Exam 3 Flashcards
What are microbes?
Tiny organisms, such as bacteria, fungi, algae, and protozoa, that are too small to be seen individually by the naked eye.
What percentage of bacterial species have been identified and studied?
Less than 1%, though they are estimated to comprise over 50% of the earth’s biomass.
What is bioprospecting?
The discovery and development of new products from biological resources.
Name applications of microbial enzymes in food production and research.
- Taq DNA polymerase used in PCR because they are isolated from heat loving bacterium
- Cellulase, makes animal food more digestible and is used to create worn out look on jeans
- Subtilisin, used in laundry detergents (breaks down stains, etc.)
What is the purpose of the Yeast Two-Hybrid System?
To determine if two proteins, ‘A’ (Bait) and ‘B’ (Fish), interact with each other.
How does the Yeast Two-Hybrid System indicate protein interaction?
If proteins ‘A’ and ‘B’ interact, they bring together a DNA binding domain (A) and an activator domain (B), resulting in the expression of a reporter gene, such as lacZ.
What is CRISPR (clustered regularly interspaced short palindromic repeats)?
A prokaryotic immune system that helps bacteria remember and defend against viruses by using repeated DNA sequences called CRISPR in their genomes.
How does CRISPR provide immunity?
By using segments of spacer DNA, sequences from previous exposures to foreign DNA, such as viruses or plasmids.
What is Cas9 and its function in CRISPR?
Cas9 is protein that works together with guide RNA to cut DNA at specific target sequences.
Cas genes vs Cas9
Cas genes are what encoed the proteins that work with the CRISPR sequences.
Cas9 is a protein encoded by the genes, which does the cutting.
What does Cas9 require to cleave target DNA?
Cas9 is complexed with a crRNA (crispr RNA) and a separate trans-activating crRNA (tracRNA) to cleave target DNA. The crRNA guides Cas9 to the target DNA sequence, while the tracRNA helps stabilize the Cas9-crRNA complex and facilitates cleavage
Describe the basic steps of gene editing using CRISPR/Cas9.
Scientists design a guide RNA that matches the target DNA sequence.
Cas9 uses this guide RNA to find the target DNA.
Once located, Cas9 makes a cut in the DNA.
Then a new piece of DNA can be inserted, and enzymes help repair the break in the DNA.
CRISPR was named the biotech breakthrough by who
By the American Association for the Advancement of Science (AAAS) in 2015
How are microbes used in food production?
They are used in both traditional and modern biotechnology to produce bread, yogurt, cheese, and alcoholic beverages.
What was the first recombinant DNA food ingredient approved by the FDA?
Chymosin; used to make cheeses (1999).
What is rennin, and how is it used in cheese production?
An enzyme traditionally extracted from the stomachs of calves and used to create curds in cheese production.
What is chymosin, and why is it used instead of rennin?
A cloned form of rennin produced in bacteria. It is less expensive and easier to produce.
What is fermentation?
The process of deriving other compounds from sugars in the absence of oxygen.
What is lactic acid fermentation used for?
To make yogurt, sour cream, sauerkraut, vinegar, and certain cheeses and breads.
What is alcohol fermentation used for?
To make beer, wine, and champagne.
How are bacteria used to produce therapeutic proteins?
Bacteria are used to produce medically important proteins, such as insulin, which can be used in human treatments.
What was the first recombinant protein expressed in bacteria for human use?
Insulin was the first recombinant molecule expressed in bacteria for human use, developed in 1978.
What is Humulin, and when was it commercially available?
Brand of synthetic insulin, made by Genentech in 1982.
Who developed the first vaccine?
Edward Jenner in 1796.
What virus did Jenner use to vaccinate against smallpox?
Cowpox.
What are vaccines, and how do they work?
Vaccines contain parts of a pathogen or whole organisms that stimulate the immune system against infection by that pathogen.
What is an antigen?
A foreign substance, such as bacteria, fungi, viruses, proteins, lipids, or carbohydrates, that stimulates an immune response.
How does the immune system respond to antigens?
Antibodies are produced in a process called antibody-mediated immunity, involving B cells and T helper cells.
What do B and T helper cells do?
- B cells recognize and bind to the foreign antigen.
- With the help of T helper cells, B cells undergo activation to form plasma cells to produce antibodies.
What role do antibodies play in immunity?
They bind specifically to antigens, marking them for destruction by macrophages, which phagocytize the antibody-coated antigens.
What are the 4 major strategies in making vaccines?
- Subunit Vaccines
- Attenuated Vaccines
- Inactivated (killed) Vaccines
- mRNA Vaccines
What are subunit vaccines?
