Hon Bio

Today in class we learned about mitosis and meiosis in the cell cycle. Mitosis is when a cell starts with two chromosomes (2n) and ends with two daughter cells that hold two pairs of chromosomes (2n). 

Mitosis: 

Meiosis is when the cell starts out with one cell containing two sets of chromosomes and ends with four daughter cells with one set of chromosomes (1n). 

Meiosis: 

Chapter 6 discussion

In chapter six of, Your Inner Fish, it talks about the relationship between DNA, Embryology, and germ layers. It first mentions the scientist Karl Ernst Von Baer who discovered that organs are derived from 3 developing layers in the embryo. These three germ layers, the ectoderm, endoderm, and mesoderm, are within all animals, and are where organs are created from.

In this picture, you can see how each layer corresponds to a different set of organs.

What controls the body plan is a small piece of tissue called the organizer. It is also revealed that DNA controls the organizer, and therefore controls the body plan. This connects all there concepts to evolution, and how our bodies change over time. 

Class 28

Today we reviewed the unit test and I got a 94%:). After, we talked about our new project where we would fly through the cell and explain the organelles. 

Next we learned how to use the microscope and studied a dog flea, cheek cells, plant leaf, and a sample from the fish tank.

Unit test 4

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Bio class 27

Today in class we learned about pedigrees that depict Janie traits and genes are transferred from generation to generation. 

Example: 

We also learned about different types of pedigrees such as autosomal and sex linked. Autosomal is when there are normal circumstances and the traits are not linked to a gender. Sex linked is when the traits are linked to gender, mostly boys.

Autosomal recessive: 

Dominant: 

Sex linked:

Dominant:

Bio class 25

Today in class we learned how to solve for the phenotypic and genotypic ratios using two different genes.

Example: 

Here you have to solve for the different genotypes before you can solve for the specific ratios. Another way to do it is to use the the regular punnet square and use the fractions to solve for the ratios.

Example:

Here you can multiply the different fractions and solve for either a genotypic ratio or a phenotypic ratio.

Bio class 26

Today in class we learned about the integration of different genes. Sometimes two genes will determine a certain phenotype such as color. 

In class, we compared the different phenotypes of the labs as a result of specific combination of genes.

We also learned about incomplete dominance where there is no longer a dominant gene. 

In this example you can see the different phenotype a for a mix of two incomplete dominant alleles. By mixing the red and white colored flowers, one can create a pink bloom.

Next we learned about sex-linked genes. Here's an example:

Males contain a Y allele that certify a that they are male. This also allows the female     Gene to dictate what the phenotype will be.

Survival of the sickest chapter 1 summary

hemachromatosis is a hereditary disease, the most common genetic disease for people of European descent, in which the body can't register that it has enough iron. So it continuously absorbs as much of it as possible, and this can have very serious side effects (including death). Iron is very important for bacteria, cancer, and other things to grow which is why too much iron is so dangerous. during the black plague in Europe, people with more iron in their system were more likely to die because bacteria feeds on iron. Women, children, and the elderly were significantly less targeted than men. But people with hemachromatosis also happen to have white immune system blood cells with considerably less iron than the normal person, and this counteracted the precise way that the bubonic plague killed its victims - through their own immune system. Because of this lack of iron, people were actually able to fight off the disease, and their lives were spared.

Honors bio class 24

Today in class we learned about genetics , dominant genes, recessive genes, phenotype, and the ratios they produce. We also learned about the linnet square and how to utilize it when solving for the F1, or the first generation. 

By using the parents alleles, we can produce the predicted results of their offspring. After this, we worked on problems where we solved for the ratios: 

After we finished the worksheet, we took a quiz on the punnet square.

Honors bio class 23

Today in class we reviews the operon system and its relationship with biotechnology. We first took  a quiz on protein synthesis and then began to what controlled the production of proteins. The operon system is only present in prokaryote cells or cells without a nucleus. Their are two types of operon systems; induceible and repressive. An example of the repressive operon system is the tryptophan operon system:

At the left end their is the regulatory gene that when translated by the RNA polymerase, produces mRNA which then produces the repressor. As the RNA polymerase continues down the line it reads the genes for tryptophan. As a result, tryptophan is produced until there is enough to activate the repressor. Once activated, the repressor binds to the operator and blocks off the tryptophan gene so that it is no longer produced. 

