1. Cell City

2. What is the city border? Cell Membrane-
Regulates materials in/out of the cell
Animal Cells do not have cell walls
Only Plant Cells
These would serve as the city’s fence or wall
Rigid in structure, stronger than membranes
Animal Cells also do not have Chloroplasts
These would be like the Solar Energy Facilities in a city- taking in sunlight and putting out energy

3. What is the lawns and parks? Or could be the air even…
Cytoplasm (also called Protoplasm)
Semi-fluid substance (think gelatin) found inside the cell.
Encases, cushions and protects the internal organelles.
It is the cell landscape found in any space where organelles are not and therefore is much like the lawns and parks of our city.

4. What are the roads that give overall shape and structure to the city?
The Cytoskeleton
Roads form an effective network of communications between these areas and give an overall shape and structure to the city.
Cytoskeletons consist of a series of fibrous proteins that help organize, structure and orient the cell.
Everything knows where it belongs and where it is going. In the city, letters, for example, carry a postcode to help the postman ensure that they reach their destination.
Proteins in cells have their own postcodes too. 10 thousand million proteins, 10 thousand different kinds, and yet they all end up in the right place.

5. What is the highway or road system?
Endoplasmic Reticulum
Makes proteins “goods”
Goods are manufactured and shipped to needed areas via the road system
There are two types of endoplasmic reticulum (ER) –
Rough ER
Has ribosomes along its membrane
Source of proteins
Smooth ER
lacks ribosomes
Responsible for lipid synthesis (fat)
Processes a variety of metabolic processes

6. What are the lumberyard and builders?
Ribosomes
Protein builders or the protein synthesizers of the cell.
Those proteins might be used as enzymes or as support for other cell functions.
They are like construction guys who connect one amino acid at a time and build long chains.
Ribosomes float in the cytoplasm and also found on the Rough ER .

7. What is the post office or UPS?
Golgi Bodies
Like a post office, the golgi apparatus is used for shipping those goods created by the ER and ribosomes to the rest of cell.

8. What is the energy plant?
Mitochondria
Like cities, cells are active, energetic beings.
They too need a constant supply of energy and they produce it in exactly the same way: by converting fuel.
The most common fuel that Mitochondria consume is sugar (glucose).
In this case the energy generated is passed on, not as electricity, but as small universal molecules called ATP.

9. What is the landfill? Vacuole
A city generates waste. Some waste is transported away, for example to land-fill sites, whereas other waste is disposed of inside the city.
Of course, environmental and economic issues are important, and so as much waste as possible is broken down and recycled.
A cell also generates waste.
Carbon dioxide and urea - the by-products of energy production - are expelled and disposed of elsewhere.
Plant Cells have a Central Vacuole, Animal Cells just have a several regular vacuoles (much smaller in size)

10. What is the waste remover and recycler?
Lysosomes
Many components of the cell eventually wear out, and need to be broken down and the parts recycled.
Example: A mitochondria that has passed its sell-by date, will be engulfed, disassembled and reused by the cell.

11. What is the city hall? Nucleus
At the centre of the cell lies the nucleus. It is at the same time the command centre, the planning department and the central library - roughly equivalent to City Hall.
What is the city hall fence with security guards?
Nuclear Membrane

12. What is the rolled up blueprints for the city?
Chromosomes
Inside the nucleus
Carry the genetic instructions.
They are a sort of master plan that specifies how the cell should develop.
What is the design in the blueprints for?
Buildings/streets
It would many millions of such files to write down all the instructions for even one cell, so a special code is used, based on very long chain molecules of DNA - deoxyribonucleic acid.

