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100
What does the abbreviation DNA stand for?
Deoxyribonucleic-acid
100
What is a gene?
A gene is the basic physical and functional unit of heredity. Genes, which are made up of DNA, act as instructions to make molecules called proteins. In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases
100
What is a genome?
A whole set of all your genes plus all the DNA between your genes
100
DNA can contain 4 different kinds of bases. What are these 4 bases?
Adenine Guanine Cytosine Thymine
100
Explain basic DNA structure in terms of Sugars, Phosphates and Bases.
DNA structure - A G C T & sugar = deoxyribose Phosphate backbone Complementary base pairs: A&T, G&C **RNA - A G C U & sugar = ribose
200
Explain the “Central Dogma” of Molecular Biology.
Replication of DNA, transcription to RNA, translation to protein ***Replication - Semi-Conservative Old strand contains template or “recipe” for new strand • In vivo is complicated • Key enzyme DNA Polymerase: Adds dNTPs to 3’ end of growing strand Uses: DNA template Primer Deoxynucleotide triphosphates (dATP, dCTP, dGTP, dTTP) Transcription - RNA synthesis • Gene expression • Not all DNA is transcribed • Requires RNA Polymerase: 5’ to 3’ direction DNA template Does not require Primer • Some differences Prokaryotes vs Eukaryotes eg- pre mRNA processing in Eukaryotes: modify 5’ and 3’ ends of mRNA, remove Introns. Translation - Assemble AAs into protein from information on mRNA • Not all RNA is translated • Occurs at Ribosome: contains ribosomal proteins and ribosomal RNA (rRNA) • also requires tRNA and AAs
200
BRIEFLY explain the statement “the information for making a new strand of DNA comes from an old strand of DNA”.
This is replication. In order for a new strand to be made, a template must be used from an old strand with the same genetic code.
200
BRIEFLY explain the term Transcription.
Initiation, elongation & termination. RNA synthesis. Gene expression. Not all DNA transcribed. Requires: RNA polymerase, 5' & 3' direction, DNA template Does not require primer
200
BRIEFLY explain the term Translation.
Assembles the amino acids into protein from info on mRNA not all RNA is translated occurs at ribosome, contains ribosomal proteins and rRNA requires: tRNA & AA's
200
In one short sentence explain what an Intron is.
Noncoding sections of an RNA transcript, or the DNA encoding it, that are spliced out before the RNA molecule is translated into a protein.
300
In one short sentence explain what an Exon is.
Section of DNA/RNA that code for proteins
300
What is a codon?
a sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid or stop signal during protein synthesis.
300
What is meant by the term “Genetic Code”?
3 base code 61 codons, 20 amino acids, 3 stop codons, usually start with AUG
300
What are two differences between RNA Polymerases and DNA Polymerases?
DNA: RNA: double stranded single stranded Cytosine & Guanine Cytosine & Guanine Adenine & Thymine Adenine & Uracil Sugar = deoxyribose Sugar = ribose never leaves nucleus can leave nucleus
300
BRIEFLY explain what a Restriction Enzyme is.
Restriction enzymes cut a DNA molecule at a particular place. They are essential tools for recombinant DNA technology. The enzyme "scans" a DNA molecule, looking for a particular sequence, usually of four to six nucleotides
400
BRIEFLY explain what a Ligase Enzyme is.
In molecular biology, DNA ligase is a specific type of enzyme, a ligase, (EC 6.5.1.1) that facilitates the joining of DNA strands together by catalysing the formation of a phosphodiester bond.
400
State 3 additional applications PCR could be used for.
Genetic testing Tissue typing Paternity testing
400
What are the steps of a PCR reaction?
The first step in a PCR cycle is the denaturation step. This is the PCR step in which the hydrogen bonds holding the complementary strands of DNA together are broken. The second step in a PCR cycle is the annealing step. The annealing step is the PCR step in which the primers anneal, or attach, to the DNA template. Third step is elongation; nucleotides are added to the annealed primer. DNA Polymerase is activated which reads the code and attaches matching nucleotides to create copies. Cycles are continued (30x) until majority is the target sequence.
400
Are there any infectious, disease causing agents that cannot be detected using a PCR type reaction? If so, name one such agent or disease. (Hint: the answer is yes! You may find this a challenging question. If you know PCR can detect nucleic acid then you will have to find an infectious agent that does not contain nucleic acid. Such agents exist but are unusual.)
Bacteria contain DNA and we should be able to detect them by PCR. Viruses contain DNA or RNA and again we should be able to detect them by PCR. Another biological disease causing agent consists of protein (not nucleic acid). Because they do not contain DNA or RNA they cannot be detected with PCR. These agents are unusual but do exist.
400
Describe an application of electrophoresis.
Tank & electrical source Gel applied - to support and separate samples Dye - to watch progression of separation Dye - to locate sample of interest Molecules will migrate
500
When electrophoresed over a given period of time, will a small DNA molecule usually migrate a shorter distance or a further/longer distance through an agraose gel, compared to a large DNA molecule?
Further – “small molecules move through sieve easier so migrate further over given time”
500
True or False? “electrophoresis can separate molecules based on both size and charge”
True
500
What types of molecules can be separated using Electrophoresis?
Amino acids
500
A certain type of PAGE can be used to separate denatured proteins. What are denatured proteins?
Denaturation is a process in which proteins or nucleic acids lose the quaternary structure, tertiary structure and secondary structure which is present in their native state, by application of some external stress or compound such as a strong acid or base, a concentrated inorganic salt, anorganic solvent (e.g., alcohol or chloroform), radiation or heat. If proteins in a living cell are denatured, this results in disruption of cell activity and possibly cell death.