Fun with DNA Models!!

Adding more sugar phosphate bonds to link our DNA

Period 2's "classroom DNA"

DNA Models Day One!!

Today we started working with the Kinex DNA models.  I gave you a bit of freedom in determining the DNA sequence, and we then made one big DNA molecule. 

Only In Miss E's Room would you find boxes of DNA

Piecing it together

 Tomorrow we will then act as  DNA Helicase and DNA Polymerase as we go through DNA Replication.

Today's Daily Questions focused on points of replication

Thursday March 29^th

How does Prokaryotic and Eukaryotic DNA replication differ?

First, Prokaryotic cells have a single circular loop of DNA  while Eukaryotic cells have many chromosomes.  Because of this, the number of replication points will differ in prokaryotic and Eukaryotic cells.

How many points of replication do prokaryotic cells have?

One point of replication (two replication forks will form)

About how many points of replication do eukaryotic cells have?

Around 100 points of replication.  If there was only one, as there is in prokaryotic cells, DNA replication would take over a MONTH!!!

By having more points of replication does DNA replication happen slower or faster?

Speeds it up.  With lots of replication points in eukaryotic DNA, replication only takes about 8 hours.

Tuesday and Wednesday's Daily Questions

We have continued with our discussion on DNA structure and replication.  Tuesday's daily question focused on DNA structure.

Tuesday March 27^th

What are the three main parts that DNA is made up of?

5 Carbon Sugar (Deoxiribose), A phosphate group, and a nitrogenous Base.

How do the 4 different nitrogenous bases pair up with each other?

Adenine with Thymine (A-T) and Guanine with Cytosine (G-C)

Given the following Strand of DNA, please tell me what the complementary strand would be.

ATTGGCTCGGA

TAACCGAGCCA

We then went through notes about DNA replication.  (Check Edline for these)

Wednesday's set of daily question focused on DNA replication:

Wednesday March 28^th

There are two enzymes involved in DNA Replication.  The first one DNA Helicase  unwinds and “unzips” the double helix.

The second one DNA Polymerase adds new nucleotide bases at the replication fork.  It also acts as a “Proof Reader”.

At the end of DNA replication we have two identical DNA molecules.  How are these two molecules related? (this is the reason that DNA replication is known to be “semi conservative)   On original strand and one new strand

We then finished up the notes on DNA replication.  My plan is to start working with the Kinex models tomorrow and Friday to go through making and replicating DNA.

Good DNA Sites to visit

There are a LOT of good websites available that will help you understand the structure of DNA.  One of my favorites is The Genetics Science Learning Center put on by the University of Utah.  This will lead you through a variety of activities in all aspects of DNA including Structure, Replication, Transcription and translation.  Check it out!

Another is put on by PBS A Science Odyssey  DNA Workshop.  This also has interactive games that take you through transcription, translation and DNA replication.

Introduction to DNA

Today we began our discussion on the structure of DNA.  We started off with the following set of daily questions.

Monday March 26^th

What does the term DNA stand for?

    Deoxyribonucleic acid

What type of organic molecule is it?

    Nucleic Acid

How many strands are in DNA?

    2

What does the term RNA stand for?

    Ribonucleic Acid

How are DNA and RNA different?

    DNA is double stranded, RNA is single stranded

DNA contains the sugar Deoxyribose, RNA contains the sugar     Ribose

DNA provides instructions; RNA actually goes out and MAKES proteins

We then started into notes about DNA.  Key things to remember from today are how the bases pair up with each other.  Adenine with Thymine an Guanine with Cytosine

TEST Tomorrow!!!

I feel as though you guys REALLY got this chapter so I have high hopes for how you will perform on the exam.  Don't forget to check out the review game link!!!

http://jeopardylabs.com/play/miss-evrards-honors-biology-review-games 

Remember though - what is on there is only some BASICS to help you study.  Make sure you still look over how to make a pedigree and punnett squares and be able to APLY this information if given a genetic scenario!!

I will be at Carnegie Melon University tomorrow so you will be on your own to take this but - stay positive and I KNOW you will be just fine!! 

Chimera's...... Strange but true!!!

Here is the youtube clip that discusses how a chimera is formed and the implications it could possibly have!  There is also another interesting clip from an Episode of House that I will be showing as well!  Stay tuned for that!  Genetics is pretty mind boggling at times!!!

Why Babies are born with Blue eyes

Today we continued in our discussion about complex forms of inheritance.  We started the class with the following daily question:

Snapdragons are a type of flower that produce offspring in an incomplete dominant manor when determining flower color.

