Nucleic acids DNA

1. Nucleic acidsDNA

2. LOCATION OF DNA Mitochondrial DNA Nuclear DNA Chloroplastic DNA FUNCTIONS OF DNA • Controls protein synthesis • Carries hereditary • characteristics

3. DNA –Position in the cell DNA double helix Nucleus Chromosomes

5. HISTORY OF DNA A.Rosalind Franklin and Maurice Wilkins - X-ray photo of DNA. (1952) B.Watson and Crick- described the DNA molecule from Franklin’s X-ray. (1953) C. Watson crick and Wilkins – received Nobel price (1962). Franklin passed away Complete activity textbook pages 16-17

7. DNA Structure • DNA consists of two molecules that are arranged into a ladder-like structure called a Double Helix. • A molecule of DNA is made up of millions of tiny subunits called Nucleotides. • Each nucleotide consists of: • Phosphate group • Pentose sugar • Nitrogenous base

8. Nucleotides Phosphate Nitrogenous Base Pentose Sugar

9. Nucleotides • The phosphate and sugar form the backbone of the DNA molecule, whereas the bases form the “rungs”. • There are four types of nitrogenous bases.

10. Nucleotides A T C Adenine Thymine G Guanine Cytosine

11. Remember DNA T – A G - C

13. It's hard to believe that an alphabet with only four letters can make something as wonderful and complex as a person

14. Nucleotides • Each base will only bond with one other specific base. • Adenine (A) • Thymine (T) • Cytosine (C) • Guanine (G) Form a base pair. Form a base pair.

15. DNA Structure • Because of this complementary base pairing, the order of the bases in one strand determines the order of the bases in the other strand.

16. A T A A A T T T C C C G G G

17. DNA Structure • To crack the genetic code found in DNA we need to look at the sequence of bases. • The bases are arranged in triplets called codons. A G G - C T C - A A G - T C C - T A G T C C - G A G - T T C - A G G - A T C

18. DNA Structure • A gene is a section of DNA that codes for a protein. • Each unique gene has a unique sequence of bases. • This unique sequence of bases will code for the production of a unique protein. • It is these proteins and combination of proteins that give us a unique phenotype.

19. THE ROLE OF DNA (pg 23) • PROTEIN SYNTHESIS- DNA has the code to make all proteins • PASSING ON OF HEREDITARY MATERIAL- Passed on from parent to offspring. • REPLICATION- DNA can make a copy of itself for cell division. • CARRYS GENETIC INSTRUCTIONS- Has instructions to make all components of the cell. • MAINTAINS STRUCTURE AND REGULATION- large sections of DNA are non-coding and they maintain structure of chromosomes and regulate the functions of genes.

20. HOMEWORK PG 20 EX 1.

21. DNA REPLICATION Process of making a new DNA molecule from an existing DNA molecule that is identical to the original WHY So that genetic code is passed on to each new daughter cell formed during cell division WHEN During interphase

22. DNA REPLICATION PROCESS • UNWIND • UNZIP • COMPLEMENTARY PAIRING • REZIP • REWIND • CONTROLLED BY ENZYMES

24. DNA Replication Unzip into two single strands

25. New bases attached themselves in the correct place of each strand Free nucleotides in nucleoplasm

26. Two identical strands are formed Each strand now becomes a double helix. Strand 1 Strand 2

27. Questions on the DNA Molecule 1 G 2 3 T 4 5 • Identify the above molecule. • Give labels for parts numbered 1to 5 • 3. Describe how the above molecule • replicates itself. • What is it significance that this molecule can • replicate itself?

