1. Growth and Development (B5)
How does an organism produce new cells?

2. DNA has a double helix structure

3. The cell cycle Cell cycle: the main processes Cell growth during which
The number of organelles increase
The chromosomes are copied when the two strands of each DNA molecule separate and new strands form alongside them
Mitosis during which
Copies of the chromosomes separate
The cell divides

4. Cell growth during which
The number of organelles increase
The chromosomes are copied when the two strands
of each DNA molecule separate and new strands form
alongside them

5. Copies of the chromosomes separate The cell divides
2. Mitosis during which
Copies of the chromosomes separate
The cell divides
Cell Division by Mitosis: this produces two new cells identical to each other and to the parent cell

6. How does an organism produce new cells?
There are two types of cell division:
M_______
Mitosis
Meiosis

7. Meiosis A type of cell division that produces gametes
It is important in meiosis that the cells produced only contain half the chromosome number of the parent cell.
A zygote contains a set of chromosomes from each parent

8. Meiosis
Gametes
Zygote

9. Questions What happens in the normal cell cycle?
Cell growth
Mitosis
What happens during cell growth?
Number of organelles increase
Chromosomes are copied by separating DNA strands and forming new strands
What happens during Mitosis?
Copies of the chromosomes separate
The cell divides

10. More questions In which organs do cells divide by Meiosis?
Ovaries and Testes
How many chromosomes are in the gamete if the parent cell has 46? 23
How many chromosomes does the zygote have? Where are they from? 46
A set from each gamete. (from each parent)

11. Growth and Development (B5)
How do genes control growth and development within the cell?

12. DNA - the genetic code
The genetic code is in the cell nucleus BUT proteins are produced in the cell cytoplasm
Nucleus
Cytoplasm

13. Genes do not leave the nucleus but a copy of the gene is produced to carry the genetic code to the cytoplasm
In the nucleus
Travels to the
cytoplasm
In the cytoplasm

14. Both strands of DNA are made up of four different bases.
The bases always pair up
in the same way
A -T C - G

15. The Genetic Code
The order of the bases in a gene is the code for building up amino acids in the correct order to make a particular protein
Chromosome
made of DNA
U (not T)
In mRNA
mRNA copy
of gene
Protein made of amino acids

16. Where is the genetic code found?
Questions
Where are proteins made in cells?
In the cytoplasm
Where is the genetic code found?
In the nucleus of every cell
How does the code get into the cytoplasm?
A copy of the gene carries the code (RNA)
How many different bases are in DNA?
How is the order of the amino acids in proteins determined?
Four different bases, always pairing the same way
The order of bases in a gene is the code

17. Growth and Development (B5)
How do new organisms develop from a single cell?

18. Early embryos The zygote divides by mitosis to form an embryo
In a human embryo, up to the eight cell stage, all the cells are identical and could produce any sort of cell required by the organism (embryonic stem cells)
After this point the cells become specialised and form different types of tissue. Some of the genes are switched off.

20. Specialised Cells
After this point the cells become specialised and form different types of tissue
Although body cells in an organism contain the same genes, many genes in a particular cell are not active because it only produces the specific proteins it needs

21. One cell type becomes many!
Gene switches
Gene for insulin is on in the pancreas but off in the kidney
Gene for ADH is on in the pituitary gland but off in the salivary gland
gametes
zygote
mitosis
Specialised cell types in tissues

22. Cloning
In carefully controlled conditions of mammalian cloning, it is possible to reactivate inactive genes in the nucleus of a body cell to form cells of all tissue
types.
Adult and embryonic stem cells have the potential to produce cells needed to replace damaged tissues.

23. Plants from from single cells
New cells in plants specialise into cells of roots, leaves or flowers.

24. Unlike animal cells some plant cells remain unspecialised and can develop into any type of plant cell.
These unspecialised cells allow the production of clones of plants with desirable features, from cuttings.

25. Plant meristems
Plant meristems divide to produce cells that result in increased height, length of roots and girth of the plant.

26. If the hormonal conditions in their environment are changed, unspecialised plant cells can develop into a range of other tissues (eg xylem and phloem) or organs (eg leaves, roots, flowers)

27. Cut stems from a plant can develop roots in the presence of plant hormones (auxins) and grow into a complete plant which is a clone of the parent

28. Phototropism
Phototropism is the plant’s response to light. It increases the plant’s chance of survival
Light causes auxin to move to the opposite side of the shoot tip. The cells on the side with more auxin grow bigger.

