Terms and definitions - Science

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11 Δεκ 2012 (πριν από 4 χρόνια και 7 μήνες)

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From “Continuing Biology” Meg Bayley, David Layzell

Definitions for:

Biotechnology

(Biology 3.
6
)

To revise, cover the right
-
hand side of the table with a sheet of paper and move down the left column seeing
which words you already know the definitions of (slide the paper down a word at a time to check). Tick

these ones
off, and concentrate on the others until you have learnt them all. Then cover the left
-
hand side of the table and
have a go at writing the words to match the definitions!

If a word on the right
-
hand side is in
bold
, there is a definition for it

elsewhere in the table.

The shaded words are less important.


Bacteriophage

virus

A virus whose host is a bacterium

Callus

Undifferentiated plant tissue

cDNA

Copy or complementary DNA. DNA without introns (only exons). It is produced
using

reverse trans
criptase

Clone

A genetically identical copy of an organism. This includes cuttings, tubers,
grafting, tissue culture but
not
seed formation

Dideoxynucleotide

Modified bases which when added to a reaction mixture cause chain
termination. Used in
gene sequ
encing

DNA chip (DNA microarray)

Glass or silicon plate studded with DNA fragments

DNA fingerprinting
(profiling)

The process of analysing the DNA of an individual's body tissue or fluids for the
purpose of identification. It often includes the process o
f
Southern blotting

DNA polymerase

An enzyme that joins (polymerises) DNA

Explant

A section cut from a disease
-
free stock plant in tissue culture

Genetic engineering

The same as genetic modification, but used by speakers and writers who are
opposed to t
he techniques

Genetic modification

Transfer of genetic material from one individual to another. The recipient may
or may not be of the same species

Gene gun

A technique used to ‘fire’ ‘bullets’ of tungsten or gold coated with a gene into
cells

Gene ther
apy

The transfer of genetic material from one person to another for their medical
benefit. The same techniques are used as in any genetic modification

Ligase

A enzyme used to join sections of DNA together

Liposome

Spherical membrane similar in structure
to cell membranes. Liposomes are
used to introduce genetic material into cells

Microsatellites

STR



short tandem repeats. Short sequences (2

8 base pairs) able to repeat
up to 100 times. Humans have many microsatellites and the number of repeats
varies b
etween people. This is used to gene profile people using
PCR

Minisatellites

VNTR


variable number tandem repeats. Repeating sequences of a few tens
of bases. The significance of minisatellites is that the patterns in different
people or other organisms v
ary considerably. These can be electrophoresed to
identify or fingerprint individuals

Node

The part of the plant stem where stalks, branches, buds and flowers originate

PCR

Polymerase Chain Reaction (gene amplification). A technique for multiplication
of

DNA

Plasmid

A small circular section of DNA in a bacterium. It contains several thousand
bases compared to the millions in bacterial chromosomes

Primer

A short section of RNA used as a starting sequence for
PCR

or gene
sequencing

Recombinant DNA

DNA in
to which a foreign gene has been inserted

Restriction enzyme

An enzyme that cuts DNA at particular recognition sites of from 4 to 8 bases

Retrovirus

A virus that has RNA and not DNA as its genetic material. To replicate in a cell
it must use the enzyme

r
everse transcriptase

Reverse transcriptase

An enzyme that makes DNA from RNA

Sequencing

The process by which scientists work out the base sequence of genes. This
uses dideoxynucleotides and may be done manually or automatically

Southern blotting

A proce
ss during genetic profiling whereby a nitrocellulose sheet is placed on
top of an electrophoresis gel, and the DNA ia partially transferred to the more
stable sheet by placing blotting paper on top of the sheet and drawing the
From “Continuing Biology” Meg Bayley, David Layzell

liquid up from the gel

Stem
cell

Unspecialised cell that renews itself by dividing. Can develop into specialised
tissue. Stem cells are
embryonic

(derived from embryos) or
adult

(found in
adult tissue)

Tissue culture

Cloning of plants by taking sections of stem, root, leaf or callus

and growing
them under sterile conditions with the help of hormones and growth factors

Transformation

The transfer of plasmids between bacteria. This can happen with mammal cells
if they are chemically treated

Transgenesis

The transfer of genetic materi
al from one species to another

Variable DNA

DNA unique to each person. It is variable DNA that is used in
DNA
fingerprinting

Xenotransplantation

The transplantation of tissues and organs between different species, and in
particular the transplantation of

animal tissue into humans