Astudent isolates, purifies, and combines in a test tube a variety of molecules needed for dna replication. after adding some dna to the mixture, replication occurs, but each dna molecule consists of a normal strand paired with numerous segments of dna a few hundred nucleotides long. what has the student probably left out of the mixture

DNA ligase

Explanation:

DNA replication is an enzyme mediated, 3-step process during which the DNA molecule produces a copy of itself. The 3 steps involved are as follows;

Initiation involves the unwinding of the double helix structure of the DNA using DNA helicase enzyme

Elongation involves binding of RNA primer to the DNA strands and addition of bases to the primer to elongate the new chains. Bases are added to the leading strand continuously while the lagging strand is replicated in short segments (okazaki segments).

Termination involves the unbinding of RNA primer and substitution of its bases by DNA bases. The Okazaki fragments are then joined together using the DNA ligase enzyme.

The short, numerous segments of DNA observed in the mixture is the Okazaki fragments of the lagging strand. This is due to the absence of the enzyme involved in the joining of these fragments.

Hence, the answer is DNA ligase.

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.

if the hares very faster than they are now, and thus the lynx's hunting success rate drops because it will be harder to catch them, the rate that will change will be the pray-rate. the pray-rate will change because more hares will be able to survive, thus more individuals for reproduction, so the end result will be increasing population of hares.

the predator-rate will remain pretty much the same because there will be more than enough pray, but the hunting success rate is stagnant.