Cell Structures

1
Cell Structures

• What are the functions of the major cell
  structures?

2
Cell Wall

• Found in plants, algae, fungi and nearly all
  prokaryotes
• Lie outside the cell membrane
• Made up of fibers of carbohydrate and protein
• Plant cell walls made of cellulose
• MAIN FUNCTION provide support and protection for
  the cell

3
Image from http//users.rcn.com/jkimball.ma.ultra
net/BiologyPages/P/PlantCell.html
4
Plant Cell Wall Structure
Image from http//www.tvdsb.on.ca/westmin/science
/sbi3a1/Cells/cellwall.htm
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Bacterial cell walls

• Made up of peptidoglycan
• Different structures for different types of
  bacteria

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Fungal and Algal cell walls

• Fungal cell walls
• Composed of chitin and cellulose

• Algal Cell Walls
• Composed of polysaccharides
• Which polysaccharides depends on the algae

7
Nucleus

• Controls most of the cell processes and contains
  the hereditary information (DNA)
• Parts of the nucleus
• Chromatin and chromosomes
• Nucleolus
• Nuclear envelope

8
Image from http//sun.menloschool.org/birchler/c
ells/animals/nucleus/
9

• Image from http//www.daviddarling.info/encyclope
  dia/N/nucleusc.html

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Image from http//cellbio.utmb.edu/cellbio/nucleu
s.htm
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Chromatin and Chromosomes

• Chromatin
• The granular material visible within the nucleus
• Consists of DNA bound to proteins
• Chromosomes
• Chromatin condenses into chromosomes before cell
  division
• Contain genetic information

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Nucleolus

• Assembly of ribosomes begins here

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Nuclear envelope

• Double membrane layer surrounding the cell
• Has pores which allows material into and out of
  the cell

14
Cytoskeleton

• Network of protein filaments that help the cell
  maintain its shape
• Involved in many forms of cell movement

15
Parts of the Cytoskeleton

• Microtubules
• Hollow tubes of protein that maintain shape
• Serve as tracks for moving organelles
• Important in cell division
• Make up centrioles in animal cells
• Also make up flagella and cilia in some cells

16
Microtubules
Images from http//users.rcn.com/jkimball.ma.ultr
anet/BiologyPages/C/Cytoskeleton.html
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Parts of the Cytoskeleton

• Microfilaments
• Long, thin fibers that function in the movement
  and support of the cell
• Much smaller than microtubules

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Microfilaments
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Ribosomes

• Small particles of RNA and protein
• Function assemble proteins
• Prokaryotic and Eukaryotic ribosomes have
  different structures

20
Ribosomes consist of a small subunit and a large
subunit
Image from http//cellbio.utmb.edu/cellbio/riboso
me.htm
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Endoplasmic Reticulum

• Function Components of the cell membrane are
  assembled and some proteins are modified
• Rough ER Synthesis of proteins chemical
  modification Studded with ribosomes
• Smooth ER synthesis of lipids

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Image from http//www.winterwren.com/apbio/cellor
ganelles/er.html
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Image from http//biology.about.com/library/weekl
y/aa041300a.htm
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Golgi Apparatus

• Function enzymes in the Golgi attach
  carbohydrates and lipids to proteins
• From Golgi proteins are packaged and sent to
  their final destinations

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Image from http//cellbio.utmb.edu/cellbio/GOLGI.
HTM
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Image from http//cellbio.utmb.edu/cellbio/GOLGI.
HTM
27
Lysosomes

• Small organelles filled with enzymes
• Function break down lipids, carbohydrates and
  proteins from food particles
• Break down old organelles and other cellular
  debris

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Image from http//cellbio.utmb.edu/cellbio/lysoso
me.htm
29
Vacuoles

• Function Store materials such as water, salts,
  proteins, and carbohydrates
• In plants, a large central vacuole filled with
  fluid is used for support in the cell

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Image from http//micro.magnet.fsu.edu/cells/plan
ts/images/plantvacuolesfigure1.jpg
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Chloroplasts

• Function use energy from the sun to make
  energy-rich food molecules in photosynthesis
• Bound by two envelope membranes
• Stacks of photosynthetic membranes contain
  chlorophyll

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Image from http//www.daviddarling.info/images/ch
loroplast.jpg
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Mitochondria

• Function use energy from food to make high
  energy compounds
• Powerhouse of the cell
• Bound by two envelope membranes
• Inner membrane is folded

34
Image fromhttp//micro.magnet.fsu.edu/cells/mitoc
hondria/images/mitochondriafigure1.jpg
35
Organelle DNA

• Chloroplasts and mitochondria contain their own
  DNA
• Endosymbiotic theorymitochondria and
  chloroplasts the result of endocytosis of
  bacteria and blue-green algae whichbecame
  symbiotic

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Endosymbiotic theory
37
Image from http//www.msnucleus.org/membership/ht
ml/k-6/lc/organ/5/images/wpeA.gif
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Venn Diagram

• Use your notes and the venn diagram handout to
  compare and contrast prokaryotic and eukaryotic
  cells and plant and animal cells

39
Cell as a Factory

• See page 182