Title: A View of the Cell: Cell Structure
1A View of the CellCell Structure
2Microscopy
- the use of microscopes to study cells
- Different types of microscopes
- Light microscope
- Transmission electron microscope
- Scanning electron microscope
3Compound light microscopes
- With light as its energy source, it uses a series
of lenses to magnify up to 1500X
4Electron microscope
- Using a beam of electrons as its energy source,
it can magnify structures up to 500,000 X their
actual size
(a pin head)
5Transmission electron microscope
- TEM
- studies cellular interiors
Sample of TEM image
6Scanning electron microscope
- SEM
- studies cellular surfaces
Sample of SEM image
7The study of cellular structure and function is
called cytology, while the study of cells and
tissues in an organism is called histology.
8Levels of Organization
- Atom
- Molecule
- Organelles
- Cell
- Tissue
- Organs
- Systems
- Organisms
9The 10 Organ Systems
10Anton van Leeuwenhoek
- Mid-1600s
- Holland
- Used hand lens microscope to observe pond water
- Observed microscopic life, called them
animicules
11Leeuwenhoek Microscope
12Robert Hooke
13Robert Hooke
- Mid-1600s
- England
- Used microscope to observe living tissues
- Named chambers cells
14Other Early Discoveries
- Dutrochet (early 1800s) first to suggest parts
of all organisms are made of cells - Brown in 1831 was the first to realize nearly
ever cell contains a nucleus - Dujardin (mid 1800s) used the term sarcode to
describe protoplasm
15German cell biologists
1830s Matthias Schleidan concluded all plants
made from cells
1830s Theodor Schwann concluded that all
animals made from cells
16Rudolph Virchow
- 1855
- Germany
- New cells can only be produced from existing
cells, confirmed by French scientist Louis Pasteur
17Cell Theory
- 1) All organisms are composed of one or more
cells - 2) The cell is the basic unit of structure and
function of living things - 3) All cells come from pre-existing cells
18To be a cell
- Plasma membrane (cell membrane) made of 2 layers
of phospholipids - -controls what enters and leaves cell
- -separates cell from its environment
- Cytoplasm carbohydrate and water based solution
that suspends all internal parts of the cell - -transports chemical substances in the cell
- - within the cell, but outside the nucleus
19To be a cell
- Ribosomes tiny round bodies that produce
proteins - DNA genetic material made of nucleic acids
- a) chromatin mass of fibers scattered
- through the nucleus (thread-like)
- b) chromosomes compact chromatin
- -direct store instructions for all
cell - functions
- -control inheritance of traits
20Two types of cells
- Prokaryote bacteria, archaebacteria
- Eukaryote protists, fungi, plants, animals
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22Prokaryotic cell
- No nucleus
- No membrane bound organelles
- Small
- Simple
- Plasma membrane, ribosomes, cytoplasm, DNA
23Prokaryotic cell
- Capsule durable outer covering that some
bacteria have for protection against water,
acids, and viruses - Flagella movement
- Cell wall protective layer around plasma
membrane - Pili anchoring and DNA exchange
24Eukaryote
- More complex
- 4 basic components organelles
- Organelles small structures that carry out
specialized functions within a cell - Many variations
25Plasma Membrane
- A flexible boundary between the cell and its
environment maintains a balance of nutrients, etc - Selective permeability
- A process in which a membrane allows some
molecules to pass through while keeping others
out
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27Structure of the Plasma membrane
- Phospholipids
- A double layer that creates water-soluble
outsides surrounding water insoluble insides - TransporProteins
- Span the entire membrane to regulate which
molecules enter and which leave
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29Eukaryotic Cell Structures
30Nucleus ? cell control
- Chromatin
- Strands of genetic material (DNA) that contains
the directions for making proteins. Forms
chromosomes - Nucleolus
- A prominent body within the nucleus, produces
granules rich in RNA, each granule will become
part of a ribosome - Nuclear Envelope
- Surrounds the nucleus to keep chromatin and
nucleolus in, while allowing RNA and proteins to
exit
31Cytoplasmic Organelles
- Endoplasmic reticulum (Smooth and Rough)
- network of interconnected membranes (ER),
storage, separation, and transport of substances
made within the cell - Smooth no ribosomes
- Rough dotted with ribosomes
- Ribosomes
- Free or bound to the ER, they carry out protein
synthesis from amino acids
32Cytoplasmic Organelles
- Golgi apparatus
- A flattened stack of membranes that packages
proteins into vesicles to be secreted by the cell - Like a Post office or UPS.
33Cytoplasmic Organelles
- Vacuoles
- Membrane-bound compartments for temporary storage
of materials - May be very large in plant cells
34Cytoplasmic Organelles
- Lysosomes
- Small bodies filled with digestive enzymes that
digest worn-out organelles, food particles, and
even engulfed bacteria - Responsible for the cells recycling of materials
35Cytoplasmic Organelles
- Chloroplasts
- Containing the green pigment, chlorophyll, these
oval bodies capture light energy and turn it into
chemical energy (photosynthesis)
36Cytoplasmic Organelles
- Mitochondria
- Rod-shaped organelle with many inner folds, which
breaks down sugar to release its stored energy
for cell use (cell respiration) - Powerhouse of the cell
37Cytoplasmic Organelles
- Cytoskeleton
- Tiny rods and filaments (called microtubules and
microfilaments) that form a supporting framework
for the cell and function in cytoplasmic streaming
38Cytoplasmic Organelles
- Centrioles
- Pairs of clustered microtubules that play an
important role in cell division
39Cytoplasmic Organelles
- Cilia Flagella
- External microtubules that aid the cell in
locomotion or feeding
40Prokaryotic cell
- No nucleus
- No membrane bound organelles
- Small
- Simple
- Plasma membrane, ribosomes, cytoplasm, DNA
41Plant and Animal Cell Similarities
- Cell membrane that surrounds the cell
- Cytoplasm
- Nucleus that houses DNA
- Ribosomes for protein production
- Mitochondria that breaks down food and releases
energy for the cell. - Vacuoles for storage of food, water, and waste.
Plants have one large vacuole and animals have
many small vacuoles. - Endoplasmic Reticulum (ER)
- Golgi bodies
42Differences in Plant and Animal Cells
- Plants contain a cell wall that surrounds the
cell membrane and provides shape and support. - Plants contain chloroplasts for photosynthesis
- Plant cells have a brick-like shape where as
animal cells are more spherical. - Plants use chloroplasts to store energy in
glucose. - Plants have one large vacuole animals have many
small vacuoles.