lecture 13 Flashcards
What does photosynthesis generate and what is it used for?
generates O2 and is used for cellular respiration
How is ATP generated in photosynthesis?
cells use chemical energy stored in organic molecules to generate it, which powers work
What is catabolism
the breakdown of complex molecules in living organisms to form simpler ones
What is anabolism?
the synthesis of complex molecules in living organisms from simpler ones together with the storage of energy
What are the 3 stages of cellular respiration?
Glycolysis, pyruvate oxidation, oxidative phosphorylation
What is chemiosmosis?
the process of moving ions (e.g. protons) to the other side of a biological membrane
What is cellular respiration?
a metabolic pathway that breaks down glucose and other organic molecules and produces ATP
What are the two types of redox reactions?
Oxidation and reduction
What happens when oxidation occurs?
a substance loses electrons or is oxidized (charge becomes more positive)
What happens when reduction occurs?
a substance gains electrons, or is reduced (positive charge is reduced)
True/False: even a change in the degree of electron sharing between atoms can be considered a redox reaction.
True
What is the release of energy used for in redox reaction?
to synthesize ATP
What organic molecules are excellent sources of high-energy electrons?
organic molecules with an abundance of hydrogen
What happens when electrons associated with hydrogen ions are transferred to oxygen?
energy is released and it goes to a lower energy state
Where are electrons transferred to during cellular respiration?
NAD+
What is the oxidizing agent during cellular respiration?
NAD+ (electron acceptor)
What does NAD+ represent?
stored energy that is tapped to synthesize ATP. NAD+ is a dehydrogenase (enzyme)
What happens through the electron transport chain?
NADH passes electrons through the chain, O2 pulls the electrons down the chain in an energy-yielding tumble, the energy is used to regenerate ATP
What is the trend of each member of the electron chain?
each member of the chain is more electronegative than the one before
What are the three ways to generate ATP?
- substrate level phosphorylation
- oxidative phosphorylation linked to electron transportation system
- Photosynthetic phosphorylation
What is substrate level phosphorylation?
ATP is made directly, reactions of glycolysis and citric acid cycle
Which two methods of generating ATP involve ETS?
-oxidative phosphorylation linked to electron transportation system
-Photosynthetic phosphorylation
What is glycolysis?
uses 2 atp to split the sugar . breaks down glucose into 4 ATP, NADH, and two molecules of pyruvate (each have 3 carbon)
Where does glycolysis occur?
In the cytoplasm
What are the two major phases of glycolysis?
energy investment phase
energy payoff phase
True/False: glycolysis occurs whether or not oxygen is present.
True
Is glycolysis aerobic or anaerobic?
anaerobic
All living organisms have the core of glycolysis and are typically cytoplasmic. What does this suggest?
the first living cells did a form of glycolysis
How does glycolysis generate ATP?
substrate level phosphorylation
What did Dr. Harold Amos do?
discovered 5-methylcytosine in E. coli RNA
Who? Microbiologists known for groundbreaking work in gene expression and glycolysis
Dr. Harold Amos
Who? First-African American to get a phd from Harvards Division of Medical Sciences
Dr. Harold Amos
Who? First-African American to head a medical school department at harvard
Dr. Harold Amos
Who? Interest in starvation conditions and glucose uptake, specifically when cells are starved of nicotinamide
Dr. Harold Amos
What are the two enzymes in the energy investment phase of glycolysis?
Kinase and Isomerase
What does isomerase do?
Converts a molecule into isometric form
What are the three enzymes in the energy payoff phase of glycolysis?
Dehydrogenase
kinase
Mutase
What is mutase?
an enzyme that moves functional groups
What is Dehydrogenase?
an enzyme responsible for redox reactions
What is the main roll of fermentation?
regenerate NAD+ to keep glycolysis moving forward; it also enables cells to produce ATP without oxygen
What happens during alcohol fermentation?
pyruvate is converted to ethanol
What does alcohol fermentation release and produce?
release CO2, produce NAD+ and ethanol
What happens during lactic acid fermentation?
pyruvate is reduced by NADH, forming NAD+ and lactate as end products, with no release of CO2
What are common uses of lactic acid fermentation?
production of yogurt
muscle cells use it to generate ATP during strenuous exercise when O2 is scarce
What do obligate anaerobes do?
carry out fermentation or anaerobic respiration and cannot survive in the presence of O2
What are facultative anaerobes?
anaerobes that can survive using either fermentation or cellular respiration
What are examples of facultative anaerobes?
Yeast and many bacteria
What happens in a facultative anaerobe?
pyruvate is a fork in the metabolic, road that leads to two alternative catabolic routes; aerobic respiration or anaerobic/fermentation
