Wednesday 1/11

1. Draw a rough sketch of the picture above, and label what the numbers 1-4 are

Agenda

1. Cell Specialization Activity

2. Mutations

3. If time, discuss biology of Fat

Discuss DNA Extraction Lab

Cell Specialization

• Each of your cells contains ALL of your DNA…

• How do you get different cells if they all contain the same DNA?

• each cell only– Uses a small part of DNA instructions

• Unneeded genes are “switched off”

– Makes mRNA from part of code it needs– Makes proteins for that type of cell

Carousel Activity: Structure Matches Function

• Go to each of the 7 stations– On your own sheet of paper

– Include title of each station

– Answer questions at each station IYOW.

– FINAL QUESTION: Since each cell of your body has the same set of DNA, how can you make so many types of cells?

• Ex:

Muscle cells only make mRNA from “muscle DNA”

• Muscle cells are very long & very thin– Each cell is as long as the muscle

Muscle Cell

• Structure– Very long & thin

• Function– To shorten

• Structure Matches Function– Round cell can’t shorten– Very long cell can really shorten

• Ex:– Red blood cell makes mRNA from “blood cell DNA”

• Structure– Biconcave disk

• Function– Carry oxygen to cells

• Structure Matches Function– In small capillaries RBCs must squeeze

through– Helps release oxygen

Getting back to DNA, RNA, Protein…

• Why is the sequence of Amino acids important?

• http://www.youtube.com/watch?v=Pjt1Q2ZZVjA

In Your Notes

Write the Amino Acid sequence if the RNA is:

1. UGG-CUA-UAC-AGC:Try - Leu – Tyr – Ser

2. UGG-CUA-CAC-AGC:Try - Leu – His – Ser

3. UGA-CUA-CAC-AGC: Stop – Leu – His – Ser

4. UGC-UAC-ACA-GC

Cys – Tyr – Thr - ?

MutationsMutations• Changes in DNA that aren’t correctedChanges in DNA that aren’t corrected

• Can be triggered by:Can be triggered by:– Radiation (including sun)Radiation (including sun)– ToxinsToxins– VirusesViruses– SpontaneousSpontaneous

• May be harmful May be harmful – or may not make a real differenceor may not make a real difference

• Mutations during mitosis Mutations during mitosis – can cause cancercan cause cancer

CancerCancer

• Starts with one mutated cellStarts with one mutated cell– Cell division goes “out of control”Cell division goes “out of control”– Cell constantly dividesCell constantly divides

• It takes 2 mutations in a single cellIt takes 2 mutations in a single cell– 1) in a 1) in a Cell Division geneCell Division gene– 2) in a 2) in a Tumor Supressor geneTumor Supressor gene

• One cell must accumulate 2 or more One cell must accumulate 2 or more mutationsmutations– So chances of cancer increase with ageSo chances of cancer increase with age

• Definitions:Definitions:– Tumor = cells with abnormal growthTumor = cells with abnormal growth– Malignant = tumor spreads & damages organsMalignant = tumor spreads & damages organs– Benign = tumor doesn’t spread or harm Benign = tumor doesn’t spread or harm

(aka cyst or growth)(aka cyst or growth)– Metastisize: tumor breaks, travels in blood, starts Metastisize: tumor breaks, travels in blood, starts

new tumors.new tumors.

• TreatmentsTreatments– Chemotherapy, radiation therapyChemotherapy, radiation therapy– Target rapidly dividing cellsTarget rapidly dividing cells

• Cancer cells, skin cells, hair folliclesCancer cells, skin cells, hair follicles

Do you know any ways to Do you know any ways to prevent cancer?prevent cancer?

• Don’t smoke.Don’t smoke.

• Maintain a healthy weightMaintain a healthy weight

• ExerciseExercise

• Eat a healthy diet!Eat a healthy diet!

• Protect yourself from the sunProtect yourself from the sun

• Practice safe sexPractice safe sex

• Don’t drink too much alcoholDon’t drink too much alcohol

Antioxidants

• These help protect your cells from the effects of free radicals

• Free radicals= molecules produced when your body breaks down food or by environmental factors such as exposure to tobacco and radiation

• Free Radicals can damage cells and lead to cancer

• Antioxidants are found in fruits, vegetables, grains, nuts, poultry and fish

Video

http://www.youtube.com/watch?v=Rfm6RJlasj4&feature=fvsr

The Biology of FAT• At age of about 5 or 6

– your body decides that amount of fat is “normal” (Set Point)

• Your body works hard to maintain the Set Point• If you lose weight

– Your fat cells shrink, but don’t go away– Strong hormones signal you to EAT to fill up fat cells

• Liposuction – Seems like it should work, but it doesn’t– Remaining fat still works to keep set point– You end up weighing the same as before (or more)

• With fat in different places

• Only thing that can change Set Point– Exercise!