13. Chromosome numbers
Counted by the number of PAIRS of chromosomes in Somatic Cells
Cattle – 30 (60 total)
Swine – 19 (38 total)
Sheep – 27 (54 total)
People – 23 (46 total)
Horses – 32 (64 total)
Goldfish- 45 (90 total)

14. What is the original blueprints for the city?
DNA (Deoxyribonucleic Acid)
A DNA molecule is rather like a blueprint of two entwined strands.
Four different kinds of bases.
It is the sequence of these bases that makes up the genetic code.
The DNA molecules are organized into units or libraries called chromosomes.
What are the copies of the blueprints?
RNA (Ribonucleic Acid)
plays a critical role in helping DNA to copy and express genes, and to transport genetic material around in the cell
Single Strand
What is the copier?
Nucleolus
Disappears during cell division

15. Genes Located on chromosomes Read a gene on a strand of DNA
Many genes located on one strand of DNA
Thousands found in each animal
Two types of inherited traits
Dominant
Recessive

16. Cell Replication Mitosis Meiosis
Increases total number of “somatic” (body) cells
Results in animal growth
Chromosomes pairs are duplicated
Creates Diploid cells- chromosome pairs
Meiosis
Produces gametes
Creates Haploid cells
Only have one-half the chromosomes of normal cells

17. Stages of Mitosis IP-MAT Cycle Interphase
Period between cell divisions
Genetic material all over nucleus
Centrioles replicate
DNA replicates
Nuclear membrane, nucleolus present
Centrioles outside nucleus

18. Prophase Chromosomes Visible Nucleolus invisible
Chromosomes condense and attach to spindle
Centrioles move to poles
Spindles begin to form

19. Metaphase Chromosomes Meet up in the Middle Chromatids: paired short
thick
coiled
attach to spindle fibers at centromere

20. Anaphase Centromere splits(half goes each way)
Spindle fibers pull chromatids Apart
Chromatids separate and move toward spindles (now chromosomes)
Chromosome # at poles = 2n (diploid)

21. Telophase Chromosomes extend, invisible Spindles disappear
Nucleolus, nuclear membrane visible
Cytokenesis
division of all other cell material
cellular membrane pinches inward and divides cells (animals)

22. Mitosis: Somatic Cell Duplication

23. Meiosis Replication of Sex Cells” IP.MAT - P.MAT Cycle
Production of gamete cells
When complete, daughter cells are haploid

24. Interphase Same as in Mitosis Chromosomes invisible
Chromosomes replicate
Chromatids form
Centrioles replicate
Nuclear membrane, nucleolus present

25. Prophase I Crossing over may occur here Chromosomes visible
Nucleolus, nuclear membrane invisible
Centrioles migrate
Spindles form
Chromatids attach to spindles

26. Metaphase I Homologous pairs line up at equator
Each spindle attaches to one chromatid (not chromosome)

27. Anaphase I Homologous pairs separate Chromosome number doesn’t change
Same as mitosis

28. Telophase I Nuclear membrane may appear Spindles disappear
DNA partially de-condense
Cytokenesis same as mitosis

29. Prophase II DNA condenses Nuclear membrane disappears
Centrioles and spindles move to poles
Chromosomes attach to centromeres
Remaining stages are identical to mitosis, except sister chromatids are not identical.

30. Metaphase II Chromosome align on equator
Spindles attached at the centromere

31. Anaphase II Centromere splits
Chromatids separate and migrate to the poles

32. Telophase II Nuclear membrane reforms Nucleolus reforms
Spindles disappear
Chromosomes become invisible
Cytokenesis occurs

33. After Meiosis

34. Comparing the two Meiosis Mitosis Comparison of the two:

35. Dominant Genes
Dominant genes have the ability to mask the expression of recessives.
Written as a capital letter (R)
ALWAYS expressed
Examples:
Polled cows
White face - Herefords
Drop ears - pigs
Paint gene - horses

36. Recessive Genes
Only expressed in homozygous condition (2 matching genes)
Written as a lower case letter (r)
Examples
Horned cows
plain face cows
solid colored horses

37. Important Terms to know
Homozygous- Same
Homozygous dominant (RR)
Homozygous recessive (rr)
Heterozygous-
Different (Rr)
Gregor Mendel is known as the key scientist in relation to genetics—studied pea plants (tall vs. short, smooth vs. wrinkled)

38. Solving Genetic Problems
Use PUNNET SQUARES
Shows the probability of offspring inheritance of genetic traits
Genotype-genetic make-up of an organism
Phenotype- the physical appearance of an organism
Carrier- also means Heterozygous, gene not being shown but being passed along to offspring P p Pp p pp Pp p pp
Monohybrid Cross

