exam II Flashcards
what is the name of the process in which larger molecules are broken down into smaller products to release energy?
catabolism
With regard to metabolic reactions, what does “endergonic” mean?
Energy input is required for reaction
When electrons are transferred from donor molecules to acceptor molecules in a redox reaction, what happens to the donor molecule?
It is oxidized
Which of the following is NOT a factor that can influence the rate of an enzymatic reaction?
Pressure
Which of the following statements best describes glycolysis?
Glucose is catabolized into 2 molecules of pyruvate and 2 ATP
A site on an enzyme other than the active site that can bind molecules and influence the shape of the active site is referred to as a(n) ________.
allosteric site
Which cellular process results in the most significant production of ATP?
chemiosmosis
Where does oxidative phosphorylation occur in prokaryotes?
cytoplasmic membrane
Which of the following statements regarding chemiosmosis is TRUE?
Energy released when hydrogen ions flow down a concentration gradient is used to form ATP
What cellular process occurs in the absence of oxygen, oxidizes NADH to NAD+, and reduces cellular organic molecules?
fermentation
What is the most common lipid involved in the production of ATP and various metabolites?
fat
What is the first step of lipid catabolism?
Lipase hydrolyzes fat into glycerol plus three fatty acids.
During lipid catabolism, fatty acid chains undergo beta-oxidation to create ________.
acetyl-CoA, NADH, and FADH2
What is the first step of protein catabolism?
Proteases break down proteins into their constituent amino acids.
The process by which the amino group from an amino acid is removed to produce a molecule that can be catabolized in the Krebs cycle is referred to as ________.
deamination
What is the function of photosystems within cells?
to absorb light energy and store it in the form of ATP and NADPH
One of the major differences between cyclic and noncyclic photophosphorylation is that ________.
NADPH is made only in noncyclic photophosphorylation
Photophosphorylation is most similar to which of the following processes?
oxidative phosphorylation
The main result of the Calvin-Benson cycle, which is part of the light-independent reactions of photosynthesis, is ________.
carbon fixation
What is the final electron acceptor in cyclic photophosphorylation?
the original electron donor
What is gluconeogenesis?
the synthesis of sugars from noncarbohydrate precursors
What cellular structures are responsible for joining together amino acids to form proteins?
ribosomes
The five-carbon sugars that are required for nucleotide biosynthesis are produced in what catabolic pathway?
pentose phosphate pathway
Which of the following is NOT a way that cells regulate metabolic function?
production of all metabolic enzymes all the time
What is one metabolic process that generates the glycerol precursor necessary for lipid biosynthesis?
glycolysis
Biochemical tests are useful in identifying microbes because of all the following reasons EXCEPT which one?
Microbes use different ATP molecules.
what is metabolism?
sum of all chemical activities in the cell
what are the roles of ATP?
energy storage and transferring of phosphate group to release energy
what is the main goal of metabolism?
reproduction
what is phosphorylation?
addition of a phiospahte group to a substrate
what are the 3 types of phosphorylation?
- substrate level
- oxidatuve
3.photophosphorylation
what is oxidation?
loss of electrons
what is reduction?
gaining of electrons
what is a redox reaction?
transfer of electrons from a donor to an acceptor
what is activation energy?
energy required to bring molecules in a chemical rxn to their active site
what is an active site?
site of catalysis
what is a substrate?
a molecule that an enzyme reacts with
what are the 3 important electron carriers?
- NAD+, NADH
- NADP, NADPH2
- FAD, FADH2
why are electrons always coupled?
electrons can t exists by themselves
what is the function of enzymes?
speed up & catalyze rxns and lower activation energy
what are the two types of enzynmes?
- simple
- conjugate
what are the parts of a conjugate enzyme?
protein part: apoenzyme
nonprotein part:
cofactor (inorganic), coenzyme (organic)
what is a holoenzyme?
a whole enzyme
what factors influence enzyme activity?
temp, pH, and substarte concentration
what is the difference between competitive and noncompetitive inhibition?
competitve inhibors competes with the sunstrate for binnding at the actuve site and noncompetite inhibitors binds at the site distinct from the actuive site
what is the difference between allosteric inhibition and allosteric activation?
allosteric inhibitors change the shape of the active site so that the substrate cant bind and allosteric activation changes the shape of the active site so that the substrate will “fit’
what are ribozymes?
enzymatic RNA molecules
what is feedback inhibition?
when the final product acts as an inhibitor to the first enzyme in the pathway
The RNA part in ribozymes are?
catalytic
What happens in spliceosomes in eukaryotes?
the RNA catalyzes removal of introns
what are metabolites?
small breakdown products
what is catabolism?
breaking down of larger molecules into smaller molecules
what is cellular respiration?
complete breakdown of glucose to CO2 and H2O
what are the 4 steps of cellular respiration?
