dna, protein synthesis and biotechnology · dna rna quick check: compare and contrast dna and rna....
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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 Explain how DNA and RNA code for proteins and determine traits.
3.1.3 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.
3.3.3 Evaluate some of the ethical issues surrounding the use of DNA technology (including cloning, genetically modified organisms, stem cell research, and Human Genome Project)
Hydrogen bonds
Nucleotide
Sugar-phosphate backbone
KeyAdenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
DNA Structure…What do you remember?
Deoxyribose
•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
What Is the “Ladder”?
Quick Check1. Describe the structure of DNA2. Draw and label a nucleotide3. 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•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).
Quick Check
1. When and why does DNA replication occur?2. Describe the steps of DNA replication.
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: (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.
-messenger RNA
DNA RNA
Quick Check: Compare and contrast DNA and 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
mRNADNA
RNAPolymerase
TranscriptionAdenine (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?
mRNA Start codon
Ribosome
Methionine
PhenylalaninetRNA
Lysine
Nucleus
Translation
mRNA
Quick Check:Where does Translation
occur?
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 proteinEx: tRNA carries GAU (anti-codon)& looks for CUA on mRNA
Quick Check: Label the following
C.
D.
E.
F.
B. A.
A.
Process 1 _________________
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.
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 when mutations occur in an organism's body cells.Mutations that occur in an organism's gametes can be passed on to the organism's offspring.
Quick Check:Would a negative
mutation in a skin cell be heritable? Why or
why not?
DNA Fingerprinting
Quick Check:How are the DNA segments
organized in a DNA fingerprint?
The Human Genome Project (HGP) was a 13 year research project to sequence all the base pairs that compose human DNA.Scientists produced a gene map which showed the relative 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.
Quick Check:What was the purpose of
the Human Genome Project?
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.
✹Gene therapy: specific genes are inserted into an individual's cells (using virus) to
replace a defective or mutant allele.
Quick Check:Describe the process and 2
applications of Genetic Engineering
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.
Other Biotechnologies
Cloning
Quick Check:What are some possible
ethical issues of stem cell research and cloning?