1. Base pairing in the DNA helix is formed by

a.   hydrogen bonds

b.   covalent bonds

c.   neighboring bases on the same strand

d.   phosphate groups

e.   none of the above

2.  In general, how does a protein sequence give that protein a special function?

a.    the process of translation of the RNA triplet code, and not the actual code, 

     determines the protein function 

b.  the frequency of certain amino acids determine its function

c.  protein sequence is not important, only DNA sequence really matters.

d.  the sequence of bases in protein determine where a gene starts and stops.

e. the amino acid sequence determines the folding and thus the 3D structure of the protein which give the protein its function

3. You know the sequence of a specific protein fragment in 5 different organisms. These sequences are listed below:

human:      LTANQBC 

rat:            MTANDYY

mouse:        MTANDYY

pig:          LTASQBC

horse:      LVPNQBC

From the above information which of the following evolutionary trees is correct based on parsimony analysis, a, b, c, d, or e?

4. Based on the above information, which species is most related to humans?

1. rat

b.  mouse

1. horse

1. pig 
2. rat and mouse are equally close to humans and are the closest.

5.  Also based on the above sequence information, what type of sequence 

variation occurs between humans and the other organisms?

1. point mutations

1. deletions

1. insertions

1. trisomys

  e.  parsimony                                        

6. Embryonic stem cells are obtained by…

a.   isolation of cells from the inner cell mass of an early embryo

b.   culturing a cell line made from bone marrow cells of nude mice

c.   culturing an adult human stem cell line with developmental factors

d.   culturing stem cells from the neural plate of an embryo with high FGF and hedgehog

e.   isolating cells with nestin as a marker from a culture of stem cells derived from an embryo

7. What causes DNA fragments to migrate through an agarose gel?

a.   an electric field through the gel pulls on negative charges in the DNA

b.   gravity acts on the weight of the DNA to push it through the gel

c.   charges on the agarose that makes up the gel push the DNA down the gel

d.   a and c

e.   all of the above

8. What is the difference between recent homology and ancient homology?

a.    recent homology is differences in sequence between individuals of the same species while ancient homology is differences in sequence between individuals of different species

b.    recent homology is differences in sequence of a gene between individuals of the same species while ancient homology is genes with similar functions with similar sequences in the same organism

c.    recent homology is a difference caused by a mutation of a gene that causes a disease in a child that was not present in the parent while serial homology is a difference caused by a mutation that is passed from a parent with a disease to a child who also has the disease

d.    recent homology is where a sequence is shared by every individual in the same species while ancient homology is where a sequence is shared by individuals in the same species as well as between individuals of different but related species

e.    none of the above

9.  Polymerase chain reaction (PCR) is used to amplify one specific 

DNA segment from two individuals.  After PCR, the amplified DNA is 

analyzed by gel electrophoresis.  The PCR product produces one band 

in both cases; however, the band from one individual has moved through the gel a shorter distance than the band from the other individual.  What could best explain the difference?

  a.  the individuals have a different number of short tandem repeats in the      

       amplified region.

  b.  one of the individuals has a single point mutation in the amplified region.

  c.  one of the individuals has a long open reading frame in the amplified region.

  d.  one of the individuals has a triple version of the chromosome carrying that 

       segment of DNA

  e. none of the above

10.  A gradient of sonic hedgehog is important in establishing which cells?

  a.  the floorplate cells

  b.  neurons in the frontal lobe of the brain

  c.  retinal cells

  d.  islet cells 

  e.  none of the above

11.  The distribution of Sonic Hedgehog and FGF plays a critical role in the proper development of the dopaminergic neurons in the brainstem.  What expression patterns in the early neural tube are needed for this development to occur correctly:

a.    Sonic Hedgehog is expressed in the floorplate of the neural tube and FGF is expressed only in the brainstem.  

b.    Sonic Hedgehog is only expressed in the brainstem and FGF is expressed throughout the floorplate of the neural tube.

c.    Expression of WNT, Sonic Hedgehog, EGF, and FGF throughout the floorplate of the neutral tube.

d.    Expression of Sonic Hedgehog in motor and sensory neurons guide cell movement and shape the spinal cord.

e. None of the above. 

