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…
