detailed notes on transcription and translation

 

Amino acids are made of a carboxyl group and amine group and an R group.  
they are the subunits for polypeptide chains which ultimately make a protein.

There are twenty one amino acids which correspond to a CODON. This forms the GENETIC CODE

Transcription: mRNA is made from the DNA strand
1.   DNA unwinds and a promoter region is exposed.  There is a SENSE STRAND (TEMPLATE STRAND) of DNA to make RNA.
2.  RNA polymerase synthesizes the mRNA from a 5' to 3' direction.  RNA nucleotides are attached only on the 3' end.
3.  When the mRNA is complete it undergoes processing
 a.EDITING THE mRNA STRAND:  INTRONS are removed and EXONS remain.
b.  A polyA tail and 5' cap are placed on the mRNA in order to protect the strand from exonuclease.  Exonucleases digest and recycle mRNA.  We want them to avoid digesting the mRNA while it is being read by the ribosome
4.  mRNA is now ready for the ribosome.  IN EUKARYOTES, it leaves the nucleus.  IN PROKARYOTES, protein synthesis starts right away

Translation:  mRNA gets read by the ribosome and a polypeptide chain is formed
 Initiation: 
1. METHIONINE is the first amino acid brought by a tRNA.  tRNA has an ANTICODON which is complementary to the mRNA CODON.  The START CODON IS ALWAYS AUG. Meanwhile, the small ribosomal subunit attaches to the strand.
2.  Next the large ribosomal subunit arrives with its P site and A site.

AMINO ACYL T-RNA is the name of the tRNA attached to the amino acid.

the following is excerpted from this website as a quote:
 and is attributed to mrsdaintreysonlineclassroom. retrieved
january 20, 2016:  

Elongation
more amino acids are added and connected together to form a polypeptide, as specified by the mRNA sequence.
i. an incoming amino-acyl-tRNA (lets call this AA2-tRNA2) recognizes the codon in the A site and binds there.
ii. a peptide bond is formed through dehydration synthesis between the new amino acid and the growing polypeptide chain.
iii. the amino acid is removed from tRNA1 (bond breaks between aa1 and tRNA1)
iv. the tRNA1 that was in the P site is released, and the tRNA in the A site is translocated to the P site.
v. the ribosome moves over one codon along the mRNA (to the right in our diagram, or more specifically in the 5' ----> 3' direction.)
vi. This movement shifts the tRNA2 (which is attached to the growing amino acid chain) to the P site.
vii. tRNA3 with aa3 can now move into A site and bind with the next codon on mRNA.
viii. THIS PROCESS REPEATS, and the CHAIN ELONGATES as long as there are new codons to read on the mRNA. 

Termination
The process above repeats until a special codon, called a STOP CODON, is reached. There are 3 Stop codons: UAA, UAG, UGA.
i. the stop codons do not code for amino acids but instead act as signals to stop translation.
ii. a protein called release factor binds directly to the stop codon in the A site. The release factor causes a water molecule to be added to the end of the polypeptide chain, and the chain then separates from the last tRNA.

3. the protein is now complete. The mRNA is now usually broken down by exonuclease  and the ribosome splits into its large and small subunits.
   
4. the new protein is sent for final processing into the endoplasmic reticulum and golgi apparatus 
   

protein synthesis

 NOTES: a summary of what we learned about protein synthesis

A diagram worksheet summary


More practice generating mRNA, tRNA and Amino Acids in this link here

TRNA sung to the tune of YMCA:

and the lyrics are right here for the karaoke version! 

human blood and lymph nodes

 Human blood smear can have the following types of blood:

a red blood cell is an erythrocyte.  This erythrocyte may exhibit the antigens

A, B or Rh factor. A neutrophil and a monocyte are types of white blood cell that can "eat" foreign microbes.  A platelet is a blood protein that is used for clotting blood. Have a look at this site to see more blood cells

When you look at the lymph node slides look at this website from Yale University to help you know what you are looking at .  Further, look at this Histology blog to help you identify denditric cells 

Further, have a look at this cartoon to help understand the locations of the B-cells, T-cells and also dendictric cells in a lymph node 

In your Blood lab please do the following ,  All drawings should be done in a circle and use a petri dish to draw the circle. 

