Extras G Flashcards
Gene probe
A short, single-stranded piece of
DNA. The gene probe has a complementary
nucleotide base sequence to the gene which is
being sought. Gene probes are either radioactive
or have fluorescent molecules bound to them.
This allows identification of the probe, and the
gene it binds to.
Gene therapy
Treatment of inherited diseases by
altering a person’s genetic make-up. For
example, in 2003, trials were being carried out
on patients with cystic fibrosis (CF). These trials
involved introducing copies of the normal CF
allele into cells in the lungs. This should allow
the lung cells to produce normal CFTR protein.
Some success has been achieved with this
treatment and it is hoped that one day it may
provide a cure.
Germ cell, Germ line
A gamete, or a cell which
is able to develop into a gamete. Germ-line gene
therapy involves inserting genes into germ cells.
Any change which resulted from the insertion of
such a gene would be passed on to subsequent
generations. Because of the possible effects of
this, germ-line gene therapy is not permitted in
humans.
Genetic screening/testing
Procedure that allows
the identification of cells or individuals with a
particular DNA sequence.
Germination, Germinate
Germination is a
process that starts when a seed absorbs water. Its
food reserves are broken down by enzymes and
the embryo starts to grow. The root or radicle
emerges and grows down into the soil. The shoot
or plumule grows up towards the light. The
changes that take place during germination are
controlled by plant growth substances.
Giant chromosomes
In most organisms, as an
organ grows its cells divide. The organs of some
insects, however, grow in a different way. Their
cells just get bigger and bigger. In these giant
cells, the DNA replicates but mitosis does not
take place. When some of these giant cells are
examined under a microscope, it is possible to
see giant chromosomes. They are many times
the size of the chromosomes in other cells. The
giant chromosomes are made up of many copies
of each chromosome joined together. As these
chromosomes can be seen with a light
microscope, they are used to study chromosome
behaviour.
Globular protein
A protein where the
polypeptide chain is folded into a compact
spherical shape.
Glycerol
Glycerol, C3H8O3, is constituent of
many fats and oils. A triglyceride is formed
from a molecule of glycerol and three fatty acid
molecules. A condensation reaction removes
water from between the glycerol and each of the
fatty acids forming an ester bond. Glycerol is
also found in phospholipids.
Gymnosperm
A cone-bearing plant such as a
pine tree.
