AGRY 320 Midterm Past questions

Which of following is/are correct about DNA?

a. The Griffith experiment was not the first experiment that discovered bacterial transformation

b. Hershey-Chase experiment showed that DNA is genetic material using radioisotopes

c. The Avery, Macleod, and McCarty set out to identify the chemical responsible for genetic information using enzymes that destroy specific polymers

d. Only DNA can be genetic material

b and c

A bacterial culture with Heavy labeled DNA (15N) is transferred to 14N labelled culture medium for replication. The ratio of the total number of 15N and 14N labeled strands of DNA extracted from the culture after five generations is?

1:5

1:15

1:3

1:7

1:15

As shown in the figure, the two deoxynucleic acids are connected by hydrogen bonds. Which of these figures is the correct one?  Only one is correct.

B

If 30% of a DNA double stranded helix is Adenine, how much Cytosine is in the helix?

20%

From the list below, what is/are the benefits of plant and animal breeding?

Food security

Economical benefits

Both food security and economical benefits

None of the above

Both food security and economical benefits

What is NOT a key property of hereditary material?

Mutability

Information Content

Readability

Fidelity

Readability

What is the primary origin of point mutations?

DNA Replication

Radiation

Exposure to carcinogens

Sperm and egg development

DNA Replication

Which of the following is/are important issues during DNA replication?

Relieve tension from unwinding

DNA synthesis occurs only 5' to 3'

Need a 3' OH (hydroxyl) group to add new nucleotides

All of the above

Which statement is NOT true about Chargaff’s rules of base composition?

The amount of Thymine is equal to the amount of Adenine. (T=A)

The amount of Adenine and Thymine is equal to the amount of Guanine and Cytosine in a DNA sequence. (A & T) = (G & C)

The ratio of Thymine and Cytosine in a DNA sequence is equal to the ratio of Adenine and Guanine. (T+C) = (A+G)

The amount of Cytosine is equal to the amount of Guanine. (C=G)

The amount of Adenine and Thymine is equal to the amount of Guanine and Cytosine in a DNA sequence. (A & T) = (G & C)

Which of the components does NOT make up a DNA molecule?

Adenine, Guanine, Thymine, Cytosine

Phosphate

Deoxyribose sugar

Helium bonds

Helium bonds

Where in this DNA molecule does unwinding of DNA during replication happen? 

1

True or false: DNA replication is accomplished only semi-conservatively.

True

Which sequence, out of the options, below is the complimentary DNA base pair sequence to X ( 5' ATGCT 3')?

a. 3' ATGCT 5'

b. 5' AGCAT 3'

c. 5' TACGA 3'

d. 5' CGATG 3'

b

True or false: Synthesis does not happen in the 5' to 3' direction.

False

True or false: All mutations are single nucleotide polymorphisms (SNPs).

False

True or false: Translation occurs in ribosomes in eukaryotic cells.

True

True or false: The area of the gene that signals the end of transcription is called the terminator or termination elements.

True

True or false: RNA does not form complementary base pairing with itself.

False

True or false: The genetic code can overlap, therefore making it harder to make amino acids.

False

Which of the following proteins first binds to TATA box during transcription?

TF II A

TF II B

TF II D

RNA polymerase

TF II D

What minimizes point mutations on protein function?

Degeneracy

None of these are correct

RNAi

Mutations

Degeneracy

What are introns?

DNA sequences to which polymerases bind

The processed mRNA

Translated DNA sequences in a gene

Untranslated DNA sequences in a gene

Untranslated DNA sequences in a gene

A region in a gene called the _______ controls where RNA polymerase begins transcription.

Primer

5' UTR

Promoter

DNA polymerase

Promoter

What strand is complementary to target mRNA

Driver strand

Guide strand

Leader strand

Passenger strand

Guide strand

Which of the following is necessary for transcription to occur?

a. DNA molecule

b. RNA polymerase

c. DNA polymerase

d. 4 ribonucleoside triphosphates (ATP, GTP, UTP, and CTP)

a, b, and d

RNA is synthesizes in the ____ to ______ direction while the template DNA is read in the ______ to _____ direction.

5', 3' and 3', 5'

5', 3' and 5', 3'

3', 5' and 5', 3'

3', 5' and 3', 5'

5', 3' and 3', 5'

The DNA coding strand:

Has the same sequence as the RNA except with T's instead of U's

Is complementary to the mRNA

Is the strand that is used for synthesis of RNA

Runs in the 3' to 5' direction

Has the same sequence as the RNA except with T's instead of U's

Which of the following statements describes how the RNA sequence specifies the production of an amino acid chain?

Each base produces electrical signals sent to the cytoplasm to initiate protein assembly

Read in triplets from a fixed starting point (start codon) and each group of three bases codes for an amino acid

Each base codes for one amino acid

Each group of three bases codes for an enzyme that binds amino acids together

Read in triplets from a fixed starting point (start codon) and each group of three bases codes for an amino acid

Which of the following is NOT a reason for RNA to be able to function differently than DNA?

