Cells Test Notes Hassan Alibhai
2017-03-24 Page C1
Cell Organelles
• Every organelle is in both plant and animal cells unless otherwise noted and highlighted in red.
• The organelles listed below exclude organelles that are commonly known.
Name Description Function
Nuclear Envelope Two-layer membrane that encloses Phospholipid bi-layer membrane which
the nucleus of the cell. surrounds the genetic material.
Nuclear Pores Large protein complexes that cross Allow the transport of molecules across the
the nuclear envelope. nuclear envelope, including RNA and DNA,
as well as signal molecules and lipids.
Nucleoplasm Similar to the cytoplasm of a cell, The fluid within which all components of
the nucleus contains nucleoplasm: the nucleus float: including the nucleolus
within which floats chromosomes and chromosomes. Similar to the
and nucleoli. macroscopic cytoplasm of the cell itself.
Nucleolus Comprise of proteins, DNA and Predominately the creation of Ribosomes,
RNA and form around specific but also include other functions like
chromosomal regions. assembly of signal recognition particles and
playing a role in the cell's response to stress.
Chromatin A complex of large macromolecules Packaging DNA and controlling gene
consisting of DNA, RNA, and other expression and DNA replication
proteins in the nucleus.
Peroxisomes Small, membrane-enclosed Contain enzymes involved in a variety of
organelles morphologically similar metabolic reactions, including several
to lysosomes. aspects of energy metabolism
Plastids The general name for organelles that are specific to plant functions and exclusive
to plant cells, including chloroplasts, chromoplasts, and amyloplasts (below)
→Chloroplasts Small, membrane bound organelle A plastid that contains chlorophyll and in
that is exclusive to plants. which photosynthesis takes place
→Chromoplasts Small, membrane bound organelle Responsible for pigment synthesis and
that is exclusive to plants. storage.
→Amyloplasts Small, membrane bound organelle Synthesis and storage of starch granules,
that is exclusive to plants. through the polymerization of glucose.
The plastid and
nucleus families, and
their organelles
, Cells Test Notes Hassan Alibhai
2017-03-24 Page C2
Cell Membrane: A Closer Look
Membrane Molecule Function and Description
Phospholipid bilayer • 7nm thick
• Polar, hydrophillic head → polar group (commonly
Chlorine), phosphate, glycerol
• Non-polar, hydrophobic tail → two fatty acid
(hydrocarbon) chains → repel all large polar molecules
• In water Non-polar tails face inwards and the polar heads
face outwards
◦ This creates a structure that does not allow large, polar
molecules to cross it: requiring transmembrane proteins
Cholesterol (steroid) • Inner and/or Outer layer of the lipid bilayer
Molecules • Maintain membrane fluidity by limiting phospholipid
packaging
• Allows the membrane to operate in high (makes the
membrane rigid) or low (makes the membrane flexible)
temperatures
Membrane Proteins • Float within the bilayer, providing various functions
◦ Enzymes→ speed up biological reactions in the cell
◦ Peripheral (surface) → cell to cell interactions
◦ Transmembrane (integral) →span the entire lipid
bilayer, transport channels (passive and active
transport)
▪ Glycoproteins → carbohydrate chains that are
attached to the surface of other proteins (outer
layer) → intercellular recognition, chemical
messengers, boost the immune system of the cells
Supporting Fibres • Reinforced by a network of supporting fibres located on the
inside of the plasma membrane by transmembrane proteins
Exterior Glycolipids • Carbohydrate chains that extend out of the cell membrane
that are used for cellular identification (identity markers)
• Attached to lipid molecules embedded in the lipid bilayer
Fluid-Mosaic
Model: lateral
shifting
permitted
2017-03-24 Page C1
Cell Organelles
• Every organelle is in both plant and animal cells unless otherwise noted and highlighted in red.
• The organelles listed below exclude organelles that are commonly known.
Name Description Function
Nuclear Envelope Two-layer membrane that encloses Phospholipid bi-layer membrane which
the nucleus of the cell. surrounds the genetic material.
Nuclear Pores Large protein complexes that cross Allow the transport of molecules across the
the nuclear envelope. nuclear envelope, including RNA and DNA,
as well as signal molecules and lipids.
Nucleoplasm Similar to the cytoplasm of a cell, The fluid within which all components of
the nucleus contains nucleoplasm: the nucleus float: including the nucleolus
within which floats chromosomes and chromosomes. Similar to the
and nucleoli. macroscopic cytoplasm of the cell itself.
Nucleolus Comprise of proteins, DNA and Predominately the creation of Ribosomes,
RNA and form around specific but also include other functions like
chromosomal regions. assembly of signal recognition particles and
playing a role in the cell's response to stress.
Chromatin A complex of large macromolecules Packaging DNA and controlling gene
consisting of DNA, RNA, and other expression and DNA replication
proteins in the nucleus.
Peroxisomes Small, membrane-enclosed Contain enzymes involved in a variety of
organelles morphologically similar metabolic reactions, including several
to lysosomes. aspects of energy metabolism
Plastids The general name for organelles that are specific to plant functions and exclusive
to plant cells, including chloroplasts, chromoplasts, and amyloplasts (below)
→Chloroplasts Small, membrane bound organelle A plastid that contains chlorophyll and in
that is exclusive to plants. which photosynthesis takes place
→Chromoplasts Small, membrane bound organelle Responsible for pigment synthesis and
that is exclusive to plants. storage.
→Amyloplasts Small, membrane bound organelle Synthesis and storage of starch granules,
that is exclusive to plants. through the polymerization of glucose.
The plastid and
nucleus families, and
their organelles
, Cells Test Notes Hassan Alibhai
2017-03-24 Page C2
Cell Membrane: A Closer Look
Membrane Molecule Function and Description
Phospholipid bilayer • 7nm thick
• Polar, hydrophillic head → polar group (commonly
Chlorine), phosphate, glycerol
• Non-polar, hydrophobic tail → two fatty acid
(hydrocarbon) chains → repel all large polar molecules
• In water Non-polar tails face inwards and the polar heads
face outwards
◦ This creates a structure that does not allow large, polar
molecules to cross it: requiring transmembrane proteins
Cholesterol (steroid) • Inner and/or Outer layer of the lipid bilayer
Molecules • Maintain membrane fluidity by limiting phospholipid
packaging
• Allows the membrane to operate in high (makes the
membrane rigid) or low (makes the membrane flexible)
temperatures
Membrane Proteins • Float within the bilayer, providing various functions
◦ Enzymes→ speed up biological reactions in the cell
◦ Peripheral (surface) → cell to cell interactions
◦ Transmembrane (integral) →span the entire lipid
bilayer, transport channels (passive and active
transport)
▪ Glycoproteins → carbohydrate chains that are
attached to the surface of other proteins (outer
layer) → intercellular recognition, chemical
messengers, boost the immune system of the cells
Supporting Fibres • Reinforced by a network of supporting fibres located on the
inside of the plasma membrane by transmembrane proteins
Exterior Glycolipids • Carbohydrate chains that extend out of the cell membrane
that are used for cellular identification (identity markers)
• Attached to lipid molecules embedded in the lipid bilayer
Fluid-Mosaic
Model: lateral
shifting
permitted
