Unit 3. The notes from class contain the comprehensive information for exam 3. The textbook readings support the notes.

Transcription

1 Unit 3 The notes from class contain the comprehensive information for exam 3. The textbook readings support the notes.

2 Why do normal cells divide? Replacement Repair Growth Regeneration (Formation of sperm and egg)

3 Cell Division (mitosis) All new cells arise from previous cells Some cells reproduce once in a lifetime Example: neurons in the brain Some reproduce every few days Example: skin cells, embryo

4 Before a cell can replicate, it must replicate its DNA why? Parent cell Daughter cells

5 The cell cycle Tightly regulated! Many checkpoints that delay the cell cycle until cell is ready Mitosis is relatively fast

6 Control of the cell cycle To GO (the pedal ) A. Growth factors Stimulate cells to grow Example: growth hormone B. Growth factor receptors Allow cell to respond to a growth factor Example: GH receptor

7 To SLOW! (the brake ) Checkpoint proteins A. Tumor suppressors prevent cell from continuing in cell cycle and send cell to apoptosis if necessary B. DNA repair proteins if DNA cannot be repaired, cell should undergo apoptosis Example: UV repair A leukemia cancer cell in apoptosis

8 Cancer genes Cancer is a genetic disease = mutated genes Genes that encode normal growth proteins are called proto-oncogenes oncogene = mutated proto-oncogene, can lead to cancer cell

9 Cancer is a multi-hit disease More than one mutation in a single cell required

10 Characteristics of cancer cells 1. Immortal (unless killed) cancer cells keep dividing 2. Loss of contact inhibition results in tumor formation

11 Contact inhibition

12 3. Changes in cell membrane NORMAL SKIN CELLS ROUNDED CELL MEMBRANES

13 4. Angiogenesis tumor gets its own blood supply novartis

14 5. Enlarged nuclei, abnormal chromosomes

15 6. Undifferentiated cells don t resemble normal cells and grow very fast 7. Escape apoptosis 8. May metastasize

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17 metastasis= cancer cells enter blood vessel

18 Tumor types Malignant = cancer cells invade surrounding tissues and break off Benign tumor Benign tumors are in a fibrous capsule

19 Treatments for cancer Excision = Remove cancerous tissue by surgery

20 Chemotherapy (drugs) The use of chemicals to treat disease stop cell growth in fast growing cells What are normally fast growing cells? Many come from plants

21 Radiation Destroys DNA of fast growing cells, shrinks tumors, has side effects

22 Cancer vaccines Human papilloma virus (HPV) causes genital warts Over time, in SOME women, this leads to cervical cancer

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24 Genetics Risk factors for cancer some people inherit predispositions (cells have at least 1 mutation at birth) Age the older you are the more time for multiple mutations to arise Smoking Diet fat, meat 20 carcinogens in tobacco smoke Environment chemicals, sunlight, X-rays

25 Ch. 11 DNA = deoxyribonucleic acid 1. It s the genetic material inherited from cell to cell inherited from parent to offspring 2. It s the blueprint for life instructions for protein synthesis genes encode proteins

26 Definitions Nucleotide = building blocks of DNA Gene = group of nucleotides (DNA) that encode a protein Chromosome = strand of genes + other DNA Genome = all DNA information contained in 46 chromosomes = 3 billion nucleotides

27 Genes regulate the human life cycle Egg + sperm = embryo Fetus Newborn

28 Some people have identical DNA sequence Identical twins (monozygotic)

29 Conjoined twins

30 Fraternal Twins are dizygotic Mother releases 2 eggs, each is fertilized by a separate sperm DNA?

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32 Double helix structure Watson and Crick 1950 s

33 X-ray diffraction shows helical structure

34 Nucleotides building blocks of DNA nucleotide bases G,A,T,C

35 complementary base pair rule G and C pair A and T pair The sequence of G,A,T,C is the genetic code

36 If one strand of the DNA double helix is: TCT TAC TCT ATG GAA What is the complementary strand sequence?

37 Gene Expression When the cell uses the DNA code to make a particular protein

38 Gene Expression depends on: Tissue type liver, heart, brain etc Developmental stage/age embryo, elderly Metabolic needs making energy, taking in nutrients Disease cancer, infection, diabetes etc *All of your cells have the same DNA, but use genes differently

39 DNA fingerprinting paternity, forensics, evolution, conservation, hunt for disease genes Routine in US military, prisons

40 DNA fingerprinting 1. Isolate DNA from? 2. Perform technique that is DNA sequence specific

41 3. Gel electrophoresis to separate sizes DNA fingerprint = Different people show different sized DNA pieces depending on their unique DNA sequence of G,A,T,C

42 *Remember one chromosome is inherited from mom, one from dad M is the mother C is her newborn baby Who could the father be?

