Reading Assessment: Chapter 6 Survival of Sickest

First vaccine

cowpox

resistant to smallpox

make other people resistant by putting it on teenage boys

-worked

how vaccination works

begins with harmless version of virus 

-bodies will recgonize but not enough to cause seriou disease

-immune system produces antibodies that defnd against virus

-then if we are exposed to harmful version, our bodes are prepared to fight

different antibodies to fight off different attacks

First cell

-genetic instruction to mnufacture proteins to build human being

instructions carried out by nucleotides

-nucleotides= dna base pair

-genes  organized in 23 pairs

every pair except 23rd (sex chromosome) is a matched pair

-chromosome carries the same instructions 

-always have dominant gene over recessive

germ cells-cells that combine to provide offspring

3% dna is meant for building

97% isnt active in building

97% portion of genome plays role in evolution 

-called noncoding DNA

-made up of jumping genes

-related to viruses

mitochondria= produce energy to run cells

-live in all cells

-own heritable DNA

evolution shaped by integration and adaptation of viruses

Theory

genetic chnages product of accidental mutations (rearrange DNA)

-mutations happen when there is an error

-mutations happen when organism exposed to radiation or powerful chemicals

-sun cause mutation

sunspot peaks- energy leaked through magnetic field

occurred during massive flu outbreaks

-antigenic drift- mutation occurs in the DNA of a virus

-random mutation= advantage on its carrier, better chance to live

one species advantage could be anothers disadvantage (ie. virus to humans)

theory wrong: evolution favor a mutation that helps an organism discover adaptations to help survive

single genes have capacity to produce different proteins at once

shuffle/reshuffle to produce array of proteins

complexity- combining parts of one gene with another

not instructions anymore, scientists learn genes are an intricate network of info

McClintock

corn plants experiment

when they were stressed: DNA moving from one place to another (inserting themselves)

-affected nearby genes- turned them on and off

method:

1. relocated to specific parts of genome
2. mutations triggered by outside influences (environment)

discovered “jumping genes” (transposons)

-suggested evolution could be faster than imagine

-mutations aren’t just random

Remain in an active gene after inserted and make a difference

Example: jumping gene one one line of fruit flies turned them into superhero fruit flies

-resist starvation 

-withstand high temp

-life expectancy that was 35% longer

genome gambles on mutation

Cairns 

E coli- digestive workhorse in humans 

*cannot digest lactose

-starvation is a big threat to bacteria

experiment: deprived E coli of any food except lactose

• bacteria developed mutations that allowed them to lose their lactose intolerance

idea: bacteria targets specific area of their genome where mutations could be an advantage to them

argument idea:

hypermutation- mutation on steroids

helped bacteria produce mutations 100 times faster

-suggests genome has ability to order mutations on demand

Weismann barrier

germ plasma theory- divides the body’s cells into groups

every cell (except germ cell) is a somatic cell

theory: info in somatic cell is never passed on to germ cells

but: some viruses may be able to penetrate the barrier and carry DNA fro somatic to germ cells 

germ line mutations- mutations result in a different gene in egg or sperm that produces new trait in offspring

cancer- uncontrolled cell growth caused by mutation in the gene that is supposed to control the growth of cancerous cells

jumping genes help humans in two ways (diversity):

1. very active in brain development 
2. immune system 

Antibodies 

b-cells- building blocks for antibodies

V(D)J recombination: b-cells seek out instructions for antibody in their DNA, snip away line of instruction for other antibodies and sew rest together

(unlike jumping genes because leaves a little loop) 

once antibodies are developed, you always have them 

-immune to future infections 

Viruses

cannot produce on its own

hijack hosts cellular machinery

retrovirus-offspring born with virus permanently in DNA

HERVs-permanent place in DNA

two different types of jumping genes:

DNA transposons- cut and paste

retrotransposons- copy and paste

10/28 DNA Structure y'all

Today in class, we went over the lesson about DNA structure and function. 

Some basic concepts-

Erwin Chargaff found:
1) Composition of DNA varied from one species to another- bases= A, C, T, G
2) A=T (straight edge letters)
C=G (curved letters)

The base pairs (A to T, and C to G) are held together by hydrogen bonds

C and T are pyrimindines 
G an A are purines 

The nucleotide is made up of phosphate, sugar and a base. 
The phosphodiester is the bond between the sugar and phosphate.

The structure has two ends 
1) phosphate= 5 prime
2) sugar=3 prime (3 carbon)

The sugar molecule has an OH attached to it. It only recognizes it because it is polar (negative). 

It is a little hard to explain, so here is a picture of what I am talking about. 

In class, we also made our own paper DNA structures. 

"From Atoms to Traits" Questions

Explain the significance of Mendel

Mendel’s breading experiment with the peas changed the general perception of heritable genes from blendable to exact genes passed from parents to the offspring. The inheritance patterns of the peas were mirrored by the behavior of chromosomes in the nucleus. Genetic information was finally becoming a physical appearance in the threads inside the nucleus. 

Draw the structure of DNA and who discovered this structure 

James D. Watson and Francis Crick 

Explain each of the five examples of variations that occur to DNA and give an example of each.

