UNIT 8 : GENETICS

1. UNIT 8: GENETICS

2. What is the molecule responsible for passing on hereditary traits? What is it’s structure? • Deoxyribonucleic Acid (DNA) is a nucleic acid that contains genetic instructions used in the development and functioning of all known living organisms and some viruses • The main role is the long-term storage of information. • DNA is often compared to a set of blueprints Nucleotide Functional unit: _____________________ Phosphate a Deoxyribose b Nitrogen Base Pairs (A, T, C, G) c (Sticks and curves) T Twisted in to a double helix A C G 2 DNA consists of ________ complementary chains of nucleotides The DNA ladder consists of: U______________: alternating phosphates and deoxyribose R_________: Pairs of nitrogen bases held together by weak Hydrogen bonds ADENINE always pairs with THYMINE CYTOSINE always pairs with GUANINE Railing -- -- Steps

3. Thinking back to reproduction • If cells are going to replicate and reproduce, each cell needs to get a new copy of instructions (DNA) • How is that copy made? • (Take out note packets)

4. 3. How does DNA replicate (make more copies of itself) Splits The ladder __________________ It breaks apart at the weakHydrogen Bonds between the bases. Newly synthesized nucleotides line up by _________ ________________ Base Pairing Two new strands of DNA Result: ___________________________________ Identical to the first strand and to each other.

5. Warm Up Question 3/25/10 Complete the DNA base pair replication for each strand A A T T A A T T G G C C G G C C G G C C

7. 4. What is a gene? Gene: __________________________ Gene pool: __________________________ DNA Coding for 1 protein All available genes in a population 5. What is gene chromosome theory? Genes • exist at different loci (permanent locations) in a linear fashion on chromosomes. • Two genes associated with a specific characteristic are known as _____________ and are located on homologous chromosomes alleles DOMINANT ALLELE: Always exerts full effect, will mask the other gene characteristics RECESSIVE ALLELE: The gene is present, but not always expressed Different combinations of alleles result in different patterns of inheritance: GENOTYPE: Describes the genetic combination HOMOZYGOUS: two of the same alleles HETEROZYGOUS: two different alleles PHENOTYPE: Describes the physical appearance Pair of alleles Individual genes 6. Can offspring have traits that are different than their parents

8. Loci for a single allele Location

9. How many genes are on a single chromosome? • A Lot! • Chromosome 1 • Contains over 3000 genes • Contains over 240 million base pairs, of which ~90% have been determined • These things are mapped out on chromosome maps

10. 4. What is a gene? Gene: __________________________ Gene pool: __________________________ Codes for 1 protein All available genes 5. What is gene chromosome theory? Genes • exist at different loci (permanent locations) in a linear fashion on chromosomes. • Two genes associated with a specific characteristic are known as _____________ and are located on homologous chromosomes alleles DOMINANT ALLELE: Always exerts full effect, will mask the other gene characteristics RECESSIVE ALLELE: The gene is present, but not always expressed Different combinations of alleles result in different patterns of inheritance: GENOTYPE: Describes the genetic combination HOMOZYGOUS: two of the same alleles HETEROZYGOUS: two different alleles PHENOTYPE: Describes the physical appearance __ __ Pair of alleles ____ __ _____ _____ Individual genes __ __ What you can see 6. Can offspring have traits that are different than their parents TT Can Roll Tongue tt Cant roll tongue Can Roll Tongue Tt

11. Tongue Roller T t T t T t T T t T t t Tongue Roller NOT a tongue Roller!

12. Journal Time! • Q4: What is a gene? • Q5: What is gene chromosome theory? • Q6: Can offspring have traits that are different than their parents? Explain: • C. What genetic concept does this cartoon illustrate?

