Genetic Difference

Today we learned about characteristics that are inherited (come from nature) and those which are shaped by our environment (nurture). We also learned about blood types and how parents can have different blood types than their children.

Click the picture to link to the website we used to watch two short video clips and take a quiz on "nature vs. nurture."

Lastly, we started a segment from the BBC's four part documentary on "The Human Face." On Friday you will find out if the little girl with moebius syndrome had a successful surgery. If you are interested in continuing to watch the series on your own, that's great! But PLEASE don't ruin the surprise for the rest of the class. Thanks :)

Today, with our 5th grade visitors, we learned about Pedigree charts. We used the Weasley's family tree to look at how the trait for red hair is passed down through their family.




It's a lot of work to actually draw people on a pedigree, so instead, scientists use symbols.




Above is the pedigree for Queen Victoria's family. It traces the trait for hemophilia. A disease where the blood does not clot.


Homework: Read and take notes on the information below. You will have a 4 question reading quiz on this information at the start of class. Three questions will be definitions and one question will ask you to THINK!

An excerpt from ExploringNature.org's explanation on genetics

Gregor Mendel, was a monk in Austria in the mid-1800s who raised peas in the monastery gardens. While breeding his peas, he made some big discoveries. They were discoveries about genetics.

The peas had several traits he could see. Some plants were tall and some were short. Some had wrinkled pods and some had smooth pods. Some pods were green and some where yellow. The flowers were white or purple. Mendel looked at each trait and learned how they were passed down to the offspring plants. Since plants breed using pollen, Mendel controlled which plants pollinated other plants. This was how he discovered many important genetic rules.

How an individual looks and what their genetic code is sometimes do not match up. This is the difference between genotype and phenotype. The genotype is the actual genetic make up of an individual. The phenotype is what that individual looks like.

Traits that show up more often are called dominant traits. Traits that show up less often are called recessive traits. If an individual with dominant traits breeds with an individual with recessive traits, this can result in a hybrid offspring. Hybrid individuals can look like they have dominant traits (phenotype), but actually be hybrid (genotype).

Hybrid plants are different from dominant plants even if they looked the same. Each gene has two chances at a trait – two copies — two alleles. So a hybrid plant could be carrying the allele for a recessive trait even if you can’t see it. So, for example, a hybrid plant might be tall like its dominant parent, but it still could have an allele for shortness that you don’t see. This is the difference between genotype and phenotype. The genotype is the actual genetic make up of an individual. The phenotype is what that individual looks like.

This can be illustrated with a simple chart. It’s called a Punnett’s Square.

DNA is the molecule of inheritance

We know that DNA makes us who we are and we know that we can inherit from our parents. But how does that happen? Do all organisms have do the same process we do? No!

Bacteria reproduce asexually, using a process called binary fission.



Humans and other animals use a process called Meiosis which produces sperm and egg cells. Instead of having 46 chromosomes each, these cells only have 23 chromosomes. Why? Because this way when a sperm and egg join during fertilization, the new cell has 46 chromosomes. Believe it or not, you all started as one single cell.




Sometimes there can be unusual events during Meiosis and instead of having 23 chromosomes, a cell has 22 or 24 chromosomes. These are called non-disjunction disorders. Today in class we spent some time discussing the symptoms of these disorders.

Homework:
Tomorrow we will be looking at how traits are passed from one generation to the next. For homework you need to complete the data collection sheet for the four traits. Your 5th grade friends have also been given the data sheet to do for homework, so they will be completing the activity as well.

Strawberry DNA lab report

Below is a PowerPoint with the requirements for your lab report which is due on Wednesday April 13th. In class. You must provide a printed copy. The data has been emailed to you.

Strawberry DNA lab report

View more presentations from ilanasaxe.

Strawberry DNA Extraction

Today we extracted DNA from strawberries. We had a very successful experiment. You can see our data below.











For homework: list every thing (variable) that was controlled in this experiment.

DNA Recap & Extraction Intro

Today we recapped what we know about DNA (see post below). Tomorrow we will be extracting DNA from Strawberries. You will have a three question quiz on the procedure tomorrow at the start of class.

What do all those letters in DNA do?

On Friday we built a strand of DNA as a class and touched on some very BIG ideas about DNA.
Here's what we took away from that class:

* A reminder that DNA is double stranded helix

* DNA is made up of small units called nucleotides. Each nucleotide has three pieces.

* There are four different bases, or letters that make up DNA. These are A (Adenine), T (Thymine), C (Cytosine) and G (Guanine).

* Just like when you build a puzzle, certain pieces fit together, the small pieces of DNA (nucleotides) can only fit together in certain ways. A pairs with T and C pairs with G.


* Every three letters on a strand of DNA = 1 codon.


* 1 codon = 1 amino acid and many amino acids put together = a protein. Just like one bead from a necklace isn't very unique, when beads are put together in a certain order, they can make something very special.

* Genes are segments of DNA that code for proteins. Our DNA is the blue print of life and the instructions in our genes, make us who we are.

And now you've read all of that,
it's time for your homework:

On Monday we will be starting a week long lab on DNA extraction from Strawberries. Your job is to make a list of at least ten genes that a strawberry has. For example, if you needed to list genes that a fish has, you might say, "a gene for gills, a gene for scales etc." You might be thinking, "Make a list of ten genes?! That's impossible!" First, it's not impossible. It turns out there are 33,294 genes in a strawberry, so simply think about what a strawberry is made of, what does it look like, what does it grow on/where does it grow.