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Enzymes are Proteins

Enzymes are proteins that speed up the reactions by acting as catalysts. They increase the rate of reaction without being consumed or permanently altered by themselves. In Greek enzymes are divided into sections “En” which means “in” and second part is “zyme” means living. The study of enzymes is known as...

How To Know Your Thread Is Not Good Anymore

Definitely, the thread is not something like the metal that will last forever in your closet. You should replace it once it is too old to use or when it is about to end. Many sewing beginners must be thinking that their best basic sewing...

Food Technology - Careers

A Catalyst article about careers in the food industry. The food and drink industries are part of a chain linking farming and growing through to food processing, manufacture and finally to the sale of food in supermarkets and restaurants. This article describes some of the many career areas in food technology...

Electrophoresis gel with annotation

Di-deoxy sequencing is a way to determine the order of bases (A,C,G and T) in a piece of DNA. A set of 4 lanes (one for each base) is needed to sequence any given piece of DNA. Wherever a black
band appears in a particular lane that base is present. By reading off the order of bands across the four lanes the...

Di-deoxy sequencing gel with annotation

Di-deoxy sequencing is a way to determine the order of bases (A,C,G and T) in a piece of DNA.  A set of 4 lanes (one for each base) is needed to sequence any given piece of DNA. Wherever a black band appears in a particular lane that base is present. By reading off the order of bands across the four lanes the...

Automated DNA sequencing output

The output from an automated DNA sequencing robot used by the Human Genome Project to determine the complete human DNA sequence. Each peak shows the presence of a particular base. The sequence of bases in a given stretch of DNA can therefore be read from the order of the peaks along the trace. The sequences of...

Chromosomes in metaphase

An image representing human chromosomes in metaphase. Atomic Force Microscope image of human chromosomes in a metaphase spread.

This resource is part of the Post 16 genetics and ...

DNA replication theory

Diagramatic representation of the replication of DNA. This is the process by which the cell makes a copy of its existing DNA before it divides. This therefore ensures that each new cell receives a full complement of DNA. The DNA polymerase enzyme can only add new bases in the 5'-3' direction. This leads to...

Hydrogen bonding

Diagram showing the hydrogen bonds that form between the four bases in the DNA double helix. These weak forces between the bases keep the two complementary strands of DNA together and ensure that the correct bases are put in the right place during replication of the DNA molecule. A always pairs with T and C always...

Semi-conservative replication images

A collection of images representing semi conservative DNA replication:

Illustration depicting semi-conservative DNA replication 1. Three generations of DNA are shown. After separation of the DNA double helix, two new complementary DNA strands are synthesised (indicated by a new colour)....

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