1. The Living Cell Lecture 11 UNIV301 – Great Ideas of Science Great Idea: Life is based on chemistry, and chemistry takes place in cells

2. Cells  All living things are made of cells, which are like chemical factories  Every cell has an “inside” and an outside, separated by a cell membrane  Every cell uses raw materials and energy to produce new chemicals  Every cell must contain information on how to operate and how to make new cells

3. Observing Cells: The Microscope

5. The Cell Theory  Robert Hooke (1635-1702) Cells are like small compartments  Matthais Scheiden – plants, 1838  Theodor Schwann – animals, 1839

6. The Cell Theory, 1839  All living things are composed of cells  The cell is the fundamental unit of life  All cells arise from previous cells

7. Two Kinds of Cells  Prokaryotes (“before nucleus”)  Eukaryotes (“true nucleus”)

8. Cellular Architecture  Organelle: Any specialized cell structure  Cell membrane (cell wall in plants)  Nucleus  Mitochondria and chloroplasts (power plants)

9. Plant Cells

10. Animal Cells

11. Lipids

12. Cell Membranes  Cell Membranes  Isolate the cell  Separate cell parts  Transport  Individual molecules  Channels for specific materials  Receptors  Bind molecules  Encapsulate  Cell Wall (plants)

13. The Nucleus  Nucleus  Contains DNA  Prokaryotes  No nucleus  Eukaryotes  Nucleus  The nucleus has a double membrane. Why? Nucleus

14. Cytoskeleton  Cytoskeleton  Gives cell shape  Anchors  Allows movement  Transport system within cell within cell  Structure  Strong filaments  Complex web

15. How Is Energy Obtained? Plants – make sugar in the presence of the Sun by the process of photosynthesis Energy (light) + CO 2 + H 2 O  Glucose + O 2

16. Carbohydrates (sugars) Carbon Hydrogen Oxygen

17. Cellulose and Starch

18. How Is Energy Obtained? Plants and animals convert sugar into small energy-rich molecules by the process of glycolysis. Plants and animals convert sugar into small energy-rich molecules by the process of glycolysis. Glucose  2 Pyruvic Acids + ATP ATP  ADP + PO 4 + energy

19. ATP: The Cell’s Energy Currency  Adenosine triphosphate (ATP)  Provides energy  Structure  3 phosphate groups  Sugar molecule: ribose  adenine  Function  Removal of phosphate group provides energy

20. How Is Energy Obtained? Some animals obtain energy by the process of respiration: Some animals obtain energy by the process of respiration: Glucose + O 2  Glucose + O 2  Energy + CO 2 + H 2 O Energy + CO 2 + H 2 O

21. The Final Stages of Respiration  Glucose is broken down  CO 2 is produced  ATP is produced to serve as energy-carrying molecules  Result: 36-38 ATP

22. How Is Energy Obtained? Many organisms obtain additional energy from pyruvic acid by the process of fermentation: Many organisms obtain additional energy from pyruvic acid by the process of fermentation: Pyruvic Acid  small molecules + ATP Vinegar, alcohol, carbonic acid

23. The Energy Organelles: Chloroplasts and Mitochondria  Chloroplasts  Plant cells only  Energy transformation  chlorophyll  Double membrane  Mitochondria  Plants and Animals  Produces the cell’s ATP  Double membrane  Has its own DNA

24. Mitochondria Where ATP is manufactured Mitochondria (mtDNA) = maternally inherited Unaltered from your mother Genetic material from common ancestor Genetic anthropology

25. Genetics: The Genetic Code  KEY IDEA: All living things share the same genetic code  Classical genetics – the observation of organisms  Cellular genetics – the observation of cell division and chromosomes  Molecular genetics – the study of DNA and RNA

26. Two great mysteries of life 1.Like begets like 2.You begin life as a single cell

27. Three Stages of Genetics Research 1. Classical Genetics 2. Cellular Genetics 3. Molecular Genetics

28. Gregor Mendel (1822-1884)  Pea plant – breeding experiments  Two-characteristic variations  Established pure-breeding stocks  Studied cross breeding  Offspring’s traits are derived from parents from parents

29. Classical Genetics  Gregor Mendel’s Laws  Pea plant experiments  Purebred  Hybrid  Results  First generation all hybrid tall

30. If you cross a pure bred tall pea plant with a pure bred short pea plant, all offspring are tall. If you cross a pure bred tall pea plant with a pure bred short pea plant, all offspring are tall. T T ttTtT

31. Classical Genetics  Gregor Mendel’s Laws  Pea plant experiments  Purebred  Hybrid  Results  First generation all hybrid tall.  Cross breed those hybrids.  Second generation is ¾ tall and ¼ short!

