1. Welcome to Grade 12 Biology

2. Bio 40S Words – What do you think they mean?
Genetics
DNA
Mitosis
Meiosis
Evolution
Bacteria
Species
Ecosystem
Biodiversity
Global Warming
Mutation

3. WHMIS Workplace Hazardous Materials Information System

4. Understanding Biological Inheritance
Unit 1: Genetics
Understanding Biological Inheritance

5. Genetics is… The study of heredity.
Heredity - transmission of traits from parents to offspring.
Genes - segments of DNA - determine the inheritance & expression of one particular character, e.g. eye colour.
Alleles - two or more alternative forms of a gene, e.g. Tall (T) vs. short (t); - occupy the same locus (place) on homologus chromosomes.

6. Homologous Chromosomes
One chromosome of each homologous pair comes from the mother (called a maternal chromosome) and one comes from the father (paternal chromosome). Homologous chromosomes are similar but not identical. Each carries the same genes in the same order, but the alleles for each trait may not be the same
Review Mitosis

7. Vocabulary
Chromosomes – thread-like structures in nucleus that contain genetic information.
Chromatin – material in chromosomes composed of DNA and protein.
Chromatid – one of two distinct strands that make up each chromosome.
Cytoplasm – liquid area between the nucleus and the cell membrane of a cell.
DNA – (Deoxyribonucleic acid) - stores and transmits genetic information - codes for proteins.

9. What is Mitosis? Cell division in eukaryotic cells
Separates chromosomes into two identical sets
Followed by cytokinesis - divides the nuclei, cytoplasm, organelles & cell membrane into two equal shares
result 2 daughter cells (identical to each other and to parent cell).

10. Part of the Cell Cycle

11. Interphase: the time between cell divisions
Interphase: the time between cell divisions. At least 4 things happen: 1. Cell grows (small cell  big cell) 2. ATP is made (NRG) 3. DNA replication 4. protein synthesis (enzymes)

12. Significance of Mitosis
1. Development and growth: multicellular organisms
2. Cell replacement e.g. cells of skin & digestive tract, RBCs have short life span (~ 4 months)
200 billion RBC per day are produced in humans
3. Regeneration: e.g. starfish regenerate lost arms
4. Asexual reproduction: e.g. hydra (fresh water animal) reproduces by budding
- vegetative propagation in plants
Review…

13. Steps of cell division in Mitosis Prophase
Chromatin condenses into chromosomes (46 in humans).
Nuclear membrane breaks
Apart. Spindle fibres attach to centromeres

14. 2) Metaphase (M for middle) Chromosomes align at the equatorial plate
Single file.
3) Anaphase: Chromosomes
split apart. Sister chromatids
separate.
Centromere divides.

15. 4) Telophase Cytokinesis: Chromatin/ chromosomes
expand. Nuclear membrane
reforms.
Spindle fibres dissappear.
Cytokinesis:
Cytoplasm divides. All organelles divide equally into two parts. Two identical daughter cells are formed.

16. Meiosis…What is it used for?
cell division of sex-cells
No meiosis … too many chromosomes!! (92)
halves # of chromosomes ~ new generations receive correct # of chromosomes
the egg (23) + the sperm (23) = baby (46) =

17. Why Meiosis???? Why do animals (and plants)have sex???? Romance??
A need?

18. Meiosis…What is it used for?
It allows for genetic variation which is important for survival of the species – we are all not identical to each other (and so a disease will not wipe all of us out at once).
Leads to Evolution.

19. Meiosis What is meiosis?
cell division that results in gametes (sperm and egg cells).
Gametes have only ½ the number of chromosomes than other cells in the body (somatic cells).
Somatic cells (human) – 46 chromosomes (diploid)
Sex cells (human) – 23 chromosomes (haploids)
Meiosis takes care to ensure that all gametes are different

20. 2. The different phases of meiosis.
Meiosis is composed of 2 Cell divisions
Meiosis I
Interphase I: chromosomes duplicate into sister chromatids (DNA replication)
Prophase I: chromosomes contract, nuclear membrane disintegrates, Homologus Chromosomes partner up
- Synapsis

21. Crossing Over
Often during prophase I, the chromatids of each pair of Homologus Chromosomes may wind around each other and pieces of chromosomes or pairs of sister chromatids are exchanged. This is called CROSSING OVER. This gives us more even more GENETIC VARIATION

22. Metaphase I: the Homologus Chromosomes line up a the centre of the cell in pairs, the centromeres attach to the spindle fibers that run the length of the cell.

