Cell Differentiation

1
Cell Differentiation
2
1.1.3

• Explain how instructions in DNA lead to cell
  differentiation and result in cells specialized
  to perform specific functions in multicellular
  organisms.

3
Specialized Cells

• Multicellular organisms begin as undifferentiated
  masses of cells and variation in DNA expression
  and gene activity determines the differentiation
  of cells and ultimately their specialization.

4
Differentiation

• Only specific parts of the DNA are activated the
  parts of the DNA that are activated determine the
  function and specialized structure of a cell.
• Because all cells contain the same DNA, all cells
  initially have the potential to become any type
  of cell however once a cell differentiates, the
  process cannot be reversed.

5
DNA

• Nearly all the cells in an organism contain the
  same chromosomes and DNA.
• Different parts of the genetic instructions are
  used in different types of cells, influenced by
  the cells environment and past history.

6
Hormones

• Hormones are chemical signals that are released
  by cells that influence the development and
  activity of other cells.

7
Stem Cells

• Unspecialized cells that continually reproduce
  themselves and have, under appropriate
  conditions, the ability to differentiate into one
  or more types of specialized cells.

8
Types of Stem Cells

• Embryonic stem cells
• Adult stem cells- found in bone marrow
• Research has demonstrated both types of stem
  cells can be differentiated into specialized
  cells.

9
Specialized cells in Animals

• Nerve cells- eukaryotic, but have dendrites and
  axons for electrochemical communication in the
  body.
• They are never replaced when they die.

10
Specialized cells in Animals

• Muscle cells- eukaryotic used for movement.
• Skeletal muscles contain many nuclei and are
  striated- voluntary movement.
• Smooth muscles only have 1 nucleus- involuntary
  movement

11
Specialized cells in Animals

• Blood cells
• Red blood cells- the hemoglobin protein
  transports oxygen and carbon dioxide (influenced
  by temperature and pH)
• Do not divide
• No mitochondria or nucleus
• Plasma- transports materials
• Insulin regulates glucose levels
• Lipids, amino acids, and other ions also
  transported from digestive system.
• White blood cells- protects the body from
  infection
• Has a nucleus

12
m
13
Specialized cells in Animals

• Gametes- Sperm and egg cell
• Used in sexual reproduction
• Only contain half the DNA as the rest of the
  cells in an organisms.
• Haploid number for humans 23 chromosomes

14
Specialized Cells in Plants

• Xylem- transports water from roots to the rest of
  the plant
• Phloem- transports water and sugars from leaves
  to the rest of the plant

15
References

• http//www.sciencedaily.com/releases/2007/12/07122
  0123837.htm
• heal-thyself.us
• http//faculty.washington.edu/chudler/cells.html
• http//www.kidsbiology.com/human_biology/muscles2.
  php
• health-niche.com
• http//www.mcatzone.com/glosslet.php?letterg
• ap-bio-patrick-steed.wikispaces.com