Cells
Basic units of
Life.
Cells—Structure and Function
B2.4 g
-- Explain that some structures in the modern
eukaryotic cell developed from early
prokaryotes, such as mitochondria, and in
plants, chloroplasts.
• Prokaryotic – cells lacking a membrane bound
nucleus—ex. Bacteria
• Eukaryotic – cells having a membrane bound
nucleus among other organelles:
Cells –Structure and Function
1. A. endosymbiotic theory—proposes that
eukaryotic cells arose from living communities
formed by prokaryotic organisms.
1. B. organelles – specialized structures inside
eukaryotic cells
Cells --Structure and Function
• Relate cell parts/organelles to their function. (
B2.5i)
2. A. organelles – specialized structures inside
eukaryotic cells
Cells – Structure and Function
2.A.1. nucleus – contains cell’s DNA, control
center of cell, all cells of an organism have the
same DNA
--advantage of having DNA within a membrane=
cell can do more than one task at a time
--prokaryotes can only perform one task at a
time, i.e. make proteins, digest, or move.
Cells – Structure and Function
2.A.1. a. structures of the nucleus:
• nucleolus – dense region within nucleus, site of ribosome
synthesis
• chromatin – granular material inside nucleus, DNA bound
to protein, during cell division will form into chromosomes
• chromosomes—distinct, threadlike structures that contain
genetic material passed from one generation to the next.
• nuclear envelope—separates the nucleus from the rest of
the cell.
• nuclear pore – small openings in the nuclear envelope that
allow materials to enter and leave the nucleus.
Cells – Structure and Function
2.A.2. Ribosome – site of protein synthesis,
found in both prokaryotes and eukaryotes
2.A.3. Endoplasmic reticulum – system of
channels in which proteins (rough E.R) and lipids
(smooth E.R.) are made
2.A.4. Golgi apparatus (complex)—rearranges,
packages, and ships proteins in vesicles from the
ER for specific uses inside and outside
(secretion/exocytosis) of cell
• Fig. 5.47 Electron micrograph showing Smooth
and Rough Endoplasmic Reticulum,
Peroxisomes (P) and Mitochondria (M).
Cells – Structure and Function
2.A.5. Lysosomes – low pH and have powerful
enzymes that digest molecules
• INTERESTING FACT: lysosomes are used in tadpole
development to dissolve the tissues that make up
the tadpole tail so that the legs of the adult frog
can form
2.A.6. peroxisomes – contain enzymes that result in
the production of hydrogen peroxide, which will be
turned into water and oxygen, used to break down
lipids
Cells – Structure and Function
2.A.7. vacuoles – more common in plants than
animals used for water, sugar, and salt storage
Cells – Structure and Function
2.A.8. chloroplasts – thought to have come from
endosymbiosis of photosynthetic bacteria within
another bacterial cell
-- site of photosynthesis in plants and some
algae
-- capture energy from the sun and convert
water and carbon dioxide into high energy
sugars and oxygen
Cells – Structure and Function
2.A. 9. mitochondria – thought to have come
from endosymbiosis of energy producing
bacteria within another bacterial cell
-- site of cellular respiration in all eukaryotic
organisms
--powerhouse of cell – convert glucose and
oxygen into ATP, water, and carbon dioxide
2.B. other cell structures that are not organelles:
2.B.1. cytoskeleton – network of tubules and filaments
that give cell its structure and assist in movement
2.B.2. centrioles – tubules that assist chromosome
movement during cell division
2.B.3. cilia and flagella – structures that aid in the
movement of the cell.
2.B.4. cytoplasm – gel that fills the cell, allows for
materials to diffuse from one side of cell to other
2.B.5. plasma membrane – separates the cell from the
environment
Plant Vs. Animal Cells
3. Compare and contrast plant and animal cells.
( B2.5g)
**Compare and contrast the organelles found in
plant and animal cells.
**Make a three dimensional model of a typical
plant or animal cell. Include all of the structures
listed above.
**Write an analogy that describes each
organelle or cell structure as a part of a factory.