23. Anaphase I: after all chromosomes are aligned, one of each pair begins to move to opposite poles of the cell (sister chromatids remain connected to one another).
*This is the stage where the chromosome # is reduced by half.* 2n to n (in humans 46 to 23)

24. Meiosis square dance

25. Telephase I – cytoplasm divides  2 haploid cells result.

26. Meiosis II (may begin with a short resting phase, called interphase II)
Prophase II – chromosomes begin to move to the cell’s equator (happens at the same time for all cells). Each chromosome still has 2 sister chromatids joined at a centromere.

27. Metaphase II – centromeres for each chromosome are attached to spindle fibers - line up at the cell’s equator.
Anaphase II – sister chromatids are pulled apart.

28. Telephase II – cytoplasm splits for each cell – 4 haploid gametes.
Sperm = spermatogenesis; Egg = Oogenesis

29. Home work
Make a T-Chart showing the differences between mitosis and meiosis.

30. Meiosis ~ Gametogenesis - “creation of gametes.”
Spermatogenesis (the formation of sperm)
Male testes have tiny tubules diploid cells - spermatogonium (diploid cells)
these mature to become sperm (haploid cells)
each one spermatogonium becomes 4 sperm
Starting at puberty, a male will produce literally millions of sperm every single day for the rest of his life.

31. Spermatogenesis

32. Oogenesis – the formation of egg cells
formation of haploid cells from an original diploid (primary oocyte.
The female ovaries contain the primary oocytes.
Two major differences between the male and female production of gametes.
1. Oogenesis only leads to the production of one final ovum (large egg cell)
three come out much smaller than the final ovum. These are called polar bodies
they eventually disintegrate, leaving only the larger ovum.
2. The production of one egg cell via oogenesis normally occurs only once a month, from puberty to menopause.

33. Oogenesis Part One http://www.youtube.com/watch?v=VPezOuOnq1g
Part Two

35. Remember Meiosis ensures that:
The chromosome # remains constant from one generation to the next.
That each sexually reproduced offspring will receive 2 complete sets of genetic instructions.
Meiosis allows for genetic diversity.

36. More vocabulary
Gametes: reproductive cells – sex cells (eggs and sperm); haploid cells ( ½ the number of chromosomes: in humans – 23 chromosomes).
n = # of chromosomes in a gamete cell
Somatic Cells: regular body cells with full chromosome content (diploid cells); in humans: 46 chromosomes. 2n
Centromere: the structure that holds the chromatids together.
Centriole: spindle fibre involved in cell division.

37. More vocabulary
Genotype: the genetic composition of an organism – the combination of alleles, e.g. Bb.
Phenotype: The physical appearance of the individual based on their genotype, e.g. brown eyes.
Punnett square: A chart that shows possible genotype/phenotype of offspring.
Homozygous: Two copies of the same allele/gene, e.g. BB or bb
Heterozygous: Two different alleles for the same trait, e.g. Bb.

38. More vocabulary
Purebred: The same as homozygous; used in breeding circles. BB, bb
Hybrid: Same as heterozygous. E.g. Bb
Dominant traits: Expressed in both homozygous and heterozygous forms (alleles denoted by capital letters, e.g. B_)
Recessive traits: Expressed in only the homozygous form (bb)
Carrier: Someone who carries the recessive allele, b, but doesn’t show it. (Bb)

39. Mendel
Gregor Mendel (1822 – 1884) is considered the “Father of Genetics”
first to study how traits were passed on.
Studied pea plants in an Austrian monastery.
Pea plants ideal to study : they self-pollinate  ( the sperm fertilizes the ovule in the same plant) and have a short life-span
In a pea plant, the gene for producing seed shape may occur in two alternative forms:
R_ = round; rr = wrinkled

40. Mendel Videos
Song

41. More videos Monk in a garden:
Rap
Bill Nye Genes
Bill Nye Cloning

42. Questions on Gregor Mendel
What were the 7 traits that Mendel studied in pea plants?
Which were the dominant of these traits? (Name all 7)
Which were the recessive of these traits? (Name all 7)
What is self-pollination?
What is cross-pollination?
What is purebred?
What is hybrid?
What is segregation?
Textbook
Page 

