Download Structure and Function of Cells

Chapter 4
Honors and Lab Biology
 Quick
Write:
◦Why do we need to learn about
cells?
Healing time is radically reduced and scarring almost
eliminated by bioartificial skin!
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Cells that do NOT contain membrane bound
organelles. (unicellulat)
Cells that DO contain membrane
bound organelles.
Cells were discovered due to microscopes in
the early 17th century
ROBERT HOOKE 1665 (english scientist)
examined a slice of cork, he saw “little boxes”
they reminded him of small rooms….cells!
These were dead plant cells.
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ANTON VAN LEEUWENHOEK 1632-1723
(dutch microscope maker) first to observe
living cells
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Is the smallest unit of matter that can carry
out all the processes of life.
Organelle: parts within a cell!
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1. All living things are composed of one or
more cells
2. Cells are the basic unity of structure and
function in an organism
3. Cells come from the reproduction of
existing cells.
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Matthias Schleiden (1838) botanist, all plants
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Theodor Schwann (1839) zoologist, all
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Rudolf Virchow (1855) physician, cells come
are composed of cells
animals are composed of cells
ONLY from other cells.
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Not all cells are alike! They vary in…
◦ A) size
◦ B) shape
◦ C) internal organization
SIZE: range from .2m – 0.2um (most are 10-50um)
-not all are microscopic (most are) ex: giraffe’s nerve
cells extend 6.5 ft. down it’s leg!!
Cells are limited in size by the ratio
between their outer surface area and
their volume
 Organelles:
parts of a cell,
have specific jobs
 Tissues:
groups of cells
that have a similar function
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!
 Organ
systems- a group of
organs that work together to
perform a set of related tasks.
Digestive system includes: the
stomach, esophagus,
intestines and mouth.
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Cells→Tissues→Organs→Organ Systems
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Cell Membrane – separates cell from external
environment, gives shape and flexibility to
cell, selectively permeable
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Cytoplasm:
◦ gelatin like aqueous fluid called cytosol
◦ Cytoplasmic streaming
◦ Mostly water but also salts and organic molecules
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Mitochondia: power house of the cell! Where
cellular respiration occurs, production of ATP,
has it’s own DNA
◦ Cristae: inner membrane creating many folds to
increase surface area
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Ribosomes: where proteins are made,
◦ Free Floating Ribosome: make proteins for the cell
◦ Ribosomes attached to ER: make proteins to be
exported from the cell
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Endoplasmic Reticulum: (ER) acts as a
highway for molecules to move around the
cell.
◦ Smooth ER: does NOT contain ribosomes
◦ Rough ER: does contain ribosomes
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Golgi Apparatus (bodies) processes,
packages, and secretes
a) product is assembled (moves from ER to golgi, where it is
put together and adjusted)
b) product is packaged (in new sacs)
c) product is mailed out (sent out of cell)
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Cilia: short hair like projections beat
together to move an organism ex: humans
trachea cilia move fluids and mucus! YUM
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Flagella: long, whiplike projections, single or
in pairs, rapid movement, ex: sperm
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Nucleus: brains! Control center of cell, DNA
& RNA are made here!
◦ Nuclear envolope: double membrane will pores
◦ Chromatin: fine strands of DNA & protein
◦ Nucleolus: inside nucleus where ribosomes are
made
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Lysosome: digestive enzymes, digest food,
disease causing bacteria, old organelles, ex:
lysosomes eat up tissue between fingers in
embryos, usually only in animal cells
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Cytoskeleton- helps shape & support cells
◦ Microtubules: long slender protein tubes form
spindle fibers during mitosis
◦ Microfilaments: fine protein threads
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Centrioles: cell reproduction
Centrosome: cell reproduction
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Cell Wall: rigid covering made of cellulose,
protects cell, goes OUTSIDE cell membrane
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Central Vacuole: huge structure which may
take up 90% of the space in plant cell
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Plastids
◦ a) chloroplasts : site for photosynthesis
◦ b) chromoplasts: stores red and yellow pigment
◦ c) leucoplasts: non pigmented