1.  Draw a clear, colour drawing of a human blood smear on high power.  Label the cells that you find, including erythrocytes, and WBCs such as lymphocytes, monocytes, neutrophils, eosinophils. 

2.  Draw a clear, colour drawing of a slide of a lymph node and label whatever structures you can.  Draw this under low and medium power. 

3.  Copy this cartoon of the lymph node to familiarize yourself with where the cells are. 

"Cross-section of a lymph node with sections labelled.1) Capsule; 2) Subcapsular sinus; 3) Germinal center; 4) Lymphoid nodule; 5) Trabeculae" 

copyright Benutzer:Gleiberg

Mitosis and meiosis lesson notes and questions

 Although you studied mitosis and meiosis in the past, it is worth a look again to make sure you have all the steps down correctly.  It will help you to understand our next unit which is Genetics.  This video explains how alleles are connected to the steps of mitosis and meiosis.  I also assume this is familiar from last year.

Your teacher will review these steps, explaining some of the complex parts and  give you time to answer the questions.  Next, your teacher will review the answers to the questions.  After this you will do a creative assignment to demonstrate that you understand this material.  

Please watch this video


Answer the following questions on your own paper and hand this in. 

 Answer in full sentences and draw your answers.  Draw in ink or photograph a model using lego, string or other material

1.  What is Chromatin?  How many strands are there in a human?
2.  How many chromatids are there in a human?
3.  What is the 2n  or diploid number?
4.  What is mitosis used for?
5.  What is meiosis used for?
6.  Define "Gamete"
7.  What is the Haploid number?
8.  What organ makes sperm, what makes egg?
9.  How many chromatids are in a sperm or egg?
10 Draw a fertilization
11.  Draw how sperm cells are made using the number 46 to represent the chromatid number.
12.  Draw and label Chromatin, Chromatid, Sister chromatids, Chromosome.  And show me a homologous chromosome
13.    Draw a mitosis with 2n= 6.  Label the stages in detail. Remember to draw Interphase and show chromatins.
14.  Draw a meiois with 2n=6.   Label the stages.
Again, draw interphase and show the chromatin.
15a. Why does crossing over happen during prophase I?
15b.  What is primary nondisjunction.  What can happen to the chromatid number?

immune system topics for quick poster presentation

 1. Alaskan Serum relay of 1925, the story of Togo and Balto

2.  Influenza: H3N2 subclade K flu, Avian Flu H5N1 

3. TB

4. Measles

5. Meat allergy alpha gal case 

6.  HPV and cervical cancer 

7. Mpox clade 1 &2

8. Tetanus ER protocols and the story of the boy in 2017 in Oregon who was not immunized against Tetanus

9. Meningitis B in Nova Scotia:  The story of Kai 

The Immune System Study Questions

 We reviewed the immune system in class.  

1.  The immune system can be divided into SPECIFIC  responses and NONSPECIFIC responses.  

a.  What are the two kinds of specific responses and what cells are involved?

b.  What are the two kinds of nonspecific responses? 

2.  For barriers, describe the kinds of barriers that are in the 

a. respiratory system

b. digestive system 

c.  reproductive system

d.  skin 

3.  The inflammatory response happens when there is a break in the barrier.  List all the steps of the inflammation response, including all the cells that are involved and the cell communication that takes place.  

4.  Is inflammation LOCAL , happening in a specific place, or is it SYSTEMIC, happening all over the body?  

5.  Describe the following cases where the inflammatory response is not working properly. What is the cause, the symptoms and the treatment?

a.  allergy to a  food item

b.  sepsis

6.  What are the two kinds of SPECIFIC IMMUNITY and what cells are involved ?

7.  What is a major histocompatibility complex and how does it help protect the body?

8.  Describe the steps of the humeral response.

9. describe the steps of the cell mediated response.

10 How does a T-cell get trained to do its job properly and to not attack the body?  

11.  Give some examples of "autoimmune" diseases. 

Fetal circulation

 

 Click on the picture below to play the video 
 
 

Today we explored fetal circulation.  First we drew our conception of how fetal circulation might occur. Next we compared fetal and baby circulation in depth in the table below.  Finally we drew a schematic diagram to compare the two and listened to a baby cry because the newborn's first breath is when the ductus arterioles and the foramen ovale closes successfully