43. Generations Parent Generation (P): The original parents.
F1 generation: The progeny (offspring) produced from a cross between P.
F2 generation: The progeny resulting from cross of F1 individuals.
Inbreeding: When individuals of a progeny are allowed to cross with each other (e.g. 2 individuals from F1)

44. Mendel’s Pea-Plant Traits
Phenotype (dominant, recessive)
Genotype
Seed shape
Round, wrinkled
RR, Rr, rr
Seed colour
Yellow, green
YY, Yy, yy
Seed coat colour
White, grey
WW, Ww, ww
Pod shape
Smooth, wrinkled
NN, Nn, nn
Pod colour
Green, yellow
GG, Gg, gg
Flower position
Axial, terminal
AA, Aa, aa
Plant height
Tall, short
TT, Tt, tt

45. Punnett Squares
- Shows segregation and combination of male and female cells (gametes) - Can be expressed using a simple matrix. - Checkerboard diagram illustrates possible results of a cross between the gametes of two individuals.

46. Ratio The relationship of two quantities, for example
The ratio of apples to oranges is 5 to 3.
or 5 apples : 3 three oranges or 5/3 - three different ways of writing it

47. Ratios in Genetics Offspring in a ratio
Genotypic ratio – 1TT: 2Tt: 1tt
Phenotype ratio – 3 tall : 1 short

48. Use of Legends
In Genetics legend show what the assigned letters stand for
e.g. use the letter “t” to represent plant height.
T_ = Tall, tt = short
The _ means it could be T or t
Make your legends complete and easy to follow!

49. Punnett Squares Shows predictionsof offspring genotypes/phenotypes.
Mendel’s plants  Tall = TT or Tt; short = tt
Cross a heterozygous tall pea plant with a homozygous recessive short pea plant
What will the offspring’s genotypes and phenotypes be?
What percentage of offspring could be tall?

50. T t Tt tt Genotypes  2 Tt : 2 tt ratio
Phenotypes  2 tall : 2 short ratio
50% probability that the offspring will be tall or short.

51. Males vs. Females What is the difference between boys and girls?
Both males and females have 44 autosomes (non-sex-linked chromosomes), and 2 sex-linked chromosomes.
Sex-linked chromosomes (2 each)
The males have an X chromosome and a Y chromosome.
The females have two X chromosomes.
How much of our DNA is the same as another human of the same sex?
99.9%. Point one percent of our DNA is different.

52. Homozygous or Heterozygous?
Purebred or hybrid?
Test Cross: involves crossing an unknown dominant traited individual with a homozygous recessive individual. Used to determine whether the unknown is a purebred or a hybrid.

53. A Karyotype of a Human’s Chromosomes - Male or female?

54. Mendel’s Laws
Law #1: Genes in Pairs Genetic characters are controlled by unit factors (genes/alleles) that exist in pairs - passed from parents to offspring. When two organisms produce offspring, each parent gives the offspring one of the alleles from each pair.

55. Law #2: Law of Dominance One allele can mask the expression of another allele. That allele is dominant to the other, (which is recessive)

56. Law #3: Law of Segregation - Basically Meiosis
Law #3: Law of Segregation - Basically Meiosis!! During the formation of gametes, the paired factors separate (segregate) randomly so that each gamete receives one factor or the other.

57. Law #4: Law of Independent Assortment
During gamete formation, segregating pairs
assort independently from each other.
(In humans, that’s a mixture
of 25,000 genes!)

58. Law #4: Law of Independent Assortment - continued
The inheritance of a pair of alleles affecting one characteristic occurs independently of alleles affecting any other characteristic.
i.e. The gene that controls one trait has no influence on the inheritance of a gene with a different trait.
e.g. The gene that controls is a seed is round or wrinkled is NOT linked to the gene that determines if the seed is yellow or green (the genes are not on the same chromosome).

