Chapter 13 - Tecniques In Biotechnology

Question 1

What is biotechnology?

Answer 1

Biotechnology manipulates cellular processes for genetic engineering or to make products that are of use to humans.

Question 2

What does biotechnology cover? (What processes)

Answer 2

Genetic testing, gene manipulation, cell replacement therapies and tissue engineering.

• PCR
• Gel electrophoresis
• DNA sequencing
• Gene therapy
• Recombinant DNA technology

Question 3

What is a genome?

Answer 3

A genome is the complete set of genetic information of an organism.

Question 4

Describe what DNA molecules consist of.

Answer 4

All DNA molecules consist of two strands of alternating sugars (deoxyribose)

• Phosphate Group
• sugar molecule
• nitrogenous base

Question 5

What are the four different nitrogen bases?

Answer 5

Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)

Question 6

What are nucleotides?

Answer 6

The basic structural unit of a nucleic acid.

Each nucleotide consists of deoxyribose (a 5 carbon sugar), a phosphate group and a nitrogenous base.

Question 7

What is DNA sequencing?

Answer 7

DNA sequencing is the determination of the precise order of nucleotides in a sample of DNA.

• Determines the exact order of nucleotides in a gene
• Allows for different strands of DNA to be compared

Question 8

Describe Frederick Sanger’s DNA sequencing method.

Answer 8

1. The DNA to be sequenced must be de-natured and separated into single DNA strands. The DNA splits into a template strand and a complimentary strand.
2. A primer than anneals to the template strand
3. Four reaction mixtures are made.
4. The template strand with the attached primer is added to these mixtures, followed by all four dNTP’s (nucleoside triphosphate) and specially ddNTPS. Only one ddNTPS is added to each mixture.
5. The polymerase attaches the dNTPS to the template strand at the primer until the ddNTPS is attached. Once the ddNTPS is attached the sequence is terminated as it lacks a Hydroxly group.
6. A’s a result, DNA fragments of different lengths are formed across all four mixtures.
7. Gel electrophoresis is used to sequence the DNA.

Question 9

What is the purpose of electrophoresis?

Answer 9

To determine a person’s DNA profile/ fingerprint.

To distinguish one person’s DNA from someone else’s DNA.

Question 10

Explain the process of electrophoresis

Answer 10

1. DNA pieces are placed on a semi-solid gel and an electric current is passed through electrodes at either ends.
2. The DNA, which is negatively charged, moves through the gel towards the positive electrode
3. The DNA strands form a barcode like pattern.
   This banding pattern is known as an individual’s DNA profile or DNA fingerprint.

Question 11

What are DNA fingerprints used for?

Answer 11

• Tracing ancestry
• forensic science
• identification of heredity diseases
• Establishing a person’s DNA profile

Question 12

What does PCR stand for?

Answer 12

Polymerase chain reaction

Question 13

What is PCR?

Answer 13

PCR is when segments of DNA are artificially multiplied through a series of repeated cycles of duplication using an enzyme called DNA polymerase.

Question 14

Describe the process of PCR.

Answer 14

1. To initiate duplication, a primer (a segment of DNA complimentary to the targeted sequence of DNA) initiated replication by the taq DNA polymerase.
2. The DNA polymerase replicates itself many times, doubling the number of DNA each replication.

Question 15

Why is temperature so important during PCR?

Answer 15

Heat is essential to seperate the strands of DNA but cool conditions are essential for the synthesis of the DNA by the enzyme.

Question 16

What is Recombinant DNA technology?

Answer 16

Recombinant DNA technology, also referred to as genetic engineering, involved the introduction of DNA into cells, where the DNA is foreign to that organism or has been modified in some way. It has huge potential for replacing faulty genes with healthy ones.

Question 17

What are transgenic organisms?

Answer 17

Transgenic organisms are those whose genome has been altered by the transfer of a gene or genes from another organism. The introduced genes become part of the transgenic organism’s DNA and can be passed on to future generations.

Question 18

What are bacteriophages or phages?

Answer 18

Viruses that infect bacterial cells.

Question 19

What are restriction enzymes?

Answer 19

Certain enzymes that cut the DNA at a certain sequence of nucleotides.

Question 20

What is a recognition site?

Answer 20

The point in which the enzyme cuts the DNA.

Question 21

What are the differences between straight cuts and staggered cuts?

Answer 21

A straight cut is when the restriction enzyme makes a clean cut across the two strands of DNA. Straight cuts produce blunt ends in which both strands terminate in a base pair.
A staggered cut results in sticky ends, which is when a stretch of unpaired nucleotides overhang at the break in the strands.

Question 22

What is the recognition site and bacterial origin of BamHI?

Answer 22

GATC - Bacillus amyloliquefaciens

Question 23

What is the recognition site and bacterial origin of EcoRI?

Answer 23

AATT - Escherichia coli

Question 24

What is the recognition site and bacterial origin of HindIII?

Answer 24

AGCT - Haemophilus influenzae

Question 25

What is the recognition site and bacterial origin of Taql?

Answer 25

CG - Thermus aquaticus

Question 26

What is ligation?

Answer 26

When an enzyme known as DNA ligase is capable of combining two small components of a single-strand DNA into one single structure.

Question 27

Explain the steps of producing an organism with recombinant DNA.

Answer 27

1. Isolate the gene and cut it out using a restriction enzyme.
2. Isolate a plasmid from a bacterial cell and cut it using the same restriction enzyme used in step 1.
3. Splice the human DNA into the plasmid using DNA ligase enzymes to join the sticky ends.
4. Treat the bacterium so it takes up the recombinant plasmid. Once this is successful, the bacterium will multiply so that the either the human gene or the product of the gene can be used.

Question 28

What is a plasmid?

Answer 28

Small circular strand of DNA distinct from the main bacterial genome ; it is composed of only a few genes and is able to replicate independently within a cell.

Question 29

What is a vector?

Answer 29

A bacterial plasmid, viral phage or other such agent used to transfer genetic material from one cell to another.

Question 30

What is gene therapy?

Answer 30

Gene therapy aims to treat or cure genetic abnormalities by replacing faulty genes with healthy ones.