28. ANIMATION

29. H bonds break Two strands seperate

30. Nucleotides with Complementary bases are assembled alongside each strands Sugar phosphate backbone is made by joining the adjcent nucleotides ( DNA polymarase enzyme( ) )

31. Two identical DNA molecules are formed

32. HOMEWORK pg 20 Ex 1 ANSWERS 1 A Deoxyribonucleic acid B Double helix C Adenine, Thymine, Cytosine and Guanine D Weak hydrogen E Pyrimidines 2. Nucleotides join with matching bases e.g. A-T and C-G 3. It is made of small molecules called nucleotides 4. These are complimentary bases for each C there will be a G attached on the other strand of DNA

33. DNA Profiling Each PERSON’S DNA profile is unique!

34. What is DNA Profiling? A technique used by scientists to distinguish between individuals of the same species using only samples of their DNA

35. Where do we get DNA

36. DNA profiling • Technique used to identify sequence of bases • The nucleotides are separated from each other in • the order that they are found in strand of DNA. • Nucleotides appear as dark bands • The sequence in this segment • of DNA reads CTT- AGT • Use as DNA fingerprint • Unique for every person

37. DNA Profiling can solve crimes • The pattern of the DNA profile is then compared with those of the victim and the suspect. • If the profile matches the suspect it provides strong evidence that the suspect was present at the crime scene (NB:it does not prove they committed the crime). • If the profile doesn’t match the suspect then that suspect may be eliminated from the enquiry.

38. Solving Medical Problems DNA profiles can be used to determine whether a particular person is the parent of a child. A childs paternity (father) and maternity(mother) can be determined. This information can be used in • Paternity suits • Inheritance cases • Immigration cases

39. DNA Fingerprinting • DNA fingerprinting is often used by the police in • identifying the suspect of a crime. • A useful but controversial method • A sample of a suspect’s bodily fluid or tissue is to be • compared with a sample found at the scene of a • crime. • The pattern of lines represents a person’s specific • genetic make-up. • DNA fingerprinting use in 11/9 disaster to identify victims

40. Problem 1: X is a DNA sample found at the scene of a murder. 9 suspects were requested to provide DNA samples. Which person is likely to be the murderer? Could this be disputed? 1 2 3 4 5 6 7 8 9 X

41. HOMEWORK PG 28 CASE STUDY 2

42. ANSWERS CASE STUDY 2 1 From Chantal T 2 Possibly as a result of a tussle with the killer. 3. The victim 4. Chantal T 5. The sample might be from the victim themselves and not the killer. 6. No, we can confirm that her skin was under the victims nails, not that she committed the murder.

43. Bacterial DNA - Manufacturing of insulin • Diabetics need insulin to live • Diabetes use insulin from pigs and cattle. This is not the same as human insulin and sometimes produces side effects. With genetic engineering, bacteria are used to produce some human insulin

45. 1. A ring of DNA is taken from a bacterium 6. The insulin is collected and purified ready for use • The bacteria • reproduce, making clones of themselves • A piece is cut out using enzymes • as ‘chemical scissors’ 3. A cell is taken from a human pancreas. The gene for insulin is cut from the chromosome 4. The insulin gene is put into the ring of bacteria DNA

46. Pg 26 Ex 2

47. USES OF DNA FINGERPRINTS • SOLVE CRIMES • PATERNITY SUITS/Inheritance cases • IDENTIFICATION OF DEAD BODIES. • DIAGNOSIS OF INHERITED DISORDERS • DEVELOPING CURES FOR INHERITED DISORDERS Why is there still controversy?

48. STRUCTURE OF RNA RIBONUCLEIC ACID • RNA is a small molecule • It has a single strand • It is made up of monomers called • nucleotides • A nucleotide consists of a • A sugar molecule = Ribose • A PHOSPHATE Portion • A NITROGEN base • Cytosine • Uracil • Adenine • Guanine

49. RNA Three types and location 1. Messenger RNA (mRNA) - Nucleus and cytoplasm 2. Transfer RNA (tRNA) - cytoplasm 3. Ribosomal RNA (rRNA) - ribosome

50. FUNCTIONS • Messenger RNA (mRNA) – transfers DNA code to ribosomes for translation. Acts as a template for protein synthesis. • Transfer RNA (tRNA) – brings amino acids to ribosomes for protein synthesis. • Ribosomal RNA (rRNA) – Ribosomes are made of rRNA and protein.