13. 3/26 Warm-up One of a paired set of genes that codes for a particular trait Always expressed (Capital Letter) Represented by a Lower Case letter Two of the same Genetic Make up Tt Physical Appearance Match the following terms with their definitions • Homozygous • Heterozygous • Allele • Genotype • Phenotype • Dominant • Recessive D F A E G B C

14. 7. What insights did Mendel give us into patterns of inheritance? In the 18th century, an Austrian monk and teacher Gregor Mendel developed some basic principles of heredity without any knowledge of genes or chromosomes. He experimented with pea plants. As a result of mathematical analysis of ratios associated with characteristics in the offspring, Mendel proposed that characteristics were inherited as a result of the transmission of hereditary factors. When an individual pure for the dominant trait is crossed with an individual pure for the recessive trait, the physical appearance of the offspring is like that of the dominant parent. Dominance Law of ____________________: When gametes are produced, the genes separate so that each gamete receives only one copy. A gamete will receive one allele or the other. The direct proof of this was later found when the process of meiosis came to be known. Law of ____________________: PUNNETT SQUARE SOLUTIONS: Stem Length: Seed Color: Seed Shape: Pure Tall X Pure Short Hybrid yellow X pure green Monohybrid cross

15. Dominance • Dominant allele represented by a Capital Letter • Always masks over any recessive alleles • For example: Tongue Rolling (T) Not tongue rolling (t) Tt = what phenotype? (remember phenotype and physical appearance)

16. 7. What insights did Mendel give us into patterns of inheritance? In the 18th century, an Austrian monk and teacher Gregor Mendel developed some basic principles of heredity without any knowledge of genes or chromosomes. He experimented with pea plants. As a result of mathematical analysis of ratios associated with characteristics in the offspring, Mendel proposed that characteristics were inherited as a result of the transmission of hereditary factors. When an individual pure for the dominant trait is crossed with an individual pure for the recessive trait, the physical appearance of the offspring is like that of the dominant parent. Dominance Law of ____________________: When gametes are produced, the genes separate so that each gamete receives only one copy. A gamete will receive one allele or the other. The direct proof of this was later found when the process of meiosis came to be known. Segregation Law of ____________________: PUNNETT SQUARE SOLUTIONS: Stem Length: Seed Color: Seed Shape: Pure Tall X Pure Short Hybrid yellow X pure green Monohybrid cross

17. Segregation • Every person has two alleles for any given trait (one from the mom, one from the dad) • Offspring will get either one of those • Ex: • Of a mom is Tt for tongue rolling she can give either the T or the t, and this is determined by chance. • Same for the father with Tt. He can give T or t • This is demonstrated by a punnett square

18. 7. What insights did Mendel give us into patterns of inheritance? In the 18th century, an Austrian monk and teacher Gregor Mendel developed some basic principles of heredity without any knowledge of genes or chromosomes. He experimented with pea plants. As a result of mathematical analysis of ratios associated with characteristics in the offspring, Mendel proposed that characteristics were inherited as a result of the transmission of hereditary factors. When an individual pure for the dominant trait is crossed with an individual pure for the recessive trait, the physical appearance of the offspring is like that of the dominant parent. Dominance Law of ____________________: When gametes are produced, the genes separate so that each gamete receives only one copy. A gamete will receive one allele or the other. The direct proof of this was later found when the process of meiosis came to be known. Segregation Law of ____________________: PUNNETT SQUARE SOLUTIONS: Hybrid = 2 together Stem Length: Seed Color: Seed Shape: Pure Tall X Pure Short Hybrid yellow X pure green Monohybrid cross T T Y y R r Y y yy RR t t Tt Tt R r Rr y y yy Tt Tt Y y Rr rr

19. 3/29 Warm up(questions from the box) • Why do they call it genetics? • What does DNA stand for? • Why can someone look more like 1 parent than another? • Why are we learning about genetics?