59. Animation on Mendel’ Laws

60. BIG Punnett Square P-Generation
Cross a homozygous Tall, Green plant (dominant traits) with a short, yellow (recessive) plant. What will the offspring look like?
T_ = Tall G_ = Green
tt = short gg = yellow
Cross TTGG (homozygous dominant)
with ttgg (homozygous recessive)

63. What are the genotypes of the gametes for each plant in the cross
What are the genotypes of the gametes for each plant in the cross? (Remember, offspring inherit one allele from each parent.)
“Male” plant gametes = TG, TG, TG and TG
“Female” plant gametes = tg, tg, tg and tg TG tg
TtGg

64. F1 generation All genotypes are TtGg
All phenotypes are 100% Tall and Green
Each offspring produced will have the same genotype and phenotype.

65. Now cross two members of the F1 generation to interbreed and work out the geno and phenotype combinations. How many will be Tall and Green?
What are the genotypes of each parent plant?
What are the genotypes of each parent plant’s gametes (list all combinations).
Test cross.
Find the genotype and phenotype ratios.

66. TG Tg tG tg TtGg x TtGg “Male” gametes = TG, Tg, tG and tg
“Female” gametes = TG, Tg, tG and tg TG Tg tG tg
TTGG
TTGg
TtGG
TtGg
TTgg
Ttgg
ttGG
ttGg
ttgg
Genotypic ratio
1 TTGG : 2 TTGg :
2 TtGG : 4 TtGg :
1 TTgg : 2 Ttgg :
1 ttGG : 2 ttGg :
1 ttgg
Phenotypic ratio
9 Tall, Green plants:
3 Tall, yellow plants:
3 Short, Green plants:
1 Short, Yellow plants:

67. Genotypic ratio
1 TTGG : 2 TTGg : 2 TtGG : 4 TtGg : 1 TTgg : 2 Ttgg : 1 ttGG : 2 ttGg : 1 ttgg
Phenotypic ratio
9 Tall, Green plants
3 Tall, yellow plants
3 Short, Green plants
1 Short, Yellow plant
All Heterozygous Dihybrid Crosses will give this 9:3:3:1 ratio.

68. Exceptions to Mendel’s Laws

69. Exceptions to Mendel’s Laws
Co-dominance – Both alleles are dominant and expressed.
e.g. A red flower crossed with a white flower = red and white striped flowered plants.
RR = red flowers WW = white flowers
RW = red and white striped flowers
What would the phenotopic ratio be if we crossed 2 RWs? RW X RW

70. R W RR RW WW Genotypic ratio -- 1 RR : 2RW : 1 WW
Phenotypic ratio – 1 red : 2 striped : 1 white

71. 2) Incomplete dominance – Both alleles are blended and expressed. e. g
2) Incomplete dominance – Both alleles are blended and expressed. e.g. Cross a red flower and a white flower = pink flowers. RR = red flowers WW = white flowers RW = pink flowers What would the phenotopic ratio be if we crossed 2 RWs?

72. R W RR RW WW Genotypic ratio -- 1 RR : 2RW : 1 WW
Phenotypic ratio – 1 red : 2 pink : 1 white

73. 3rd Exception – Lethal Alleles
Sometimes the phenotype that results from an allele is death.
These usually occur as mutations with essential genes (genes you need to survive).
Both dominant and recessive lethal alleles exist.

74. Lethal Genes e.g. Huntington’s Disease e.g. Cystic Fibrosis
caused by a dominant and lethal gene
HH and Hh – homozygous and heterozygous
person lives long enough (usually in their 30s) so they can pass along the lethal gene onto their offspring.
e.g. Cystic Fibrosis
caused by a recessive and lethal gene
life expectancy is 5 years without medical treatment
this genetic disorder exists only in the homozygous state (cc), This occurs when both parents are carriers (Cc).

75. Dominant Lethal in the Homozygous State e.g. Dwarfism
dominant (A)
lethal only in the homozygous state (AA)
in the heterozygous state, dwarf only.
AA (die early/stillborn)
Aa (dwarf)
aa (normal)
What is the probability that two dwarfs have a normal child?
What is the probability of those that are still living?

76. Crested ducks http://www.pinterest.com/pin/353673376958491230/
CC – stillborn (eggs don’t hatch)
Cc – crested
cc – non-crested

77. More Exceptions
4) Polygenic Traits – traits controlled by a number of different genes.
These genes may be on the same or on different chromosomes.
Each gene contributes a small but equal increment to the trait being expressed – a blending result.
Examples include skin colour, height, eye colour, hair colour and intelligence.

