DNA Flashcards
Draw a nucleotide and name the three components
Phosphate group, nitrogenous base, pentose sugar
Compare DNA and RNA
DNA has the nitrogenous base thymine whereas RNA has the nitrogenous base uracil.
DNA is double stranded whereas RNA is single stranded
DNA has the pentose sugar deoxyribose whereas RNA has the pentose sugar ribose
DNA and RNA are what type of polymer?
Nucleic acid
What is the function of helicase during DNA replication?
Helicase unwinds and unzips the DNA double helix, separating the two parent strands of the DNA molecule from one another by breaking the hydrogen bonds between complementary base pairs.
What is the function of DNA polymerase?
DNA Polymerase copies the DNA template strands, by joining up free DNA nucleotides by complementary base pairing during DNA replication.
Outline the process of DNA replication.
Helicase unwinds and unzips the DNA double helix, separating the two parent strands of the DNA molecule from one another by breaking the hydrogen bonds between complementary base pairs.
Each strand then acts as a template for synthesizing a new strand of DNA.
DNA Polymerase copies the DNA template strands, by joining up free DNA nucleotides by complementary base pairing.
Two identical copies of DNA are produced.
What is meant by the sem-conservative theory of DNA replication?
A newly formed DNA molecule consists of one original strand and one newly synthesized strand
Where does DNA replication occur in a eukaryotic cell?
Nucleus
Where does transcription occur?
Nucleus
What is the end product of transcription?
pre-mRNA
What is the definition of transcription?
DNA template strand is copied into pre-mRNA via complementary base pairing using RNA polymerase.
Pre mRNA undergoes RNA Processing. Introns are removed, a 5’ methyl cap and 3’ poly-A tail are added to form mRNA.
mRNA leaves the nucleus and goes to a ribosome.
What occurs during RNA processing?
Introns are removed. A 5’ methyl cap and 3’ poly-A-tail are added.
What enzyme is used during transcription?
RNA polymerase
What is the product formed after RNA processing?
mRNA or mature mRNA
Why are the introns spliced out?
Because they don’t code for the protein
What is the role of mRNA?
carry the code (for the protein) from the nucleus to the ribosome
A set of three nitrogenous bases in mRNA is called…
a codon
What is the monomer of a protein?
Amino acid
Draw the structure of an amino acid
Amino group, residual group, carboxyl group
What is the difference between a polypeptide and protein?
A polypeptide is a sequence of amino acids that has not been folded whereas a protein is a polypeptide that has been folded
What is meant by the genetic code being degenerate?
Multiple codons can code for the same amino acid
If a polypeptide has 90 amino acids, what is the minimum number of bases needed to code for it?
270 bases
If an mRNA molecule has 90 bases, what is the number of amino acids it could code for?
30 amino acids
What is a stop codon?
a codon that does not code for an amino acid
What is meant by DNA being universal?
It is the same in all living organisms
If a DNA molecule contains 30% cytosine, what percentage would be thymine?
20%
If a DNA has 100 base pairs and 60 are guanine, how many would be adenine?
40
Define translation
Ribosomes read the mRNA code for ___________.
tRNA brings the correct and specific amino acid to the ribosome.
tRNA anticodons are complementary and specific to mRNA codons.
Amino acids are joined together by a peptide bond, in a condensation polymerisation reaction, and a ____________ polypeptide is formed.
What is the function of mRNA
Carries the code from the nucleus to the ribosome
What is the function of tRNA
Bring the correct and specific amino acid to the ribosome
What is the function of rRNA
Structural component of a ribosome
What holds a tRNA molecule in its clover shape?
hydrogen bonds
What is the starting product of translation?
mRNA
What is the ending product of translation?
Polypeptide
Where is a polypeptide folded into a protein?
rough endoplamsic reticulum
What is a genetically modified organism (GMO)?
This is an organisms whose genome has been altered.
What is a transgenic organism (TGO)?
They are genetically modified organisms where genes from a different species (____) are added to their genome.
What is the function of an endonuclease/restriction enzyme?
Cut DNA at a specific recognition site
What is a DNA probe?
Probes are a single stranded piece of DNA that is complementary to the target sequence with a radioactive label.
What is a sticky end?
When DNA is cut and unpaired nucleotides with exposed bases are created
What are blunt ends?
When DNA is cut and there are no unpaired nucleotides with exposed bases
What is the function of DNA ligase?
Join the DNA by the sugar-phosphate backbone
During genetic engineering, why is the same endonuclease used to cut the plasmid and target gene?
So they have complimentary sticky ends
What term is used to describe the target gene and plasmid combined?
recombinant DNA
What enzyme is used to join the target gene and the plasmid during genetic engineering?
DNA ligase
Why are bacteria used for genetic engineering?
Can make their own proteins
Rapidly reproduce by binary fission (Produce many copies of the gene and can also create the target protein)
What two properties of DNA allow it to be separated by gel electrophoresis?
size and charge
Do the smaller fragments of DNA move more or less distance in gel electrophoresis?
more
How many bands must match a crime scene sample for a suspect to be considered guilty?
All bands
How many bands must match a father in a paternity gel electrophoresis?
All that do not match the mother
How do you determine the species who are most closely related using gel electrophoresis?
Most matching bands
List the complementary base pairing rules.
Adenine-Thymine (DNA)
Adenine-Uracil (RNA)
Cytosine-Guanine (DNA and RNA)
What is a polymer?
Polymers are long chains made from many repeating monomers
What is the function of RNA polymerase?
Copies the DNA template strand into pre-mRNA via complementary base pairing during transcription
What are the components of the sugar-phosphate backbone?
Pentose sugar and phsophate group
What holds the nitrogenous bases together? How many bonds are there?
Weak hydrogen bonds
Adenine + Uracil = 2 hydrogen bonds
Adenine + Thymine = 2 hydrogen bonds
Guanine + Cytosine = 3 hydrogen bonds
What is a set of 3 nucleotides in DNA called?
Triplet
Name the three types of RNA
tRNA (transfer RNA), rRNA (ribosomal RNA), mRNA (messenger RNA)
Outline the steps involved in genetic engineering.
- Plasmid is removed from bacteria and cut with the same endouclease as the target gene
- Target gene and plasmid are joined together at the sugar-phosphate backbone by DNA ligase, forming a recombinant plasmid/DNA
- Recombinant DNA is placed back inside a bacteria
- Bacteria rapidly divides by binary fission making many copies of the target gene and target protein