characteristics of living things:
Growth, response to stimuli (response
to the environment), reproduction,
organization, metabolism (turn energy
to cellular components + break down
organic chemicals), homeostasis
(regulation of internal environment, i.e:
temperature), and adaptation.
Cells: simplest units of life, of
which all living things are
composed.
Discovered by Robert
Hooke in 1665. He
viewed cork through a
microscope.
Cell theory: All living things are made of
cells, cells are the basic blocks of life,
and new cells come from pre- existing
cells (through division)
Types of cells: Eukaryote
(complex cells, contain nuclei,
example: plants and animal cells)
and prokaryorte (simple cells, no
nuclei, example: bacteria)
Eukaryote cell structure:
Plasma membrane:Flexible material, keeps cell
contents within the cell, selectively allows certain
materials into and out of the cell (waste goes out,
food, water, and oxygen goes in)
Cytoplasm:Consists of all cell contents,
made of two key parts: Cytosol ( A
jelly-like fluid (mostly water), chemicals
are transferred through it, and chemical
reactions occur here), and organelles
(specialized organs of the cell)
Organelles: Nucleus (The 'control center' of the cell, consists of several
parts: Nuclear membrane (surrounds the nucleus, similar to the cell
membrane, and contains pores), Nucleolus (manufactures ribosomes (an
organelle)), and chromatin (An assembly of chromosomes (DNA), codes
for the production of proteins in the cytosol)), Ribosomes (Used to
produce proteins (they receive signals from the nucleus and use them to
correctly construct proteins), are sometimes attached to endoplasmic
reticulum), Endoplasmic Reticulum (Branched Tubules attached to
nucleus, come extent out into the cell, can be either smooth or rough
(Rough E.R. have ribosomes attached to it)), Golgi Body (or Golgi
Complex) (Small pancake-like structure Used to chemically modify certain
chemicals and proteins, Vesicles deliver proteins/chemicals, Golgi body
changes them to the desired structure, and Modified chemicals are
transported out of the Golgi body via vesicles to their desired location),
Rough Endoplasmic Reticulum: Ribosomes produce
proteins here, The E.R. serves as a transport
mechanism for the proteins, proteins can move
through the E.R. to get to other sections of the cell,
Sections of the E.R. can break off as vesicle to
surround proteins and transport them further through
the cell (Often to the golgi body.)
Smooth Endoplasmic Reticulum:
No ribosomes are attached,
Certain chemicals are: Created,
Stored here, and Transport from
here to other sections of the cell
through vesicles.
DNA: Deoxyribonucleic Acid Genetic information
(Heredity – to pass traits from one cell to its
offspring), DNA codes for the production of proteins
For chemical signaling between cells, For enzymes
to mediate biological reactions (eg: metabolism).
Since the DNA codes for protein production it
controls the functions of the cell.
Mitochondria (Mitochondria (singular: mitochondrion) are the “power
centers” of the cell They make the usable energy ATP for the cell ATP
stands for adenosine triphosphate, Many of the reactions that turn food
into energy (ATP) occur in the mitochondria, Cellular Respiration (glucose +
oxygen = carbon dioxide + water + ATP), Mitochondria are the only
organelle (other than the nucleus) that contains DNA), Vacuole (Storage
sacs in the cell, Vacuoles can contain different materials, depending on
the type of cell: Food, Waste, Water, etc..., Vacuoles can be drastically
different sizes (Very small in animal cells Very large in plant cells))
Animals Vs. Plants: Animal cells and plant
cells have some slight differences in
organelles (Animal cells: Lysosomes,
Centrioles Plant cells: Cell wall, chloroplasts)
Animal organelles: Lysosomes: Similar to a
vacuole, Contains destructive enzymes, Can break
down old organelles, or even the whole cell,
Centrioles: Used during cell division, Produce
spindle fibre to help separate DNA .
Plant organelles:Cell Wall: A rigid structure surrounding the cell
membrane Made of cellulose, which is a long molecule made up of
sugar, Chloroplasts: Contain chlorophyll, Photosynthesis happens
here (Water + carbon dioxide + light = glucose + oxygen), Vacuole:
Very large water-filled sacs, Used to keep the cell pressing firmly
on the cell wall.