy stored in glucose to be released a little at a time so that it
can be efficiently transferred to other molecules with only a small amount lost as heat
What are the stages of glycolysis (3) - ANSWER Stage 1: one glucose molecule is
§
converted into 2 glyceraldehyde-3-phosphate molecules (G3P) molecules. Uses 2 ATP
Stage 2: Each G3P is converted to a molecule called 3-phosphoglycerate. Each G3P
§
produces one ATP and one NADH Net ATP is 0 and net NADH is 2
Stage 3: 3-phosphoglycerate is converted to pyruvate. Each 3-phosphoglycerate at this
§
stage produces one pyruvate and one ATP. Therefore one glucose has been converted 2
pyruvate and produced 2 ATP and 2 NADH
What are the anaerobic metabolism pathways? - ANSWER In plant cells and yeast:
§
pyruvate undergoes fermentation and is converted into ethanol in a process oxidizing the
high energy molecule NADH into NAD+
In most animal cells and bacteria, pyruvate is reduced so that NADH can be oxidized to
§
NAD+ and lactate (lactic acid) is formed.
, § In either case, the NADH produced during glycolysis is consumed resulting in a net yield of
2 ATP per glucose molecule
What are the stages of aerobic respiration? - ANSWER -Glycolysis
-Conversion of pyruvate to acetyl-CoA
-Krebs Cycle
-ETC
-Formation of ATP by ATPsynthase
Conversion of pyruvate into acetyl CoA - ANSWER · Pyruvate in the cytosol of the cell is
transported to the mitochondria, the site of ATP production
· A carrier molecule on the inner mitochondrial membrane brings pyruvate into the matrix
· Pyruvate is decarboxylated (removal of a carbon) by the pyruvate dehydrogenase complex.
· Complex takes pyruvate, NAD+ and CoA and converts it to acetyl-coA, NADH and CO2.
· Acetyl-CoA can then enter the Krebs Cycle
· Glucose yielded 2 pyruvate so net energy production at this stage is 2 NADH
Krebs cycle - ANSWER Acetyl CoA combines with oxaloacetate (OAA) to form citrate (a 6C
§
molecule). CoA is released and can be recycled to produce more acetyl-CoA
Citrate is broken down by several chemical reactions to remove two of the carbons and
§
create succinate. Removal of carbons transfers energy to two NAD+ to form two NADH
releases the carbon in the form of two CO2. A GTP is also produced