32. If you cross two hybrid pea plants, If you cross two hybrid pea plants, ¾ will be tall and ¼ will be short. ¾ will be tall and ¼ will be short. T t TTTTt ttTtt

33. Classical Genetics Mendel Laws 1.Genes exist (“atoms of inheritance”) 2.Each parent contributes half. 3.Some are dominant and some are recessive.

34. If you cross a pure bred tall pea plant with a hybrid pea plant, what would the first generation of offspring look like? If you cross a pure bred tall pea plant with a hybrid pea plant, what would the first generation of offspring look like? T T TTTTT ttTtT

36. Gregor Mendel’s Three Laws of Heredity 1.There exist “atoms of inheritance” or genes 2.Each parent contributes half 3.Some genes are dominant, others are recessive 4.Genes are expressed independently of each other (WRONG)

37. Cellular Genetics  Use microscope to observe cells dividing  Chromosomes – elongated colored objects

38. Cellular Genetics  Use microscope to observe cells dividing  Chromosomes – elongated colored object  Mitosis (one cell becomes two)  Most cellular division in your body  Humans 23 pairs (before division 46 pairs)  2 daughter cells same as parent  Meiosis (one becomes 4 gametes)  Crossing-Over (reshuffle = end of meiosis)  Recombination yields different mix of genes

39. Mitosis  Mitosis is cell division (Not sexual reproduction)  Observe chromosomes  Multi-step Process 1. Copy chromosomes 2. Spindle fibers 3. Migration of chromosomes 4. Nuclear membrane reforms

40. Mitosis

41. Meiosis Meiosis is s exual reproduction 1 cell forms 4 gametes Gametes are genetically unique Multi-step process 1. Copy chromosomes 2. Crossing over

42. Meiosis Meiosis is s exual reproduction 1 cell forms 4 gametes Gametes are genetically unique Multi-step process 1. Copy chromosomes 2. Crossing over 3. Segregation 4. Segregation again Result: 4 daughter cells, each with ½ normal number of chromosomes. Each chromosome is unique!

43. Molecular Genetics  What chemical carries the genetic message?  How is that molecular message translated into the chemicals of life?

44. The Discovery of DNA Oswald Avery (1877-1955) Oswald Avery (1877-1955) DNA is composed of deoxyribose (5- carbon sugar), phosphate, and one of four bases (ATGC). A = T; G = C Sugar=Phosphate=Base (1:1:1 ratio)

45. Nucleotides: The Building Blocks of Nucleic Acids Nucleotides are made of three molecules 1. Sugar DNA: deoxyribose RNA: ribose 2. Phosphate ion 3. Base Adenine (A) Guanine (G) Cytosine (C) Thymine (T)

46. DNA’s Double Helix Nucleotide: Building blocks in nucleic acids (A phosphate linked to a sugar linked to a base)

47. DNA Structure  Join nucleotides by alternating phosphate and sugar  DNA  2 strands of nucleotides  Joined by base pairs  Bonding pattern  Adenine:Thymine  Cytosine:Guanine

48. DNA Base Pairing Adenine:Thymine Adenine:ThymineCytosine:Guanine

49. The Replication of DNA DNA replication occurs before mitosis & meiosis Process 1. DNA double helix splits 2. New bases bond to exposed bases 3. Results in two identical DNA strands

50. Proteins – Enzymes

51. Amino Acids  Amino group  Carboxyl group  Side-group (20 different things)

52. Protein – sequence of amino acids  Primary – chain of amino acids  Secondary – folding of chain  Tertiary  Quaternary

53. How Does DNA Make Protein? 1. Chromosomes (DNA) carry the genetic message 2. Messenger RNA copies the genetic message 3. Transfer RNA holds an amino acid 4. Ribosomal RNA assembles a protein

54. RNA Structure 1. Single strand of nucleotides 2. The sugar is ribose 3. Thymine is replaced by uracil (U), which bonds with adenine

55. DNA to Proteins  Protein pulls apart DNA  Make one Messenger RNA (mRNA)  Single stranded molecule carries one gene  64 combinations of bases  Codons (3 DNA letters) copied to mRNA  Transfer RNA (tRNA)  Codon at top matches to mRNA codon  Associated Amino Acid attached  Ribosomes  Machine that makes proteins  Two units (small & large) – reads mRNA  Attaches amino acids from tRNA (creates a protein)

56. From DNA to Protein 1.Transcription: Use DNA to make mRNA 2.Attach mRNA to ribosome 3.Translation: RNA to amino acids 4.Fold amino acids into protein