Lab 7 Flashcards
What does biotechnology mean?
The use of organisms or their components to make or modify products useful to humans.
What are common examples of biotechnology?
- selective plant and animal breeding
- use of yeast in fermentation to make bread, cheese, wine …
What is the main idea of modern biotechnology?
manipulating DNA
What type of molecule is DNA?
large, double-stranded molecule
What is DNA made up of?
a series of nucleotides.
What are nucleotides made up of?
- a nitrogenous base (adenosine, cytosine, guanine, or thymine)
- a sugar (deoxyribose)
- a negatively charged phosphate group
What is between the two strands of DNA? What types of bonds are formed?
- complimentary nitrogenous bases
- hydrogen bonds
What joins the nucleotides between the two strands of DNA?
phosphodiester bonds.
What is the information in DNA transcribed into?
complimentary RNA.
What is the central dogma?
the flow of information from DNA to RNA to protein
What does forensic mean?
the use of scientific methods in a wide array of scientific or investigative methods.
What is forensic biology?
the study of DNA from body tissues and fluids
What must biological samples for DNA analysis contain?
nucleated cells.
What are examples of suitable samples for forensic analysis?
- bodily fluids
- hair
- organs
- skin
- bones
What type of blood cells on their own can’t be used for forensic analysis?
red blood cells.
What are the steps for analyzing crime scene DNA?
- DNA extraction
- Polymerase chain reaction (PRC)
- Restriction fragment analysis
…restriction digest
…gel electrophoresis - Interpreting the results
How does extraction of DNA work?
DNA is extracted from the nuclei of cells in the sample. This is done by chemically lysing the cells and nuclei to liberate the DNA, which is then chemically precipitated out of solution.
How does the PCR work?
identical copies of DNA sequences are created rapidly. The copies of specific sequences can then be used in analysis. This is used to copy a particular DNA sequence of interest instead of the entire DNA complement.
What are the 4 ingredients needed for PCR?
- DNA extract
- Each of the four deoxyribonucleotide triphosphates (dATP, dCTP, dGTP, dTTP)
- Primers
- DNA polymerase
What happens once all 4 ingredients for PCR are present?
They are combined and then placed in a thermal cycler
What is a thermal cycler?
an automated system that maintains a series of temperatures for specified time periods.
What are the 3 steps in each PCR cycle?
- denaturation of DNA
- heat to separate the 2 strands of the DNA double helix
- annealing of primers
- cool so that primers can bond to the single strands of DNA
- extension of primers
- heat to allow DNA polymerase to add dNTPs to the end of the primers
What happens at the end of each PCR cycle?
the DNA sequence specified by the primers is doubled in quantity, which causes a huge increase. it results in billions of identical copies of the specific DNA sequence.
How does restriction fragment analysis work?
restriction enzymes cut DNA within the specific recognition sequences/sites.
What are the steps in restriction fragment analysis?
1 .restriction digest
2. gel electrophoresis
Explain restriction digest.
a restriction enzyme is added to the PCR product and the solution is put in an incubator. the enzyme cuts the DNA in the PCR into specific fragment sizes and numbers
Explain gel electrophoresis.
the restriction fragments are separated based on size. the gel uses the negative charge of DNA and the diff. in size of fragments. Agarose gel is put in a chamber with salt water to conduct electricity. each has wells for each sample. after samples are put in, the electrodes are attached to each end of the chamber and a current is applied. The negatively charged DNA moves towards the positive end. the larger fragments can’t travel as far as the small ones. after the DNA migrates enough, the current is turned off and the gel is removed.
How are forensic analysis results interpreted?
a ladder is used to look at DNA fragments of a known size. It is used to analyze the size of unknown sized fragment
How does paternity/maternity testing work?
DNA from the child is cut by a restrictive enzyme. The child has to match fragments with their mother or father. If they don’t match, they aren’t a parent.
What is recombinant DNA?
it is DNA formed from two different sources being combined into one molecule.
What is an organism that has gotten genes from an artificial process called? (including recombinant DNA technology)
GMO- genetically modified organism
also called a transgenic organism
Why are some bands of DNA fragments darker?
they are more concentrated.
