Genetics Week 8 Resource

March 8-12

Hi Everyone! As we begin Week 8 of Genetics, many students begin to have some trouble with the material being covered. Take comfort in this: genetics is an EFFORT class!!!If you put in the work, study smart, and push yourself to do your best, I am confident you can finish the course with the grade you want. Keep in mind that the Tutoring Center offers many services that you can take advantage of!

Also, make sure you come to Genetics group tutoring, every Tuesday at 6:30-7:30 You can check the Baylor tutoring website (baylor.edu/tutoring) for more information or to schedule a free, private, one-on-one tutoring appointment!

Keywords: Translation, Gene Regulation, Operons

Review! Chapter 15 The DNA code is degenerate! o 64 possible codons (3 nucleotides that can each be ATCG) but only 20 amino acids o This means that a specific amino acid is coded for by more than one codon How to know how many amino acids come from a gene: Only count the nucleotides between the start and stop codon (including the start codon but NOT the stop codon)- why is that? Hint: think about how translation works! Each amino acid has three nucleotides (codon). Here are some amazing genetics videos made by the tutoring center to help understand the processes of transcription and replication-these are found on the tutoring website! Molecular components of translation: https://youtu.be/l3ayESyldd0 Process of translation: https://youtu.be/J-m2F7V04Kk

All figures, diagrams, and information are sourced from Pierce Genetics 7ed, unless otherwise stated.

Chapter 16

To the right is a figure from your textbook summarizing the levels of gene regulation you are responsible for. The yellow boxes represent the gene regulation method, while the images between the boxes are the result of that mode of regulation. As you can see, there are several tiers to gene regulation. This is for Eukaryotes!

In Bacteria, transcription is usually the most important level of gene regulation (in the form of the operon)

What is an operon? A set of structural genes in a bacterial cell along with the promoter, operator, etc. that controls transcription. ONLY in prokaryotes!

There are several types of operons:

Positive operon. The regulator protein is an activator, when the regulator protein is bound it turns on transcription.

Negative operon. The regulator protein is a repressor, when the regulator protein is bound it turns off transcription.

Inducible operon Transcription is off until it gets turned on.

Repressible operon Transcription is on until it gets turned off.

Make sure you can combine positive/negative and inducible/repressible in any combination and be able to answer if the regulator protein is normally bound and if it is normally made in its active state!

The lac operon is a common example of a negative inducible operon.

All figures, diagrams, and information are sourced from Pierce Genetics 7ed, unless otherwise stated. This operon breaks down lactose for energy under positive control-if lactose is present and there are no mutations, we will make basal levels of permease and beta gel If glucose is in the cell, the bacteria will break that down over lactose so the cell will inhibit the lac operon.

For max operation of the lac operon: low glucose, presence of lactose.

Chapter 17

Gene Regulation Prokaryotes Both Eukaryotes Operons DNA binding proteins • Chromatin structure influence the ability of RNA • Nuclear membrane polymerase to initiate separates transcription transcription and translation in time and space • Greater diversity of mechanisms for gene regulation (see image above)

Regulation of Genes in Eukaryotes Histones DNA Chromosomes • Methylation of • DNA methylation: • DNase Histones: activation/ represses DNA hypersensitive repression of them! • CpG islands: know sites • Acetylation of what constitutes • Chromatin Histones: stimulates them and what they remodeling-does transcription do NOT acetylate histone proteins

You will need to know the definitions, functions, and how they work of all of these in the table! Professors love to mix these definitions up on exams so really get these in your head!

That’s it for this week! I hope this is useful for you all and please do not hesitate to reach out if you have any questions. Also, remember that past resources can be found and downloaded from the tutoring center website: https://www.baylor.edu/support_programs/index.php?id=967950

All figures, diagrams, and information are sourced from Pierce Genetics 7ed, unless otherwise stated.