Enzyme fin the blank
enzymes act as vitamins
are a type of
- which speed up metabolic reactions. they
protein
amino accas
- molecule, which are polymers of smaller
joined into a long chain. these chains coil into
a_spiral
and then fold up to produce a particular shape. their
activity depends upon their shape, which is specic
they are
relatively fragile and
- in water. the shape can be destroyed by
various factors, which include changes in ph
tempahce
solvents and metal lons. each enzyme is
to a particular reaction
te. it will catalyze only one reaction. enzymes are now named according to who
they act on e. g. urease catalyses the hydrolysis (splitting) of urea but older names
do not reflect this. one model of the way enzymes work is the lock and
- theory. the enzyme has a shape on it's surface, called
the active
- site, which fits the substrate molecule (the one it acts on).
the substrate binds into this site, is held by a particular charge pattern, reacts and
then leaves as the product(s).as the enzyme is not changed in each reaction it can
act over and over again and a few enzyme molecules can catalyze many
substale molecules. the number of molecules that one enzyme can
catalyze in a minute is called the
__number. this can be
from 15 to 36 million. many enzymes need another molecule or metallon, called a
cofactor, to be present to work. many
are cofactors to
enzymes (and are called coenzymes). amounts of enzymes are regulated in various
ways so that reactions do not get out of -
e. g. by a gene
turning off production, by other enzymes in feedback mechanisms and by hormones.
control
protein
turnover
cubetrate

transcription is a process in which information is rewritten. it is something our cells must do, in a more specialized and narrowly defined way. in biology, transcription is the process of copying out the dna sequence of a gene in the similar alphabet of rna. it needs to happen in the nucleus because that's where the dna is. dna is always inside the nucleus unless the cell is dividing.

transcription is the first step in gene expression, which involves copying a gene's dna sequence to make an rna molecule. transcription is performed by rna polymerases. it has three stages: initiation, elongation, and termination. rna molecules must be processed after transcription in eukaryotes.

explanation:

long version:

the protein synthesis consists two processes which are, transcription and translation. transcription takes place in the nucleus. it uses dna as a template to make an rna molecule. rna then leaves the nucleus and goes to a ribosome in the cytoplasm, where translation occurs. transcription is the first part of the central dogma of molecular biology: dna → rna. it is the transfer of genetic instructions in dna to messenger rna (mrna). during transcription, a strand of mrna is made that is complementary to a strand of dna.  

these three stages are:

  initiation: in which   is the beginning of transcription.occuring when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

    elongation: in which is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

    termination: in which is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.

it's not c. i took the quiz and got it wrong. so my best guess is b.

have a great day, and hope this .