Bio Engineering Interview Questions and Answers
1.What is therapeutic cloning?
In the process of cloning DNA or a part of DNA is duplicated. This process is also called somatic cell nuclear transfer. In this process embryo is utilized for cloning. Embryo comprises of stem cells which is later employed in regeneration applications. The embryonic stem cells are renewable and are pluripotent.
2.Explain the mechanism of ELISA. What are its uses?
ELISA stands for enzyme linked immunosorbent assay. It is a wet lab type analytical biochemistry assay. It can detect presence of a substance in a liquid or wet sample by using one subtype of heterogeneous, solid-phase enzyme immunoassay. ELISA can be used as ligand binding assays. It is also used as a diagnostic tool in medicine and plant pathology. Quality check operations can also be performed in various industries with the help of ELISA.
3.Explain microarrays. How are they related to DNA?
Microarrays are matrix in the form of arrays where DNA oligonucleotides of DNA sequences are spotted. They can be used for gene expression profiling, single nucleotide polymorphism detection, detection of alternative splicing and for various other purposes. Microarrays have the capability to perform hybridization of coda with the help of probes. A microarray chip is capable to perform a large set of genetic related experiments concurrently.
4.What is the principle behind DNA fingerprinting?
DNA fingerprinting is the technique of genetic fingerprinting. In this technique, DNA sequence can be used for identification of an individual. The main application of DNA fingerprinting is forensics. The main principle behind behind DNA fingerprinting is Polymerase Chain Reaction. This technique is also popularly known as DNA profiling.
5.What do you understand by MRI?
MRI stands for Magnetic Resonance Imaging. This technique uses medical imaging that provides a detailed structure of internal organs; especially soft tissues.MRI provides good contrast between different soft tissues. A strong magnetic field is used in MRI which generates images and models of the specified organ. MRI works on the principle of nuclear magnetic resonance to generate image of nuclei of atoms inside the body.
6.What is BMI?
BMI stands for body mass index. This index represents the comparison of the person’s height and weight. The weight of the person is divided by the square of the person’s height. The SI unit for measuring BMI in kg/sq.m. BMI should not be treated as a technique for measuring body fat.
7.What is Alzheimer’s disease?
Alzheimer disease is the most common form of dementia. It is a brain disease caused due to tau protein misfolding. This disease is incurable. This is degenerative disease. It can be diagnosed through MRI scan or PET. This disease is found in generally above 65 years of age. Its symptoms include irritation, confusion, mood swings and aggression. This disease is named after German psychiatrist and neuropathologist Alois Alzheimer in 1906.
8.What is EEG scan? Explain the wave patterns seen in an EEG scan.
Electroencephalography is commonly known as EEG. It is the recording of the electrical activity along the scalp. This technique can measure the fluctuations in voltage resulting through the ionic flow of current within the neurons of the brain. In EEG multiple electrodes are placed on the scalp which is used to record brain’s spontaneous electrical activity over a short period of time. EEG can be used for the diagnosis of coma, encephalopathies, and brain death.
Wave patterns commonly observed in EEG are delta – state of sleep, theta – drowsiness, alpha – relaxation, and beta – active thinking and gamma.
9.What is prosthetic limb? What are its drawbacks?
It is an artificial device which can be used to replace a missing body part. It is based on the principle of biomechatronics. It can be used to replace body part missing from birth, due to injury or due to defect. The main drawback of prosthetic limb is its cost. Moreover, prosthetic limbs have to be replaced every 3-4 year due to the wear and tear. If the limb has fit tissues then the sockets in the limb have to be replaced every month.
10.Differentiate between gram positive and gram negative bacteria.
In gram staining protocol, gram positive bacteria are stained dark blue or violet. Crystal violet stain can be retained by the gram positive bacteria because of the high amount of the peptidoglycan in the cell wall. Gram-positive cell walls typically lack the outer membrane found in Gram-negative bacteria.
In gram staining protocol, gram negative bacteria do not retain crystal violet dye. Gram negative bacteria have pathogenic capability. Gram negative bacteria have cytoplasmic membrane which is not present in gram positive bacteria.
11.Explain the biological neuron model. How is it different from artificial neuron?
Biological neuron is also commonly known as spiking neuron model. This model is mathematical description of the properties of the nerve cell or neuron. This model is formulated to predict and describe the biological processes. This is different from artificial neuron because, artificial neuron is based on computational effectiveness. Artificial neuron is based on the synaptic weight for determining the neuron output.
12.What is RCCS? What is its lifespan?
RCCS stands for rotary cell culture system. It is a device designed to grow three-dimensional cell clusters in microgravity. This device was developed by NASA to study the cell tissues of mammals—including humans—in microgravity. Tissues grown in the RCCS are larger and three-dimensional, with structural and chemical characteristics similar to normal tissue. RCCS has no moving parts, thus cells are less prone to damage and hence provides longer life span.
13.What is blood brain barrier?
Blood brain barrier is caused in central nervous system, when blood circulation is separated from the brain extra cellular fluid (BECF). This phenomenon occurs along all capillaries. It consists of tight junctions around the capillaries that do not exist in normal circulation. Cells of the barrier actively transport metabolic products such as glucose across the barrier with specific proteins. This barrier also consists of astrocytic end feet and also includes a thick basement membrane.
14.What is LMO? State some of its importance.
LMO stands for living modified organism. LMO are those organisms that have been genetically modified through the application of biotechnology. LMO also includes organisms that have been modified by novel recombinant DNA techniques as well as those that have been modified by mutagenesis or classical breeding and selection techniques. Importance of LMO’s is that they can eat hazardous waste.
15.Explain pathogens. Name some types of pathogens.
Pathogens are those organism which feeds on other organism for their food. Pathogens can be transported through many different routes, including airborne, direct or indirect contact, sexual contact, through blood, breast milk, or other body fluids, and through the fecal-oral route. Pathogens can be used to suppress pest population. Different types of pathogens are viral, bacterial, fungal etc.
16.Differentiate between retrovirus and provirus.
A retrovirus is a RNA virus which can be duplicated in a host cell using the reverse transcriptase enzyme. It can produce DNA from its RNA genome. The produced DNA is then incorporated into the host’s genome by anintegrase enzyme. The RNA virus thereafter replicates as part of the host cell’s DNA. Retroviruses are enveloped viruses that belong to the viral family Retroviridae.
Provirus is a virus genome which can integrate into DNA of host cell. In inactive viral infections the virus will not replicate itself but through replication of its host cell. This state can last over many host cell generations.
17.What is frame shift mutation? Is this mutation similar to single-nucleotide polymorphism?
This is the type of mutation in which DNA sequence is changed due to addition and deletion of nucleotides. This mutation changes the code for amino acids. This is also called framing error or reading frame shift. This mutation will cause the reading of the codons after the mutation to code for different amino acids. No, this mutation is not similar to single-nucleotide polymorphism. In single-nucleotide polymorphism nucleotide is replaced, rather than inserted or deleted.
18.What are immunoglobulins? Explain its structure.
Immunoglobulins are popularly known as antibody. These are large Y-shaped protein produced by B-cells that is used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. Immunoglobulins are “Y” shaped structure which is having two tips and each tip of immunoglobulins contains a paratope. Immunoglobulins are typically made of basic structural units—each with two large heavy chains and two small light chains. The general structure of all antibodies is very similar; a small region at the tip of the protein is extremely variable.
19.Explain superiority of TLC over paper chromatography.
TLC is superior over paper chromatography because of inorganic nature of adsorbent concentrated sulfuric acid spray. The spray is then followed by heating. It may be used to develop on the chromatogram by charring. Also, amino acid mixtures require 18 hours for separation on paper. It requires 3 hrs using cellulose TLC. The advantages of TLC lie in adsorbents which don’t allow separation on paper. In TLC we have much wider choice of adsorbents depending upon needs and sample.
20.Explain is isotopic tracer technique?
This technique is used to understand chemical reaction and interactions in bio-chemistry and chemistry. In this technique, one or more of the atoms of the molecule of interest is substituted for an atom of the same chemical element, but that element belongs to different isotope. It can be used to detect the difference in number of neutrons separately from the other atoms of the same element. The atom has the same number of protons; it will behave in almost exactly the same way chemically as other atoms in the compound, and with few exceptions will not interfere with the reaction under investigation.
21.Explain the technique of gene conversion.
Gene conversion refers to the event in DNA genetic recombination. This event occurs at high frequencies during meiotic division but which also occurs in somatic cells. Through this process we can transfer DNA information from one DNA helix to another DNA helix, whose sequence is altered. Gene mutation can also be accomplished through this process. IT may lead to non-Mendelian inheritance. This phenomenon has often been recorded in fungal crosses.
22.Differentiate between introns and exons.
An intron refers to any nucleotide sequence within a gene which is removed by RNA splicing to generate the final mature RNA product of a gene. The term intron refers to both the DNA sequence within a gene, and the corresponding sequence in RNA transcripts. Introns are found in the genes of most organisms and many viruses.
An exon can be referred to a sequence in DNA or its RNA transcript. In broad sense. An exon is a nucleic acid sequence that is represented in the mature form of an RNA molecule.
23.Explain forbidden clones.
Clones refer to producing genetically identical individuals. Forbidden clones refer to clones of those cells which had immunological reactivity with self antigens. Embryonic life is eliminated from these types of clones. Such type of clones is called ‘forbidden clones’.
24.Explain gram staining method.
This method is used to identify bacterial species into two communities i.e. Gram positive and gram negative. This method is based on chemical and physical properties of their cell walls. It can be used to detect peptidoglycan, which is present in a thick layer in Gram positive bacteria. Purple/blue colour refers to the gram positive bacteria. Red colour stain refers to the gram negative bacteria. This method is very popularly used in the identification of bacterial organism.