RNA cannot be double stranded at any time

Catalyze chemical reactions

RNA can bend

RNA is usually single stranded

RNA cannot be double stranded at any time

What is the correct sequence of events of the lifecycle of mRNA in a eukaryote?

a. Translation - Transcription - Decay - Processing - Nuclear Export

b. Transcription - Processing - Nuclear Export - Translation - Decay

c. Processing - Transcription - Nuclear Export - Translation - Decay

d. Translation - Nuclear Export - Processing - Transcription - Decay

b

True or false: The repressor, I+ gene product, is trans-acting meaning that the gene product can regulate all structural lac operon genes, whether residing on the same DNA molecule or on different ones.

True

True or false: Operons are found in the genomes of prokaryotic organisms.

True

True or false: All transcription factors contain a dimerization and/or a ligand-binding domain.

False

True or false: The higher cycle threshold (CT) value, the lower amount of original DNA molecule.

True

True or false: Next generation sequencing has revolutionized the biological sciences, allowing labs to perform a wide variety of applications and study biological systems at a level never before possible

True

True or false: Nowadays, Sanger sequencing is the most successful and widely adopted sequencing technology.

False

True or false: Trans-acting sequences are sequences located in or very near the same DNA molecule as the target gene.

False

What are advantages of PCR?

a. Billions of DNA copies in few hours

b. None of the other statements are advantages of PCR

c. Generate substantial amounts of DNA Sample

d. It helps to detect viruses in plants, humans etc.

a, c, and d

Which of the following statements BEST explains the denaturation step?

Separate all DNA into single stranded DNA using heat

An enzyme is required to accomplish the denaturation step of PCR.

The denaturation step requires the lowest temperature of the three steps in PCR

Taq polymerase is required for the denaturation step in PCR.

Separate all DNA into single stranded DNA using heat

What do all transcription factors (regulatory proteins) contain?

a mutation

a DNA binding domain

an activation repression domain (allosteric site)

all of the above

A and C

B and C

B and C

Which of the following represents the correct order of steps in a PCR cycle?

a. Annealing, denaturation, extension.

b. Elongation, annealing, denaturation.

c. Denaturation, annealing, extension.

d. Annealing, elongation, denaturation.

c

The lac operon in addition to responding to the presence or absence of lactose is also sensitive to glucose levels. In the absence of glucose, and presence of lactose:

a. the cAMP levels will be high and the CAP-cAMP complex will activate transcription of the lac operon genes (Z, Y, A)

b. The inducer-repressor will bind to the operator and there won't be a transcription of the lac operon genes (Z, Y,A)

c. the cAMP levels will be low and the CAP-cAMP complex will repress transcription of the lac operon genes (Z, Y, A)

d. the cAMP levels will be low

a

During PCR, if any of the following circumstances arise: 1) there are no primers in the reaction, 2) there are no dNTPs in the reaction, 3) there is no Taq polymerase in the reaction.

Non-specific PCR of random templates will occur

The PCR reaction will not commence

PCR would proceed normally

The reaction will cease after a few cycles

All of the above are true

The PCR reaction will not commence

Which one is a mechanism for regulating gene expression at the transcriptional level?

All are regulation mechanisms at the transcriptional level

Control the amount and/or rate of RNA synthesis

Protein modification

RNA processing

Control the amount and/or rate of RNA synthesis

In the lac operon, the repressor protein exerts a negative effect on the expression of the structural genes in the absence of the inducer molecule. In the case of the lac operon, what is the inducer molecule?

sucrose

lactose

galactose

fructose

lactose

PCR cycle has three components and each one requires specific temperature conditions:

Denaturation, where all DNA is separated into single-stranded DNA, occurs at ____°C. this step allows access of the primers to the template/target DNA.

92~95

72

50~65

92-95

PCR cycle has three components and each one requires specific temperature conditions:

The elongation or extension of the primer DNA molecule occurs at ____°C

92~95

72

50~65

72

PCR cycle has three components and each one requires specific temperature conditions:

Primer base-pairing to the target sequence also known as annealing occurs at ____°C

92~95

72

50~65

50-65

Which disorder is generally revealed by the appearance of the disorder in the male and female progeny of unaffected parents?

Autosomal recessive disorder

What stage of meiosis is the basis for mendel’s law?

Anaphase I

What is a loci?

A technique for crossing two homozygous individuals

The genotype that differs from the wild-type individual

Where a gene resides on a chromosome

All of the above

Where a gene resides on a chromosome

What kind of cell division happens in sex cell?

meiosis

What kind of cell division happens to somatic cells?

mitosis

What is the law of equal segregation or Mendel’s first law?

a. When the members of a gene pair segregate equally into the product cells, often sperm or eggs, at mitosis.

b. When the members of a gene pair segregate equally into the product cells, often sperm or eggs, at meiosis.

c. When the loci are placed equally across a chromosome

d. Both A and C

b

What is a locus?

A technique for crossing two homozygous individuals

the genotype that differs from the wild-type individual

All of the above

Where a gene resides on a chromosome

Where a gene resides on a chromosome

True or false: Mitosis can only take place in diploid organisms.

False

True or false: Cross pollination is when the anthers of a plant pollinate with the stigma of the same plant.

False

True or false: Self-pollination or “selfing” of a plant is when the anthers of one plant pollinate with the stigma of another plant.

false

True or false: Meiosis has 1 cell division.

False

True or false: A pure-breeding line refers to a homozygous individual.

true

What genetic test would you do to determine if an individual is homozygous or heterozygous for a single gene?

testcross