43 Rape case

44 DNA technology 1. Transgenic bacteria = cloning genes into bacteria = recombinant DNA Example: Human Growth Hormone

45 Human Growth Hormone (hgh) cloned into bacteria (1980s) Pre-1980s Pituitary dwarfs received hgh purified from cadaver brains Drawbacks? Today receive hgh that has been cloned 26 inches tall

46 Cloning a gene into bacteria Isolate DNA and cut out gene.ggattgcgtacgctttgatcgtagtaataggacctagtgt gtacgtaagcggccacagttgtaccacatt.. gatcgtagtaatagg

47 Introduce hgh gene into bacteria Bacteria make hgh protein Bottle, sell, and inject into child

48 Advantages of recombinant DNA Bacteria can supply world s need Clean, disease free, easy to produce

49 2. Transgenic plants (GM plants)

50 A few genetically modified plants

51 Benefits Drawbacks Increased crop yield Resistance to drought, freezing increased seed costs Decreased use of pesticides pesticide resistant bugs Decreased use of herbicides resistant weeds Increased nutrition new allergens Increased shelf life may spread to other plants Can remove allergens harmful to insects?

52 Bt corn Corn plant engineered with gene that codes for a protein lethal to the corn borer Round-up ready soybeans are resistant to herbicide

53 *Example: Golden Rice Many in world are deficient in Vitamin A Leading cause of childhood blindness (500,000 new cases per year) Rice engineered to produce vitamin A! Controversial.

54 Do we need legislation for labeling of GM foods? Should GM genes, plants, animals, be patented?

55 3. Transgenic animals These goats produce human TPA (blood clot buster) in their milk (pharming)

56 How are transgenic animals made? Inject the gene (DNA) into the animal embryo Implant embryo in mother If the drug is made in milk, then..

57 Mouse model organism models for human disease (Alzheimer) genetically modified to be diabetic

58 This pig is genetically engineered to be able to digest more and produce less manure Other pigs produce meat high in omega 3 fatty acids

59 This pig is genetically engineered to have an immune system similar to humans

60 genetically engineered salmon grow faster

61 Cloning and stem cell research

62 Animals that have been cloned

63 To clone an animal (reproductive cloning) End product = animal that is a genetic copy of the cloned individual

64 Reproductive Cloning 1. Take nucleus (with DNA) from a somatic cell 2. Add to empty donated egg Skin cell nucleus + DNA-less egg = This egg has a full set of chromosomes

65 Pipetting DNA into an egg Animal embryo Human reproductive cloning is illegal

66 Human Therapeutic Cloning End product = cloned cells to treat disease

67 Therapeutic Cloning making stem cells 1. Take nucleus (with DNA) from a somatic cell 2. Add to empty donated egg Skin cell nucleus + DNA-less egg = This egg has a full set of chromosomes

68 3. Grow (in lab dish) for ~ 2 weeks gw 4. Remove cells from embryo and grow in lab dish

69 Therapeutic Cloning making stem cells Continue to grow cells in lab dish Can grow large quantities of cells brain cells, liver cells, etc.. No rejection of tissue

70 Reproductive vs therapeutic cloning

71 Uses of ES cells tissue transplants new liver cells, pancreas cells Alzheimer disease, spinal cord injury, Parkinson s disease, multiple sclerosis, diabetes, burned tissue, stroke, lung disease, heart disease, arthritis

72 Other advantages of stem cells Not limited by organ donation 80,000 people in the US are waiting for a transplant Over 5,000 people die each year waiting organ a perfect match recipients must take immunosuppressants for life

73 Sources of ES cells In-vitro fertilization 800,000 unused embryos currently frozen What happens to these? Should people be able to donate them?

74 donated sperm and eggs Should people be able to donate for stem cell research?

75 therapeutic cloning there are also fetal stem cells in umbilical cord blood and adult stem cells in bone marrow

76 Therapeutic cloning is not whole organism cloning ES cells/embryo reproductive cloning -> Implant into female (uterus)->->-> - birth ILLEGAL in most countries, rarely successful in animals Therapeutic cloning Place cells into culture dish Cells divide to produce more ES cells Use to treat /cure disease