Genetics and Medicine Exam

What was one major surprise from the Human Genome Project published in 2003?

Protein-encoding genes make up ~1.5% of our genome.

What are the control sequences?

Promoter, operator, repressor.

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

During mitosis, chromosomes are more condensed than during interphase.

Which of the following statements about genetic diversity over a few generations is false?

Genetic diversity is enhanced by mutations.

transcription

DNA to mRNA

Antigenic Drift

Small changes in the viral genetic make-up

Pandemic

new incidences of the disease increase & spread rapidly, very wide global distribution

Epidemic

new incidences of the disease increase rapidly, but geographically confined. Ex. SARS

DNA packing

prevent access to genes for transcription

During which stage of meiosis does crossing over and formation of tetrads occur?

prophase I

The 3-D structure of RNA is very different from DNA because of the following

the 2'-hydroxyl (-OH) makes RNA more chemically reactive. a series of ribonucleotides connected by covalent bonds. the base pairing prevents formation of an anti-parallel double helix. the nitrogenous base uracil.

During mitosis, the chromosomes move because _______________________________.

they attach to a dynamic, precisely regulated mitotic spindle.

The results of the Human Genome Project have changed how we view our DNA/genome. What were the major surprises? Identify the incorrect answer.

A single individual's DNA was sequenced; therefore little was initially learned from it.

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?

G1

antigenic shift

Large changes in genetic makeup is referred

Repressor

protein binds operator & turns off gene expression

miRNA

a class of functional RNA that regulates the amount of protein produced by a eukaryotic gene

Endemic

disease is maintained in the population, wide geographic distribution. Ex. Common cold.

A genome graph

is a network of DNA sequences typically from 1,000 or more individuals.

siRNA

class of double-stranded RNAs about 23 nucleotides in length that silence gene expression; act by either promoting the degradation of mRNAs with precisely complementary sequences or by inhibiting the transcription of genes containing precisely complementary sequences

translation

mRNA to amino acid residue sequence (protein)

James Allison and Tasuku Honjo were awarded the 2018 Nobel Prize in Physiology or Medicine because of which one of the following?

They identified key proteins on T cells, called immune checkpoint proteins, that were normally responsible for turning off activated T cells.

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

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

The Hershey-Chase experiments in 1952 were important because they showed that

DNA was the hereditary material.

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.

Sporadic

disease occurs occasionally in low numbers, not geographically confined. Ex. Tetanus, rabies, plague, measles.

"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. Their approach is based on the one correct statement below.

Only through very large data sets can identification of mutations common to a particular cancer group be correlated with a specific treatment approach. In this initiative, there is an increased focus of including men and women, people of all ethnicities, and people of color. The goal is not just to have a genome data base but to include saliva, blood, and stored tumor samples in addition to clinical information to discover new and important patterns in cancer progression and response to treatment not presently known. Each cancer has a specific oncogenic signature, and therefore the medical treatment must be tailored for the patient.

Lactose:

Operon is on.

Most genetic disorders of humans are caused by

recessive alleles

Vitamin D-resistant rickets is an X-linked dominant bone disorder. A man with this form of rickets marries a normal woman. What proportion of the couple's sons is expected to have vitamin D-resistant rickets?

0%

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

50% of the parent DNA

What is chromatin state regulated by?

A circadian clock because histones are modified on a circadian basis.

What is CRISPR/Cas9? Identify the one incorrect answer.

A method of protein sequencing.

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

AaNNPPzz

Over the past 10 years we have learned a great deal about cancer through genomics projects such as The Cancer Genome Atlas (TCGA) Project. Which one of the following is incorrect?

All breast cancers show the same oncogenic signature.

There is the need for differential gene expression for the humans because of one of the following. Identify the one correct answer.

All cells contain the same genotype.

Autism is a complicated genetic disorder. Identify the one false statement.

Autism is a disease similar to cancer where mutations accumulate as a function of age.

What early evidence prior to 1953 supported the hypothesis of Watson and Crick that DNA carried the information for genetic inheritance?

Frederick Griffith's experiments when he was trying to develop a vaccine to pathogenic pneumonia.

James Allison was awarded the 2018 Nobel Prize in Physiology or Medicine for the following medical breakthroughs. Which statement below is false.

He pioneered the use of immune checkpoint inhibitors to treat COVID-19.

Mary Claire King in 1990 identified the gene associated with increased risk of breast cancer. Based on her initial work, we now know the following except one incorrect statement.

In 2015, Myriad Genetics argued before the Supreme Court that naturally occurring DNA should not be patent eligible.

Which of the following is true about double-stranded DNA?

Its 3-D conformation is quite different from RNA's 3D conformation.

No lactose:

Operon is off Repressor bound to operator. RNA polymerase cannot bind. Repressor is constitutively expressed.

The structure of DNA is very stable because of the following.

Orientation of the strands is antiparallel. The two strands are held in register through precise hydrogen bonding between adenine & thymine and guanine & cytosine. Stability results because of a large number of noncovalent interactions including hydrogen bonds, hydrophobic interactions and van der Waals interactions. The absence of uracil.

The ENCODE Project revealed new insights about the human genome. Identify the one correct answer.

Recognition that evolutionary change occurs through sequences that alter gene regulation.

Which of the following was a novel deduction that Watson and Crick were able to make about DNA based on Rosalind Franklin's X-ray diffraction data, i.e., Photo 51?

The consistent width of DNA led them to conclude that purines must base-pair with pyrimidines.

Development of new protocols based on DNA analysis such as testing for genetic diseases using blood from the pregnant woman rather than amniocentesis.

The shotgun approach was fast but not reliable.

The latest update from the Human Genome Project in 2018 reports all of the following except one below. Identify the incorrect statement.

There is one gene product for each gene.

viral adaptation

Virus can adjust to host such that evades defense mechanisms and takes over cellular metabolism for virus benefit.

We have learned a great deal about COVID-19 except one incorrect response below. Identify it.

We now know that COVID-19 was engineered for biological warfare and escaped from a military laboratory.

Operon

a functioning unit of DNA containing a cluster of genes under the control of a single regulatory promoter.

What are transcription factors?

a protein that binds a gene's promoter and regulates transcription and can be activators or silencers

Which of the following allows for a single gene to encode for more than one polypeptide?

alternative mRNA splicing.

In many organisms including humans, chromosomes are found in homologous pairs. Homologous chromosomes

are identical in the arrangement of their genes, but some versions of the genes (alleles) may

Cells with two of each kind of chromosome are described by the term

diploid

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

heterozygous for the trait and able

mRNA splicing:

introns are removed and exons spliced together.

Mutations in DNA are _____ but modifications in _____ are not.

permanent, chromatin

Promoter

region of DNA that facilitates transcription of gene(s) site for RNA polymerase to bind DNA

Operator

region on DNA near promoter acts as switch for gene expression to be on or off determines whether RNA polymerase can bind to promoter