BIOL 151 Exam Review

Practice Exam 2 Overview

  • This document contains multiple-choice and true/false questions relevant to BIOL 151, supervised by R. Phillis in Fall 2025.

Question Types

  • Questions are structured with numbered questions containing lettered multiple-choice answers.

  • True/False questions require respondents to denote "A" for True and "B" for False on the answer sheet.

  • Some questions may have responses that extend beyond True/False.

Adrenaline Pathway Questions

Problem [2-7]

  • Predict how specific changes affect the duration of the Adrenaline pathway response.

  • Answer Choices:

    • A = The response lasts longer.

    • B = The response is shorter.

    • C = The response does not change.

    1. If the amount of Monoamine Oxidase outside the cell decreases.

    2. If Adrenaline binds to the receptor more tightly.

    3. If the GTPase activity of G protein alpha is increased.

    4. If binding of G protein alpha to Adenylyl Cyclase lasts longer.

    5. If the amount of Phosphodiesterase in the cell decreases.

    6. If a lower concentration of cAMP is required to activate regulatory subunits of PKA.

Effects on EGF Pathway

Problem [8-12]

  • Identify signaling events that can block EGF pathway signaling through the Adrenaline pathway:

    1. GEF activity of the Adrenaline receptor targets both G protein alpha and Ras.

    2. cAMP concentrations increase NF1 (Ras GAP) activity.

    3. ERK may activate genes encoding Phosphodiesterase.

    4. Activated PKA could target MEK.

    5. Activated PKA could express a phosphatase targeting Raf.

Cell Cycle Control Questions

Problem [13-18]

True Statements about Cell Cycle Control:

  1. Increased growth factor signaling leads to an increase in cells in G2 phase.

  2. CDKIs prevent Cyclins from binding or activating CDKs.

  3. Once started after mitosis, the cell is committed to complete division unless DNA damage or cell defects arise.

  4. DNA quantification can indicate growth factor signaling.

  5. High p53 levels prevent progression past the next cell cycle checkpoint.

  6. Many cell cycle control genes were identified in yeast through genetic screens for mutations affecting division or checkpoint integrity.

Analyzing Cell States

Problem [19-24] - Conditions of a Cell with High Cyclin D Levels:

  • Only one copy of each homolog exists:

  • CDK4/6 is active.

  • Rb is fully phosphorylated.

  • A kinase is phosphorylating Cyclin E.

  • CDK2 is inactive.

  • DP1 is phosphorylated.

  • The cell is in G1 phase.

Problem [25-30] - Additional Analysis of Cell State:

  • Conditions were defined for E2F not binding to Rb and DP1 not phosphorylated:

    1. TK2 phosphorylated.

    2. MEK is not phosphorylated.

    3. cAMP binding to the regulatory PKA subunits.

    4. A kinase phosphorylating Cyclin E.

    5. Rb fully phosphorylated.

    6. The cell has passed the G1 checkpoint.

Problem [31-40] - Another Cell Analysis:

  • Features: DP1 phosphorylated, Exonuclease and Endonuclease present:

    1. CDK2 binding to Cyclin A.

    2. DNA polymerase III is active.

    3. Ras binds GDP.

    4. Adenylyl Cyclase is active.

    5. The cell is in G2 phase.

    6. Mismatched G-T base pairs are present.

    7. MDM2 binds to p53.

    8. Mismatch repair is activated.

    9. Pyrimidine dimer binding protein is active.

Mutated Ras Gene Analysis

Problem [40-43]

  • Analysis of a mutant Ras gene from tumor cells exposed to radiation:

    • Findings: 9 base pair deletion affecting the GTPase function of Ras.

    1. The tumor Ras gene may have sustained a double-strand DNA break.

    2. Non-homologous end joining may have repaired the Ras gene.

    3. The mutant Ras gene could be repaired using the non-mutant copy as a template.

    4. This mutation blocks signaling through the EGF pathway.

DNA Segment Examination

Problem [44-47] - Healthy Cell in the S Phase:

  • Notable Features: Both double-stranded and single-stranded DNA, RNA primers present:

    1. Helicase has acted on DNA.

    2. RNA primers are present only on the lagging strand.

    3. DNA polymerase I has completed its function.

    4. Dideoxy nucleotides are incorporated by DNA polymerase III.

PCR Amplification Overview:

  • Given the sequence: 5’-GTACCGTGACCAGTACAGTTACGACGATTACACTTACA-3’

  • Complementary strand: 3’-CATGGCACTGGTCATGTCAATGCTGCTAATGTGAATGT-5’

Primer Annealing Analysis

Problem [48-51] - Top Strand as Template:

  • Which primers will anneal?

    1. 5’-GTACCGTGACC

    2. 3’-CATGGCACTGG

    3. 5’-TTACACTTACA

    4. 5’-AATGTGAATGT

Problem [52-55] - Bottom Strand as Template:

  • Which primers will anneal?

    1. 5’-GTACCGTGACC

    2. 3’-CATGGCACTGG

    3. 5’-TTACACTTACA

    4. 5’-AATGTGAATGT

Primer Stability at Higher Temperatures

Problem [56]

  • Which primer remains bound at higher temperatures?

    • a. The primer to the top strand.

    • b. The primer to the bottom strand.

Replication Bubble Analysis

Problem [57-62] - Understanding the Replication Bubble:

  • Statements concerning the replication bubble:

    1. Top strand serves as a template for the leading strand at the left fork.

    2. Top strand serves as a template for the leading strand at the right fork.

    3. Helicase binds at the origin, releasing DNA after bubble formation.

    4. Okazaki fragments found at the bottom strand of the right fork.

    5. DNA polymerase I may be more active on the top strand than on the bottom of the right fork.

    6. Primase is more active on the top strand of the left fork.

Sanger Sequencing Gel Analysis
Problem [63-66] - Observations about the Gel:

  • Key facts regarding the Sanger sequencing gel:

    1. Bottom band in the C lane is the smallest DNA fragment on the gel.

    2. The top band in the A lane is the smallest DNA fragment on the gel.

    3. The first 10 nucleotides of the DNA sequence in the gel are 5’-CAGCGATTAC.

    4. The first 10 nucleotides of the DNA sequence in the gel are 3’-CAGCGATTAC.