1. Unit 7
Cell Growth & Division
Amoeba

2. Something to Think About !!!!
When a living thing grows, what happens to its cells?
2. Does an animal get larger because each cell increases in size or because it makes more of them?

3. Answers to Think About It:
Living things grow by producing more cells.
The cells of an adult animal are no larger than those of a young animal –there are just more of them.

4. One More Thing To Think About ……
Why do cells make so many new cells rather than continuing to grow indefinitely?

5. Answer : One More Thing To Think About:
The larger a cell becomes, the more demands the cell places on its DNA and the more trouble the cell has moving enough nutrients and wastes across the cell membrane.

6. DNA Overload
1.The information that controls a cell’s function is stored in DNA
2.DNA is located in the cell’s nucleus
3.DNA is able to meet the cell’s need when cells are small
4.If a cell were to grow too large, there is not enough information in the DNA molecule to control the larger cell

7. Exchanging Materials
1.If cells were to grow larger than normal, the cell’s volume and its surface area would prevent the cell from maintaining homeostasis.
It becomes more difficult for the cell to move needed materials in and waste products out

8. When do new cells need to be produced?
Replacement
Cells get damaged and need to be replaced.
Not all cells can be reproduced.
Growth
The addition of more cells to make the organism larger

9. Life Span of Various Human Cells
Cell Type
Lining of esophagus
Lining of small intestine
Lining of large intestine
Red blood cells
White blood cells
Smooth muscle
Cardiac muscle
Skeletal muscle
Nerve cells
Life Span
Cell Division
2-3 days
Can divide
1-2 days
Can divide
6 days
Can divide
Less than 120 days
Cannot divide
10 hours to decades
Cannot divide
Long-lived
Can divide
Long - lived
Cannot divide
Long-lived
Cannot divide
Long-lived
Most do not divide

10. The Cell Cycle
G1 Phase
M Phase
S Phase
G 2 Phase

11. Cell Cycle
It is a series of events that cells go through as they grow and divide.
The cell cycle consists of four phases:
G1 - Cells increase in size
synthesize new proteins
synthesize new cell organelles
S - Chromosomes are copied which gives the cell a duplicate set of DNA
G2 - Preparation for Mitosis
90% of time is
spent in interphase I N T E R P H A S

12. Mitosis (M Phase)
1. It is the part of the cell cycle where the division of the nucleus and cytokinesis, (division of the cytoplasm), take place.
2. Mitosis is divided into 4 steps(phases)
Prophase
Metaphse
Anaphase
Telophase(cytokinesis)

14. Prophase 1st and longest phase of mitosis Nuclear envelope disappears
Chromosomes condense –
Now, you can see sister chromatids and centromere
Spindle forms(microtubule structure that helps separate the chromosomes.)
Sister Chromatids
Centromere
Nuclear envelope
Spindle

16. Chromosomes move to the equator of spindle
Metaphase
Chromosomes move to the equator of spindle
Each chromatid is attached to spindle with centromere
Spindle
centromere

17. Metaphase

18. Sister chromatids are pulled apart to opposite poles of the cell
Anaphase
Centromeres split
Sister chromatids are pulled apart to opposite poles of the cell
Each chromatid is now a separate chromosome
Sister Chromatids

19. Anaphase

20. Telophase Nuclear envelopes (2) reform
Chromosomes begin to uncoil and return to a tangled looking mess.

21. Telophase

22. Cytokinesis Cytoplasm divides Two new daughter cells are now separate
Cytokinesis usually occurs at the same time as telophase.
Pinching in of
cell membrane

25. Okay, Now it’s your turn!

26. 1 2 3 4 5 6 7 Interphase? Prophase? Metaphase? Anaphase? Telophase?
Prophase
Anaphase
Interphase

28. What is Cancer ?
Cancer is uncontrolled cell division (mitosis) that can’t be stopped.
A mass of cells called a tumor is a result of this uncontrolled cell division.
There are 2 types of tumors:
Benign = non-cancerous
Malignant = cancerous and they invade and destroy other tissues.

29. Malignant Pancreatic Cancer Tumors

30. Benign Facial Tumors
(neurofibromatosis)

31. Cancerous Cells Affects Homeostasis
Interferes with nervous system tissue and blocks important nerve connections.
Cancer cells absorb nutrients needed by the healthy cells.
Prevent organs from functioning properly.
Lung Cancer

32. Asexual Reproduction
It Only Takes One !

33. Characteristics of Asexual Reproduction
Only one parent is involved.
Offspring are genetically identical to their
parents.

34. 1. Binary Fission Asexual Reproduction in single- celled organisms
The simplest type of asexual reproduction.
A unicellular organism divides by mitosis to form two daughter cells of equal size.
Both the nucleus and cytoplasm divide equally.
Amoebas, paramecia, and bacteria reproduce this way.
All cells that come from a single cell are genetically identical to each other

35. Binary Fission in Paramcecium

36. Binary Fission in Bacteria

37. Regents Practice Question # 1
A pattern of reproduction and growth in a one celled organism
is shown below.
Which statement best describes this pattern of reproduction?
(1) All genetic material comes from one parent.
(2) Only some of the genetic material comes from one parent.
(3) The size of the parent determines the amount of genetic material.
(4) The size of the parent determines the source of the genetic material.