78. 5) Multiple Alleles – three or more alleles of the same gene but only 2 alleles required to express the trait. e.g. blood groups
3 alleles
4 different blood types
Determined by the presence or absence of antigens in the blood.

79. IAIA Type A Blood IAi IBIB Type B Blood IBi IAIB Type AB Blood ii
Genotype
Phenotype
IAIA
Type A Blood
IAi
IBIB
Type B Blood
IBi
IAIB
Type AB Blood ii
Type O Blood

80. What are the genotypes/phenotypes from the cross between 2 AB parents
What are the genotypes/phenotypes from the cross between 2 AB parents? Show the cross between IAi and Ibi. A B AA AB BB
Genotypes: 1 AA, 2 AB, 1 BB
Phenotypes: 25% Type A, 50% Type AB, 25% Type B

81. Mendel’s 6th Exception Sex-linked Traits (X-linked)
Many genes are located on the X chromosome (some on the Y). X is a BIG chromosome, Y is a smaller chromosome.
In humans there are 46 chromosomes, and only 2 of these are sex chromosomes (X and Y). Females – XX and males – XY. The other 44 are autosomes.
In meiosis, each egg (female) gives an X chromosome.
In meiosis, each sperm (male) give either an X or a Y chromosome (50 : 50).

82. X Y XX XY At fertilization (XX cross XY)
Geno: 2 XX : 2 XY Pheno: 50% girl: 50% boy
Because the Y chromosome carries less DNA than the X, the Mendelian ratio does not occur if the genes are on the X chromosome and are recessive.
The Disappearing Male? X Y XX XY

84. Fruit Flies
Thomas Morgan (scientist) experimented with Drosophilias (fruit flies). He found that there were more white-eyed males than white-eyed females. Red-eyed fruit flies were dominant. R = Red, r = white

85. Fruit Flies
Can we have a Carrier Male?

86. Cross a homozygote red-eyed female with a white-eyed male
Cross a homozygote red-eyed female with a white-eyed male. XRXR cross with XrY All the offspring will have red eyes; no white-eyed children.
Geno
½ XRXr
½ XRY
Pheno
½ female carrier
½ red-eyed male Xr Y XR
XRXr
XRY

87. Can a female carrier have a colourblind girl?
Colourblindness
A recessive sex-linked disorder. Most common is red-green colourblindness.
B = normal, b = colourblind
XBXB cross XbY
How many of the children will be colourblind? Xb Y XB
XBXb
XBY
Geno
2 XBXb, 2 XBY
Pheno
50% Normal males
50% Female carriers
Can a female carrier have a colourblind girl?
Other diseases on X-chromosome – hemophilia, muscular dystrophy.

88. Colourblindness XBXB cross XbY
A recessive sex-linked disorder. Most common is red-green colourblindness.
B = normal, b = colourblind
XBXB cross XbY
How many of the children will be colourblind?

89. What is a mutation
Is it good? Why?
Is it bad? Why?

90. Chromosomal Mutations http://www.youtube.com/watch?v=hiRt2uy0dpY
- when segments of chromosomes, entire chromosomes or even complete sets of chromosomes are involved in genetic change.
Changes in chromosome # 1 Non-disjunction.
A failure of homologus chromosomes to separate during meiosis, resulting in an abnormal number of chromosomes.
A gamete with +/- 1 chromosome may still fuse with an egg or sperm. Some survive, but most are spontaneously aborted.

91. Common Non-Disjunction Disorders Down Syndrome, “Trisonomy 21”
The individual is born with 47 chromosomes. ( an extra #21 chromosome)
The frequency of this disorder increases with increasing maternal age. 50% of individuals die by 4 years old (without medical help ) most live to approximately 65 years.
Mental retardation,
epicanthic folds of the eye,
short stature,
cardiac deformities.
Strapper = horse groom

92. Turner Syndrome (XO) – one X chromosome
45 chromosomes, short stature, webbed neck, may have slight retardation, immature genitals, sterile, occurs 1 in 2500 conceptions.
Kleinfelters Syndrome (XXY)
47 chromosomes, tall, female-like breasts, some mental retardation, (50%), normal male, small testes, produce little to no sperm.
It doesn’t matter how many X-chromosomes a person has, it is the presence of the Y chromosome that makes an individual a male. The Y chromosome has a “testis determining factor” that stimulates growth of male reproductive organs.

