BIO100 Exam #3 DNA Profiling Study Guide
Illustrate how these discoveries were applied to technologies.
- modern sequencing technologies are able to produce millions of bases of DNA sequencing data - human genome project (DNA sequencing) - ancestry/23andMe - assess for disease risks across genome
Evaluate how we utilize biotechnology in law, health, and science.
Biotechnology is the manipulation of organisms or their components to make useful products. They're utilized in law, health, and science through DNA testing, GMOs reducing pesticides, damages to health and environment, and cloning.
Describe the process of protein synthesis, including how the genetic information is transferred during transcription and translation.
DNA directs the production of RNA through the process of transcription. The molecule that results is called messenger RNA (mRNA). At the ribosomes in the cytoplasm, each mRNA codon is translated into an amino acid of a protein. Polypeptide is chain that consists of a string of amino acids and serve as a functioning protein.
Identify the structure and molecular make up of DNA
DNA is a double helix structure made by repeating a smaller unit called nucleotides. Each nucleotide is composed of three parts: a sugar molecule called deoxyribose, a phosphate group, and a nitrogenous base. There are four types of nitrogenous bases in DNA: adenine (A), guanine (G), cytosine (C), and thymine (T). The nitrogenous bases form the "rungs" of the DNA ladder, with A pairing with T and G pairing with C through hydrogen bonds, holding the two strands together.
Outline the process of DNA to RNA to protein.
DNA is a double-stranded nucleic acid that will be transcribed into an RNA inside the nucleus. The RNA will exit the nucleus to provide instructions for protein synthesis in the ribosome located within cytoplasm. Inside the ribosome, amino acids will be gathered together to form a protein.
Summarize how DNA is replicated in a semi-conservative way
DNA is replicated in a semi-conservative way when the two strands of an original DNA molecule separate from each other. Due to the base-pairing rules, each separated strand can serve as a template to precisely rebuild the other strand. In the end, two new DNA molecules are produced, each containing one newly created strand and one strand from the original molecule. In other words, each new molecule conserves half of the original molecule.
Describe where and how DNA is stored within the cell.
DNA is stored within the nucleus within eukaryotic cells, within chromosomes. Each chromosome is made up of a long, linear strand of DNA that is wrapped around proteins called histones, forming a structure known as chromatin. The chromatin is further coiled and condensed during cell division to form more compact structures called chromosomes
Describe how scientists can analyze DNA profiles and how this information is applied.
DNA profiling is a technique used to identify individuals based on their unique DNA characteristics. The process involves analyzing specific regions of the DNA molecule that vary b/w individuals (such as short tandem repeats, or STRs) and comparing these regions to those of other individuals. To analyze a DNA profile, scientists first obtain a sample of DNA (such as blood, saliva, or hair) from the individual of interest. They then use various techniques to isolate and amplify the DNA, and finally, they analyze the DNA using methods such as gel electrophoresis, PCR, or DNA sequencing to determine the length and sequence of the STRs. The resulting DNA profile can be compared to DNA profiles from other individuals to determine whether there is a match. **Gel Electrophoresis allows visualization of DNA samples based on their lengths, and it's a mixture of molecules that's placed on a gel b/w a positively charged electrode and a negatively charged one**
Investigate how differences in DNA sequences can be used in DNA profiling
DNA profiling, also known as DNA fingerprinting, is a technique that uses differences in DNA sequences to identify individuals. DNA profiling relies on the fact that no two individuals (except identical twins) have exactly the same DNA sequence
Describe the early discoveries in molecular biology including PCR and DNA sequencing.
Discovery of the structure of DNA: In 1953, James Watson and Francis Crick proposed the double helix structure of DNA, which helped to explain how genetic information is stored and replicated. Discovery of DNA replication: In the 1950s and 1960s, experiments by Matthew Meselson and Franklin Stahl showed that DNA replication is a semi-conservative process, in which each new DNA molecule contains one old and one new strand of DNA. Discovery of DNA sequencing: In the 1970s, Frederick Sanger developed a method for sequencing DNA, which allowed researchers to determine the order of nucleotides in a DNA molecule. Discovery of PCR: In 1983, Kary Mullis developed the polymerase chain reaction (PCR), a technique for amplifying specific segments of DNA. PCR has revolutionized molecular biology and has numerous applications in research, medicine, and forensics.
Examine how the structure of DNA fits in the central dogma.
It describes the flow of genetic information from DNA to RNA to protein. DNA carries the genetic information that determines the sequence of amino acids in a protein, but proteins are synthesized by the ribosomes in the cell. The process of synthesizing proteins from the genetic code of DNA involves two main steps: transcription and translation.
Name some cell types and relate their overall shape and internal structure to their special functions.
Neurons: Long, thin branching structure (axon) and dendrites for transmitting information Red blood cells: Biconcave shape for gas exchange, lack nucleus and organelles for increased hemoglobin capacity Muscle cells: Long, cylindrical shape with parallel fibers for generating force and contraction
Describe the structure and function of the cell nucleus and its contents.
Nucleus is a membrane enclosed organelle that houses most of the cell's DNA packaged as a chromosomes. It's surrounded by a nuclear envelop and controls the activities of the cell by directing protein production.
Identify on a cell model or diagram the three major cell regions (nucleus, cytoplasm, and plasma membrane)
Nucleus: A membrane-bound region where most of a cell's DNA is housed Cytoplasm: The fluid-filled region b/w the plasma membrane and the nucleus inside a eukaryotic cell; consists of the cell's organelles and cytosol Plasma Membrane: A thin, flexible layer surrounding the cell that regulates the passage of molecules into and out of the cell; consists of a phospholipid bilayer in which proteins are embedded
Identify the organelles on a cell model or describe them and indicate the major function of each.
