Define: Metabolism, catabolism and anabolism
Metabolism- Sum of all anabolic and catabolic processes in a cell or organism
catabolism- Rxn’s that increase entropy e.g. hydrolysis
anabolism- Rxn’s that involve the decrease of entropy e.g. condensation
What are the two laws of thermodynamics?
1st- energy cannot be created nor destroyed. only converted into another form
2nd- Entropy in the universe is constantly increasing
How many carbon atoms are in: glucose, pyruvate, acetyl-CoA and citrate?
glucose- 6
pyruvate- 3
acetyl-CoA- 2
citrate- 6
- What does ATP stand for?
- What class of biologically important molecules is ATP related to?
- Describe how ATP is used to provide energy
ATP- Adenosine Triphosphate
Molecules ATP is related to- Nucleotides (protein)
ATP usage: When a cell needs energy, it breaks ATP to form ADP and a free phosphate molecule.
Identify the location in the cell and net products of: glycolysis, matrix rxn’s, and ETS (oxidative phosphorylation)
glycolysis- Cytoplasm (2 ATP, 2 NADH, 2 pyruvates)
matrix rxn’s- Krebs cycle, pyruvate oxidation (2 ATP, 8 NADH, 2 FADH2, 2 CO2,)
ETS- Inner membrane, cristae or mitochondria (32 ATP)
Explain what’s happening in these specific steps:
a) conversion of PEP to pyruvate in glycolysis
b) conversion of isocitrate to alpha-ketoglutarate in Krebs cycle
PEP to pyruvate- ADP becomes ATP and a phosphate is lost
isocitrate to alpha-ketoglutarate- NAD+ is oxidized to NADH and CO2 is removed
If a patient was deficient in the enzyme that converts fructose-1,6-biphosphate into DHAP, what molecule might start building up in the cell?
ADP, NAD+
What is the role of: NAD+, NADH, FAD, FADH2 and which is in the oxidized/ reduced form?
NAD+ - Oxidized
NADH- Reduced
FAD- Oxidized
FADH2- Reduced
- NADH and FADH2 reduce o2 to h2o through the ETC.
- The energy released is used to make a proton gradient across the inner mitochondria.
- The protons flow down this concentration gradient through the ATPase and the energy released is used to make ATP.
- Describe the role of oxygen in the ETS
- How does lack of oxygen affect the ETS and Krebs cycle?
- Is glycolysis affected? Why?
- What is the effect of cyanide on the ETS?
- The ETS uses oxygen (and glucose) and converts them to ATP
- Krebs cycle doesn’t need oxygen but it can only occur if oxygen is present because it needs by-products from the ETC which requires oxygen.
- Cyanide blocks the passage of electrons throughout the chain stopping ATP from being produced. No ATP= ETC stops working. (basically the person dies)
How many glucose molecules would be produced by hydrolysis of these and how many ATP in aerobic conditions?
- 2 maltose
- 3 sucrose
Hydrolysis:
2 glucose for maltose (2x36=72)
1 glucose for sucrose (3x36=108)
Aerobic conditions:
4 glucose for maltose (4x36=144)
3 glucose for sucrose (3x26=108)
What is the real purpose of fermentation?
Makes it possible for ATP to still be produced in the absence of oxygen
How is ATP synthesized by the ETS?
In chemiosmosis protons diffuse through ATP synthase to make ATP
How do these foods enter into the metabolic cycles of cellular respiration?
- Proteins
- Lipids
Protein: Your body has to break down proteins into amino acids before they can be used by your cells.
Lipids: Glycerol turns into G3P and continues through the remainder of the cellular respiration. Fatty acids must break down (beta-oxidation), which takes place in the matrix.
Define photosynthesis and write the equation
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy
6CO2 + 6H2O —> C6H12O6 + 6O2
What is the relationship between light rxn’s and the Calvin cycle?
ATP and NADPH are formed during light reactions which are used in the Calvin cycle. The Calvin cycle produces ADP, NADP+, and phosphates that are used in the light reactions.
What are the products of the light rxn and the Calvin cycle?
Light Rxn: Oxygen
Calvin cycle: Sugar
What is photophosphorylation and chemiosmosis?
photophosphorylation- use of light energy from photosynthesis to provide the energy to convert ADP to ATP
chemiosmosis- movement of hydrogen ions across a membrane during cellular respiration or photosynthesis.
Describe the flow of protons and electrons in the light dependent rxn’s and the associated molecules (photosystems 1 and 2)
When the sun hits ,it excites the electrons to go down the ETC which then creates the electro chemical gradient to drive the ions from the stroma to the lumen and at the same time the electrons directly make NADH.
Anaerobic cellular respiration of glucose equation
C6H12O6 + 6O2 → 6CO2 + 6H2O
How do plants exchange gases with air?
As it travels through the air space of the leaf it diffuses and leaves the stomata