The induceible operon system is different because it switches off an active repressor. An example of an induceible system is the lactose operon system:

As you can see, once lactose is present the repressor is deactivated and un-binds itself from the operator. This allows the RNA polymerase to read the gene and produce whatever that gene dictates.

Honors Bio Class 22

Today in class we reviewed the the process of protein synthesis. In a prokaryotic cell protein synthesis takes place in two main steps; transcription and translation. In eukaryotic cells the mRNA is transcripted twice, first inside the Cell nucleus and second, outside the the nucleus in the cytoplasm. RNA polymerase is needed to create mRNA in order to code for the protein. Before we can use the mRNA, the spliceosome needs to cut out all the introns that are useless when coding for the protein.In both cells, tRNA is used to collect the amino acids that are floating around the cytoplasm. tRNA and the amino acid are connected by the enzyme tRNA aminoacyl synthetase. Once they are bonded both the amino acid and the mRNA and the tRNA are moved to the ribosome. The ribosome will begin to read the mRNA in the 5' to 3' direction. Depending on the codons, certain tRNAs with matching codons will be accepted into the ribosome. The tRNAs will bring with them, their amino acid which will create a polypeptide chain which will eventually create a protein.

Hon Bio Class 21

Today in class we went over the DNA replication process. Some of the important enzymes includes: 

We went step by step starting with the breaking of the hydrogen bonds by the Helicase enzyme: 

Then we moved on to the addition of RNA nucleotide which were put in place by RNA Primase. After that, DNA polymerase III added DNA nucleotides in the 3' - 5' direction. This left a lagging strand of DNA that lacked nucleotides.

RNA nucleotides are then added to the lagging strand but some spaces are still left open for the placement of DNA nucleotides. Polymerase I replaces RNA nucleotides with DNA nucleotides in the lagging strand to allow for phosphate diecer bonds to form. Ligase allows the okasaki fragments to bond and form a strand of new DNA.

We checked the results of our bacteria a found that only one of them glowed.

Survival of the Sickest Ch 3 Summary

Chapter 3 in Survival of the Sickest  Dr. Moalem explains how folic acid, vitamin D, and cholesterol all work together. He explains that though the sun is necessary it is constantly a problem for our bodies. Many of the things we are constantly exposed to in nature have this dual relationship...helps one on hand and hurts on another.  We  are always evolving in this balancing act.   We need the sun for the vitamin d it supplies us,but at the same time we are receiving the vitamin d the sun is taking away our folic acid. Now to counteract that our bodies create more cholesterol so that losing that folic acid is no longer an issue. The folic acid isn't dependent on the cholesterol; the vitamin D is.  Now our skin color is the way color it is due to the amount of sun you are exposed to year round. Africans have such dark skin due to the amount of sun they experience. The amount of sun won't make a person very dark if they don't have the traits that allow them to make lots of melanin.  For example, African genetics code for lots of melanin whether exposed to lots of sun or not, whereas European genetics codes for less melanin even if exposed to lots of sun.  There skin is darker so that not as much folic acid is taken from there bodies. I also learned that sun tan lotion is sometimes bad for the human body because it keeps the important vitamin D from absorbing the frolic acid. This results in excess cholesterol which is sometimes harmful to human bodies.

Bio Class 20

Today in class we spent most of our time working on a new lab experiment that involved bacteria. Our goal was to try and get our prokaryote bacteria to glow by immersing them in PGLO. However, we knew that it would be hard to successfully get the PGLO in to the cell because of the cell membrane. Our solution to this problem was to put the bacteria through heat shock in the hopes of opening up a hole in the membrane. Before we could reach this process, we had to set up the different solutions of bacteria and PGLO. Here are the steps we took before the heat shock process:

We had to be very careful when going through these steps to avoid adding excess bacteria to our tubes.

After these steps we were finally able to put the -PGLO tube and the +PGLO tube through heat shock. :

After the 50 seconds were up we had to immediately  place the tube back into the ice bath to keep the DNA from slipping out of the cell.

After heat shock we filled the tubes with LB broth to act as the food for our bacteria and place them into four different Petri dishes with different environments for the bacteria to grow in. 

Our class hypothesis was:

We would check for the results next class.

