Lecture 5 Flashcards
What is the difference between metabolism, catabolism, and anabolism?
Catabolism: Breaking down molecules to make energy (ATP) and precursor molecules
Metabolism:
Anabolism: Using energy (ATP) from catabolism and
building blocks to make/repair
macromolecules, ultimately for reproduction
Metabolism
all chemical reactions and physical workings of the cell
Catabolism(exergonic)
Breaking down “ganing energy” molecules to make energy (ATP) and precursor molecules for anabolism
• Overall, makes energy (exergonic)
Anabolism (endergonic)
requires energy Using energy (ATP) from catabolism and building blocks to make/repair macromolecules, ultimately for reproduction
Metabolism
for cell to maintain itself, and for it to live
how is it related to catabolism and anabolism?
Intermediates in catabolism can be used in anabolism
What are some important characteristics of enzymes (Table 7.1 entries underlined in red in
lecture slides)?
Acts as organic catalysts to speed up the rate of cellular reactions, have an active
site for target molecules called substrates, are not used up or permanently changed by the
reaction, can be recycled thus function in extremely low concentrations, affected by
temperature and pH (affect structure of the enzyme, very important to their structure, can be
regulated by feedback by feedback and genetic mechanisms
Do enzymes catalyze a reaction in a single direction only, or can they be reversible?
Reversible, a given enzyme can usually catalyze a given chemical reaction in either direction
Are all enzymes proteins?
Most enzymes are proteins (a few are RNA)
What is the difference between an apoenzyme and a holoenzyme?
Protein portion, the cofactos form the holoenzyme
Are enzymes very specific or non-specific in the kinds of substrates that they bind?
Very specific to what they bind too
What are some ways in which enzymes can be inhibited?
Blocking access to the substrate, lack of specificity, failure to release products, damage or structural change to the enzyme
How could you recognize a word as likely being the name of an enzyme?
“-ase”
What are general names of enzymes involved in breaking down carbohydrates, proteins, fats, and nucleic acids?
Carbohydrase: digests a carbohydrate substrate •
Amylase: acts on starch, producing glucose •
Maltase: digests maltose •
Protease: hydrolyzes the peptide bonds of a protein, yielding amino acids •
Lipase: digests fats •
Nuclease: digests DNA or RNA **shape greatly affects enzymes
What is meant by the term “metabolic pathway”?
enzymes working together,
Why might enzymes be regulated?
Regulation may be in response to levels of substrate,
product, or other environmental parameters, avoid making an enzyme if a substrate is not
present, prevent activity if no more product is needed
Are constitutive enzymes regulated?
No not regulated or always on, involved in basic cellular processes,
What are two levels at which enzymes can be regulated?
enzyme synthesis (make enzyme or not) , enzyme activity
What is meant by enzyme induction and repression?
turning on or increasing expression(induction) turning off or decreasing expression: enzyme repression
What is the difference between competitive and non-competitive inhibition?
Competitive: inhibitor molecule binds at same site as substrate/ noncomp: inhibitor molecule binds to enzyme
elsewhere
What does feedback inhibition refer to?
Starting enzyme throughout, end product will react with first enzyme, prevent activity of other enzymes
What are the three major components of ATP, and what is ATP used for?
Three major components: nitrogen base(adenine) 5-carbon sugar (ribose) chain of 3 phosphate, used for: endergonic reactions, used as an energy source, common energy currency for cellular respiration
What are three major cellular electron carriers?
Major cellular electron carries include NADH, FADH (flavin adenine dinucleotide), and quinones
What sort of enzymatic reactions would ATP be used to drive (make favorable)?
?Enzymes that perform enderogonic reactions…
Which are located in the cytoplasm, and which are found in the cytoplasmic membrane?
What are redox reactions?
involve transfer of electrons from one molecule to another. Redox reactions can be written as two “half reactions” that involve the molecules being oxidized or reduced
What are some major differences between fermentation, aerobic respiration, and anaerobic respiration (when using glucose as an example substrate)?
Oxidation of glucose, Aerobic respiration (yields the most
ATP: 36-38 per glucose) yields more energy, anaerobic 2-36, fermentation 2 per glucose,
What is the fate of glucose (complete vs. incomplete oxidation)? in fermentation
What happens to theglucose in ana and aerobic, glucose is oxided to carbon dioxed, in fermentation you
don’t get complete oxidation
What is the terminal electron acceptor (TEA)?
Molecular oxygen aerobic ana:oxidized usually inorganic molecule, fermentation: organic compounds, come from products of glycolosis,
What types of organisms perform fermentation, aerobic respiration, and anaerobic respiration (both taxonomically, and in terms of their relationship to oxygen)?
?
How much ATP is produced, and what is the term used to the process of ATP production during glycolysis?
2 ATP, 2 NADH, and 2 pyruvate
Where in the cell does glycolysis take place?
cytoplasm
What are the products of fermentation?
Alcohols (e.g. ethanol), organic acids (e.g. lactate, acetate, beer, wine
What are the major products of the Krebs cycle, and what molecule is used as the primary input?
Pyruvate is oxidized completely to CO2 • Additional NADH is produced, as well as GTP, FADH • NADH (and
FADH) are used as e- input to electron transport chain, doesn’t make ATP itself, electron to electorn chain
What are some major components of the electron transport chain?
Proteins embedded in the cytoplasmic membrane, such as • NADH dehydrogenase •Cytochromes • Terminal oxidases
And where in the cell is the electron transport chain located?
mitochondria
During electron transport what molecule is pumped out of the cell
NADH
What force is produced through electron transport?
exergonic reaction
what does the enzyme ATP syntase use this force to make?
proton motive force
What is the process called?
oxidative phosphoriation
How does electron transport chain differ inanaerobic respiration from aerobic?
other molecules act as TEA
different electron transport proteins are used
How do strict fementors make a proton motive force
through glycolysis
ATP synthase
how might a cell be able to utilize substrates such as amino acids or fatty acids as substrates for catabolism
They can contribute nitrogenous groups to nucleotides to form nucleic acids
In anabolism, what sort of building blocks are used to synthesize nucleic acids, proteins, starch,
and lipids? Where does the energy required for this synthesis come from?
nucleotides
amino acids
cabrs
fatty acids
-Using energy (ATP) from catabolism
Where do electrons transported through this chain eventually end up?
Electrons from NADH are passed through the electron transport chain
These exergonic transfers allow transport of H+ out of the cell against the concentration gradient
Proton motor force What does the enzyme ATP synthase use this force to make, and
what is the name of this process
ATP is made by a process called substrate-level phosphorylation
In contrast to oxidative phosphorylation in respiration
Glucose was used as a generic example of a substrate for heterotrophic catabolism. In very
general terms, how might a cell be able to utilize substrates such as amino acids or fatty acids as
substrates for catabolism
. Extracellular proteins are digested by secreted proteases. Enzymes deaminate (remove NH3) and desulfurylate (remove S) amino acids, which leads to the formation of a variety of metabolic intermediates, including pyruvate and acetyl CoA.
Nucleic acids can be degraded into nucleotides by nucleases and further processed by removing phosphate
Also, fatty acids can be oxidized to form acetyl CoA, which enters the Krebs cycle
How do microbes that are strict fermenters (no respiration or electron transport chain) make a
proton motive force, and why would they do this?
They can make ATP through glycolysis…
PMF can also be used for transport and flagellar motility
