DNA, Protein Synthesis and
Biotechnology EOC Review
3.1.1
Explain the double-stranded, complementary nature of DNA as related to its function in the cell.
3.1.2
3.1.3
3.3.3
Explain how DNA and RNA code for proteins and determine traits.
Explain how mutations in DNA that result from interactions with the environment (i.e. radiation and chemicals) or
new combinations in existing genes lead to changes in function and phenotype.
3.3.1
Interpret how DNA is used for comparison and identification of organisms.
3.3.2
Summarize how transgenic organisms are engineered to benefit society.
Evaluate some of the ethical issues surrounding the use of DNA technology (including cloning, genetically modified
organisms, stem cell research, and Human Genome Project)
DNA Structure…
What do you remember?
Nucleotide
Hydrogen
bonds
Deoxyribose Sugar-phosphate
backbone
Key
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
What Is the “Ladder”?
•DNA: Deoxyribonucleic Acid
•2 long chains of nucleotides
•Joined together in the form
of a ladder
•Ladder is twisted in the
form of a double helix or
spiral
•Adenine pairs with Thymine
•Guanine pairs with Cytosine
Quick Check
1. Describe the structure of DNA
2. Draw and label a nucleotide
3. Identify the complementary base pairs for the
following nitrogenous bases:
ATG CTG CGA
DNA Replication
•During cell division a copy of DNA must be
made during Interphase through the process of
Replication.
•When new cells are formed each new cell gets
an exact copy of the genetic information.
Steps of Replication
Quick Check
1.When and why does DNA
replication occur?
2.Describe the steps of DNA
replication.
•During replication, each strand serves as a pattern to make new DNA molecule.
1.
The 2 nucleotide strands separate at base
pairs.
•
They unzip like a zipper using DNA
Helicase (enzyme)
2. Each strand then builds its opposite strand
by base pairing with nucleotides that float
freely in the nucleus.
3. Each new DNA molecule has 1 nucleotide
strand from the original DNA molecule and
1 nucleotide strand made from free
nucleotides in the nucleus. We call this
semi-conservative.
4. The strands are zipped up and proofread
for mutations (mistakes).
RNA
▪ RNA: ribonucleic acid
▪ Carries out protein synthesis
▪ Differences from DNA:
▪ different sugar (ribose)
▪ single strand
▪ different base-URACIL instead of
thymine
3 Types of RNA:
-messenger RNA
• Messenger RNA: (mRNA) carries
nucleotide sequence from nucleus to
ribosome in transcription.
• Transfer RNA: (tRNA) picks up amino
acid in cytoplasm and carries them to
ribosome in translation.
• Ribosomal RNA: (rRNA)found in
ribosome, joins mRNA and tRNA;
forms protein in translation.
Quick Check: Compare and contrast DNA and RNA
DNA
RNA
The genetic
information that is
passed from a parent
to its offspring is
found in DNA
molecules. Segments
of DNA known
as genes code for the
production
of proteins. These
proteins cause
specific traits to be
expressed.
Protein
Synthesis
Rap
Transcription
Adenine (DNA and RNA)
Cystosine (DNA and RNA)
Guanine(DNA and RNA)
Thymine (DNA only)
Uracil (RNA only)
Quick Check:
What is the product of
Transcription?
RNA
Polymerase
DNA
mRNA
Translation
Nucleus
Quick Check:
Where does Translation
occur?
Lysine
Phenylalanine
Methionine
tRNA
Ribosome
mRNA
Start codon
mRNA
•
•
•
•
Translation
Conversion of RNA into amino acid sequence that makes a protein
The mRNA leaves the nucleus and enters the cytoplasm
Ribosomes attach to mRNA
tRNA (carrying anti-codon) picks up the correct amino acids and
carries them to the mRNA strand forming the protein
Ex: tRNA carries GAU (anti-codon)& looks for CUA on mRNA
Process 1 _________________
Quick Check: Label the following
F
.
C.
B.
A.
E.
A.
D
Process 2 _________________
What polypeptide would be
determined by a gene with the
base sequence
AAGGATCCG?
What polypeptide would be
coded by the following set of
nucleotides?
TCATATAGCGCAACA
What polypeptide would be
coded by the following set of
codons?
AUGCCUACGUGGGAC
Quick Check:
Synthesize the proteins!
Gene mutations result when one or more base pairs are inserted,
deleted, or substituted in an organism's DNA sequence and are not
repaired by an organism's enzymes. They may harm, benefit, or
have no effect at all on an organism and/or the organism's
offspring.
Quick Check:
Would a negative
mutation
in
a
skin
cell
Mutations that occur in somatic cells can only be passed on to the
daughter cells
of
the
mutant
cell.
Cancer
is
a
disease
that
results
be
heritable?
Why
or
when mutations occur in an organism's body cells.
Mutations that occur in an organism's gametes can be passed on
why not?
to the organism's offspring.
DNA Fingerprinting
Quick Check:
How are the DNA segments
organized in a DNA
fingerprint?
Quick Check:
What was the purpose of
The Humanthe
Genome
Project (HGP)Genome
was a 13 year research
Human
project to sequence all the base pairs that compose human DNA.
Scientists produced a gene
map
which
showed
the
relative
Project?
location of each known gene on every human chromosome. The
gene map also showed the DNA sequences of all the human
genes which is used in biotechnology applications.
Genetic engineering involves
taking genes (identified by
HGP) from one organism and
placing them into another in
order to express desired trait.
Applications of Genetic
Engineering include:
✹In medicine, genetic
engineering is used to
mass produce hormones,
such as insulin and
human growth hormone
as well as
vaccines.✹In agriculture,
genetic engineering is
used to create genetically
modified organisms, such
as crop plants that are
more resistant to disease.
Quick Check:
Describe the process and 2
applications of Genetic
Engineering
✹Gene therapy: specific genes are inserted
into an individual's cells (using virus) to
replace a defective or mutant allele.
Other Biotechnologies
Quick Check:
What are some possible
ethical issues of stem cell
research and cloning?
Since stem cells have
the potential to become
any type of cell, scientists
hope that by injecting or
transplanting stem cells
into diseased or
damaged tissue, the stem
cells (primarily
embryonic) can replace
abnormal or missing
cells.
Cloning
Stem Cells Ted Talk