Biology Unit 9 Biotechnology IHS Skavaril

DNA sequencing

Process used to determine the order of nucleic acids in DNA

The four step of the Sanger Method of DNA sequencing

1. Cut

2. Copy

3. Sort

4. Read

What type of macromolecule do scientists use to complete Step 1 of the Sanger method

Restriction enzymes

What are the two types of cut restriction enzymes can make in DNA

Blunt ends and sticky ends

What is the mass of the average DNA sample taken from humans

1-10 nanograms

What is the mass of DNA needed for Sanger sequencing

1000 nanograms

What is the process used to complete Step 2 of the Sanger Method

Polymerase chain reaction (PCR)

What are the four substrates needed for PCR

1. DNA (to copy wanted DNA)

2. Primers (to mark the starting line)

3. DNA polymerase enzymes (to make the DNA)

4. Nucleotides (the building blocks)

How many copies of DNA are made after 1 PCR cycle

2

• Equation: 2ᕽ (x = the amount of PCR cycles)

What is the process used to complete Step 3 of the Sanger Method

Gel electrophoresis

What electric charge does DNA segments have

Slightly negative

What direction does DNA segments move in the gel

To the positive end

How can you tell what DNA fragment is the longest/shortest

The shorter pieces are further down the positive end of the gel

How to read sequence of the DNA fragment made during PCR

Read from shortest DNA strand to longest

• Sequence of original DNA fragment is the complement of the read DNA

Selective breeding

A way to make sure desired trats are passed down to the next generation

• e.g. dogs: same ancestors (wolves) but bred for specific traits

Hybridization

Type of selective breeding; when humans bred 2 things together to get the best traits of each.

• e.g. mules: cross of horse and donkey

Inbreeding

Type of selective breeding; once a trait has been identified, they breed within the family to keep the traits

• e.g. pugs: small, flat nose

Recombinant DNA

Taking a gene from one organism and inserting it into another organism

Plasmids

Circular DNA molecules in bacteria that only code for a few proteins

Why is it necessary to cut the gene to be inserted and the plasmid with the same restriction enzyme

So they have the same sticky ends so the actual gene can be inserted into bacteria

CRISPR

• Direct gene editing in organism’s genome

• An enzyme cuts the DNA → DNA can be changed

• When certain bacteria are attacked by a virus, they incorporate part of the invader's DNA into their own, allowing them to create specialized molecules that humans can harness

4 applications of biotechnology

• Genetically modified organisms (GMO)

• Clones

• DNA finger printing (forensics)

• Gene therapy

Gene therapy

Correcting the underlying genetic conditions to treat a disease

Cloning

Process of making an exact copy of an organism

The 5 steps of cloning

1. Remove egg from donor

2. Remove nucleus from egg

3. Take nucleus out of somatic (body) cell

4. Insert somatic nucleus into egg cell

5. Implant egg back into donor

Restriction enzymes

Enzymes that cut and destroys foreign DNA

How many bases are in the human genome

6 billion

Research efforts that resulted from the Human Genome Project

• Sharing of scientific data

• Sanger sequencing & gel electrophoresis

How do we know when ddNTPs stop DNA replication

With a bright fluorescent light (it glows)

What is used in Sanger sequencing

Scientists use a mix of regular nucleotides and dideoxynucleotides (ddNTPs)

Describe how people increase genetic variation

Sexual reproduction or controlled mating of organisms

Describe how scientists copy the DNA of living organisms

Polymerase Chain Reaction, plasmids in bacteria

Describe the use of recombinant DNA

Can be used to create more plasmids, more proteins, or injected into other organisms

Describe how transgenic organisms are produced

• Plasmid Injection

• CRISPR

Describe the benefits of genetic engineering for agriculture and industry

Increase in yield (plant grown), disease resistant, pesticide resistant = more food for more people

Describe how biotechnology can improve human health

Gene therapy

Describe how DNA is used to identify individuals

DNA fingerprinting

Describe ethical issues with biotechnology

• How far do we take this technology? 

• If we discover a cure to a disease, do we charge for it? What is a human life worth?

• Ex: Designer Babies. Who decides what is right or in fashion? Who decides access to these technologies?

The four reagents that must be added to the reaction mixture in Sanger sequencing

• Template DNA

• dNTPs

• ddNTPs

• DNA polymerase

When would a scientist want to use polymerase chain reaction (PCR) before they analyze a DNA sample

When only a small amount of DNA is available

When gene therapy is successful, how does it treat the disorder

By replacing a faulty gene with a normal gene in the human genome

The CRISPR system allows biologists to alter the nucleotide sequence of specific genes. What task could theoretically be achieved by applying the CRISPR system

Transferring a gene from one organism to another

Transgenic

Organisms that contain genes from a different species