Purple Curves

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tallest trees
adult human
chicken egg
frog embryo
most eukaryotic cells
mitochondrion
most bacteria
virus
proteins
diameter of DNA double helix
atoms
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Quick Review

• Where does most of the cell's work take place?
• What happen to the proteins once they leave the
  golgi apparatus and enter the cytoplasm?

Cytoplasm

• become plasma membrane protein,
• stay in the cytoplasm for use in the cell,
• stored in vesicles until needed for transport.

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"A cell is like a factory, where each department
doing a specialized task"
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What is a Cell?

• Cell basic or smallest living unit of life of a
  living organism.
• Protoplasm complex jelly-like substance.
• 70 is water rest is mineral salts, proteins,
  carbohydrates, fats.
• Made up of 3 main parts
• Cytoplasm
• Cell surface membrane
• Nucleus

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(i) Cytoplasm

• Part of the protoplasm between cell membrane
  nucleus
• Jelly-like fluid in which many chemical reactions
  or cell activities take place.
• 90 water enzymes, organelles (specialized
  structures)

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nuclear pore
chromatin (DNA)
nucleus
nucleolus
nuclear envelope
flagellum
cytoplasm
plasma membrane
rough endoplasmic reticulum
ribosome
smooth endoplasmic reticulum
Golgi complex
free ribosome
vesicle
mitochondrion
vesicle
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(ii) Cell surface membrane

• Partially-permeable membrane
• Controls movement of substances into and out of
  the cell.
• Allows only some substances to cross it.
• (e.g. small molecules glucose, water, O2, CO2
• prevents larger molecules from crossing starch,
  proteins

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• made of proteins and fats
• double phospholipid layers
• (fats, proteins, phosphate groups)

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(iii) Nucleus

• Parts of a nucleus
• Nuclear envelope, nucleoplasm, nucleolus
• Nucleoplasm dense material inside nucleus
• Nucleolus(1) or nucleoli (2) Making proteins.
• Control cell activities
• e.g. cell growth, repair of worn-out parts.
• Essential for cell division.

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nuclear envelope
nucleolus
nuclear pores
chromatin
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• Chromatin Network of long, thread-like
  structures
• Contains hereditary material (DNA and proteins),
  instructions for the cell to carry out all
  chemical reactions
• Controls cell division
• Chromosomes when chromatin threads condense and
  become highly coiled during cell division
  (rod-shaped)

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Plant cells Cell Wall

• Non-living layer
• Made up of Cellulose (a complex sugar)
• Surrounds cell membrane of plant cell
• Fully permeable to water, gases, dissolved
  substances
• Protects the plant cell from injury
• Supports and gives a fixed shape to plant cell

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Membrane Network Endoplasmic Reticulum (ER)
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rough endoplasmic reticulum
ribosomes
0.5 micrometers
smooth endoplasmic reticulum
0.5 micrometers
vesicles
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Endoplasmic reticulum

• 2 types rough and smooth
• For synthesis and transport of substances
• Rough ER (RER) ribosomes are attached on outer
  surface
• Continuous with nuclear envelope
• Transports proteins made by ribosomes to Golgi
  Apparatus for secretion out of the cell.

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Endoplasmic reticulum

• Smooth ER (SER) no ribosomes attached on outer
  surface
• Makes substances fats, steroids (sex hormones
  in mammals)
• Detoxification converts harmful substances into
  harmless materials.

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Ribosomes

• Small round structures
• Needed to make proteins in the cell
• 1. Attached to RER membrane make proteins that
  are transported out of the cell
• 2. Free ribosomes in the cytoplasm make
  proteins that are used within cytoplasm of the
  cell

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Golgi Apparatus

• Stack of flattened spaces surrounded by membranes
• Vesicles tiny round structures enclosed by a
  membrane
• Fuse on one side and pinch off from opposite side
  of Golgi apparatus
• Stores and modifies substances made by ER
• Packages the substances in vesicles for secretion
  out of the cell

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ORGANELLES

• MITOCHONDRION (mitochondria)
• Power house of a cell
• Aerobic respiration food substances are oxidized
  to release energy
• Energy is used for cell activities e.g. growth,
  reproduction, movement etc.

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PLANT CELLS - Chloroplasts

• Oval shaped structures
• Contain green pigment chlorophyll
• Absorbs sunlight for photosynthesis, for plants
  to make food

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ORGANELLES

• VACUOLES
• Fluid-filled space enclosed by membrane
• Storage of various substances
• Animal cells many small vacuoles store water,
  food. Exist temporarily
• Plant cells one large, central vacuole, filled
  with cell sap, contains dissolved substances e.g.
  sugars, mineral salts, amino acids, helps to
  maintain shape of plant cell
• Membrane tonoplast

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mitochondrion
chloroplast
Golgi complex
central vacuole
smooth endoplasmic reticulum
vesicle
cell wall
rough endoplasmic reticulum
plasma membrane
nucleolus
nuclear pore
nucleus
chromatin
nuclear envelope
free ribosome
ribosomes
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ORGANELLES

• CENTRIOLES
• Small, hollow cylinders.
• Found as a pair near the nucleus.
• Play an important part in cell division.
• Only in animal cells. Absent in plant cells.

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Differences between plant and animal cells
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Websites

• http//www.sciencenetlinks.com/lessons.cfm?Benchma
  rkID5DocID88
• http//www.beyondbooks.com/lif71/4a.asp
• http//www.ljcreate.com/products/scope_demo.asp