Cell notes

The Cell Theory
 All organisms are composed of one or
more cells.
7.1 Cell Discovery and Theory
Cellular Structure and Function
 The cell is the basic unit of structure and
organization of organisms.
Chapter 7
 All cells come from preexisting cells.

Prokaryotic Cell
 Simple structure
 Contains a plasma
membrane
 Does not contain
membrane-bound
organelles
 No Nucleus
11,000x
Chapter 7

Eukaryotic Cell
 More complex
structure
 Contains a plasma
membrane
 Contains membrane-
bound organelles
 Has a nucleus
400x
Chapter 7

7.3 Structures and Organelles
Chapter 7

Plasma (Cell) Membrane
 Thin, flexible boundary between the
cell and its environment
7.2 The Plasma Membrane
 Allows nutrients into the cell
 Allows waste to leave the cell
 (Selectively Permeable)
Chapter 7

 The plasma membrane is composed of the
phospholipid bilayer.
 A phospholipid means:
a glycerol backbone
two fatty acid chains
a phosphate group.
Chapter 7

Fluid Mosaic Model
 The phospholipid
bilayer allows other
molecules to “float”
in the membrane.
Other Components
 Proteins
 Cholesterol
 Carbohydrates
Chapter 7

Proteins
 Transmit signals inside the cell
 Act as a support structure
 Provide pathways for larger substances to enter
and leave the cell
Chapter 7

Cholesterol
 Prevents fatty acid tails from sticking
together
Chapter 7

Carbohydrates
 Identify chemical signals
Chapter 7

Cilia
 Short, numerous
projections that look
like hairs
Flagella
 Longer and less
numerous than cilia
 Create movement
with a whiplike
motion
400x
26,367x
7.3 Structures and Organelles
Chapter 7

Passive Transport
 Movement of particles from a high to low
concentration across the membrane
without using energy
7.4 Cellular Transport
Cellular Structure and FunctionChapter 7
High
Low

Diffusion
 Movement of particles from an area of high
concentration to an area of lower
concentration
Chapter 7

 Diffusion is controlled by
 Temperature
 Pressure
 Concentration
Dynamic Equilibrium
 When diffusion of material into the cell
equals diffusion of material out of the cell
Chapter 7

Facilitated Diffusion
 Movement of materials across the
membrane from a higher to a lower
concentration by using proteins
Chapter 7

Osmosis
 Diffusion of water across a selectively
permeable membrane
Chapter 7

Blood CellPlant Cell
Isotonic Solution
 Water and dissolved substances diffuse
into and out of the cell at the same rate.
11,397x
Chapter 7

Blood Cell
Hypotonic Solution
 Solute concentration is higher inside the
cell.
 Water diffuses into the cell.
Plant Cell
13,000x
Chapter 7
 BLOWS UP the cell.

Plant Cell
Hypertonic Solution
 Solute concentration is higher outside the
cell.
 Water diffuses out of the cell.
Blood Cell
13,000x
Chapter 7
 SHRINKS the cell.

Active Transport
 Movement of particles from low to a high
concentration across the cell membrane
using energy
Chapter 7
Low
High

Endocytosis
 The cell surrounds and takes
particles into the cell
Chapter 7

Chapter 7
Exocytosis
 Secretion of material out of the
plasma membrane

 Protein pump
 Moves three Na+
ions out of the cell and
two K+
ions into the cell
 Important for nervous system impulses
for transmitting information
Chapter 7
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_the_sodium_potassium_pump_works.html

Transformation of Energy
 Energy is the ability to do work.
8.1 How Organisms Obtain Energy
Cellular Energy
 Thermodynamics is the study of the flow
and transformation of energy in the
universe.
Chapter 8

Metabolism
 All of the chemical reactions in a cell
Cellular Energy
 Photosynthesis—light energy from the Sun
is converted to chemical energy for use by
the cell
 Cellular respiration—organic molecules
are broken down to release energy for use
by the cell
Chapter 8

