Transcript cell wall - El Camino College

CELLS 
Two main types of cells are ______ and _______.
A. Prokaryotic; eukaryotic
B. Bacterial; animal
C. Nerves; muscles
D. Plant; animal
The boundary structure that physically
defines a cell is the
.
A.Cell wall
B.Selective permeability
C.Plasma membrane
D.Protein coat
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Where is the secreted protein insulin
synthesized?
A. In the Golgi apparatus
B. On the rough ER
C. On ribosomes in the cytoplasm
D. In the nucleus
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Cell Is the Basic Unit of Life

Cell theory: An organism can be one celled or
multicellular
 Multicellular
 Humans

organisms have billions of cells
have over 200 types of cells
Hooke first described cells in 1665
 Schleiden
(1838) recognized plant cells
 Schwann (1839) reported animal cells
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
cells are too small
to be viewed by
the naked eye,
one way to
increase resolution
is to increase
magnification,
such as by using a
microscope
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Cell types

two major types:
 Prokaryotic:
bacteria
and archae


lacks a nucleus
Without a system of
internal membranes
 Eukaryotic:
algae,
fungi, plants, animals


has a nucleus
has internal
membrane-bound
compartments

Prokaryotes
 Little
internal organization
 Much smaller than eukaryotes
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■ Eukaryotes
DNA contained
in nucleus
Membrane-enclosed
organelles
Internal compartments
for special functions Figure
5.2
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
Different eukaryotic cells
 Protist,
fungi, plants= cell wall beyond the
plasma membrane
 Protist, plants= chloroplasts
 Plants= central vacuole
 Animals= centrioles
Cell Structure

Cellular structure is organized:
The Plasma Membrane
• Defines the boundary of the cell
• Consists of a bilayer of lipids with proteins for
communication with external environment
– Selective permeability
– and act as markers= blood types
• Fluid mosaic model
– Mobility of components of the membrane
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Nucleus: The Administrative Office




command and control
center of the cell
stores hereditary
information: DNA
Surrounded by a
double-membrane
nuclear envelope
Nuclear pores are
gateways for molecules
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
Nucleolus
dark-staining region of the nucleus
 contains the genes that code for the rRNA
(ribosomal RNA) that makes up the ribosomes
 the subunits leave the nucleus via the nuclear
pores and the final ribosome is assembled in the
cytoplasm

Mitochondrion: Power Plant




Double-membrane organelle
Inner membrane folded
into cristae
Harnesses energy from
chemical breakdown
Cellular respiration

Produce ATP
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Chloroplast: Photosynthesis




Double-membrane
organelle
Contains grana,
made of thylakoids
Converts CO2
and H2O into
sugars using light
Chlorophyll enables
photosynthesis
Figure 5.10
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The Endoplasmic Reticulum:
The Factory Floor


Interconnected tubes
and flattened sacs
Rough ER
 Ribosomes
 Makes
membrane
and secreted proteins

Figure 5.4
Smooth ER
 Makes
membrane
vesicles
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Golgi: Shipping Department

Stacked, flattened
membrane sacs

Processes new
proteins and lipids
 Adds
specific
chemical groups
 Targets
them
to their destinations
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Vesicles: Movement in the Cell

Vesicles
 Membrane-enclosed

sacs
Transport vesicles
 Moving
substances
from one location
to another
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Lysosomes: Clean-up Crew



Small spherical organelles
Contain enzymes to break down macromolecules
Release simple sugars, amino acids,
and fats to be recycled
 To
 As
 To
clear cell of damaged organelles
a source of food
destroy invading bacteria
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Peroxisomes: Detoxy centers


Derivate from membranes in the cell
The functions are:
1.
2.
detoxify harmful byproducts of metabolism
convert fats to carbohydrates in plants seeds for
growth
The Central Vacuole: Storage
A specialized structure in plants and fungi
 Breaks down substances
 Stores chemicals
for later use
Figure 5.8
 Fills with water to
provide rigidity

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Cytoskeleton:
microfilament 
intermediate
filament


microtubule
Gives the cell
its shape
Provides
internal support
Is responsible
for movement
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Movement

Used as tracks for vesicle movement or the
whole cell
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Cilia and Flagella

Cilia beat in unison like oars

Flagella beat like whips
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Centrioles
•
•
•
complex structures
In animal cells and
protists
Functions:
•
•
anchor locomotory
structures
assemble microtubules near
the nuclear envelope for the
cell division
Cell Wall
– found in
• Plants
• Fungi
• protists
– function in:
• Protection
• maintaining cell shape
• preventing excessive water
loss/uptake
Extracellular matrix (ECM)
• Outside the plasma
membrane
• in animal cells
• mixture of proteins:
Collagen and elastin
for protective layer
• ECM coordinates cells
functioning as tissues
Evolution of Organelles
• Eukaryotes most likely evolved from prokaryotes
– Larger prokaryotes ingested smaller prokaryotes
• Free-living mitochondria and chloroplasts were captured
– Formed an endosymbiotic relationship with the host cell
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Extra credit…. Make flash cards
with all the following terms
Cell
Chloroplast
Chromosome
Cilium
Ribosome
Rough ER
Smooth ER
Vacuole
Vesicle
Cytoplasm
Cytoskeleton
Nuclear envelope Eukaryote
Flagellum
Nucleolus
Fluid mosaic
Nucleus
model
Organelle
Golgi apparatus
Plasma membraneExtra cellular
matrix
Lysosome
Mitochondrion
Prokaryote
peroxysome
Review Question
1: Cell theory includes the principle that
A) cells are the smallest living things
B) all cells are surrounded by cell walls
C) all organisms are made up of many cells
D) Nothing smaller than an organelle is considered alive.
2: The plasma membrane is:
A) carbohydrate layer that to protect
B) double lipid layer with proteins inserted in it
C) thin sheet of structural proteins that lines the inside of some body cavities
D) composed of blood plasma that has solidified into a protective barrier.
3: Organisms that have cells with cytoplasm and no organelles are called
______________, and organisms whose cells have organelles and a
nucleus are called ______________
A) cellulose, nuclear
B) flagellated, streptococcal
C) eukaryotes, prokaryotes
D) prokaryotes, eukaryotes
4: Within the nucleus of a cell you can find ________
5: The endomembrane system within a cell includes
A) cytoskeleton and ribosomes.
B) prokaryotes and eukaryotes
C) endoplasmic reticulum and Golgi
D) mitochondria and the chloroplasts.
6: Which of the following statements is true?
A) All cells have a cell wall for protection and structure.
B) Eukaryotic cells in plants and fungi, and all prokaryotes, have
a cell wall.
C) There is a second membrane composed of structural
carbohydrates surrounding all cells.
D) Prokaryotes and all cells of eukaryotic animals have a cell wall.