Name: ___________________________________________
Date: _____________
Chapter 12-13: DNA, RNA, and Genetic Engineering
Chapter 12: DNA and RNA
What is DNA again?
 __________________________________________________
 Long double-stranded molecule of nucleotides
 Stores genetic code that is ________________________________ to future generations and cells
 Codes for synthesis of _________________________
What is a nucleotide?
 A nucleotide has 3 parts:
o A ______________________ (deoxyribose for DNA)
o A ______________________________________
o A __________________________________
Nitrogen base pairing
 The ___________________ of nitrogen bases are what determines your genetic code
 The order of the bases determines the _____________________ that are made
 4 different bases exist:
o Purines: _______________, Adenine
Grade A Pure
o Pyrimidines: Cytosine, _______________________
 Pairing is also called Chargaff’s Rule
o A=T, ____________________
But what is the structure?
 In the early 1950s Rosalind Franklin used ________________
diffraction took a “picture” of DNA
o Difficult to tell what the structure is from the image
o Strands twisted around one another
 James Watson and Francis Crick used Franklin’s images and their models to determine the correct structure:
________________________________________
o Two strands wound around one another
o “___________________________________”
o Later discovered that _______________________________
hold the two sides of the ladder together
o Can only form between adenine and thymine, or guanine
and cytosine (___________________________)
o The base pairing explained Chargaff’s Rule
DNA Structure
 DNA is very _________________; E. coli’s contains 4,639,221 base pairs (length
=1.6 mm)
o Must fit in an organism 1/1000 its length
o Must be _________________________ very tightly to fit
 Human cell contains almost 100 times the base pairs
o Chromatin consists of DNA packed around proteins called
_____________________
o These compact together during mitosis to create our visible
________________________
DNA replication
 Remember that before a cell divides it has to ______________ its DNA
o
If we ________________________ each strand, we can
use it to make a copy of the other
o If we have an A, we match it with a T; if a G, we match it
with a C (called ____________________________)
 In prokaryotes, replication begins at one point and proceeds
typically in _____________________________
 In contrast, eukaryotes begin replication in _________________
of locations (due to its longer length)
 Two replication forks formed, each strand has a new complementary strand added
o TACGTT  ATGCAA
o Results in two ______________________ DNA molecules
o One strand is new, the other old
 DNA was unzipped (breaking of hydrogen bonds)
o ____________________________________ (enzyme) joins individual nucleotides to produce a DNA
molecule
What is RNA?
 _________________________________
 _________________________ molecule between DNA and proteins
 Differs from DNA in 3 ways:
◦ __________________ stranded (vs. double)
◦ ______________________ instead of deoxyribose
◦ Utilizes uracil instead of thymine (____________, G-C)
Type of RNA
 There are 3 types of RNA:
◦ ______________________ RNA (mRNA)- carries copies of
the protein instructions
◦ ________________________ RNA (rRNA)- makes up the
ribosome, along with several proteins
◦ _____________ RNA (tRNA)- take the appropriate (base
pairing anti-codon to codon) amino acid to the ribosome
Protein synthesis: how we make proteins?
 Two processes or steps:
◦ ____________________- mRNA is made from the DNA and travels to the cytoplasm to find a ribosome
◦ ____________________- tRNA brings to the ribosome the amino acids to build the primary structure of
a protein and the result is a free polypeptide that will then fold up into the shape of the protein
 Remember: amino acids are held together by peptide bonds
Transcription
 RNA polymerase binds to DNA and separates the strands
 RNA polymerase uses one strand to serve as a __________________
to create a strand of RNA
 RNA polymerase only binds to regions of DNA called promoters
(landing pad)
 The RNA is next edited, removing the _________________, while leaving the exons (exons=expressed)
Translation
 Proteins are made by joining __________________________
(1 of 20) into long chains (polypeptides)
◦ How do 4 letters lead to so many different amino
acids?
◦ Read 3 letters at a time, called a ________________
◦ UCGCACGGU
◦ UCG-CAC-GCU
◦ Serine-Histidine-Glycine
◦ Some codons code for the same amino acid
◦ _______________ is the start codon
 _________________ – 3 nucleotides that code for an amino acid. Found on the mRNA.
 _________________ - Fit the codon. Found on the _________________
 DNA: master plan; never brought to work site
 mRNA: blue prints made from master plan
 Ribosomes: building site
 tRNA: trucks unloading materials
Mutations
 ______________________ – changes made in the genetic
material; can occur during copying
 _______________________________ – effect only one
nucleotide; can be substitution, insertion, or deletion
 ____________________________ – an insertion or deletion
that affects the remaining string of nucleotides.
 ___________________________________ – changes in the number or structure of chromosomes.
 ______________________________ – when an organism has extra sets of chromosomes.