20. 8. What are some genetic diseases caused by recessive alleles • SICKLE CELL ANEMIA • Causes red blood cells to be shaped like sickles, they get stuck in the capillaries and deprive body cells of oxygen. • Rare in the USA, but common in some African countries. This is because carriers of the disease are more immune to malaria. Hence, being a carrier increased chance of survival. • CYSTIC FIBROSIS • Affects about 1 in 1600 people in the USA • It is caused by a recessive defective gene inherited from both of the parents. • The result is that the body produces thick sticky mucus in the lungs which has to be removed • Excessive mucous occurs in the pancreas causing digestive problems • The most serious problem is the blockage of air passages in the lungs, results in many infections • Both parents must carry the gene, and there is a 1 in 4 chance of their child being born with CF C c S s Ss Cc CC Cc Cc cc 50% carriers SS Ss Ss ss 25% with Disease More complex! 9. Are there other patterns of inheritance? Are the relationship between genes and traits more complex than Mendel’s Laws illustrate with peas? MULTIPLE ALLELES MORE THAN TWO ALLELES ARE INVOLVED BLOOD TYPES in humans. Three possible alleles: ____ ____ ____ EACH INDIVIDUAL INHERITS SOME COMBINATION OF 2 ALLELES Sample Crosses: Mom: Type AB Mom: Type O Dad: Type B Dad: Type B His mom type o

21. Co-Dominance • Remember: Each trait is represented by the same letter! If there are multiple alleles (expressions) then we need something other than just a capital and a lower case • Ib , IA , i • BOTH alleles are expressed (different than dominant and recessive) • Both A and B allele are expressed (blood type AB) • i is recessive (blood type o) • A and B dominate over O, but A and B are co-dominate IA IB IB i AB B A B

22. 8. What are some genetic diseases caused by recessive alleles • SICKLE CELL ANEMIA • Causes red blood cells to be shaped like sickles, they get stuck in the capillaries and deprive body cells of oxygen. • Rare in the USA, but common in some African countries. This is because carriers of the disease are more immune to malaria. Hence, being a carrier increased chance of survival. • CYSTIC FIBROSIS • Affects about 1 in 1600 people in the USA • It is caused by a recessive defective gene inherited from both of the parents. • The result is that the body produces thick sticky mucus in the lungs which has to be removed • Excessive mucous occurs in the pancreas causing digestive problems • The most serious problem is the blockage of air passages in the lungs, results in many infections • Both parents must carry the gene, and there is a 1 in 4 chance of their child being born with CF C c S s Ss Cc CC Cc Cc cc 50% carriers SS Ss Ss ss 25% with Disease More complex! 9. Are there other patterns of inheritance? Are the relationship between genes and traits more complex than Mendel’s Laws illustrate with peas? each person only inherits 2 MULTIPLE ALLELES MORE THAN TWO ALLELES ARE INVOLVED BLOOD TYPES in humans. Three possible alleles: ____ ____ ____ EACH INDIVIDUAL INHERITS SOME COMBINATION OF 2 ALLELES IA IB i Sample Crosses: Mom: Type AB Mom: Type O Dad: Type B Dad: Type B His mom type o IA IAIAi ii IA IB IBIB IB i IB i IB i B B O O IA IB AB B A B ii

23. Sickle Cell Anemia Heterozygous individuals have a resistance to malaria. (may be why the disease persists in the population) Both alleles expressed

24. Both alleles expressed Malaria can not attack the sickle cells (individual unaffected by malaria)

25. (Warm up)Nature vs. Nurture • Which has a greater effect on what determines our traits?

26. 10. Can patterns of heredity can be more complex? • CROSSING OVER during MEIOSIS & GAMETE FORMATION increases variety • CONTINUOUS VARIATION • Results when several genes influence a trait • Height: TTTTTTT --------- tttttttt • Skin Tone • Many different variations of the trait are expressed Can environment influence heredity? Can certain environmental conditions alter phenotypes? Plants require sun to “turn on the gene” produce green chlorophyll. In the absence of sun, the gene will not be expressed, and the plants will be white. 2. Pigment producing genes of the arctic fox do not function in the winter due to the cold temperature. In the warmer summer, the genes function As a result, the fur is white in the winter and to produce a reddish-brown pigment. the animals blend in to the background. Now the fox resembles the tundra of summer When an icepack is placed on the shaved skin of a Himalayan hare, the fur grows in dark. TWIN Studies (upbringing means the same thing as environment) Twin’s genes are identical, so any difference between them must be caused by slight differences in their environment throughout their lives. Ex: Height differences due to differences in nutrition Muscular development in an athlete. *Environment can determine gene expression NOTE:only changes in DNA of the sex cells can be passed on to the next generation