38. Regents Practice Question # 1 ( Answer)
A pattern of reproduction and growth in a one celled organism
is shown below.
Which statement best describes this pattern of reproduction?
(1) All genetic material comes from one parent.
(2) Only some of the genetic material comes from one parent.
(3) The size of the parent determines the amount of genetic material.
(4) The size of the parent determines the source of the genetic material.

39. Asexual Reproduction in multi-cellular organisms
It can be a result of wound repair or growth.
There are many different methods for asexual reproduction in multi-cellular organisms.
Budding
Sporulation
Regeneration
Vegetative Propagation

40. 2. Budding
A new organism develops as part of a parent.
The new organism is called the bud
The bud is a duplicate of the parent. It may separate or remain attached to form a colony.
In budding there is an equal division of the nucleus, but unequal division of cytoplasm. So, one of the daughter cells is larger than the other.

41. Yeast Budding
Desert Cactus
Hydra Budding

42. Regents Practice Question # 2
The diagram below illustrates asexual reproduction in yeast.
Yeast produce offspring that usually have
(1) genes that are different from those of the parent
(2) genes that are identical to those of the parent
(3) half of the genetic information of the parent
(4) organelles that are not found in the parent

43. Regents Practice Question # 2 (Answer)
The diagram below illustrates asexual reproduction in yeast.
Yeast produce offspring that usually have
(1) genes that are different from those of the parent
(2) genes that are identical to those of the parent
(3) half of the genetic information of the parent
(4) organelles that are not found in the parent

44. Regents Practice Question # 3
Which diagram represents the reproductive
process of budding?

45. Regents Practice Question # 3 (Answer)
Which diagram represents the reproductive
process of budding?
Correct Answer

46. 3. Sporulation
Spores are specialized asexual reproductive cells that contain a nucleus and small amount of cytoplasm.
Spores are produced in large numbers by mitosis.
They are surrounded by a tough protective coat that enables them to survive extreme conditions such as heat or cold.
When conditions are favorable, the spores develop into a new organism.
Bread mold, mushrooms, mosses, and ferns reproduce this way

47. Sporulation in Ferns
Diagram of Mold Spores

48. Moss Sporulation

49. 4.Regeneration
The development of a new organism from a part of a parent organism
Occurs in starfish, planaria and sponges
Regeneration can also replace lost body parts. For example lobsters can replace a lost claw.

50. P L A N R I R E G N A T I O

51. PLANARIAN REGENERATION

52. Starfish Regeneration

53. Vegetative Propagation
Occurs only in plants.
New plants develop from the roots, stems, or leaves of the parent plant
There are many different ways for this type of reproduction to occur:
runners
bulbs and tubers
cuttings

54. Examples: strawberries, blackberries, spider plants, mint , ivy
Runners
Stems that grow over the surface of the soil and at certain points the runner puts down roots and new plants grow from there.
Examples: strawberries, blackberries, spider plants, mint , ivy
Strawberry Plant
Ivy Plant

55. Bulbs and Tubers
Any plant that stores its complete life cycle in a specialized underground storage structure.
Each bulb can develop
into a new plant.
Examples: onions, tulips,
chives , lilies, potatoes,
carrots, radishes

56. Pieces of roots, stems, or leaves develop into new plants.
Cuttings
Pieces of roots, stems, or leaves develop into new plants.
Cutting
Rooting
Planting

57. Regents Practice Question # 4
Thousands of genetically identical trees have been discovered growing in a remote, undisturbed mountain area in Colorado. These trees are most likely the
result of
(1) genetic engineering
(2) asexual reproduction
(3) meiotic cell division
(4) biotechnology

58. Regents Practice Question # 4 (Answer)
Thousands of genetically identical trees have been discovered growing in a remote, undisturbed mountain area in Colorado. These trees are most likely the
result of
(1) genetic engineering
(2) asexual reproduction
(3) meiotic cell division
(4) biotechnology

59. Regents Practice Question # 5
Which process usually results in offspring that
exhibit new genetic variations?

60. Regents Practice Question # 5 (Answer)
Which process usually results in offspring that
exhibit new genetic variations?
Correct Answer

61. Regents Practice Question # 6
A technique used to reproduce plants is shown
in the diagram below.
This technique is a form of
(1) sexual reproduction
(2) gamete production
(3) asexual reproduction
(4) gene manipulation

62. Regents Practice Question # 6 (Answer)
A technique used to reproduce plants is shown
in the diagram below.
This technique is a form of
(1) sexual reproduction
(2) gamete production
(3) asexual reproduction
(4) gene manipulation