With that said –
what would the Genotype of a Red flower be? FrFr (The "r's" would be superscripts)
 What would the genotype of a white flower be? FwFw (The"w's" would be superscripts)
   What would the PHENOTYPE of a heterozygous flower be? PINK
What would the outcome of a cross between two red flowers be? All REd
What would the outcome of a cross between two white flowers be? All White
What would the outcome of a cross between two pink flowers be? 25% Red, 25% White, 50% Pink

The rest of the period we continued through our heredity notes.  8th period finally got to watch the video that discusses why most babies are born with blue eyes.  Check it out here!!

Please make sure to keep up to date with your notes.  We are about to wrap up with this chapter.  The last thing we STARTED to view was the video about Chimera's  I will post this clip as well as some more information in a later posting!!

More Complex forms of heredity and pedigrees

Daily Question for today went something like this

A male and female who are NOT colorblind have a son who IS color blind. He marries a girl, they have 3 children (2 girls and a boy) all of which see normally. The son then has two kids, a boy and a girl. The BOY is color blind. Draw out a pedigree showing the inheritance of this trait. Then determine if this is a dominant or recessive trait.

First, I had you draw the pedigree with JUST the males/females and coloring in only the individuals we KNEW expressed the trait (WERE colorblind.) Based on that, most of you were able to tell me it had to be recessive since it showed up in the offspring of parents that did NOT express the trait.... ok... thats a start. THEN i filled in the rest of the pedigree and asked you - what is WRONG with this?!?! It looked something like this.....

So your FIRST question should be - WHY isn't the male heterozygous in the two cases where they had offspring that that DID express it but the mother IS? MISS Evrard!!! YOU MESSED UP.... This CAN'T be right?!?!?!?!

Well...... I am the first to admit I do often mess up... but in this case.... NOPE.... think harder................

WHAT could cause a recessive trait to show up more often in MALES than females?!?!?! It's as if there is no OTHER allele there to counter act it..... say like if I had only ONE of that chromosome.....

YUP - Not only was this a recessive trait - it was X-linked. It shows up more often in males because if they inherited it (from their mother) they don't have the advantage of having a second X that may contain the "good" allele from their dad since their dad is who gave them their Y chromosome.

After this we went on to predict the outcome of more x-linked scenarios and moved into other complex forms of inheritance. In the notes we have moved from polygenic inheritance (which we discussed yesterday) to Incomplete dominance. This led 2nd period into a pretty in depth discussion on eye color and then why some people have two different colored eyes..... 8th period... Hold on tight - we have a long period tomorrow so you will get there as well!!!

Fainting Goats Clip

Here is the clip of the fainting goats that we watched in class today

http://www.youtube.com/watch?v=AEmRfxxGGcE&featrue=fvsr

What I find hilarious is just their reaction to the "white man crazy goat" The farmer speaks of "myotonia" as being the condition that they have. That is not the actual GENE that causes it. Myotonia is just "a medical term that refers to a neuromuscular condition in which the relaxation of a muscle is impaired"

Can you see this in humans? Yes - here is a link detailing information about this genetic disorder that also affects humans. NOT in the same way though as the goats.

http://ghr.nlm.nih.gov/condition/myotonia-congenita

Myotonia of the tongue

With goats, remember, a lot of it has to do with their fear response. What controls THAT is specific areas of the brain sometimes referred to as the "fear factory"

Here is a good link that describes in a little more detail the genetics behind "fainting goats"

http://science.howstuffworks.com/environmental/life/zoology/mammals/fainting-goat1.htm

Pedigrees and Fainting Goats - Isn't Bio Fun?!?!

Today we started with another daily question that deals with Pedigrees

Using the following pedigree answer the questions below

1st: How many childred did the FIRST set of parents have? How many boys/girls?

The first set of parents had two kids - one boy and one girl.

Of those Children, which child had children of their own? (The boy or girl)

The BOY

How many boys/girls did He have? 3 boys and 1 girl

Based on this pedigree, the trait that is being seen must be dominant or recessive?

It must be recessive, how do i know this? A trait that shows up in children that is NOT expressed in either parent MUST be recessive. If this was a DOMINANT trait - at least ONE of the parents would have to also express it.

Because of this (the fact that it is recessive), what can we say about the genotypes of teh first and second set of parents?

Both of them would have to be carriers of the trait (so you would fill them in half way)

After this we analzyed another pedigree (handout - please see edline for the document if you missed it, or get it from me) This allowed us to determine genotypes of parents based on their offpsrings phenotypes.

We will now be moving in to more complex forms of heredity. MOST of our traits are not simple dominant or recessive. So simple Punnett squares are not very valuable for the majority of our traits. To START this off though we watched the "fainting goat video" (see blog above) then moved on in our notes to complex forms of inheritance. (Please check edline for notes if you missed)

Punnett Squares

I haven't posted on here yet this week. So here is a run down of what we have done so far!! We have moved from just simple dominant/recessive traits to showing how we can model mendel's laws with punnett squares and pedigrees.