THE FAT CAT ATE THE ________
 Delete H (Frameshift / deletion)
TEF ATC ATA TET HER AT
 Change H to L (Substitution)
TLE FAT CAT ATE THE RAT



DNA: TAC GCA TGG AAT
RNA: AUG CGU ACC _____
AA: Met Arg Thr Leu




 Substitution
DNA: TAC GTA TGG AAT
RNA: AUG CAU ACC UUA
AA: _____ His Thr Leu



 Insertion
DNA: _____ CGC ATG GAA T
RNA: AUA GCG UAC CUU A
AA: Ile
Ala Tyr Leu
Chapter 13: Genetic Engineering
Selective Breeding
 Where did all the breeds of _____________ come from?
◦ Humans bred dogs to have certain _______________, breeding dogs that had the best versions
◦ Selective breeding only allows the traits we ______________ to be passed down to the next generation
 ___________________________ is crossing different organisms with two different desirable traits
◦ Disease resistance plant crossed with food-producing capacity plant
 Inbreeding is the continued breeding of organisms with _______________________ characteristics
◦ _____________________ desired characteristics
◦ Only allowing a dog to mate with another of its own breed
◦ Can increase the likelihood of genetic ________________________________
Increased Variation
 Breeders can increase variation by inducing _________________________, which are the ultimate source of
genetic variability
◦ Mutations are ____________________ changes in DNA
◦ Occur spontaneously or increase chance through chemicals and radiation
◦ Most are ____________________, a few can be desirable
 Most useful in ________________________
 Used to create polyploidy (extra chromosomes) in plants, which is less harmful to plants
Manipulating DNA
 Genetic engineering is making changes in the DNA code of a living organism
◦ __________________ the code
◦ Read the code
◦ __________________ the code
◦ Replace the code in the organism
 Removing the code: extraction; DNA is separated from the other parts of the cell
◦ _______________________ of DNA is done by rupturing the cells and adding a precipitating reagent
such as ethanol, and then the DNA can be spooled onto a glass rod or sucked out with a pipette.
 Cutting DNA into pieces is done with ___________________________ enzymes; each one cuts DNA at a specific
sequence of nucleotides.
 Separating DNA can be achieved by using __________________________________
◦ The cut DNA is put into the well at one end (negative end – black) of the gel. DNA
molecules are negatively charged and will travel to the positive end when current is
applied
◦ Smaller fragments travel ________________; separates DNA fragments based on
______________
◦ Used to create a genetic “fingerprint” or help isolate a gene
 Reading the DNA occurs by tagging some bases while copying the DNA, the colored tags
help determine the order of bases
 Polymerase chain reaction makes _________________ of a particular gene
Cell Transformation
 Transformation is the process of a cell taking __________________ DNA and
incorporating it into its own
◦ _____________________ organisms are organisms with foreign DNA
◦ E.coli is used daily as a transgenic organism to produce human drugs, ex.
human _________________ and TPA (clot buster for heart attacks)
◦ Bacteria make great transgenic organisms because they have a tiny
circular DNA, called a plasmid
 Foreign DNA is joined to the ___________________, plasmid DNA ensure that
the sequence will be replicated
◦ Plasmid also has a label (genetic marker) so can distinguish if it has the
gene
 Transforming plant cells involve using a bacteria that inserts a small DNA plasmid
into the plant (normally causing tumors)
◦ Scientists inactivate the tumor gene, and use the bacteria to deliver the gene of interest
Transgenic Organisms
 Plants are important transgenic organisms. In the year 2000, 52% of soybeans, and 25% of corn grown in the US
were transgenic (or genetically modified); most were modified for _________________________ resistance
 Animals also being used, like the cow that makes milk with a human protein
◦ Modify mice to have ______________________ systems to act like humans
◦ Animals that produce more growth hormone so they grow faster
Manipulating DNA
 ____________________ – making a genetically identical organism from a single cell
◦ In 1997, Ian Wilmut cloned, the now deceased, Dolly from the mammary
cell of a sheep
 Gene therapy – using genes to treat _________________, such as cystic fibrosis
 Genetically modified ____________________ (food) – altered so less pesticides are
needed
Stem Cells
 Stem cells are _____________________ cells (not differentiated)
◦ All body cells have all the DNA, but only use the genes to make the proteins needed for that cell type
once it becomes specialized
◦ Types: embryonic, amniotic, _________________, cord blood