Nucleotides
The 4 Nitrogenous bases
What is Thymine, Cytosine, Adenine and Guanine
Name the types of RNA
What is
Messenger RNA (mRNA)- carries copy of DNA sequence to the site of protein synthesis at the ribosome
Ribosomal (rRNA)- catalyzes peptide bonds between amino acids
Transfer (tRNA)- mediates between mRNA and protein- carries amino acids for polypeptide assembly
What is a codon and what are the start and stop codons
What is
Codon – a sequence of three bases; each codon specifies a particular amino acid
Start codon – AUG (initiation signal for translation)
Stop codons – UAA, UAG, UGA (stop translation and polypeptide is released)
Name and define three types of mutations that occur in the DNA sequence?
What is
Silent - A mutation that does not result in a change to the amino acid.
Missense -A mutation that causes one amino acid in the protein sequence to be changed to a different one.
Nonsense- A mutation that results in a stop codon where there used to be a codon for an amino acid.
What are GMO’s?
What is (Genetically Modified Organisms) An animal, plant or microbe whose DNA has been altered using genetic engineering techniques.
The three parts of a nucleotide
What is a sugar, a phosphate group and a nitrogenous base
Name 2 Replication enzymes and describe their function
What is
DNA Helicase- unwinds double helix
Topoisomerases- prevent twisting of the unzipped DNA
RNA Primase- short sequence of ribonucleotides that initiates the new strand
DNA Polymerase- builds new strand of DNA
DNA Ligase- puts together the okazaki fragments on the lagging strand
Proofreading enzyme- checks for accuracy of complementary nucleotides used in the original DNA strand
Explain the wobble effect
What is Two or more codons code for the same aa(amino acid) (3rd base doesn’t have to be the same)
What type of frameshift mutation is shown? : CAG CCC —----- > CAG TCC CAC T
What is Insertion mutation
Name the goals of biotechnology
What is
Correct a genetic defect (gene therapy)
Get a cell or organism to make a desired product
The two sides of an anti-parallel
What is 1 side the 5th carbon from deoxyribose is on top called “5 prime or 5’ end and the other side the 3rd carbon form deoxyribose is on top called “3 prime or 3’ end
The two steps in DNA replication
What is
Double helix is unwound, making two template strands available for new base pairing
New nucleotides form base pairs with template strands and linked together by phosphodiester bonds. The template DNA is read in the 3’ to 5’ direction. During DNA synthesis, new nucleotides are added to the 5’ end of the new strand
What is a polysome?
What is Several *free floating ribosomes located in the cytoplasm work together to translate the same mRNA, producing multiple copies of the polypeptide. (A strand of mRNA with associated ribosomes)
What is a deletion mutation?
What is A mutation that causes the loss of one or more nucleotides in a DNA sequence.
What is recombinant DNA?
What is Joining together of DNA molecules from two different species that are inserted into a host organism to produce new genetic combinations.
The difference between how DNA is arranged in Prokaryotes vs. Eukaryotes
What is in prokaryotes the DNA is found in one circular chromosome while Eukaryotes DNA is a long thread that is wrapped around protein called histones
What is RNA splicing and the definition of the different parts
What is
RNA splicing removes introns and splices exons together that appear in the primary mRNA transcript pre-MRNA to produce a mature mRNA
Introns- intervening regions, noncoding sequences Exons- expressed regions, coding sequences
A ribosome structure has a large and small subunit. What are the three tRNA binding sites of the large subunit
What is
A (amino acid) site binds with anticodon of charged (contains aa) tRNA
P (polypeptide) site is where tRNA adds its amino acid to the growing chain
E (exit) site is where tRNA sits before being released from the ribosome
What is the difference between point and frameshift mutations?
What is Point mutations are a change in any single base codon (nucleotide) of a DNA sequence. Frameshift mutations are an addition or deletion of a base (which results in a change to codons in a gene→ change in many acids).
Describe plasmids
What is found in bacteria, small and easy to manipulate, have one or more restriction sites, many have genes for antibiotic resistance, have a bacterial origin of replication, replicate independently of the host chromosome
The two types of nucleotides and their main difference
What is Pyrimidines and Purines- Pyrimidines contain 1 ring of carbon (thymine and cytosine) while Purines contain 2 rings of carbon (adenine and Guanine)
Name and define the 3 steps of transcription
What is
Initiation- requires that RNA polymerase recognize and bind tightly to a promoter sequence on DNA
Elongation- RNA elongation in its 5’-to3’ direction and is antiparallel to the template DNA when RNA polymerase add nucleotides
Termination- is specified by a specific DNA base sequence (RNA transcript pulls/ falls away from the DNA template and RNA polymerase)
What are the three steps of translation?
What is
Initiation – tRNA and small ribosomal subunit bind mRNA. Small subunit moves along the mRNA until it reaches the start codon, AUG (methionine). Large ribosomal subunit joins the complex, tRNA is now in the P site of the large subunit
Elongation – the second tRNA enters the A site. A peptide bond forms between that aa and the aa on tRNA in the A site. Once the first tRNA has released methionine, it moves to the E site
Termination – translation ends when a stop codon enters the A site
Name a disease that is an example of a point mutation?
What is Sickle-Cell Disease
What are restriction enzymes and what are their purpose?
What is
Enzymes that degrade the DNA molecules by breaking phosphodiester bonds that hold nucleotides together
Bacteria defend themselves from viruses by cutting the viral DNA into fragments with restriction enzymes.