1. MITOSIS & MEIOSIS

2. Starter Transcribe and translate the strand of the DNA sequence below.
Coding CGA | GTA | AAT | GCG | TAC
Complement
RNA
Amino acids

3. Starter Transcribe and Translate the strand of the DNA sequence below.
Coding CGA | GTA | AAT | GCG | TAG
Complement GCT | CAT |TTA | CGC |ATC
RNA
Amino acids

4. Starter Transcribe and Translate the strand of the DNA sequence below.
Coding CGA | GTA | AAT | GCG | TAG
Complement GCT | CAT |TTA | CGC |ATC
RNA CGA | GUA |AAU| GCG |UAG
Amino acids

5. Starter Transcribe and Translate the strand of the DNA sequence below.
Coding CGA | GTA | AAT | GCG | TAG
Complement GCT | CAT |TTA | CGC |ATC
RNA CGA | GUA |AAU |GCG |UAG
Amino acids Arg | Val | Asn |Ala |Stop

6. Cell Cycle Mitosis

7. Mitosis Model In this example, the cell has 4 chromosomes
This is known as the DIPLOID NUMBER (also known as 2n, n= number of chromosomes from each parent)
What is the Diploid Number for Humans?

8. Interphase Normal cell function.
At the end the chromosomes shorten and thicken and become visible under the microscope (if stained)
Nuclear Membrane

9. Prophase Each Chromosome replicates itself
The chromosomes are made up of 2 CHROMATIDS held together by a CENTROMERE (not shown)
Centrioles form and move to opposite sides

10. Chromosome
Chromatid
Chromatid
Centromere

11. Metaphase Spindle fibres form from centrioles
The chromosomes line up, along the equator of the spindle

12. Anaphase
The spindle fibres contract pulling the chromatids apart and to opposite poles of the cell
Once separated, the chromatids are now known as chromosomes

13. Telophase
2 new “Daughter” cells are formed
Nuclear membrane reforms

14. End Result How do the cells compare With the mother cell?
With each other?
Why is Mitosis important?
Daughter cells

15. Passing Information to the Next Generation
Humans are similar because we all have the same genes.
What gives us our quirky differences though, is the inheritance of different alleles to those genes.
Gametes always have half the normal amount of DNA in them, compared to regular body cells.
This is so that when two gametes combine, the resulting zygote contains the correct amount of DNA.
How you doin’?
You look like a rat.

16. MITOSIS & MEIOSIS

17. Diploid and Haploid
Normal body cells have the normal number of chromosomes 46
We call these cells DIPLOID. It means that each body cell contains two of each chromosome – one from mum and one from dad.
Gametes though, have half the normal number of chromosomes 23
We call these cells HAPLOID. There’s only one copy of each chromosome. 2n n
At fertilisation, a haploid sperm will fuse with a haploid egg.... which makes a cell with the normal, diploid number of chromosomes 

18. WHADOOSH! n n 2n

19. Meiosis Involves 2 Nuclear Divisions
It’s easy to explain why meiosis requires two nuclear divisions. You already know that gametes need to be haploid divisions will get you from diploid to haploid. n
Mum
Dad 2n n
Meiosis I
Meiosis II
2 x 2n 2n
Meiosis begins by just taking a regular, diploid body cell. n 2n n

20. A Quick Summary
Just like any cell in the cell cycle, a regular cell is minding it’s own business as it goes through interphase. We know that during interphase, a cell with replicate it’s DNA. Meiosis I then occurs. Copies of the same chromatids, Homologous pairs are separated, halving the chromosome number. Meiosis II then occurs. Now, sister chromatids are separated. Meiosis II is what causes ‘2n’ (diploid) cells to become ‘n’ (haploid) cells.

21. Tasks Mitosis Meiosis Define the following words:
Chromatids, Haploid, Diploid, Daughter cells, Homologous pair
Draw and label a diagram of Meiosis
Make a diagram to show the simillarities and differences between mitosis and meiosis.
Mitosis .
Meiosis

22. Plenary: Mitosis and Meiosis?

23. Plenary: Mitosis and Meiosis?

24. Plenary: Mitosis and Meiosis?

25. Plenary: Mitosis and Meiosis?

26. Plenary: Mitosis and Meiosis?

27. Plenary: Mitosis and Meiosis?

28. Plenary: Mitosis and Meiosis?

29. Plenary: Mitosis and Meiosis?

30. Plenary: Mitosis and Meiosis?

31. Plenary: Mitosis and Meiosis?

33. Meiosis creates genetic variation

34. Independent Segregation of Chromosomes
Genetic Variation
During all of the amazing things that happen during meiosis, two events in particular, are very interesting.
These two processes create genetic variation during meiosis:
Crossing Over
Independent Segregation of Chromosomes
Crossing over occurs during prophase I.
Basically the two chromosomes in each homologous pair twist around each other.
Wherever they ‘touch’, genetic material is swapped between them.
At the end of crossing over the genetic composition of each c’some is now different
Independent segregation happens in metaphase I.
Basically, when the homologous chromosomes line up, they do so randomly.
This means that when they are pulled apart in anaphase, the combination of chromosomes going into the daughter cells is also random.

35. Crossing Over
During prophase I, the individual chromosomes of each homologous pair, come into very close contact with each other. They twist and almost look ‘tangled’.
Wherever the chromatids cross over, is called a chiasma
Now we are ready for the next process that confers genetic variation.... INDEPENDENT SEGREGATION OF CHROMOSOMES...

37. Mutations Chromosome mutations
Mutations that affect large regions of DNA that is contained within chromosomes
Gene mutations
Mutations that affect small regions of DNA, usually one base

38. Gene mutations - substitution

39. Silent mutation
A silent mutation alters DNA sequence, but has no apparent detectable effect on a phenotype or a function.
The amino acid sequence is not changed because of the change in base so a normal functioning protein is produced.

40. Gene mutations – deletion

41. Gene mutations - substitution

42. Gene mutations – insertion (frameshift)

43. Sickle cell mutation
Sickle cell disease (also called sickle cell anaemia) is an inherited disorder caused by a gene mutation which codes for a faulty beta chain haemoglobin protein. The substitution of one base in the 438 bases causes an amino acid change, resulting in a slightly different version of the protein being produced. This leads to the characteristic sickle cell shape observed in the red blood cells.

44. Cystic fibrosis mutation
Cystic fibrosis is an inherited recessive condition caused by a mutation of the CF gene. This gene codes for a membrane-based protein that functions in transporting chloride ions across the membrane. A deletion of one triplet (3 bases) coding for the 508th amino acid in the gene causes a faulty protein to be produced. Chloride transport is defective and leads to excessive water build up in the cell. Mucus secreting glands produce a thicker than normal mucus which is characteristic of the symptoms of CF.