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Amino acids contain which two functional
groups?
a.
and
b.
and
c.
and
d.
and
Answer: c
ATP serves as a common energy source for
organisms because
(a) it is the smallest energy molecule.
(b) it stores the least energy of any
energy source.
(c) its energy can be easily transferred
to do cellular work.
(d) it is extremely stable and can be
stored in the cell for long periods of time.
(e) traces of it have been found in fossils
of ancient organisms dating back to the
beginning of life on Earth.
Answer: c
All of the following are true about enzymes
EXCEPT:
a. Enzymes accelerate reactions by lowering
the energy of activation.
b. Some enzymes are allosteric.
c. Most are proteins.
d. All enzymes in the human are most active
at 37 C and at a pH around 7.
e. They catalyze reactions in both directions.
Answer: D
The bonding of two amino acid molecules to
form a larger molecule requires
a. the release of a water molecule.
b. the release of a carbon dioxide molecule.
c. the addition of a nitrogen atom.
d. the addition of a water molecule.
e. an increase in activation energy.
Answer: a
A particular poison binds to certain enzymes
at positions other than the active site,thus
deactivating the enzyme. This is an example of
a. noncompetitive inhibition
b. competitive inhibition
c. denaturing
d. allosteric inhibition
e. irreversible inhibition
Answer: D
Certain metabolic pathways are affected by the
Buildup of a product which interacts with an enzyme
Catalyzing one of the initial steps of the pathway;
This can be an example of
(a) transcriptional regulation.
(b) thermodynamic regulation.
(c) translational regulation
(d) feedback inhibition.
(e) posttranscriptional modification.
Answer: d
Which of the following statements regarding
coenzymes is true.
(a) They are essential for metabolic
reactions in animals but not in plants.
(b) They can facilitate metabolic reactions
by combining with enzymes and their active
sites.
(c) They are minerals that alter the pH of
cells and thus increase the probability of
chemical reactions.
(d) They are synthesized in the rough ER
of eukaryotic cells.
(e) They typically work best at temperatures
Answer: b
below 37C.
•Made of nucleotides (nitrogen base,
pentose sugar, phosphate)
•Informational
•C, H, O, N, P
•Phosphodiester linkage
•Deoxyribose
•Double stranded
•Thymine
•Makes up genes
•Ribose
•Single stranded
•Uracil
•Structure and protein synthesis
Peptide bond
• C, H, O, N, sometimes S
• Molecular tools
• Structure, enzymes, antibodies
Transport, movement, receptors, hormones
• Chains of amino acids linked by peptide
bonds
•Gives protein its properties
Secondary
Primary
Tertiary
Quaternary
Heat
pH changes
High salts
2001- Proteins- large complex molecules- are
major building blocks of all living organisms.
Discuss the following in relation to proteins.
a. The chemical composition and levels
of structure of proteins.
2008-
Substrate bound to active
site by weak interactions
(hydrogen bond, ionic bond,
Van der Waals force, etc.)
The enzyme cystathionine b-synthase (CBS) catalyzes the condenation of serine and homocysteine to produce
cystathionine, an important intermediate in the biosynthesis of cysteine. Deficiency of CBS activity results in toxic
levels of homocysteine and is the most common cause of homocystinuria, a disease whose symptoms include
dislocated eye lenses, skeletal and vascular problems, and mental retardation. Mammalian CBS is a unique heme
protein that requires the cofactor pyridoxal 5'-phosphate (PLP). Although heme is essential for activity inmammalian
CBS, the chemistry is performed by PLP, and heme is not present in the enzyme of lower organisms. Why, then, has
nature included a heme in the CBS of mammals? Our hypothesis is that the heme of CBS is acting as a regulator of
enzyme activity. A number of studies demonstrate that there is communication between the heme and the active site,
e.g. small molecule binding and reduction of the heme both diminish enzyme activity. In collaboration with Professor
Jan Kraus (University of Colorado, Denver), we are currently probing the enzyme and the heme with a variety of
spectroscopic and biochemical methods, such as electronic absorption and magnetic circular dichroism (MCD), and
resonance Raman spectroscopies, site-directed mutagenesis, and radiochemical enzyme assays in an attempt to unlock
the mystery of the heme in this enzyme.
All of the following are true about enzymes
EXCEPT:
a. Enzymes accelerate reactions by lowering
the energy of activation.
b. Some enzymes are allosteric.
c. Most are proteins.
d. All enzymes in the human are most active
at 37 C and at a pH around 7.
e. They catalyze reactions in both directions.
Answer: D
Certain metabolic pathways are affected by the
Buildup of a product which interacts with an enzyme
Catalyzing one of the initial steps of the pathway;
This can be an example of
(a) transcriptional regulation.
(b) thermodynamic regulation.
(c) translational regulation
(d) feedback inhibition.
(e) posttranscriptional modification.
Answer: d
Amino acids contain which two functional
groups?
a.
and
b.
and
c.
and
d.
and
Answer: c
Which of the following statements regarding
coenzymes is true.
(a) They are essential for metabolic
reactions in animals but not in plants.
(b) They can facilitate metabolic reactions
by combining with enzymes and their active
sites.
(c) They are minerals that alter the pH of
cells and thus increase the probability of
chemical reactions.
(d) They are synthesized in the rough ER
of eukaryotic cells.
(e) They typically work best at temperatures
Answer: b
below 37C.
ATP serves as a common energy source for
organisms because
(a) it is the smallest energy molecule.
(b) it stores the least energy of any
energy source.
(c) its energy can be easily transferred
to do cellular work.
(d) it is extremely stable and can be
stored in the cell for long periods of time.
(e) traces of it have been found in fossils
of ancient organisms dating back to the
beginning of life on Earth.
Answer: c
The bonding of two amino acid molecules to
form a larger molecule requires
a. the release of a water molecule.
b. the release of a carbon dioxide molecule.
c. the addition of a nitrogen atom.
d. the addition of a water molecule.
e. an increase in activation energy.
Answer: a