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 •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

• 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!

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 in somatic cells can only be passed beoccur heritable? Why or on to the daughter cells of the mutant cell. Cancer is a disease that results when mutations occur inwhy an organism's body cells. not? Mutations that occur in an organism's gametes can be passed on 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 Human the Genome Project (HGP) was a 13 year research Human Genome 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 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

Quick Check: What are some possible ethical issues of stem cell research and cloning?