12.  Which of the following is true about gel electrophoresis?

a.   smaller pieces of DNA will move farther down the gel

b.   DNA fragments can be resolved on the basis of their size

c.   The gel is made of agarose

d.   It can be used for DNA fingerprinting.

  e.  All of the above

13. What is a teratoma?

1. a marker for pancreatic cells

1. a morphogen

1. a way to link suspects to crime scenes

1. a drug added to induce stem cells to differentiate

1. what is commonly produced when test animals are injected with embryonic stem cells 

14. Which are the four main features used to diagnose Parkinson's Disease? 

1. Resting tremor, slowness of movement, rigidity, balance problems

1. Joint tenderness, resting tremors, impaired speech, lack of emotional response

1. Twitching, impaired speech, massive cognative decline, rigidity

1. Slowness of movement, massive cognitive decline, balance problems, impaired speech

1.  Rigidity, joint tenderness, facial numbness, slowness of movement

15. What is L-Dopa?

1. a morphogen for dopaminergic neurons

1. a toxin that causes dopaminergic neurons to die in Parkinson's Disease

1. a precursor for dopamine used to treat Parkinson's Disease

1. a neurotransmitter

1. a morphogen of neural tissue

16. What is used to determine the number and integrity of chromosomes?

  a.  DNA sequencing

  b.  Nuclear transfer

  c.  Gel electrophoresis

  d.  PCR

  e.  Karyotype

17. A deletion of a single base pair changes the sequence of a gene such that the next original base triplet codon (for the amino acid tyrosine) is changed to a stop codon.  Which process of gene expression will be primarily disrupted?

  a.   DNA replication

  b.  Translation

  c.   Transcription

  c.  Reverse Transcription

  e.  All of the above

18. Why does the insulin gene come on only in the pancreas?

a.    the gene only exists in cells of the pancreas 

b.    the promoter is only attached to the gene in cells of the pancreas

c.    the coding sequence of the gene codes for a protein that can only be translated in the pancreas

d.    the promoter only allows the coding sequence to be transcribed in cells of the pancreas by switching to “on” in these cells

e.    the insulin protein only exists outside the pancreas

19. What is the basis of inheritance of the genetic code from any organisms to its offspring?

1. The specific combination of expressed genes in an organism determines the genotype of its offspring

1. The collection of proteins in an organism is passed onto progeny and determines inheritance

1. The faithful replication of DNA determines the inheritance of the genetic code

1. The transcription of the genome determines inheritance

1. None of the above

20. The following best describes the process by which DNA is decoded into protein:

  a.   DNA replicates into a temporary copy which is converted into protein by RNA

b.   copy of DNA is converted by transcription into protein

c.   DNA is copied into RNA by transcription which is then decoded into protein by translation

d.   DNA is copied into RNA by translation which is decoded into protein by transcription

e.   All are incorrect

21. Which of the following are potential sources of DNA evidence?

a. blood

b. urine

c. molars (teeth)

d. bone

e. all of the above

22. You discover a strain virus which is causing lethal infections in anyone infected. You know little about the virus and decide to use a sample of the virus you have been given to first look for potential genes in its genome in order to predict how the virus works.  Which of the following tools will you use to identify each of the genes:

1. You will identify candidate genes by predicting the presence of mRNA

1. You will identify candidate genes by similarity to known promoter sequences

1. You will identify candidate genes by mutating the virus
2. You will identify candidate genes by finding sequences with long open reading frames and amino acid distributions of the correct pattern

1. None of the above

23. You are in charge of identifying bodies from a massacre using DNA fingerprinting.  You obtain mitochondrial DNA from a victim and need DNA from one other source to make a match.  Which of the below is not a useful source:

1. From the victim’s mother

1. From the victim’s grandfather (father’s side)

1. From the victim’s brother

1. From the victim’s sister

1.      From the victim’s grandmother (mother’s side)

24. Which is the correct pairing of bases in DNA?

  a. A/C  G/T

  b. A/G  C/T

  c. A/U  C/G

  d. A/T  G/C

  e. Any of the bases can bind to any of the other bases                                                  

      DAD                        MOM

   1        2     3        4        5    

25. This is the pedigree for a family at the locus a recessive gene which causes early-onset Parkinson’s Disease. Unaffected individuals are denoted by hollow circles and squares and diseased individuals are denoted by filled in circles and squares. Which of the following DNA Fingerprints of the region corresponds to this family?