Ch 6 Survival of the Sickest Summary

In chapter 6 of Survival of the Sickest, it talks about how scientists have  realized that DNA can be modified by other factors, and not just random mutations. Lamarckism or, the  inheritance of acquired traits, seems to be superseding the original theory of Darwin that is mentioned in his book Origin of the Species. Barbara McClintock provided evidence in the 1950's for traits caused by jumping genes. Jumping genes are whole sequences of DNA that has been prompted to move from one place to another, by stress in the environment. Occasionally, jumping genes, or transposons, preform a "cut and paste" process, or a "copy and paste" process. Cut and paste is when whole sequences are removed and relocated, and copy and paste is when sequences are duplicated first, and then relocated. Jumping genes are what make up large portions of our junk DNA, or DNA that does not code for proteins.

This chapter also talked about the relationship of viruses, DNA, and RNA. Retroviruses are made up of RNA and can be inserted into, or written into, DNA. HIV is an example of a retrovirus, and is combated by the drug "cocktail" therapy. Cocktail therapy targets the enzyme that helps RNA become apart of DNA, in the hopes of slowing the process. Retroviruses that are already a part of DNA are called HERV's, also known as Human Endogenous Retroviruses. Some HERV's have a positive effect on DNA and are known for playing a number of roles such as producing a healthy placenta.

Bio Class 19

Today in class we took a quiz on "The Journey of Man" and then turned to the whiteboard for an activity. We discussed DNA and its properties such as: nucleotides: phosphate+sugar+base 

Adenine, thymine, guanine, cytosine: makes up DNA. Hydrogen bonds connect base pair.

Phosphate diester bond: through dehydration synthesis

Purines and Puyrimidines: 1 group vs 2 groups

3' base and 5' base: 

3 prime base has an OH group.

Special enzymes help to unzip DNA when mitosis in a cell occurs or there is a need for replication: 

Form atoms to traits

1.) Mendel was important because he helped adjust and prove Darwin's theory. By crossbreeding pea plants, he was able to prove that the offspring did indeed share similar traits. He also proved that heritable variations are their own separate entities that are always passed on but not always present.

2.) DNA:

Discovered by James D. Watson and Francis Crick. 

3.) 1. Copying errors during DNA replication such as copying the wrong letter of skipping a letter.

2. Substitution of different strands of DNA can cause mutations, and can change the variation.

3. Point mutation is when a single base pair changes for example muscle growth in dogs such as the whippet.

4. Insertion is when a base pair sequence is inserted into a gene that can cause different traits to become present. For example wether pea plant seeds are wrinkled or not.

5. Gene copy number is when duplicating errors occur in cell division leading to variations in a species. For example, humans look very different from each other but we are all the same species.

4.) evo-devo is the study of the effects of changes in important developmental genes and the role they play in evolution.

5.) lactose intolerance into adult hood can be traced back to the genes of our ancestors. In Africa the ability to digest milk was useless because of milks lack of abundance. However, when our ancestors reached Europe, they began to herd milk producing animals that made the gene of lactose tolerance more prominent.

Honors Bio Class 18

Today in class we finished watching a movie about the origin of man, and how we were able to populate the entire planet. Last class we left off at Australia, the place where man supposedly traveled to after leaving Africa. However, the narrator found proof in India that our ancient ancestors had indeed passed through India to get to Australia. He found this proof in a man among a remote village on the outskirts of India that had a similar mutation in his DNA in relation to our ancestors DNA. The reason why the narrator was only testing men was because of the Y chromosome. The Y chromosome is special because it does not change when it is transferred to offspring and would provide untainted proof. 

After Australia, the narrator studied the movement of the second group of ancestors that instead moved through Central Asia and Europe. We see proof that our ancestors moved through Pakistan, and Afghanistan through the study of one mans blood, Niazov. 

This man had DNA that could be traced back to the original group of ancestors that had made the trek from Africa to Afghanistan. from this point on, it took humans 10,000 years longer to get to Europe because of the drought caused by the ice age. However once they reached Europe and the Arctic Circle many physical changes took place. One of the most noticeable changes was the color of skin. Dark skin was for people that lived in an environment that had constant sunlight where dark skin could offer protection. Light skin on the other hand, was for places with less sunlight so that the skin could pick up as much sunlight as possible in order to receive nutrients. 

Honors Bio Class 17

Today in class we discussed the readings from homework that set up an overview of the trek our first ancestors took. The readings also questioned what enabled humans to populate most of the world in such a short expanse of time. The first traces of our ancestors can be found in Africa, dated back to 50,000 years ago. However, evidence of their existence was also found in Australia, implying that our ancestors had somehow traveled from Africa to Australia. one theory is this:

Long before the continents had fully separated, there was a land bridge that had connected Africa to Australia. This land bridge would have offered an acceptable route to reach our ancestors destination.
After discussing this possibility in groups, we watched a video that went into depth on the mindset of our ancestors, and what may have prompted them to leave Africa.