29. REVISE
Check your knowledge

30. Growth and Development (B5)
How does an organism produce new cells?

31. DNA has a ____________ structure
double helix

32. The Cell Cycle Cell cycle: the main processes Cell growth during which
- ______________________________ ___________________________ when the two strands of each DNA molecule separate and new strands form alongside them
Mitosis during which
____________________________
- The number of organelles increase
- The chromosomes are copied
Copies of the chromosomes separate
The cell divides

33. Cell growth during which
_______________________________
____________________________ when the two strands of each DNA molecule separate and new strands form alongside them
The number of organelles increase
The chromosomes are copied

34. ____________________________ _______________________
2. Mitosis during which
____________________________
_______________________
Copies of the chromosomes separate
The cell divides
Cell Division by Mitosis: this produces ____ new cells identical to each other and to the parent cell
two

35. How does an organism produce new cells?
There are two types of cell division:
M_______
Mitosis
Meiosis

36. Meiosis A type of cell division that produces
It is important in meiosis that the cells produced only contain the chromosome number of the parent cell.
A contains a set of chromosomes from each parent
gametes
half
zygote

37. Meiosis
Gametes
Zygote

38. Questions What happens in the normal cell cycle?
Cell growth
Mitosis
What happens during cell growth?
Number of organelles increase
Chromosomes are copied by separating DNA strands and forming new strands
What happens during Mitosis?
Copies of the chromosomes separate
The cell divides

39. More questions In which organs do cells divide by Meiosis?
Ovaries and Testes
How many chromosomes are in the gamete if the parent cell has 46? 23
How many chromosomes does the zygote have? Where are they from? 46
A set from each gamete. (from each parent)

40. Growth and Development (B5)
How do genes control growth and development within the cell?

41. DNA - the genetic code cell nucleus
The genetic code is in the ________ BUT proteins are produced in the cell __________.
cytoplasm
Nucleus
Cytoplasm

42. copy of the gene
Genes do not leave the nucleus but a _______________ is produced to carry the genetic code to the cytoplasm
In the nucleus
Travels to the
cytoplasm
In the cytoplasm

43. Both strands of DNA are made up of ____ different bases.
four
The bases always pair up _______________
A - ? C - ?
in the same way T G

44. The Genetic Code order of the bases
The _____________________ in a gene is the code for building up amino acids in the correct order to make a particular ________.
protein
Chromosome
made of ____
DNA
__ (not T)
In mRNA
mRNA ____
__________
copy
of gene U
Protein made of __________.
amino acids

45. Where is the genetic code found?
Questions
Where are proteins made in cells?
In the cytoplasm
Where is the genetic code found?
In the nucleus of every cell
How does the code get into the cytoplasm?
A copy of the gene carries the code (RNA)
How many different bases are in DNA?
How is the order of the amino acids in proteins determined?
Four different bases, always pairing the same way
The order of bases in a gene is the code

46. Growth and Development (B5)
How do new organisms develop from a single cell?

47. Early embryos The zygote divides by ________ to form an embryo mitosis
In a human embryo, up to the _____
_____ stage, all the cells are identical and could produce any sort of cell required by the organism (embryonic stem cells)
eight cell
After this point the cells become __________ and form different types of
_________.
specialised
tissue

49. Specialised Cells
After this point the cells become ________ and form different types of
________.
specialised
Although body cells in an organism contain the same genes, many genes in a particular cell are _________ because it only produces the specific _________ it needs
tissue
not active
proteins

50. One cell type becomes many!
Gene switches
Gene for insulin is on in the _________ but off in the kidney
Gene for ADH is on in the ____________ but off in the salivary gland
gametes
pancreas
zygote
mitosis
Specialised cell types in tissues
pituitary gland

51. Cloning
In carefully controlled conditions of mammalian cloning, it is possible to __________ inactive genes in the nucleus of a body cell to form cells of all tissue
types.
Adult and embryonic _________ have the potential to produce cells needed to replace damaged tissues.
reactivate
stem cells

52. Plants from from single cells
New cells in plants specialise into cells of roots, leaves or ________.
flowers

53. Unlike animal cells some plant cells remain ____________ and can develop into any type of plant cell.
unspecialised
These unspecialised cells allow the production of _______ of plants with desirable features, from _______.
clones
cuttings

54. Plant meristems
Plant meristems divide to produce cells that result in increased ___________________ and ______ of the plant.
height,
length of roots
girth

55. If the hormonal conditions in their environment are changed, unspecialised plant cells can develop into a range of other tissues (eg _____________________) or organs (eg ____________________)
xylem and phloem
leaves, roots, flowers

56. Plant Hormones
Cut stems from a plant can develop _______ in the presence of plant hormones (________) and grow into a complete plant which is a _______ of the parent
roots
auxins
clone

57. Phototropism the plant’s response to light
Phototropism is _________________________. It increases the plant’s chance of _________.
survival
Light causes ______ to move to the opposite side of the shoot tip. The cells on the side with more auxin grow ______.
auxin
bigger

58. Questions Division of a cell by mitosis creates ____ cells.
When do mammalian embryonic cells become specialised?
How do cells control which proteins they produce?
If animal stem cells can produce cells to replace damaged tissues, what can plant stem cells do?
two
The eight cell stage
They can inactivate genes or reactivate inactivated genes.
Develop into any type of plant cell