a)

DAD    MOM    1     2    3     4    5 

b)

DAD    MOM    1     2    3     4    5 

c) 

DAD    MOM       1     2    3     4    5 

d)

DAD    MOM    1     2    3     4    5 

e)

DAD    MOM    1     2     3     4    5 

26. You wish to use a line of embryonic stem cells.  Which two tests would you perform to determine if these cells could be used:

1. Karyotype and telomerase levels 
2. No teratoma formation in nude mice, glucose-dependent insulin production and formation of islets

1. Teratoma formation in nude mice, hedgehog responsiveness
2. Karyotype, glucose-dependent insulin production and formation of islets 

1. None of the above  

27. How does gene expression contribute to cellular differentiation?

1. Gene expression increases as cell differentiate

1. Gene expression decreases as cells differentiate

1. Gene expression is not altered as cells differentiate

1. The specific combination of expressed genes orchestrates the differentiation of cells

1. None of the above

DAD    MOM    kid#1     kid#2    kid#3     kid#4    kid#5 

28. Marked above is the DNA fingerprint for a recessive gene for a set of parents (DAD and MOM) and their 5 children. Child four could be which of the following?

1. A child swapped at childbirth

1. An adopted child

1. A child produced by the MOM but with a different DAD

1. Answers a, b, c.

1. Answers a, b.

29. Detectives at a crime scene find a tarot card as well as a shell casing from the murder weapon. You get the samples to analyze in your crime lab. The fingerprints on the shell casing do not match those of the card, which suggests that two individuals were involved. You find small but distinct tissue samples from both the tarot card and the shell casing, and extract mitochondrial DNA from both samples. Analysis of this DNA shows that the mitochondrial sequences are the same. You search a database of recent tarot card buyers, ex-cons living in the area and rifle owners to identify possible suspects. You come up with the following combinations of suspects.  Which pairs of individuals could be suspects.

  a. A mother and son

  b. Brother and sister

  c. Husband and husband’s sister

  d. Sister and sister

  e. All of the above

30. You obtain a small tissue sample at a crime scene.  You PCR amplify the standard number of polymorphic sites and determine a genetic fingerprint.  With this data, which of the following is true?

1. As long as you have another reference sample (felon’s database), you can see if it matches the sample from the crime scene

1. You can determine the personality profile of the criminal

1. You can immediately identify who the criminal is no matter where in the world they come from, even without a reference sample.

1.  All of the above are true

1. None of the above are true

31. Why is mitochondria DNA easier to collect and analyze than nuclear DNA

a. it is shorter than nuclear DNA so is easier to copy in a test tube

b. there are fewer numbers of mitochondria genes in each cell so they are easier to find and remove from these cells

c. mitochondrial DNA is a plasmid so it travels more predictably on an agarose gel

d. mitochondrial DNA exists in the cytoplasm so can be collected even after the cell dies

e. there are hundreds of copies of mitochondrial genes in each cell so fewer cells need to be obtained 

32. In general, cells differentiate in the body because of distinct signals.  Choose from below the most likely signal.

1. Karyotype

1. Telomerase

1. DNA replication

1. Signals from neighboring cells

1. None of the above

33. A new gene called blarney, is found in humans, which when mutated, causes a speech impediment.  The DNA sequence of the same gene in Chimps shows that it has exactly the same protein coding sequence as the human wild type.  Given that speech has evolved dramatically from chimps to humans, which is the most accurate conclusion to make about the blarney gene:

1. It is not possible that changes in blarney caused the evolution of speech. 

1. Changes in blarney caused the evolution of speech.

1. The sequence of the promoter also needs to be looked at before conclusion should be made.

1. The sequence of blarney mRNA needs to be looked at before any conclusions can be drawn.

1. The sequence of the blarney protein needs to be looked at before any conclusions can be drawn.

34. What is an open reading frame?

a.    the total combination of genes that can be expressed in a particular differentiated cell type

b.    a stretch of DNA that codes for a protein, flanked by a region that codes start and a region that codes stop

c.    only the DNA region that contains the base pairs that specify amino acids 

d.    the RNA sequence that contains the triplet codes for the amino acid sequence of a protein

e.    none of the above

35.  You are using recombinant DNA technology to clone a new gene. To clone this gene and have it be expressed in a bacterial cell, you need to do the following steps:

1.  Isolate the piece of DNA, break it up into small parts and determine the order of the bases.

1.  Isolate the piece of DNA, determine the order of the bases, and introduce the product into a petri dish of bacterial cells.