1. Point Mutation (Class of Mutation)- A single base pair change. A whipper dog can vary between a small version and a big version of itself. The mutation stops the signaling molecule gene that regulates muscle growth. The muscle growth is uncontrolled because it does not have a stop signal. 
2. Insertion- One or more extra nucleotides are inserted into replicating DNA. In a pea plant there is a base pair sequence that makes peas wrinkled. The inserted base pair stops starch synthesis which then changes the peas’ sugar and water content. 
3. Gene Copy Number- Entire gene is duplicated by copying errors during cell division, leading to differences between species and variation among members. Chimps normally have a single gene for the starch digesting enzyme, whereas humans can have 10 copies of the gene. 
4. Duplication- Sequences that contain the same base pair repeated 8 or more times (homopolymers). A pig’s gene of two additional C-G pairs in a sequence stops the signal in pigment cells, producing a light colored coat. Copying mistakes within cells can cause the sequences to lose bases, letting the gene signal pigment cells and producing dark spots on the pig. 
5. Regulatory- Mutations in the DNA that controls when and where genes are activated that can produce trait alterations by changing the formation of body parts during the organisms development. The shape difference between the teosinte plant and the cornstalk is because the changes in the gene that controls the cell division during stem development. 

What is eve-devo?

Evolutionary development is a field of biology that compares the developments of different organisms to determine the ancestry and relationships between them. It is the understanding of how development is changed over time. 

Make a connection between human migration and the mutation of lactose intolerance. 

The ability to digest milk into adulthood, has arisen independently in groups of different continents. It provides a nutritional advantage to humans and connects to the changes of DNA sequences and human cultural evolution. Example- Mutations affecting the same gene dominate in East African and Saudi Arabian populations who herd milk-producing animals. 

"Does Race Exist" in a Black and White World

Do common beliefs of race correspond to underlying genetic differences among populations? No. The article, “Does Race Exist” explains that in some cases, yes, but most of the time no. People are sorted broadly into groups according to genetic DNA. Physical features that are brought about by natural selection are used to separate people into races. The article says that people with similar skin color or facial features from evolution can be different in relation to their DNA. For an example, humans from two different homelands that have a hot climate may have similar skin tones because their adaptation to the sun. However; genetically they are different. People that are similar to each other in their DNA might be exposed to different forces. The article explains how scientists figure out the correspondence between each group by relying on tiny genetic variations of the DNA called polymorphisms. Short pieces of DNA that are similar in pattern of one another are called alus, which are part of polymorphisms. They are used to determine the relationship of populations to one another. Scientists look at hundreds of these polymorphism and eventually can group individuals based off of their DNA. They have a distinct effect in one group but may vary in another group, so the traits effected by natural selection are bad predictors of detecting which individual should go in each group. The usual assumption of race do not always reflect a person’s genetic background. There has been so much genetic mixing, that there are no true races among humans. The concept of race only applies to the social aspect of humans, which is still important. Modern mapping of the human DNA can now point out the different forms of a gene that are brought up by mutation. So race does exist but it has no validity for humans at an biological perspective. 

National Geographic Article- Answering Questions

How the first modern humans reached Australia and New Guinea:

Migrated out of Africa

Went along the coast of Southeast Asia (Sunda, one land mass), and reached Australia and New Guinea (Sahul) 

Sea level was much lower

Indicating that settlers had knowledge of seafaring 

46,000 to 41,000 years ago 

If dates are correct, Australia was populated 10,000 years before Europe. 

-Humans avoided cold, and favored tropical regions to which they adapted from Africa 

10/15 Hardy-Weinberg Problems

Today, we learned how to use the Hardy-Weinberg equation. Mr. Quick sent out a video that explains it really well, and helped me understand how to use it in different circumstances! 

10/11 Evolution and Gene Frequencies (Lab)

Today we performed a lab (to determine the effect of random mating in a population of tigers possessing a recessive gene!) where we have 25 red beads and 25 green.

Green= h
Red= H

We put them all into a paper bag and chose two beads without looking. If they were both green (hh) they were dead. (not naturally selected to survive the cold environment)
HH was the recessive trait. (no fur)
Hh was the dominant trait. (fur) 

Hypothesis- The recessive gene will eventually go away after 10 generations.

Reading Assessment: Chapter 8 Survival of Sickest

10/4 Parents Day

During parents day, the students and parents looked at pairs of a person (with some differences) and decided which one we found attractive. Based on the data, we were able to conclude that women are more attractive to "caring and sharing" men (feminine faces) who will make good partners. However; during ovulation women are more attracted to masculine faces who will father healthy offspring. 

10/1 Brine Shrimp Lab/Natural Selection

Natural selection and how it applies to different species:

Adaptation---> Change---> Offspring

DNA Mutation passed on causes variation of shape, size, color, or texture. One cannot evolve, but a population can. Generations evolve. 

+... Better adapted

-... Greater chance of dying. 

Brine Shrimp Lab:

Today we set up our lab by preparing five beakers of 30-mL salt solutions using sodium chloride and distilled water. Each solution have 0%, 0.5%, 1%, 1.5% and 2% of NaCl.

We are trying to figure out which solution the shrimp has a better chance of adapting to. 

If the solution of salt is too high, each egg will be covered in a hardened, brown film.

So...

We counted and put 20-40 eggs in each solution and will count them after 24 hours to see which had survived.