93. Non-Disjunction on Sex Chromosomes
XYY Syndrome or Jacob’s Syndrome:

94. Chromosomal Mutations (cont’d)
Changes in chromosomal structure (5 types)
Deletions: due to loss of a chromosome segment after breakage. e.g. Cri-du-chat Syndrome – deletion of portion of the arm of chromosome 5, severe retardation, cry resembles cat.
Duplication: due to an increase in the amount of genetic material carried by a chromosome, usually not problematic and may actually provide genetic variation.

95. B. Changes in chromosomal structure (continued)
iii: Inversions : portion of the chromosome breaks and it may rotate 180° and reattach on the same/original chromosome
iv: Shifts: part of a chromosome becomes inserted in a different region on the same chromosome
v.: Translocations part of a chromosome may be inserted on a different/non-homologous chromosome (translocation).
These all may be fatal to the zygote.

96. “Boy With an Extra X”
Read story. Answer these questions in your notebook (complete sentences).
Did Tom have all the Kleinfelter’s Syndrome symptoms? Which symptoms did he have?
What is a good idea to have genetic testing done? Why?
How would you feel if you found out you had a genetic disorder? What would you do about it?
Likewise if you were to have a child with a genetic difference. How would you feel? What would you do?

97. Pedigrees
A geneticist’s way of charting the passage of a trait from one generation to the next.
In a pedigree chart, the darkening of squares/circles indicates the presence of the trait under study.
Pedigree Legend

98. How to Draw a Pedigree
Draw a pedigree for a family with a husband and wife and 4 children – 2 girls and 2 boys (in that order). The father is colour-blind (a recessive, sex-linked disorder) and the two girls are carriers. I II

99. Xd Y XD
XDXd
XDY

100. Draw a pedigree of the following family showing the genotypes of all the individuals (place these under the individuals in the pedigree). Make a legend! The inability to roll one’s tongue is recessive to the ability to roll one’s tongue. It is not sex-linked.

101. A man who can roll his tongue marries a woman who cannot roll her tongue. They have three children: a daughter followed by two sons. The oldest and youngest children are able to roll their tongues, but their middle child cannot. The daughter marries a man who is able to roll his tongue, but their son cannot. The middle son marries a woman who is able to roll her tongue. The youngest child marries a woman who is unable to roll her tongue, but they have no children.

102. Hemophilia – the Royal Disease

103. Pedigree Activities Pedigree Studies Applied Genetics Baby Pierre
Queen Victoria

104. Heredity vs. Environment
“Nature vs. Nurture”
Environment can affect the expression of a gene.
e.g. 1) height genes determine approximate height of a person, but environment (i.e. nutrition may or may not allow the individual’s potential to be reached (poor diet  shorter ; poor posture  shorter)
e.g. 2) intelligence affected by prenatal environment (alcohol – FAS – or nutrition), as well as early years environment (stimulating environment helps mental development).

105. e.g. 3) high blood pressure: predisposition inherited, but influenced by diet, exercise, stress, smoking.
e.g. 4) coat colour in siamese cats: dark legs, face and tail result because the black fur gene can only be expressed at cool temperatures; fur at extremities darkens, fur close to warm body stays light.

107. Pre-Natal testing
Testing for diseases or conditions in a fetus or embryo before it is born.
Down syndrome, chromosome abnormalities, genetic diseases and other conditions, such as spina bifida, cleft palate, Tay Sachs disease, sickle cell anemia, thalassemia, cystic fibrosis, Muscular dystrophy, and fragile X syndrome.
Screening can also be used for prenatal sex discernment.
Tests include amniocentesis, ultrasonography including nuchal translucency ultrasound, serum marker testing, or genetic screening.

108. Amniocentesis
Amniocentesis a small amount of amniotic fluid, which contains fetal tissues, is sampled from the amniotic sac surrounding a developing fetus, and the fetal DNA is examined for genetic abnormalities.
carries a small risk of miscarriage
15 – 18 weeks

109. Karyotypes
The “picture” of the arrangement of all homologus pairs of chromosomes in an individual.
Karyotypes can be studied to identify the presence of a genetic disorder, and pinpoint the chromosome responsible for the disorder.

110. Normal Karyotype (Male)

111. Down Syndrome (Trisonomy 21) in a Female

112. Klinefelter Syndrome (XXY)