- glycolysis
- synthesis
- kreb’s cycle
- electron transport chain
what is fermentation in cells?
after glycolysis, pyruvic acid is converted into another compound (organic waste products)
where does cellular respiration occur in prokaryotes and eukaryotes?
prokaryotes- cell membrane
eukaryotes- mitochondria
what is glycolysis also named as?
energy investment/producing stage
what happens in glycolysis?
glucose is converted into a more usable form called pyruvate in the cytoplasm
what are the products of glycolysis?
NET YIELD: 2 pyruvate, 2 ATP, and 2 NADPH
what happens in the synthesis stage of cellular respiration?
- two pyruvate are transported by active transport into the mitochondria
- pyruvate is oxidized and converted into two acetyl CoA
- CO2 is released and two NADPH are produced
what happens in the kreb’s cycle?
2 acetyl CoA enters and CO2 is released
what are the products of the kreb’s cycle?
2 ATP, 6 NADPH, and 2 FADPH
what happens in the electron transport chain?
- electrons are transferred from NADPH and FADPH to protein complexes and electron carriers
- electrons are used to generate a proton gradient as protons are pumped across the intermembrane space
what is the goal of ETC?
extract high energy electrons from NADH and FADH2
what happens to energy as it is transported through the ETC?
some of it is lost, so cells can capture energy
what is the function of the ETC?
ATP production and to release energy
what is another name for the kreb’s cycle?
tricarboxylic acid (TCA) cycle
substrate level phosphorylation is used to produce ATP in which stages?
glycolysis and kreb’s cycle
what is chemiosmosis?
H+ flow and ATP production
what happens in chemiosmosis?
protons travel down their electrical gradient thru a portion of ATP synthase pairing it to make ATP
what is the function of the proton motive force in chemiosmois?
to drive H+ back into the cell thru a channel called ATP synthase
what is the final electron acceptor in chemiosmosis?
oxygen
what happens when the H+ passes thru ATP synthase?
the enzyme carries out the reaction
what are the results of chemisosmos?
oxidative phosphorylation
what is oxidative phosphorylation?
synthesis of ATP using a proton gradient from the oxidation of components of ETC
how much does ATP yield in chemiosmosis?
3 ATP for every NADH
2 ATP for every FADH2
electron carriers per glucose?
NADH = 10
FADH2 = 2
ETC per glucose?
3 x 10 NADH = 30 ATP
2 x 2 FADH2 = 4 ATP
what is the total number of ATP in cellular respiration?
glycolysis = 2 ATP
kreb’s cycle = 2 ATP
ETC per glucose = 34 ATP
TOTAL = 38 ATP
what is the balanced chemical formula of cellular respiration?
C 6 H 12 O 6 + 6 O 2 –> 6 CO 2 + 6 H 2 O + ATP
what are examples of election acceptors in anaerobic respiration?
nitrate (Pseudomonas or Bacillus), sulfate (Desulforibric), and carbonate (methanogenic bacteria)
when do the cells do fermentation?
when there is no oxygen available
what happens in fermentation of cells?
NAD+ is reduce to NADH so that it can give electrons to an electron acceptor
which organisms can do anaerobic respiration?
bacteria and archaea
why do yeast and muscle cells only do glycolysis?
it doesn’t require oxygen
how much ATP is produced in fermentation?
2 ATP
what is the final electron acceptor in fermentation?
an organic molecule
where is lactic acid fermentation done?
in the muscle cells
how is lactic acid fermentation done?
start with glycolysis and regenerate the NAD+ step: 2 pyruvate will yield 2 lactate
what is the final electron acceptor in lactic acid fermentation?
pyruvate, allowing NADH to oxidize to NAD+ so glycolysis can happen