27. Nature vs. Nurture • Which has a greater effect on what determines our traits?

28. In other words… • DNA doesn’t necessarily determine exactly who we are/going to be • More like sets the boundaries in which we will fall somewhere. • Nature determines where You Somewhere in there

29. Vocabulary Notebooks • The following terms: • Heterozygous • Homozygous • Allele • Gene • Dominant allele • Genotype • Phenotype • DNA • Sickle Cell Anemia (checking these?)

30. 3/31 Warm up • Give an example of how the environment can influence phenotype/gene expression.

31. Interesting…. • How come there are more color blind males than females?

32. 12. How is the sex of the offspring determined? Diploid cells of organisms contain two types of chromosomes. Autosomes: ______________________________________ Sex Chromosomes ____________________________________ any chromosome that is not a sex chromosome Determines the gender of an individual Humans: X and Y (XX = Female XY= Male) Not the same in all organisms! 13. What diseases are associated with the sex chromosomes? • SEX LINKED TRAITS • The genes for certain traits are located on the sex chromosomes • Sex linked traits occur more frequently in males. Show the cross: #1 Normal Male 2. Male with hemophilia c> Colorblind male Female carrier for Hemophilia Normal female Carrier female

33. Gender determination • Not always cut and dry • Check it out • Sometime not always a simple genetic basis • Reptiles! • Flies!

34. 12. How is the sex of the offspring determined? Diploid cells of organisms contain two types of chromosomes. Autosomes: ______________________________________ Sex Chromosomes ____________________________________ any chromosome that is not a sex chromosome Determines the gender of an individual Humans: X and Y (XX = Female XY= Male) Not the same in all organisms! 13. What diseases are associated with the sex chromosomes? • SEX LINKED TRAITS • The genes for certain traits are located on the sex chromosomes • Sex linked traits occur more frequently in males. Traits found on the sex chromosomes (Females have a second X copy) X X X X X Y X Y X X’ X X* X* Y X’ Y X’ X’ X* X* Show the cross: #1 Normal Male 2. Male with hemophilia c> Colorblind male Female carrier for Hemophilia Normal female Carrier female X’ Y X* Y X Y X X* X X* X Y X X’ X X X X’ X Y X X X Y X* X* X* Y X X’ X’ Y X X’ X Y

35. 4/12 Warm up • What the heck were we learning about in class almost two weeks ago?

36. I know you’ve been lost without these cartoons…

37. 4/13 Warm up • How many letters are in the genetic alphabet? • How many different 3 letter combinations could be made with these letters? • 64 different combinations!

38. How can directions code for things? • For example; CAKE? • How do we go from instructions to our final product? • (take action) • How do we go from DNA to traits? • TAKE ACTION

39. Cool Video #1 • Transcription • Making a copy of instructions to send out of the nucleus • Trick to remembering: • Transcribing is just writing it. That’s all transcription is doing! Re-writing it! (Scribes write things out)

40. How does the information encoded in the DNA produce traits? How does a gene lead to a characteristic? • DNA codes for the production of proteins • Traits are proteins, or are produced by the action of a special group of proteins - enzymes. • This is how it works: 1. The DNA code is based on the sequence of nitrogen bases. DNA stays in the nucleus (safe place for info) • Messenger RNA copies the code ( ) • Single stranded / U instead of T • Set of 3 bases on the mRNA: __ __ __ __ __ mRNA DNA  mRNA C o d o n mRNA leaves the nucleus 3. 5. transfer RNA carries in amino acids anticodons match to codons Appropriate amino acids are linked Individual amino acids link and peel off to form a This protein is the trait(suchas red pigment) or an enzyme to catalyze a reaction that produces a trait. 4.