39. Let’s Practice!! Remember- Only use one letter to represent each trait
Capital letters= Dominant
Lower case letters= Recessive
Need to draw that Tic-Tac-Toe Board and scribble out the top left box
Put the Sire (father) on top boxes
Put the Dam (mother) on left side boxes
Don’t pick a letter that could be questionable if capital or not
Examples: M/m, W/w, C/c, I/i, J/j

40. Genetic Ratios Genotypic Ratio: Phenotypic Ratio:
Percentage of offspring with each genotype
Phenotypic Ratio:
Percentage of offspring physically/visually showing each trait
Sire’s Genotype: Bb
Dam’s Genotype: Bb
Genotypic Ratio: 25% BB: 50% Bb: 25% bb
Phenotype Ratio: 75% Pink: 25% White

41. Genetic Traits in Humans
Blood Typing ABO
Tongue Rolling
Cystic Fibrosis: a genetically inherited disease in children
Breathing difficulty
Prevents normal absorption of fats and nutrients
Inheriting a recessive allele for it from both parents
Ultimately a fatal disease, but with modern medical care, about 2/3 of the people with it survive into early adulthood. 

42. Genetic Traits in Humans
Albino
Huntington’s Disease
Dwarfism
Polydactyl- extra fingers or toes
Sickle Cell Anemia
Pattern Baldness (sex-linked…more to come)
Hair Color
Eye Color and Color Blindness (sex-linked…more to come)
Plus Many More!

43. Incomplete Dominance Neither gene is dominant over the other.
BLENDING of traits
Something in the middle
Examples
Mostly in plants
Red Flower (RR) x White (rr) Flower= Pink Flower (Rr)

44. Incomplete Dominance in Animals
PIED INDIA BLUE PEACOCK
The Pied pattern can occur in almost all varieties of peafowl.
It is an incomplete dominant gene, and is an allele of the white gene.
Pied is a pattern mutation

45. Codominance
Codominance of traits in which both dominant and recessive genes are expressed.
Both traits appear TOGETHER
Example of codominance:
Blood type AB
Red and White Flowers crossed= red and white swirl flower
Red body color cattle (RR) x White body color cattle (rr)= Roan cattle (Rr--mix of red hairs and white hairs)
Blue Roan Horse

46. All Offspring Roan (RW)
Inheritance of Color X
Red Bull (RR)
White Cow (WW)
All Offspring Roan (RW)
Roan Cow (RW)
Red Bull (RR) X
Offspring 50% Roan (RW)
Offspring 50% Red (RR)

47. Lethal Genes When expressed, organism dies NO cure.
                    
Lethal Genes
When expressed, organism dies
NO cure.
Example: Paint horses lethal white “Frame overo” gene
Affected foals are carried to term and at birth appear normal, though they have pink-skinned all-white or nearly-white coats and blue eyes.
However, the colon of these foals cannot function due to the absence of nerve cells
Foals die of colic within 72 hours, or are humanely euthanized.
Carriers of the gene can be identified by a DNA test

48. Dihybrid crosses!

49. Dihybrid Crosses (2 traits)
Cross a homozygous recessive red and heterozygous polled bull with a heterozygous black and heterozygous polled cow.
bbPp X BbPp
Need to FOIL the alleles to place them correctly…remember from math? First Outer Inner Last bP bp bP bp BP
BbPP
BbPp
bbPP
BbPp
BbPp
Bbpp
BbPp
Bbpp Bp bP
bbPP
bbPp
bbPP
bbPp
bbPp bp
bbpp
bbPp
bbpp

50. Dihybrid Cross Ratios bP bp bP bp BP BbPP BbPp bbPP BbPp BbPp Bbpp
Each box 1/16 of the offspring
1/16= 6 %, 2/16=12%, 3/16=18%, 4/16=25%
Genotypic Ratio: 6% BbPP: 25% BbPp: 18% bbPP: 12% Bbpp: 25% bbPp: 12% bbpp
Phenotypic Ratio: 5 (32%)Black polled: 2 (12%) Black not polled: 7 (44%) Red polled: 2 (12%) Red not polled bP bp bP bp BP
BbPP
BbPp
bbPP
BbPp
BbPp
Bbpp
BbPp
Bbpp Bp bP
bbPP
bbPp
bbPP
bbPp
bbPp bp
bbpp
bbPp
bbpp