Transcript Ch. 7 Cell Structure and Function

Biology
Ch. 7
Ms. Haut
microscope to look at
slices of cork
 Named the tiny
chambers “cells” after
rooms in monasteries
http://www.edu365.cat/aulanet/comsoc/persones_tecn
iques/Robert_Hooke_archivos/Robert_Hooke.jpg
 Used early compound
http://media-2.web.britannica.com/ebmedia/68/99768-004-AF8F9553.jpg
 Robert Hooke
 Anton van
Leeuwenhoek
 Dutch janitor with
hobby of ocular
grinding (making
lenses)
 Used single-lens
microscope to look at
raindrops
 Found living organisms
https://mattwells.wikispaces.com/Biology+K
 Schleiden concluded
plants were made of
cells (1838)
 Schwann concluded
animals were made of
cells (1839)
 Virchow concluded new
cells could only be
produced from existing
cells (1855)
 Principles of Cell
Theory:
1. All living things are
composed of cells.
2. Cells are the basic
units of structure and
function in living
things.
3. New cells are
produced from
existing cells.
 The light microscope enables us to see the
overall shape and structure of a cell
Image seen by viewer
Eyepiece
Ocular
lens
Objective lens
Specimen
Condenser lens
Red blood cells
teaching.path.cam.ac.uk/partIB_pract/NHP1/
Light source
Figure 4.1A
Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings
 Invented in the 1950s
 They use a beam of
electrons instead of
light
 The greater resolving
power of electron
microscopes
• allows greater
magnification
• reveals cellular details
websemserver.materials.ox.ac.uk/cybersem/getf...
 Electron beam scans cell surface
 Used to see detailed structure of cell surface
Red blood cells
Figure 4.1B
Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings
http://commons.wikimedia.org/wiki/Image:SEM_blood_cel
ls.jpg
 Transmits electrons through specimen
 Used to examine the internal structures of a cell
Red blood cell in capillary
commons.wikimedia.org/wiki/Image:A_red_blood_...
Figure 4.1C
Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings
 Cell size is limited by
metabolic
requirements
 Lower limits:
 Enough DNA to program
metabolism
 Enough ribosomes,
enzymes, & cellular
components
 Upper limits:
 Surface area and
plasma membrane large
enough for cell volume
to allow exchange of
nutrients and wastes
All Cells:
1. Are surrounded by a cell membrane
2. At some time during their life contain DNA
 Prokaryotes
 Eukaryotes
 Smaller cells
 Larger cells
 Simpler structure
 More complex structure
 Cells do not have a
 Cells have a nucleus
nucleus
 Cells do not have
membrane bound
organelles
 Single celled organisms
 Cells have membrane
bound organelles
 Single celled
organisms—Protists
 Multicellular organisms
 Enclosed by a plasma
Prokaryotic
flagella
membrane
 Usually encased in a
rigid cell wall
• The cell wall may be
Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings
 Single cell
Ribosomes
Capsule
Cell wall
Plasma
membrane
covered by a sticky
capsule
 Inside the cell are its
DNA and other parts
Pili
Nucleoid region
(DNA)
Figure 4.4
 All other life forms are made up of one or more
eukaryotic cells
 These are larger and more complex than prokaryotic
cells
 Eukaryotes are distinguished by the presence of a true
nucleus
 Structure:
 Nuclear envelope:
double membrane
perforated with pores
 Contains most of cell’s
DNA in form of chromatin
(DNA and protein)
 Houses nucleolus
 Makes ribosomal parts
 Function:
 Control center of cell
 Directs protein synthesis
 RNA and proteins
found throughout
cytoplasm and attached
to endoplasmic
reticulum
 Function:
 Site of protein
synthesis
• Cells that are active in making proteins have lots of
ribosomes
http://people.eku.edu/ritchisong/301images/Endoplasmic_reticulum.jpg
 Structure:
 Structure:
 Channels made of
membranes
 Smooth ER
 Synthesizes lipids,
phospholipids, and steroids
 Carbohydrate metabolism
 Detoxifies drugs & poisons
 Rough ER
 Protein synthesis
 Membrane production
 Have lots of Smooth ER
 Extract many harmful
materials from the blood
and excrete them in the
bile or from the kidneys.
http://www.zoology.ubc.ca/~berger/B200sample/unit_8_protein_processing/images_unit
8/0_300_er.jpg
http://media-2.web.britannica.com/eb-media/52/116252-0049615DB80.jpg
 Structure:
 Stack of membranes
 Function:
 Modify, sort and
package proteins and
other molecules for
storage in cells or
secretion out of cells
http://cellbiology.med.unsw.edu.au/units/images/tem_golgi1.jpg
 Structure:
 Small membrane sack
filled with enzymes
 Function:
 Digestion of lipids,
carbohydrates, and
proteins
 Break down worn out
organelles
http://publications.nigms.nih.gov/insidethecell/ch1_animalcell_big.html
http://publications.nigms.nih.gov/insidethecell/images/ch1_lysosome.jpg
 Structure:
 Small membrane
sack filled with
enzymes
 Function:
 Contain enzymes for
specific metabolic
pathways; all contain
hydrogen peroxide
 Contain catalase
 2H2O2
catalase
2H2O + O2
 Structure:
 Saclike structures of
membrane
 Function:
 Store materials like
water, salts, proteins,
and carbohydrates
 Stores food for digestion
once lysosome fuses
with it
 Stores organic
compounds
 Stores inorganic ions
 May contain
pigments
 May contain poisons
 Plays role in plant
growth & elongation
 Protists may have
Nucleus
contractile vacuoles
• These pump out
excess water
Contractile
vacuoles
Figure 4.13B
Collapsing contractile vacuole of Protozoa
www.microscopy-uk.org.uk/.../vidjuna.html
Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings
 Structure:
 Enclosed by double
membrane
 Contains ribosomes
and own DNA
(maternal)
 Function:
 Responsible for Cellular
Respiration (converts
chemical energy in
glucose into chemical
energy in ATP)
 Grows and reproduces
by itself
 Structure:
 Enclosed by double
membrane
 Contains ribosomes
and own DNA
 Function:
 Site of
photosynthesis in
plants (converts solar
energy into chemical
energy in glucose)
http://www.s-cool.co.uk/assets/learn_its/alevel/biology/cells-andorganelles/organelles/chloroplast-b.gif
 Structure:
 Network of protein
filaments
 Microfilaments-made of
actin
 Microtubules-hollow
tubules made of tubulin
 Function:
 Helps maintain cell
shape
 Microfilaments
 Tough, flexible framework
that supports cell
 Cell movement-assembly
and disassembly for
cytoplasmic movement
 Microtubules
 Form mitotic spindle for
separating
chromosomes
 Form cilia and flagella
for cell movement
Amoeba
http://plantphys.info/organismal/lechtml/images/amoeba.jpg