41. Modeling • Now use the pieces to show transcription. • Find the base pair for the new strand of mRNA that pairs with the DNA. Tape them together one at a time as would happen inside the nucleus to make mRNA • DNA: White • mRNA: yellow • tRNA: Tan • Amino Acids: Pink ? ? ? ? ? ? ? ? ?

42. Cool video #2 • Translation • Going from mRNA to a protein • Involves mRNA, tRNA, amino acids and ribosome • Trick to remembering: • Translation is translating the code into a protein. • Like translating a foreign language into what it means • Hola Hello • GUA  Histidine(amino acid)

43. How does the information encoded in the DNA produce traits? How does a gene lead to a characteristic? • DNA codes for the production of proteins • Traits are proteins, or are produced by the action of a special group of proteins - enzymes. • This is how it works: 1. The DNA code is based on the sequence of nitrogen bases. DNA stays in the nucleus (safe place for info) • Messenger RNA copies the code ( ) • Single stranded / U instead of T • Set of 3 bases on the mRNA: __ __ __ __ __ mRNA DNA  mRNA C o d o n mRNA leaves the nucleus 3. 5. transfer RNA carries in amino acids anticodons match to codons Appropriate amino acids are linked To ribosome codon Amino acid Individual amino acids link and peel off to form a This protein is the trait(suchas red pigment) or an enzyme to catalyze a reaction that produces a trait. 4. Ribosomes bind to mRNA Protein!!! (translation)

44. Modeling • Translate your mRNA into a protein by matching up the correct tRNA with its appropriate amino acid • Match the appropriate tRNA’s with their amino acids (CAC: Valine, CUC: glutamic Acid, GUA: Histidine) • Base pair them with the mRNA, one at a time as it would occur in a cell. (GUG on mRNA would bind to CAC on tRNA) • Tape the amino acids together as they come in to form a protein. • Work on your journal/Things that you owe me. Tomorrow is the last day to hand in make up work.

45. RIGHT NOW • Journal for the page of notes we just covered • Any other missed work you owe me. For example: • Labs • Classwork / homework • Exams….

46. 4/14 Warm up • Fill in the flow chart using the following terms: • DNA, mRNA, tRNA, Ribosome, Protein, and tRNA + amino acid DNA mRNA 1. 2. transcription Ribosome 4. 5. translation Protein tRNA + Amino acids 3.

47. Whats wrong with the following sentence: • Thedogbitthemanandran • Should be broken up into words that mean something! • (The dog bit the man and ran) • That is what codons are • Broken up into 3 letters, each is one “word” that codes for a specific amino acid • GCATTTATGCCCATT • GCA TTT ATG CCC ATT • Each “word” codes for a specific Amino Acid

48. 4/15 Warm up • What would happen to this sentence if one of the letters was removed or an extra one added but we still read every three letters as a word? • THE BIG DOG BIT TED AND RAN OFF • THE BID OGB ITT EDA NDR ANO FF • THE BIG DOG TBI TTE DAN DRA NOF F • NONSENSE!!!

49. What if there was an error like this in our DNA? • Mutations!!!!

50. 15.WHAT CAN GO WRONG? A LOT!! An error in the sequence of DNA MUTATION_________________________________________________ What are the consequences if there is an error in replication, transcription or translation? • Gene mutation: change to the nucleotide sequence of DNA can be inherited from a parent or acquired during a person’s lifetime Gene Mutations Deletion TAAAACAT TAGCAACAT Substitution Inversion Translocation Both the APC I1307K mutation and mutations that cause FAP occur in the same gene, the APC (Adenomatous Polyposis Coli) gene. Individuals with FAP develop hundreds to thousands of polyps in the colon and rectum and have a very high risk of developing colorectal cancer.   The APC I1307K mutation is different from other APC mutations because the mutation itself does not cause colon cancer. Instead, this particular mutation creates an unstable spot in the gene that makes the gene more susceptible to additional genetic changes that may in turn lead to colon cancer.