21 1 biotechnology and genetic modification

Biotechnology is the use of living organisms to produce products that are useful to humans.

Bacteria are useful in biotechnology because:

Plasmids in bacteria are useful in biotechnology because they are an easy way of introducing new genes into bacteria during genetic modification.

Yeast produce ethanol for biofuels during anaerobic respiration as follows: glucoseethanol + carbon dioxide

False. ** Yeast can carry out anaerobic respiration** in the absence of oxygen.

In bread making yeast uses sugars for anaerobic respiration, producing carbon dioxide that causes the dough to rise.

False. Pectinase enzyme enables the production of clear fruit juices.

It is useful to add enzymes to washing powders because:

Lactose free milk can be produced using lactase enzymes which break down the lactose in milk.

Products that can be produced in fermenters include:

Mycoprotein is a protein-rich food produced by a fungus. It is suitable for vegetarians and often used as a meat-substitute.

Conditions that need to be controlled inside a fermenter include:

Temperature needs to be controlled inside fermenters because respiring microorganisms release heat when they respire. The fermenter therefore needs to be kept cool to ensure that microbial enzymes do not denature.

Genetic modification involves changing the genetic material of an organism by removing, changing or inserting individual genes.

True. Human genes can be inserted into bacteria for the production of human proteins, e.g. insulin.

Crop varieties might be genetically modified to introduce:

Restriction enzymes are used in genetic modification to cut specific DNA sequences, allowing for the isolation of genes. These enzymes cut DNA at specific nucleotide sequences, resulting in fragments with sticky ends.

True. ** The same restriction enzyme is used to cut the human gene and the plasmid to make sure they have the same complementary DNA bases on their sticky ends**; this allows the sticky ends to bond together.

Recombinant DNA is DNA taken from two different organisms combined into one strand.

Plasmids allow DNA to be transferred into bacterial cells.

Bacteria make copies of the modified recombinant DNA inside them as they reproduce by asexual reproduction. This passes on the recombinant DNA to their offspring.

Once bacteria have been genetically modified to contain the correct gene, they are able to reproduce quickly and synthesise the specific protein required.

Rice has been genetically modified to produce golden rice which has an increased vitamin A content.

False. Soya has been modified to provide herbicide resistance, meaning that it can be treated with a weedkiller without harming the crop. Bt toxin is produced by GM maize and GM cotton.

Advantages and disadvantages of genetic modification in crops include: