Gen and Med Biology Test

What makes RNA viral-based infections so problematic?

They can mutate, so there is not one solution against the virus, so vaccines have to be made to combat the newest version of the virus

What were the surprises from the ENCODE Project?

- >80% contains elements linked to biochemical function - 18,400 RNA Genes/20,687 protein-encoding genes - 76% of genome transcribed into RNA as end-product, not protein. -5% of human genome conserved across mammals. - 4% of human genome, not conserved across mammals, is conserved between individuals - 42% of genome accessible by transcription factors - evolution can occur by selection of RNA sequences that alter gene regulation, not just selection for protein sequences

Hemophilia is an x-linked recessive condition characterized by excessive bleeding with injury. A woman who carries the gene but its not affected marries a normal man. What proportion of the couple's sons is expected to have hemophilia?

50%

During DNA replication, one DNA strand is copied to make new DNA molecule composed of two DNA strands. This new DNA molecule contains

50% of the parent DNA

There is need for differential gene expression in humans because of one of the following.

Almost all cells contain the same genotype.

Explain alternative mRNA splicing and how it can generate diversity?

Alternative RNA splicing can create more diversity since the codons can be arranged in different orders, so the mRNA ends up being more diverse.

A researcher treats cells with an inhibitor that prevents DNA synthesis from starting. This treatment would trap the cells in which stage of the cell cycle?

Answer G1 - the cell synthesizes mRNA and proteins in preparation for subsequent steps leading to mitosis. G 1 phase ends when the cell moves into the S phase of interphase

The following statements are related to vaccine development for SARS-CoV-2.

Clinical Trial Phase 3 includes thousands of people and typically one group receives a placebo and the other the vaccine Clinical Trial phase 2 includes a much larger population but typically separates the recipients into two or more different groups such as healthy adults versus elderly, male/female, different ethnicities, different dose amounts, etc. Clinical Trial phase 1 includes a small number of people to determine if the vaccine is safe.

Antigenetic shift

Large changes in genetic makeup. Immune systems see it as a new virus.

DNA contributions by Rosalind Franklin and Maurice Wilkins

She discovered the DNA's double helix structure by looking at X-ray diffraction pictures.

Why do species have so many genes in common?

Some species evolved from common ancestor, so there would be certain similarities in different species genomes, but they would not be exactly the same.

What were the factors that led to H1N1 pandemic?

The factors were the virus evolving to make the vaccine created against it ineffective and also that the virus spreads very quickly

What are the advantages of using a genome graph rather than a single reference genome?

The genome graph is more accurate, and it has more complete genome sequences. You can identify mutations missed by sequence comparison to single reference genome. Captures regions that were not identified previously because of insertions, duplications and/or deletions.

What is the benefit of sequencing the genomes of many different species?

The genome of every animal is on record today and scientists can use that information to track ancestry of animals who lived 200 million years ago.

The Human Genome Project results and what were the major surprises.

There is repetitive DNA sequences between the gene. Protein encoding genes make up 1.5% of our genome and the other 98.5% is noncoding DNA. Gene Control sequences (promotors, enhancers, microDNA) make up 24% of the human genome. There are millions of transposable elements that are repeated throughout the genome.

How can the CDC and WHO predict?

They predict based on the number of people affected when the virus has been discovered.

Watson and Crick DNA contributions

They were able to build a detailed model of a DNA molecule using the X-ray diffraction pictures from Rosalind Franklin and Maurice Wilkins

Why are so many EIDs zoonotic?

This is because these viruses start in animals since animals are not as hygienic as human and evolve and spread to humans.

Causes of epigenetic changes

environmental factors addition of methyl and/or acetyl groups nicotine and alcohol

Transfer RNA molecules

meditate the conversation of genetic information into protein sequences.

X-linked conditions are more common in men than in women because

men need to inherit only one copy of recessive allele for the condition to be fully expressed.

These small, single stranded RNA molecules, 22 nucleotides long, can block the translation of mRNA and are involved in the expression of ~1/3 of all human genes.

microRNAs (miRNAs)

Genetic Code

the nucleotide triplets of DNA and RNA molecules that carry genetic information in living cells.

In the Hershey Chase experiment, why were 32P and 35S used?

32P(phosphorus) because phosphorus is found in DNA but not in proteins and 35S (sulfur) was used to identify proteins since DNA does not contain sulfur.

Autosomal Recessive Inheritance

50% probability of being heterozygous: not expressed. 25% probability of being homozygous recessive: expressed. If both parents are aa, each child will exhibit same phenotype. Ex. Galatosemia, Cystic Fibrosis, Sickle Cell Anemia

Who discovered RNA interference? How is it used in vivo and how it is used as an experimental tool?

Andrew Fire and Craig Mello discovered RNA interference.

"Count Me In" was established in 2018 as a nonprofit organization committed to advancing patient-partnered research with support from the Broad Institute, Emerson Collective, Dana-Faber Cancer Institute, and the Biden Cancer Initiative. These are all True statements about this program.

Patient Data included genomic data, saliva, blood and stored tumor samples and clinical histories. In this initiative, there is an increased focus of including men and women, people of all ethnicities, and people of color. Each cancer has a specific oncogenic signature, and therefore the medical treatment mist be tailored for the patient. Only through very large data sates can identification of mutations common to a particular cancer group be corelated with a specific treatment approach.

A mouse has a genotype AANnPpzz will have the same phenotype as a mouse with which genotype below. Note that the uppercase alleles A, N, P, and Z are dominant.

AaNNPPzz This is because even if only one A or N or P is uppercase, the trait is still dominant.

Mary Claire King identified the gene associated with increased risk of breast cancer. Based on her initial work we now know.

BRCA1 is localized to chromosome 17. Dr. King developed the BROCA diagnostic test in 2015, which can screen for 50-60 genes in patients suspected of a predisposition to hereditary cancers. BRCA1 and/or BRCA2 mutations increase the risk for breast cancer. BRCA1 and BRCA2 encode for proteins involved in DNA repair.

Antigenetic drift

Small changes in the viral genetic make-up. New combinations.

Transcription factors bind to

DNA

Genome Graph

It is a network of DNA sequences and typically comes from 1000 or more individuals.

Autosomal Dominant Inheritance

50% probability of being heterozygous The allele is expressed even in heterozygous. Trait appears in every generation. Ex. Huntington's disease

Technological advances to manipulate gene expression include which one of the following?

CRISPR-Cas9

The central dogma is

DNA to RNA to Protein

Stages of meiosis where crossing over and formation of tetrads occur.

Prophase 1

BCRA1 and BCRA2 are genes that are

essential for repairing damaged DNA.

Autosomal disorders are caused by

recessive allele disorders and dominant allele disorders

Reasons why the 3-D structure of RNA is different from DNA

A series of ribonucleotide connected to covalent bonds. the 2'-hydroxyl (OH) make RNA more chemically reactive. The base pairing prevents formation of an anti-parallel double helix. RNA has the nitrogenous base uracil.

What is the dicer gene and its role in vivo?

An enzyme that in humans is encoded by the Dicer1 gene.

How does one go from a genotype to a phenotype?

An individual's genotype is a combination of their alleles, and their phenotype is a combination of their traits or observable characters. Phenotype is influenced by the genotype and sometimes environmental factors also affect the phenotype.

Scientists commonly choose white blood cells that are going through mitosis to prepare karyotypes. why?

Chromosomes are more condensed during mitosis than interphase.

Gene expression in eukaryotes can occur at multiple levels. Explain

Gene Expressions happens first when epigenetic regulation breaks down the DNA before transcription can begin.

What is the benefit of human genomic information?

Genomic Data can help patients identify if they are at risk of developing certain diseases or disorders, based in if it a previous family member or someone in their genome had the same disorder.

Who holds the patent for CRISPR

Harvard and MIT and this is because they won it through many legal cases based on who owns it.

DNA contributions by William Astbury

He obtained the first X-ray diffraction picture of DNA and obtained pictures of uncrystallized DNA.

DNA contributions by Erin Chargaff

He proved that the nucleotide pairs Guanine and Cytosine connect, and that Adenine and Thymine connect as well.

DNA contributions by Linus Pauling and Robert Corey

He published the Triple Helix Model of DNA and even though it was wrong, it laid the foundation for Watson and Crick to create the correct model of DNA.