ATP: The Unit of Cellular Energy
 ATP releases energy
when the bond between
the second and third
phosphate groups is
broken.
Cellular EnergyChapter 8

http://www.phschool.com/science/biology_place/biocoach/photosynth/overview.html

Light and pigments
• Photosynthesis requires light and the
pigment chlorophyll
• The green pigment is the wavelength
reflected rather than absorbed, by plants
the most – so plants are green and other
colors are absorbed

Overview of Photosynthesis
 Photosynthesis occurs in 2 phases:
Cellular Energy
1. Light-dependent reactions (thylakoid)
2. Light-independent reactions/
Calvin Cycle (stroma)
8.2 Photosynthesis
Chapter 8

Phase One: Light Reactions
 The absorption of light is the first step in
photosynthesis.
Cellular Energy
 Chloroplasts capture light energy.
8.2 Photosynthesis
Chapter 8

Reactions of Photosynthesis
Light dependent reactions
• Grana are stacks of thylakoids in the
chloroplast that contain the chlorophyll
which captures sunlight
• Light dependent reactions take place in
the thylakoids

Cellular Energy
8.2 Photosynthesis
Phase Two: The Calvin Cycle (Light-Independent)
 In the second
phase is the
Calvin cycle,
energy is
stored in
organic
molecules such
as glucose.
Chapter 8

Light independent reactions
The Calvin Cycle
• The Calvin cycle or light independent reactions
take place in the stroma of chloroplast
• Uses ATP and NADPH from light dep. Reactions
to produce high energy sugars

http://www.biology.ualberta.ca/facilities/multimedia/uploads/alberta/Photo.html
http://www.pbs.org/wgbh/nova/nature/photosynthesis.html

Overview of Cellular Respiration
 the chemical bonds of glucose are broken
down in the presence of oxygen and
produce energy.
8.3 Cellular Respiration
Cellular EnergyChapter 8
(Glucose) + (oxygen)---->(carbon dioxide) + (water) + energy* (ATP)

Glucose
Glycolysis
Cytoplasm
Pyruvic
acid
Electrons carried in NADH
Krebs
Cycle
Electrons
carried in
NADH and
FADH2 Electron
Transport
Chain
Mitochondrion
Overview of Cellular Respiration
Mitochondrion

Cellular Energy
 Cellular respiration occurs in 3 parts.
 Glycolysis
 Kreb’s Cycle
Chapter 8
 Electron Transport Chain

Step 1: Glycolysis
 Takes 2 ATP to start
 Glucose is broken down in the cytoplasm by
glycolysis (splitting glucose).
 Occurs in the cytoplasm
 Forms 2 pyruvate from 1 glucose
Cellular Energy
 2 molecules of ATP and 2 molecules of NADH
are formed for each molecule of glucose that is
broken down.
Chapter 8

Step 2: Krebs Cycle
Cellular Energy
 The series of reactions in which pyruvate is
broken down into carbon dioxide
 Occurs in the mitochondria
Chapter 8

Cellular Energy
 The net yield from
the Krebs cycle is:
6 CO2 molecules
2 ATP
8 NADH
2 FADH2.
Chapter 8

Cellular Energy
Step 3: Electron Transport
 Final step in the breakdown of glucose
 Point at which most ATP is produced
 Produces 24-32 ATP
Chapter 8

Summary FlowchartSection 9-2
Glucose
(C6H1206)
+
Oxygen
(02)
Glycolysis
Krebs
Cycle
Electron
Transport
Chain
Carbon
Dioxide
(CO2)
+
Water
(H2O)
Cellular Respiration

Glucose
Glycolysis Krebs
cycle
Electron
transport
Fermentation
(without oxygen)
Alcohol or
lactic acid
Chemical PathwaysSection 9-1

Cellular Energy
Anaerobic Respiration
 The anaerobic pathway after glycolysis
 Two main types:
 Lactic acid fermentation (muscles)
 Alcohol fermentation (yeast & molds)

Fermentation
• A process in the absence of oxygen (anaerobic)
• Lactic acid fermentation – Occurs when body
can’t supply enough oxygen to the muscles
during exercise = soreness, burning, fatigue

Cell Tour
http://vcell.ndsu.nodak.edu/animations/flythr
ough/movie-flash.htm

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