1. Quiz:
An individual living thing is called:
A) species, B) cell, C) DNA, D) organism
The basic unit of organization for an organism is:
A) DNA, B) cell, C) species, D) metabolism
Problem solving includes:
A) replication, B) making inferences, C) testing explanations D) all of the above
Which should follow an experiment:
A) observations, B) analyzing data, C) making a hypothesis D) giving up

2. Focus on: molecular genetics, biotechnology, atoms
LEQ: Why is understanding the biology of molecules important to modern biology?
Assignment: Reading , 2.1
Focus on: molecular genetics, biotechnology, atoms
Review: characteristics of life, themes of bio
Activator: genes and homeostasis
Summarize how understanding the genes of a squirrel could help develop treatments for heart attack sufferers.
Key terms: gene, biotechnology

3. Molecular genetics is the study of DNA on the molecular level .
Genes are pieces of DNA molecules that store genetic information:
Found in all cells
Cellular function
Behavior
Regulation
Disease
DNA alteration
Mutation (DNA)
Let’s begin with a note on genes:
Genes are tiny pieces of DNA molecules that store genetic information for building cellular structures and carrying out chemical reactions. The study of DNA on the molecular level is the focus of the field of molecular genetics, a major area of scientific research.
Genes are found in all cells and even viruses. Genes are associated with cellular function. This relates to our earlier discussion of Chlamydomonas and Volvox in one way so far: the behavior of these organisms is determined by how genes are regulated (controlled). Later we will investigate more about their genetics and learn more secrets about life.
Since DNA encodes specific information in genes and genes determine cellular function, alteration of this information can result in disease. One of the principle ways this occurs is when the information is changed. This phenomena is called mutation. The DNA profile of the patient on the left is normal, but Duchenne Musular Dystrophy sufferers have some characteristic mutations that result in missing bands in lanes 1-3 on the figure above.

4. slows down metabolism during hibernation
Sirtuins are currently being studied in hibernating mammals and aging mammals.
slows down metabolism during hibernation
Shuts off genes promoting energy use
Implicated in aging
Let’s review three genes:
Sirtuins are a family of genes that control metabolism and have been implicated in aging. Interestingly, they are also at work in mammals who hibernate. Studies have shown that reduced metabolism in thirteen-lined ground squirrels is associated with the gene being used less frequently in certain cell types. It seems to act as a control that turns metabolism up and down. Mutations in sirtuins are now being associated with advancing age and some metabolic disorders.

5. Conversion of info: alpha thalessemia (sickle cell)
Changes in alpha and beta globin are associated with blood disorders and early death.
Mutation (change):
Conversion of info: alpha thalessemia (sickle cell)
Deletions of info: beta thalessemias (various)
2) The globins –The information in these genes are used to build molecules that transport oxygen in the blood called hemoglobin (left). Unfortunately, mutations in these genes can result in a group of blood disorders called Thalessemias. Thalessemias are characterized by an abnormal or reduced production of hemoglobin resulting in fatigue, shortness of breath and poor growth in patients that survive (some fetuses do not).
If the information in the alpha globin gene is changed so that information is lost alpha thalessemia will result. A related disorder called sickle cell disease is associated with changes in the information of the alpha globin genes resulting in symptoms similar to Thalessemia. Patients suffering from sickle cell disease display a characteristic sickle-shaped red blood cell.
Loss of information in the beta globin genes necessary to make hemoglobin will result in beta thalessemias of various types and generally the same symptoms.

6. Predict what would happen if Lrp5 levels dropped
Lrp5 gene suppresess tryptophan metabolism in serotonin secreting cells of the stomach
Predict what would happen if Lrp5 levels dropped
3) Lrp5 is gene associated with our discussion on systems and the skeleton. This gene seems to help control how the amino acid tryptophan is changed into serotonin in cells of the digestive tract. That happy and sedated feeling you get after a big meal is associated with serotonin’s action in the brain, but serotonin seems to be regulating how your skeleton maintains homeostasis. Low levels of serotonin permit bone-building osteoclasts to divide and build skeleton in classic fashion. Like previous examples, mutation is associated with disease.
Let’s play a game of flip the arrows, Lrp5 mutant mice were found to have increased levels of serotonin (↑). Flip the arrow in the circulatory system and the arrows on the right side of the diagram: Bone formation decreases (↓). Early studies have shown that this complex interaction allows bone-consuming osteoclasts to eat bone without osteoblasts filling in the missing bone mineral. The implications for people who suffer osteoporosis could be enormous.
In short: if normal genes lead to healthy cell function, noticeably mutated genes lead to cell dysfunction and disease.

7. Biotechnology offers great promise but also raises many issues.
Biotechnology is the use and application of living things and biological processes.
Using genes and living organisms as tools in the study of life is the focus of biotechnology. Nowadays, scientists use living organisms for various research and technological applications from the latest advances in energy to the next generation medicines.

8. What do genes do in cells?
Summary:
Through our understanding of DNA and gene products, we can study biology on a molecular level.
What do genes do in cells?
What happens when the function of a gene is altered?
Use an example to explain your answer.
Reflection: “No organ is an island” ~ Gerard Karsenty.