A carrier of a genetic disorder who does not show symptoms is most likely ____________ to transmit to offspring.

Heterozygous for the trait and able.

What does a typical karyotype reveal and what can it not reveal?

Karyotypes reveal when a pair of chromosomes is missing or deformed from a karyotype, and this usually means that the person has a disorder.

What drives new emergent and re-emergent infectious diseases?

It is driven by socio-economic, environmental, climate change and other ecological factors.

Why is the inheritance of so many traits difficult to explain using only Mendel's view of genetics?

Mendel was correct for the traits he investigated, but his principles must be extended (not discarded) to explain more complex patterns of inheritance.

What are the political issues with genomics studies?

Privacy Concerns. The universal genome could store information about from whom the genome(s) came. Ability to capture ancestry, medical history, etc.

How does prokaryotic gene expression differ from eukaryotic?

Prokaryotic Gene expression happens in the cytoplasm and Eukaryotic Gene expression happens in the nucleus.

How does DNA changes to RNA?

RNA polymerase reads the DNA and turns it into mRNA.

What is RNA splicing? Where does it occur?

RNA splicing is when RNA is turning into messenger RNA and it happens in the nucleus

Why are so many of the infectious emerging diseases due to RNA viruses?

RNA viruses can mutate, so no one vaccine can stop it

In what way is SARS-CoV-2 different from the viruses that cause influenza and Ebola?

SARS-CoV-2 has one single-stranded RNA genome

Was the ruling against Myriad good or bad in the long run? What are the implications from a business perspective?

The Myriad was able to be patented in 2012 and the supreme court ruled against the patent since DNA is not patent eligible.

Sanger Method of DNA sequencing

The Sanger method targets a specific region of DNA and binds that DNA with a primer that then determines the sequence.

Watson and Crick novel deduction about DNA based on Rosalind Franklin's X-ray diffraction data.

The consistent width of DNA meant that purines must base-pair with pyrimidines.

What is the ENCODE Project?

The encode project is a group that is trying to build a comprehensive part list of functional elements in the human genome.

What are the global strategies to keep ahead of the infections and potential pandemic?

The global strategies are to identify how the disease spreads and whether there is need to call it a pandemic or an epidemic and close down large public areas.

These statements are all true about the lac operon

The lac operon messenger RNA carries information for synthesis of several proteins. The promoter is the binding site of RNA polymerase. The operator is the binding site for the lac repressor.

What is a whole genome or shotgun sequencing?

The random manner in which DNA is broken down into smaller fragments.

What is G0?

The stage where the cell is neither dividing nor preparing to divide or in a distinct quiescent phase that occurs outside of the cell cycle.

What was one major surprise from the Human Genome Project published in 2018.

There are more RNA-encoding genes than protein-encoding genes.

What holds the DNA anti-parallel strands together?

They are held together by hydrogen bonds.

What is the role of non-coding RNAs (miRNA and siRNA)?

They play a big part in regulating genetic expression and they also play a role in transcription and translation.

Viral adaption

Virus can adjust to host such that evades cell defense mechanisms.

What can we learn from comparison of genomes?

We can compare genomes to study evolution by looking at the relationships between different genomes of the species for difference.

What have we learned from The Cancer Genome Atlas (TCGA) Project?

We have learned about the oncogenic signatures across human cancers and that not all signatures are the same, Tumors are made up of 33-66 genes and the mutation of cancer is mostly a single base pair substitution.

How is herd immunity acquired?

When the majority of unaffected people are vaccinated and cannot get the virus and so the virus cannot spread

What is the G2 phase?

When there is extensive cellular growth under a high synthesis rate of proteins.

Who decides whether a disease outbreak is an epidemic or pandemic?

World Health Organization

What is the value of using a pedigree to track genetic traits and what it cannot determine?

You can determine when traits in a family are dominant, or recessive based on what traits the offspring gains from the parent.

What are the advantages of being able to predict virulence of human pathogens?

You can warn humans about the spread early, so they can protect themselves and stop the virus from turning into an outbreak.

What type of RNA is considered coding RNA?

mRNA