Subunit vaccines are made by injecting portions of a pathogen’s structure, like purified proteins, to stimulate an immune response.
What are attenuated vaccines?
Attenuated vaccines use live pathogen that are weakened so they can’t replicate, creating immunity without causing disease.
What are inactivated (killed) vaccines?
Inactivated vaccines are made from pathogens that have been killed or inactivated, making them safe for vaccination.
What are mRNA vaccines?
mRNA vaccines contain non-replicating mRNA in a lipid nanoparticle, which enters cells and teaches the immune system to recognize the pathogen (e.g., Pfizer/BioNTech and Moderna COVID-19 vaccines).
How are many subunit vaccines produced?
They are made using recombinant DNA technology, where vaccine proteins are produced in microbes (e.g., Hepatitis B and HPV vaccines).
How is the Hepatitis B vaccine created using recombinant DNA?
Genes for viral surface proteins are cloned into plasmids and introduced into yeast. The yeast produces fusion proteins that are purified for the vaccine.
What is Gardasil?
Gardasil is a vaccine that protects against nine strains of human papillomavirus (HPV).
What are some major diseases targeted for vaccine development?
Biotechnology companies are working on vaccines for diseases like influenza, tuberculosis, malaria, HIV, and COVID-19.
Why is sequencing microbial genomes important?
Helps identify genes involved in metabolism, cell division, and disease, and finds new strains for tasks like bioremediation and identifying pathogens.
What was the impact of sequencing the Streptococcus pneumoniae genome?
Led to the discovery of new surface protein genes, resulting in improved vaccines and treatments, especially for children.
What is metagenomics?
The study of genetic material recovered directly from environmental samples, providing insight into microbial communities in various ecosystems.
What is the microbiome?
The collection of genomes of microorganisms in a specific environment, such as the human body.
What is the Human Microbiome Project?
Launched in 2008, this NIH project aimed to sequence genomes of human-associated microbes to better understand health impacts and cataloged over 2,200 genomes by 2019.
What are the goals of the Human Microbiome Project?
The project aims to determine if people share a core microbiome, understand microbial community formation, study health-related changes, and develop microbiome analysis methods while addressing ethical issues.
What is microbial diagnostics?
Involves techniques like RFLP analysis, PCR, and DNA sequencing to detect and track microbes, particularly in clinical and food samples.
How are microarrays used in tracking contagious diseases?
Microarrays test up to 50,000 species in parallel to detect pathogens, examine host responses, and identify gene expression “signatures” for specific pathogens
Why is plant transgenics important for agriculture’s future?
With a doubling world population and limited arable land growth (increase by only 10%), transgenics helps improve crop productivity by directly transferring beneficial genes, meeting food demands more efficiently.
What is plant transgenesis?
The direct transfer of genes to plants to develop traits like vaccine production, pesticide production, and herbicide resistance.
What are some standard methods for plant transgenesis?
Selective breeding/hybridization
and cloning.
What is conventional selective breeding and hybridization?
It involves sexual crossing between two lines and backcrossing hybrids with parents.
This method can take years and may include polyploid plants to enhance traits.
What are polyploid plants?
Plants that have multiple sets of chromosomes, (can increase desirable traits especially size). Colchicine is used to make polyploid plants by causing cells to have extra sets of chromosomes.
What is plant cloning?
Process of growing new plants from a single cell, allowing for the consistent reproduction of desirable traits.
what are plant cloning techniques
- protoplast fusion w plant tissue culture (PTC)
- leaf fragment technique & Ti plasmid (w PTC)
- gene guns w PTC
- chloroplast engineering w PTC
- antisense technology
What is a protoplast?
A plant cell with its cell wall removed, usually with the enzyme cellulase, to allow fusion with another cell.
What is protoplast fusion?
Protoplast fusion combines two plant cells without cell walls (protoplasts) using polyethylene glycol, allowing for hybrid plant development. Example: broccoflower.
What effect does an equal ratio of cytokinin and auxin have on plant cells?
The formation of an undifferentiated callus.
What effect does a higher level of cytokinin and lower level of auxin have on plant cells?
It promotes the growth of shoot buds.
What effect does a higher level of auxin and lower level of cytokinin have on plant cells?
It stimulates root formation.
Plant cloning: leaf fragment technique
Small discs are cut from a leaf and cultured with genetically modified Rhizobium radiobacter (formerly Agrobacterium tumefaciens) to introduce new genes.
How does Rhizobium radiobacter assist in plant gene transfer?
It contains a Ti plasmid with T-DNA that integrates into the plant cell’s DNA, allowing genetic modification.
