Search Results

Polymerase chain reaction PCR - Animation

By: HWC, Views: 481

Polymerase chain reaction (PCR) is a method that amplifies fragments of DNA. The purpose of PCR is to create copies of a specific region of DNA. To use this technique, researchers must know the base sequences at either end of the region of interest. They use this information to create...

The Lagging Strand in DNA Replication and Replication in Action

By: HWC, Views: 6145

The lagging strand is the strand of nascent DNA whose direction of synthesis is opposite to the direction of the growing replication fork. DNA backbones run in opposite directions, the strands in a DNA molecule are oriented antiparallel to one another. New DNA is made by enzymes called DNA...

Semidiscontinuous DNA replication

By: HWC, Views: 6289

During DNA replication, one of the two DNA strands, the leading strand, is replicated continuously, or all at once, in the 5' to 3' direction. The other strand, called the lagging strand, is replicated discontinuously, or in pieces, in the 3' to 5' direction. This is necessary because DNA poly...

Replication of DNA and Chromosomes/ How do cells replicate their DNA? (Animation) no Audio

By: HWC, Views: 6386

DNA replication in E. coil begins at a site called oriC where a replication bubble forms. At either end of this bubble is a replication fork. Since DNA polymerase Ill can read its DNA template strand only in the 3' to 5' direction this means that one strand (leading) can be read continuously b...

New DNA Strand Replication

By: HWC, Views: 6136

First step: strands are separated • Helicase unwinds the DNA double helix at the replication fork • SSBs coat the single strands to prevent reannealing • Polymerase attaches nucleotide at 3' end • Synthesis is in 5' to 3' direction DNA Polymerase: • Only extends nucleic ac...

Hershey Chase Experiments

By: HWC, Views: 3816

Hershey and Chase knew that T4 bacteriophages consist of proteins and DNA. They asked which viral component must enter a bacterial cell to infect it: DNA or protein? They grew viruses with either radioactive sulfur, which labels the viral protein, or radioactive phosphorus, which labels DNA. ...

DNA Sequences - Dideoxy Sequencing

By: HWC, Views: 5979

A short, radiolabeled primer is annealed to the single-stranded DNA to be sequenced. The DNA serves as a template for in vitro DNA synthesis. The DNA-primer mixture is split into four separate tubes. DNA polymerase and a solution of dNTPs are added to each tube. One of the four 2',3' dideoxy-N...

Transferring genes into plants Animation

By: HWC, Views: 4043

Researchers extract DNA from an organism that has a trait they want to introduce into a plant. The genetic donor can be a bacterial cell, a plant cell. or even an animal cell. The desired gene will be transferred into a plasmid, a small circle of bacterial DNA. The gene is cut out of th...

ribosome

By: HWC, Views: 6326

The trp operon in E. coli contains five structural genes corresponding to enzymes that convert chorismate into tryptophan. The trpE gene contains a 5' untranslated region that plays an important role in the regulatory mechanism called attenuation. The 5' UTR contains four regions. Region 1 en...