Transcript Cell Structure - 7th - walker2015

Cell Structure
Chapter 7
7-1: Introduction to Cells
The Discovery of Cells
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In 1665, Robert Hooke, an English scientist,
used a simple microscope (which magnified
objects 30 times their normal size) to observe
“little boxes” in thin slices of cork.
He called the boxes “cells” because they
reminded him of the small rooms in which
monks lived.
The Discovery of Cells
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In 1675, Anton van Leeuwenhoek, a Dutch
scientist, used a stronger microscope (that
could magnify objects 300-fold)
He named pond water creatures
“animalcules” or “tiny animals”.
First to observe living cells
Cell Theory
1.
2.
3.
All living things are made up of one or more
cells.
Cells are the basic units of structure and
function in organisms.
All cells arise from existing cells.
Similarities and Differences in
Prokaryotic and Eukaryotic Cells
Average Cell
Size
Cell Wall
Cell Membrane
Nucleus
Cytoplasm
DNA
Prokaryotic
1-10 µm
Eukaryotic
10-100 µm
YES
YES
NO
YES
YES, in
cytoplasm
SOMETIMES
YES
YES
YES
YES, in nucleus
Continuation on next slide
Similarities and Differences in
Prokaryotic and Eukaryotic Cells
Ribosomes
Membrane
Enclosed
Organelles
Mode of
Locomotion
Found in --
Prokaryotic
YES
Eukaryotic
YES
NO
YES
One or more
flagella
Bacteria only
One or two
flagella or cilia
Fungi, protists,
plants, animals
7-2: Inside the Eukaryotic Cell
Directing Cellular Activity
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Nucleus – membrane bound structure that
contains the cell's hereditary information and
controls the cell's growth and reproduction
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The nucleus (nuclei – plural) houses
deoxyribonucleic acid (DNA)
Genetic material in
cells
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Directing Cellular Activity
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Ribosomes – Organelles that help in the
synthesis of proteins
Directing Cellular Activity
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Cytoplasm – the gel-like substance found
between the cell membrane and the nucleus
Directing Cellular Activity
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Centriole – one of a pair of organelles that
are found in animal cells that function in the
formation of spindle fibers during cell division
Protein Processing
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The endoplasmic reticulum and the Golgi
apparatus are organelles that prepare
proteins for extracellular export
Endoplasmic reticulum (ER) – a network of
membranes throughout the cytoplasm of the
cell
Protein Processing
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Two types of ER
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Rough ER – proteins are made in ribosomes and
then packaged into vesicles
Smooth ER – makes lipids (fats) and helps in
cleaning harmful substances in the cell
Protein Processing
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Golgi complex – responsible for sorting and
correctly shipping the proteins produced in
the ER
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Resembles a post office in cells
Storage and Maintenance
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Lysosome – a vesicle that contains specific
enzymes that breaks down large molecules
They also help recycle materials in the cell by
digesting old, damaged, or unused organelles
Lysosomes are in animal cells
Storage and Maintenance
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Mitochondrion (mitochondria = plural) – an
organelle that uses energy from organic
compounds to make ATP
Storage and Maintenance
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Vacuole – an organelle that stores water,
ions, nutrients, and wastes; it can also store
toxins and pigments
Storage and Maintenance
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Chloroplast – an organelle that uses light
energy to make sugar from carbon dioxide
and water
Plant Cell vs. Animal Cell
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Cell wall – provides additional support for
certain cells; they have cellulose which aids
in its structure
Plant Cell vs. Animal Cell
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Organelles that are
exclusively found in
plant cells
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Cell wall
Central vacuole
Chloroplast
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Organelles that are
exclusively found in
animal cells
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Lysosome
Centriole
Picture of animal cell vs. plant cell
Cellular Movement
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Flagella – long finger-like projections that
push cells forward by snakelike wriggling
Cellular Movement
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Cilia – short hair-like projections of certain
cells that beat in a regular fashion to create
currents that sweep materials along
7-3: From Cell to Organism
Levels of Organization
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Cell – the smallest unit of life
Tissue – group of cells that work together and
have a common function
Organ – group of tissues that work together…
Organ system – group of organs…
Organism – group of organ systems…
Cellular Differentiation
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Cellular differentiation – The normal process
by which a less specialized cell develops or
matures to possess a more distinct form and
function