Structure
Animal Cell
Plant Cell
Nucleus
X
X
Ribosomes
X
X
Endoplasmic reticulum (rough and smooth)
X
X
Cytoplasm
X
X
Microtubule
X
X
Central vacuole
X
Peroxisome
X
X
Mitochondrion
X
X
Chloroplast
Plasma membrane (cell membrane)
X
X
Cell wall
X
X
Golgi Apparatus
X
Centriole
X
Cilia and Flagella
X
X
X
Endosymbiotic Theory
4. Explain that some structures in the modern
eukaryotic cell developed from early
prokaryotes, such as mitochondria, and in
plants, chloroplasts (B2.4 g ).
• Prokaryotic – cells lacking a membrane bound
nucleus—ex. Bacteria
• Eukaryotic – cells having a membrane bound
nucleus among other organelles:
Endosymbiotic Theory
4. A. endosymbiotic theory—proposes that
eukaryotic cells arose from living communities
formed by prokaryotic organisms.
B2.4 g
4.B. organelles – specialized
structures inside
eukaryotic cells
Cell Membrane
5. Explain the role of cell membranes as a highly
selective barrier (diffusion, osmosis, and active
transport). ( B2.5h)
5.A. cell membrane – flexible barrier that
surrounds cell
• Controls what enters and leaves the cell
Cell Membrane
5.B. Bilipid layer – two layered sheet
5.B.1. Flexible yet strong
5.B.2. Mosaic – different pieces sitting side by side to
form a larger structure
• Phospholipid – hydrophobic tails and hydrophilic heads
(main component)
• Proteins – often act as channels for substances to enter and
leave cell
– Cell recognition
– Enzyme excretion
• Carbohydrate chain – identification marker for the cell
• Cholesterol – helps strengthen membrane
Cell Membrane
**Make a model of a typical animal cell that
demonstrates cell membrane structures.
--include a description of each structure and a
key on a separate sheet of paper
Cell Membrane
5.B.3. Selectively permeable – some substances
can move across the membrane others cannot
5.B.4. Transport – moving material across the
cell membrane
5.B.4.a. Passive – no energy required
http://www.northland.cc.mn.us/biology/biolo
gy1111/animations/passive1.swf
Cell Membrane
• Diffusion – random movement of particles
from high concentration to low concentration
– Solution: a mixture of solvent and solute
» Solute – dissolved material
» Solvent – material that does the dissolving (usually water
for living things)
– Concentration gradient – molecules move from high to low
concentration
» Oxygen – into cell
» Carbon dioxide – out of cell
Cell Membrane
•
Osmosis: diffusion of water across a selectively permeable membrane—high
concentration to low concentration
– Isotonic solution – solute concentration equal on both inside and
outside of cell when cell is placed in solution
» No net movement of water in or out of cell
» Cells have a .9% NaCl solution so IV bags have a .9% NaCl
solution
– Hypertonic solution – solution outside the cell has a higher
concentration of solutes than the cell
» Water moves out of the cell
» Fresh water fish in salt water
» Cell shrinks – crenates
– Hypotonic solution – solution outside the cell has a lower
concentration of solutes than the cell
» Water enters the cell
» Salt water fish in fresh water
» Cell swells – causes turgor pressure (keeps plant cells rigid)
Cell Membrane
5.B.4.b. Facilitated diffusion – movement of
particles from high concentration from high
concentration to low concentration through a
channel
– Large and charged molecules: polar molecules (glucose) and
ions (amino acids)
Cell Membrane
5.B.4.c.Active – requires energy – low
concentration to high concentration
• Against the concentration gradient
• Requires a channel and energy (ATP)
» Types:
• Exocytosis – carry macromolecules out of cell
• Endocytosis – bring macromolecules into cell
• Phagocytosis – taking large substances into cell
• Pinocytosis – liquids and small particles into cell
• http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapt
er2/animation__how_the_sodium_potassium_pu
mp_works.html
http://www.maxanim.com/physiology/Endocyto
sis%20and%20Exocytosis/Endocytosis%20and%
20Exocytosis.htm
Cell Membrane
– Sodium potassium pump:
» The same carrier protein moves sodium ions (Na+) to the
outside of cell and potassium ions (K+) to the inside of
cell
» Uses ATP to change shape of channel
» Three sodium ions are carried outward for every two
potassium ions carried inward causing the inside of the
cell to be negatively charged compared to the outside .
Cell Membrane
**Contrast movement by facilitated diffusion
with movement by active transport