1.  Isolate and sequence the piece of DNA, insert the DNA into a viral vector, allow the vector to infect a bacterial cell, and check for the correct gene expression in the bacterial cell.

1.  Insert the protein product of the gene into the bacterial cell, allow it to integrate into the genome, and check for its expression using gel electrophoresis. 

1.  None of the above.

36. Recent research has shown that there may be a ‘putative’ Adam, based on his Y chromosome that may be the progenitor to all other humans. Which of the following facts about the Y chromosome allow this to be true:

1. The Y chromosome recombines every generation.
2. The Y chromosome is large and thus accumulates many insertions and deletions
3. Y chromosome is inherited only from the father and does not undergo recombination.
4. The Y chromosome has a fast mutation rate. 
5. All are true

37.  A pre-historical grave is exhumed in which 8 human remains are found.  A stone marker indicates that a whole family was buried at the site.  A mitochondrial PCR sample from each skeleton is analyzed by gel and shows the following.  Assuming the remains represent a complete family, which one is the 

father

a.  1

b.  2

c.  Any of 2-8 can be.

d.  None of these samples match the profile of the father

e. There is no way to know from this data.

38. How does the protein sonic hedgehog dictate the different differentiation of neurons at different locations in the neural tube?

a.     hedgehog is only secreted by certain cells in the brain so that their immediate neighbors know to differentiate into different cell types

b.     high levels of hedgehog causes immediate neighbors to die if they are the wrong cell type which leaves different cell types surviving next to cells that produce hedgehog than cells that are farther away

c.     cells are stimulated to secrete hedgehog if they contact neighboring cells of the same type and hedgehog causes cell death so that cell types alternate according to their immediate neighbors

d.     the floor plate in the ventral region secretes hedgehog which is then detected at lower and lower levels by cells farther from the source to tell cells in the tube where they are and thus what they should differentiate into

e.     none of the above

39. What are the main approaches to curing diabetes?

a. increase dopamine function or replace dopaminergic neurons

b. inject FGF or replace dopaminergic neurons

c. inject insulin or replace islet cells

d. inject nestin or replace islet cells

e. both a and c list common treatments

40. How can a new cell type be created from a totipotent stem cell?

a. place the cell in the correct environment 

b. add new genes to the genome

c. add the correct drugs or proteins to substitute for the environment

d. all of the above

e. a and c only

41. How many copies of a DNA sequence must me collected from cells to do analysis using current technology i.e. field-use of PCR?

a. 1

b. 10 

c. 100

d. 1000

e. it is not the number of copies that matters but the total amount of DNA in the sample (the total amount of base pairs that make up the sample)

42. Which of the following is not true about the role of sonic hedgehog in a developing embryo? 

1. it is a morphogen

1. low levels are required for dopaminergic neurons

1. high amounts of sonic hedgehog will induce a cell to become a motor neuron

1. low amounts of sonic hedgehog will induce a cell to become a sensory neuron

1. it is necessary for the embryonic eye to separate into two eyes

43.  Samples of DNA are taken from a family and show below.  The samples were PCR-amplified for the haemoglobin gene.  The family consists of parents, and 6 children.  Child 3, the oldest, develops sickle cell anemia, a recessive blood disease associated with a mutation in the haemoglobin gene.  Which kids besides child 3 will also develop this disease?

a.  2, 4 and 6.

b. You cannot tell from this data.  

c. 1 and 5.

d. All of them

e.  None of them

44.  The father of the above family develops Huntington’s disease, a dominant neurodegenerative disorder.  In addition, child 2 of the family also develops the disease.  If the gel above showed amplified regions of the gene responsible for the disease, indicate who else in the family, besides child 2, will develop this disorder.

a.  4 and 6.

b. You cannot tell from this data.  

c. 3, and 5.

d. All of them

e.  None of them

45. What best describes the process of converting the RNA sequence CUUGAUCCA into the amino acid sequence LAP?

  a.  Transcription 

  b.  Replication followed by decoding

  c.  Translation

  d.  Reverse transcription

  e.  Decoding

THIS IS THE END OF THE EXAM

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