Molecular+genetics+notes

Student-created notes for the molecular genetics unit.

Nathan Menezes
 * April 19th**

Today we started the genetics unit! We began the class by discussing anything we already know about DNA. We then got into groups to prepare a 7 min presentation on biotech. Presentations are on Monday!

//Corina Lee//
 * April 25th, 2012**

Discussed the test and DNA day, and received the presentation marks. We drew a sample nucleotide. For the DNA nucleotides, there is only one phosphate group, but for the dNTP, there are three in total.

DNA vs. dNTP:





1. Why do we use Taq polymerase and not human DNA polymerase?
 * Questions:**

a) we don't like to use up our DNA polymerases because they are so precious b) it can withstand higher pressure and not denature c) it can withstand high temperatures and not denature (correct) 2. How many phosphate groups are on a dNTP?

a) guanine b) 3 (correct) c) 1

Some dNTPs: []

Some general stuff and some information on biotech: []


 * Homework:**

April 26th, 2012 sageban



April 30th, 2012 Nathan Menezes

Transcription

Transcription takes DNA and creates a complementary mRNA molecule.

Stage one: InitiationR To begin transcription, RNA polymerase must bind to DNA and open the double helix. It recognizes a segment of DNA upstream of the gene that is going to be transcribed. This area is called the promoter and is often rich in Ts and As (TATA box).

Stage Two: Elongation RNA polymerase now builds the single-stranded mRNA in the direction of 5' to 3'. It does not require a primer. RNA pol uses only one strand of DNA for mRNA synthesis. This is called the template strand. The other strand is the coding strand.

Stage Three: Termination The primary transcript must be modified before it is ready to leave the nucleus. First, a 5' cap is added to protect the mRNA from digestion by enzymes in the cytoplasm, and to aid in initiation of translation. Next, a poly-A tail of 200 to 300 adenines are added by poly-A polymerase. This also protects the mRNA from degradation, and aids in the termination of translation. This entire process is known as capping and tailing.

Questions: 1) What segment of DNA does RNA polymerase recognize? A) upstream (correct) B) downstream C) in the middle D) anywhere

2) Transcription is step __ of protein synthesis. A) 1 (correct) B) 2 C) 3 D) 4

May 1, 2012 Ajay Thakar Transcription

1) When a tRNA has bound its appropriate amino acid, it is called... A) amino tRNA B) tRNA-amino sequence C) Aminoacyloate tRNA D) Aminoacyl tRNA E) Charged tRNA F) Both D and E G) None of the above

2) Ribosomes start reading mRNA and creating polypeptide bonds in sets of _ nucleotides. A) 1 B) 2 C) 3 D) 4
 * Answer: F**


 * Answer: C**
 * Wednesday ,May 2, 2012 - Rida Gull**
 * Post-translational Modifications**

May 3rd, 2012 - Eisha Vijay

Today we did the Way to Glow Lab.

Here is the website of previous semester 57 that has an animation: scroll down to see the plasmid animation
 * http://biologysemester57.wikispaces.com/Molecular+Genetics

Here is a youtube link to learn more about plasmids:
 * []

//Corina Lee//
 * May 7th**

We did not have biology today! The exhibit critique was due today. Please hand it in to Kate if you haven't already!

Read and take notes on p. 264-265. Copy table 265, and be able to answer the following:
 * Homework:**
 * Comparing Prokaryotes and Eukaryotes**

1. What is coupled transcription-translation? Why is this possible? 2. Which type of cell does not contain introns? 3. How does a ribosome recognize eukaryotic mRNA? Prokaryotic mRNA? 4. How does the start amino acid differ in prokaryotes and eukaryotes? 5. In general, how do prokaryotic and eukaryotic genomes differ?

//Corina Lee//
 * May 8th**

Took up homework on mutations and the comparison between prokaryotes and eukaryotes. Did an activity in class to get a better understanding of mRNA replication process.

May 9th Pam

Todays try this: What molecule determines the reading frame of mRNA? Answer: Ribosome

Today in class we... -Recieved and filled out a new package during class entitled //Control Mechanisms for Protein Production//. This is the last topic/lesson for the unit. -it is generally about how proteins do not need to be coded at all times. There are mechanisms and processes that regulate when proteins are produced

__In class answers for the package__:

19000 insulin gene regulation


 * housekeeping genes**: genes that are switched on all the time because they are needed for life functions vital to an organisms (ex. single binding proteins)


 * Transcription factors**: proteins that switch on genes by binding to DNA and helping RNA olymerase to bind

glucose galactose
 * __correct typos in the following 2 sentences__* To use the energy in lactose for growth, E. coli must spit __LACTOSE__ into its two monomers. The enzyme used to break down __LACTOSE__ is beta-galactosidase.


 * When does the cell need to make B-galactosidase** ? ONLY WHEN LACTOSE IS PRESENT!

operon repressor protein proteins

operator RNA

inducer


 * To summarize:**
 * When is lactose absent:** the repressor binds the operator, RNA pol is blocked, no genes transcribed
 * When is lactose present:** lactose binds the repressor, it falls off the operator, RNA pol can bind and transcribe

SKILL TESTING QUESTION: When lactose is not present, the repressor protein binds to _ a) the promoter b) the operon c) the operator d) represseron

Answer: the operator

-copy table 1, p 255 Read the desription of the trp operon on p 256-257 and summarize. How is it different from lac operon? - copy table 2 p 258
 * Homework as part of the package** :

We also had extra time to complete the inclass activity about transcription/translation that wwe started yesterday

N'oubliez pas (DON'T FORGET): The bitstrip comic about transformation is due tomorrrow!

__

May 10th Pam

Today, Kate was absent (hope you're feeling better!) so we had time to work individually on any work that has yet to be completed. Also, the bitstrip comics were due; hope you guys had fun making them :)

Today's still testing question:

Which of the following is NOT one of the four levels of control in eukaryotic gene expression?

a. pretranscriptional b.postranslational c.transcriptional d. posttranscriptional e. translational

answer: a. pretranscriptional

extra review : []


 * Monday, May 14, 2012** - Rida Gull

Wed, may 16

Today in biology was the molecular genetics test......... Don't forget that the shoe lab for population has the write up due tomorrow. Soon we will be starting the homeostasis unit. here's a brief overview

http://www.youtube.com/watch?v=AIpdl11Kxyo&feature=youtube_gdata_player

question: homeostasis is used to A. make Homer Simpson stay with his sister b) Make your home warm c) maintain a constant internal environment within the body

answer: c