In Africa, there is a tribe called the San Bushman tribe, that is supposedly the closest living relatives to our ancestors. When studying their features we noticed that they shared characteristics from people all over the world; Asian eyes, European cheek bones, and African mouth shape and skin color. These traits imply that every single human may have possibly originated from these people, and through natural selection, different traits became more prominent. But why did our ancestors leave? Scientists have found evidence of an massive ice age that had taken place around  the same time we were evolving. The ice age greatly effected the climate, resulting in fluctuations of food availability. Also, our ancestors had begun to develop their own language and a more sophisticated way of thinking. this also resulted in advancements of technology, which may have also helped prompt the immigration.

Does Race Exist?

After reading the article “Does Race Exist” and analyzing the data collected through lessons in class on evolution and on the origin of man, one question stood out from the rest: Can race be used as a genetic identifier for different ethnic groups?. My answer to this question is no. Classifying people based on their physical characteristics varies among individuals because they are based on their personal opinions of what is required to be a part of a certain race. Although you can argue that obvious characteristics such as skin color, and hair color, should enable people to come to similar conclusions, scientists debate that categorizing is not that simple. The reason for this can date back to the origins of man, and its immigration throughout the world.

           The first evidence of man can be found in Africa, the proposed birth place of the first human, before it began its great trek around the world. By implying that this theory is true, it suggests that all humans have an ancestral line that can be traced back to Africa. This concept contradicts the generalization that all “African-Americans” are black, since there is a possibility that “Europeans” share the same ancestor. Also, traits such as skin color and facial features are greatly influenced by natural selection. Different groups of people may be exposed to many variations of selective forces, causing their physical traits to be greatly modified. Although two different groups may appear to be different physically, it does not mean that they aren’t similar genetically. This can be further proved through the study of DNA and its many variations of polymorphisms (mutations). Polymorphisms are what can be used to help identify and group the differences between people. However, they do not always dictate a characteristic that can be physically seen or identified. Most Polymorphisms dictate subtle differences such as resistance to a certain disease or an allergy to a certain drug. For this reason, using traits such as skin color and hair color to genetically classify people will most likely result in incorrect data; possibly leading to harmful repercussions.

quiz!!

Answers

1.) The picture above shows evidence for evolution because it depicts the similar characteristics of a whale throughout its lifetime. All the animals appear to have distinct characteristics that are carried through the timeline. It also depicts a common ancestor for all the different animals that have seemingly evolved from the mesonychid.

 

2.) E, North America

 

3.) a dragonfly, bird, and bat are all forms of analogous structures that serve as evidence for convergent evolution. this means that their are many similarities, but the underlying structure is completely different.

 

4.) The  Common Decent Lab shows evidence through DNA by depicting different animals with minimal differences in their DNA. This shows evidence for a common ancestor, therefore supporting the theory of evolution. One is the difference between a human and a Chimpanzee. Scientists have found there to be only a 2.5% difference in the DNA. Another example is the DNA of a human and an Old World Monkey. Their difference is only 9%!!! Proving that humans are really not  that different from primates.

 

5.) Homology is the when structures have enough similarities to prove they descended from a common ancestor. One example is the many similarities between the wing of a bat and a bird, both structures are used for flying and are shaped similarly. Another example is a human and an orangutan, both have five fingers used for grasping, and the structure of the arm bones are also very similar.





Honors Bio class 16

Today in class we discussed how to solve for allele frequency based on population and genes. we used the equation p^2 + 2(pq) + q^2 = 1, and p + q = 1. p^2 = AA, q^2 = aa, 2pq = Aa.

We also mentioned the Hardy-Weinberg ideals for a population so that nothing influences the result:

We applied this in the activity we did using sex gamies: 

After we collected our data we put them I to columns and analyzed it. We found that the majority would always be the dominant trait, and therefore the recessive gene would on be present in those with heterozygous genes. For the recessive gene to appear, we would have to mate with a Heterozygous + Heterozygous, or introduce hh back into the gene pool. However, through natural selection, the recessive gene hinders those who carry it (sometimes), and can cause them to have a shorter life expectancy,

We then took a really hard quiz on what we had learned (calculating frequencies).