28 Unit 4 Study Guide

The following provide suggestions of what you should review for each RIQ and Exam in BS161.

RIQ 024

1. Draw a table listing the epigenetic changes associated with increased vs decreased transcription. Apply this to gene expression data to make predictions about the epigenetic modifications present for certain genes in certain tissues. (See PCA Regulation of gene expression I, part 2C, and ICA Regulation of gene expression I, Activity 3.)
2. Draw a table listing the key proteins for regulation of gene expression and regulation. For each protein, indicate the type of molecule (DNA, unprocessed RNA, or mRNA) that the regulator protein binds to, the name of the specific type of nucleotide sequence the protein binds to, and the effect this binding has on gene expression. (See PCA Regulation of gene expression I, part 3.)
3. Draw a model of a eukaryotic gene, the primary transcript produced when this gene expressed, and the mature (processed) mRNA produced when all exons are included. (See PCA Regulation of gene expression I.)
4. Based on provided gene expression data, draw a model of a gene that shows the binding (or not) of transcriptional regulators and RNA polymerase to explain the gene expression data. (See ICA Regulation of gene expression I, Activity 3E.)

RIQ 025

1. Draw a table to summarize the similarities and differences in gene expression between eukaryotes and prokaryotes. (See PCA Regulation of gene expression II.)
2. Draw models of the trp operon when (1) there are high levels of tryptophan, and (2) when there are low levels of tryptophan. (See PCA Regulation of gene expression II and ICA Regulation of gene expression II.)
   1. Label key DNA sequences, proteins, and tryptophan in each model.
   2. Explain what controls the DNA binding of TrpR, and how this binding affects expression of the operon.
   3. State the function of the proteins encoded by the operon genes and connect this to why expression occurs under some conditions but not others.
   4. Use the above to predict the effects of mutations in regulatory proteins (TrpR) on trp operon expression.
3. Draw models of the lac operon when (1) there are high levels of lactose and low levels of glucose, and (2) when there are low levels of lactose and high levels of glucose. (See PCA Regulation of gene expression II and ICA Regulation of gene expression II.)
   1. Label key DNA sequences and proteins, and sugars in each model.
   2. Explain what controls the DNA binding of LacI and of CRP, and how binding of each of these affects expression of the operon.
   3. State the function of the proteins encoded by the operon genes and connect this to why expression occurs under some conditions but not others.
   4. Use the above to predict the effects of mutations in regulatory proteins (LacI, CRP) on lac operon expression.

RIQ 026-027

1. Draw models of the lac operon when (1) there are high levels of lactose and high levels of glucose, and (2) when there are low levels of lactose and low levels of glucose. (See PCA Model of gene regulation and ICA Model of gene regulation.)
   1. Explain what controls the DNA binding of LacI and of CRP, and how binding of each of these affects expression of the operon.
   2. State the function of the proteins encoded by the operon genes and connect this to why expression occurs under some conditions but not others.
2. For a culture of E. coli cells grown in the presence of glucose and lactose,
   1. State which sugar will be consumed first and why.
   2. Based on parts 3 and 4 above, predict how lac operon transcription is affected by changing sugar conditions, based on the models of the operon under those conditions. (See PCA Model of gene regulation and ICA Model of gene regulation.)
3. Draw a table to show the key enzymes and sequences important for the processes of transcription, RNA processing, translation, and DNA replication. Use this table, the gene schematic in part 4 of PCA Alleles and phenotypes, and your knowledge of gene expression to propose (See PCA Gene expression I & II, PCA Regulation of gene expression I in addition to PCA Alleles and phenotypes):
   1. Mutations that specifically affect how much transcription of a gene is occurring
   2. Mutations that specifically affect the specific sequence of an mRNA
   3. Mutations that specifically affect the length of an mRNA
   4. Mutations that specifically affect the specific sequence of a protein
   5. Mutations that specifically affect the length of a protein
4. Describe the general reaction carried out by the enzyme encoded by the blood type allele. Draw models and refer to structure-function relationships and the role of enzymes to explain how different combinations of blood type alleles (A, B, and O) relate to the different blood type phenotypes (A, B, AB, and O).