Nucleus: Control Center of the cell, containing the genetic material (DNA) and directing the cell's activities Mitochondria: Powerhouses of the cell, generating energy (ATP) through cellular respiration Endoplasmic Reticulum (ER): A network of membrane-bound sacs and tubes that is involved in protein and lipid synthesis Golgi apparatus: A series of flattened, membrane-bound sacs that modifies, sorts, and packages proteins and lipids for transport within the cell or for secretion outside the cell Lysosomes: Membrane-bound organelles that contain digestive enzymes, breaking down and recycling unwanted or damaged cellular material Peroxisomes: Similar to lysosomes but contain different enzymes that are involved in the breakdown of fatty acids and the detoxification of harmful substances Ribosomes: Small, non-membrane-bound organelles that are responsible for protein synthesis Cytoskeleton: A network of protein fibers that helps maintain the cell's shape and assists with movement Centrosomes and Centrioles: Centrosomes are composed of two centrioles and are involved in the organization of the cytoskeleton and cell division Plasma membrane: Surrounds the cell and regulates the passage of molecules into and out of the cell. It is also involved in cell signaling and communication
Summarize the process of PCR and Compare it to DNA Replication.
PCR (polymerase chain reaction) is a laboratory technique used to amplify a specific segment of DNA. It involves a process of heating and cooling called thermal cycling which is carried out by machine. PCR becomes a three-step process after a double-stranded DNA molecule starts the process: 1) Denaturation: heating the DNA sample to separate the double-stranded DNA into single strands. 2) Annealing: cooling the sample to allow primers (short DNA sequences that match the target DNA sequence) to attach to the complementary single-stranded DNA. 3) Extension: heating the sample to a temperature optimal for DNA polymerase (an enzyme that synthesizes DNA) to extend the primers and synthesize new complementary strands, resulting in the amplification of the target DNA segment. DNA replication occurs in cells and involves the copying of the entire genome, while PCR occurs in the laboratory and amplifies a specific segment of DNA.
Describe how scientists manipulate DNA to produce genetically modified products.
Scientists can manipulate DNA in various ways: It can be isolated from a cell and put into a genomic library, visualized using nucleic acid probes, synthesized directly, produced from a cell's messenger RNA, or be edited within living cells. Genomic Library is the entire collection of DNA segments from an organism's genome. Each segment is usually carried by a plasmid or phage. Nucleic acid probe: A labeled single-stranded nucleic acid molecule used to find a specific gene or other nucleotide sequence within a mass of DNA. Gene Editing: The CRISPR-Cas9 system is a technology that allows the nucleotide sequence of specific genes to be edited in living cells. DNA Synthesis: DNA can be created from scratch in the laboratory using an automated DNA synthesizer. Complementary DNA is a DNA molecule made into vitro using mRNA as a template and the enzyme reverse transcriptase. A cDNA molecule therefore corresponds to a gene but lacks the introns present in the DNA of the genome.
List the similarities and differences between the various nucleic acid molecules.
Similarities: 1) DNA and RNA are nucleic acids and polymers of nucleotides that contain sugar, a phosphate, and a nitrogenous base. 2) The nitrogenous bases in both DNA and RNA include adenine (A), guanine (G), and cytosine (C). 3) They play a critical role in the storage and transmission of genetic information in cells. Differences: 1) DNA has a double-stranded helical structure, while RNA is typically single-stranded 2) DNA uses the nitrogenous base thymine (T), while RNA uses uracil (U) instead of thymine. 3) The sugar molecule in DNA is deoxyribose, while RNA uses ribose 4) DNA is located in the nucleus of eukaryotic cells and in the cytoplasm of prokaryotic cells, while RNA is found in both the nucleus and cytoplasm of eukaryotic cells and solely in the cytoplasm of prokaryotic cells. 5) DNA provides the genetic information that is passed from one generation to the next, while RNA is responsible for protein synthesis and gene expression.
Examine how the structure of DNA fits in the central dogma
The structure of DNA is central to the central dogma of molecular biology, which describes the flow of genetic information within a biological system. DNA serves as the template for the synthesis of RNA, which is then translated into proteins. The double-stranded structure of DNA allows for the faithful transmission of genetic information from one generation to the next, and the sequence of nucleotides in DNA determines the sequence of amino acids in proteins.
Compare and contrast transcription and translation.
Transcription: In this step, a segment of DNA is copied into RNA by an enzyme called RNA polymerase. This process involves the following steps: - RNA polymerase binds to a specific region of DNA called the promoter - The DNA double helix is unwound, and one of the strands is used as a template for RNA synthesis - RNA polymerase adds complementary RNA nucleotides (A, U, C, G) to the growing RNA chain, according to the base pairing rules (A-U and C-G) - The RNA chain is elongated until RNA polymerase reaches the end of the gene, which is signaled by a termination sequence - The RNA molecule is released and the DNA double helix reforms Translation: In this step, the RNA molecule is used as a template to synthesize a protein. This process involves the following steps: - The RNA molecule binds to a ribosome, which reads the RNA sequence in groups of three nucleotides called codons - Each codon codes for a specific amino acid - Transfer RNA (tRNA) molecules bring amino acids to the ribosome, based on the codon sequence - The ribosome joins the amino acids together to form a polypeptide chain, which folds into a protein - The process continues until the ribosome reaches a stop codon, which signals the end of protein synthesis
Explain how errors in replication can lead to mutations
When DNA polymerase inserts the wrong nucleotide, or when there are structural abnormalities in the DNA molecule, it can lead to errors in the genetic code.