There were no daily questions on Monday, we just continued our discussion about predicting genotypes based on phenotypes. Most of you seem to have a pretty solid understanding of WHAT a punnett square is and how to set one up. You had time though to work through that section in the book as well as move forward into more complex form of inheritance.

Tuesday: We started with a Daily Question

Achondroplasia is a genetic disorder of bone growth.

A=Allele for Achondroplasia

a = Allele for Normal Bone Growth

1st off: is Achondroplasia (Dwarfism) a dominant or recessive disorder? Well since i represented the allele with a Captial letter, we know it must be a DOMINANT disorder

Next: What is the GENOTYPE of someone who is HETEROZYGOUS for Achondroplaisa?

Aa and that person would have normal bone growth.

What is the PHENOTYPE of someone who is homozygous recessive?

They would nave NORMAL bone growth

Using a punnett square, find the chances that two people heterozygous for achondroplasia could have a normal child. There would be a 25% chance they would have a child WITH achondroplasia. See punnett square below

What does this MEAN then? That two dwarfs that are Heterozygous have a 25% chance of having an averaged sized child. Those of you who have followed Little People Big world can now see how this couple could have 2 children that were averaged size. What does that mean about THEIR genotypes?!?! They MUST be heterozygous. So EVERY time they have children, there is a 25% chance they will be average sized.

Pics from taking an inventory of our traits

We had a fun time taking an inventory of our traits, here are some of the pictures!!!!

Learning how to learn

Today we went through a couple scenarios about parents and offspring that made you analyze and predict genotypes. I have told you before that learning to "struggle through" scenarios is how you learn things the BEST. So I gave you some time to hash it out with those around you. Since this is a fairly new skill to you guys I want to model how I answered these (see the image above). I talked about them in class and showed you my paper - but here it is again. There is something to be said about HOW to read a question. Many of you looked right at them, got ovewhelmed and said "Miss E - I need help" and then were quite discouraged when i said no. Let me tell you though, some of the conversations I heard going on between you guys was AMAZING!!! You are really starting to learn to work through problems!! I KNOW this is frustrating, but this is a KEY skill to learn when solving ANY sort of complex problem!!

Wednesday's Daily Question and Activities

Today's Daily Question was based off of this concept map

After going over this - we then started to take an inventory of our traits - always a favorite!! Some of the traits we looked at: Widows peak, tongue rolling, cleft chin, Dimples, and whether you can taste PTC (phenylthiocarbamide) or not. After looking into this more - APPARENTLY this is a myth that it is only one gene that determines if you can taste it or not. For more information you can go to http://udel.edu/~mcdonald/mythptc.html Basically what this is saying if that environmental factors play a role as well. This is not a suprise at all, as we will see later in this chapter that MOST genes are influenced by the cellular environment and there are hardly ANY characteristics that we have that follow simple mendelian patterns of heredity!!

Tuesday's Daily Questions and Discussion

Daily Questions:

*If someone exhibits a dominant phenotype – what are the possible genotypes they could be? Homozygous Dominant (TT) or Heterozygous (Tt) - Remember - a recessive allele can be present but is not expressed when a dominant allele is paired with it.

*If someone exhibits the recessive phenotype, what are the possible genotypes they could be? Homozygous Recessive (tt) - there is only ONE possible outcome to this. The ONLY way a recessive phenotype is expressed is if there are ONLY recessive alleles for that trait.

*True or False: Dominant traits are more common in a population. VERY VERY FALSE!!! Dominant only means that it is expressed if present- NOT that it is more common OR that it is "better" (For instance - the allele for having 6 fingers is dominant over having 5 fingers......)

After the daily questions we continued through notes focusing on predicting genotypes based on phenotypes. One trait we looked at was the presence or absence of a widows peak..

Monday's Daily Questions and discussion

Homologous chromosomes each have different forms of a gene on them (one from your mom and one from your dad) These different “forms” are known as Alleles.

These can either be dominant or recessive. Those that are recessive are Hidden if a dominant allele is present.

The two alleles an organism has for a specific trait is known as its Genotype. The actual characteristic that it has (the Physical appearance is known as its Phenotype

** After the daily questions we went through the first couple sections of this chapter. Please continue to refer to your study packet. We focused MOSTLY on the concept of what genes/alleles are the difference between genotype and phenotype and dominant vs recesive alleles.

Identical Twins Video

Intro to heredity

So we are now starting on a new unit on heredity. I think you guys are going to enjoy this, as it has to do with why we have the traits we have and what can we pass on to our offspring. We are going to try this blog out to see how that goes. When you have any questions throughout the chapter, this will be a good place to ask them. so HERE WE GO!!!!!