Cellular Structure and Function
Plant Cell Structures and Organelles
Cellular Energy
How Organisms Obtain Energy
Transformation of Energy
 Energy is the ability to do work.
 Metabolism is all of the chemical reactions in a
cell
 Photosynthesis—light energy from the Sun is
converted to chemical energy for use by the
cell
Cellular Energy
How Organisms Obtain Energy
ATP: The Unit of Cellular Energy
 ATP (adenosine
triphosphate) releases
energy when the bonds
are broken.
 Heterotroph and
Autotroph both use for
energy
Cellular Energy
Photosynthesis
Overview of Photosynthesis
 Photosynthesis requires light and the pigment
chlorophyll
 Photosynthesis occurs in two phases.
 Light-dependent reactions
 Light-independent reactions
Cellular Energy
Photosynthesis
Phase One: Light Reactions
 The absorption of light is the first step in
photosynthesis.
 Water is split into Hydrogen and Oxygen
 In the chloroplasts the chlorophyll captures light
energy.
Cellular Energy
Photosynthesis
Phase One: Light Reactions
 Occurs inside thylakoid membrane
 Converts ADP to ATP
 Oxygen is given off by plant
Energy storing components
 NADP+ and ATP
Chapter 8
Cellular Energy
8.2 Photosynthesis
Phase Two: The Calvin Cycle (Light-Independent)
 In the second
phase of
photosynthesis,
energy is stored
in organic
molecules such
as glucose.
Chapter 8
Cellular Energy
8.2 Photosynthesis
Phase Two: The Calvin Cycle (Light-Independent)
 The thylakoid
membrane is the
key to energy
transfer
 Process called
electron transport
drives the
production of
energy
 Hydrogen moves
from thylakoid into
the stroma.
Chapter 8
Cellular Energy
8.2 Photosynthesis
Phase Two: The Calvin Cycle (Light-Independent)
 Process called electron
transport drives the
production of energy
Plant Leaves
• Stomata surrounded by guard cells that allow
flow of gases and water
• Palisade mesophyll contains the chloroplasts
for photosynthesis
• Spongy mesophyll contains the vascular tissue
of the plant that transport water & nutrients
Plant Leaf Stomata & Guard Cells
Cell Membrane
•
•
•
•
Lipid bilayer
Regulates what enters and leaves the cell
Composed of lipids and membrane proteins
Communicates with the outside environment
Plant Cell Wall
• Rigid layer that lies outside the cell’s
membrane
• Consists of a carbohydrate called cellulose
Chloroplast
• Photosynthesis occurs in this organelle
• Contains stacks of thylakoids that house
photosynthesis reactions
• Stroma is the fluid that fills the chloroplast and
surrounds the thylakoids
• Contains pigment chlorophyll
Central Vacuole
• Large area used to store enzymes, water,
waste, and other materials
• Also can be used to store toxins and pigments
Nucleus
• Controls most functions of the cell
• Stores plans for all proteins and genetic material
as chromosomes
• Surrounded by a nuclear envelope
– Nuclear envelope contains pores that act as a
passage way out of the nucleus
Cytoplasm
• Jello-like material inside cell
• Includes everything between the cell
membrane and nucleus
Mitochondria
• The mighty mitochondria!
• Generate energy that powers all of the cell’s
activities
Endoplasmic Reticulum (ER)
• Consists of tubes and sacs that ship molecules
from one part of the cell to another
Golgi Apparatus
• Like the ER, consists of a series of sacs
• Receives newly made proteins & lipids
• The golgi packages each product and
addresses it to where it needs to go
Ribosome
• Small, roughly spherical organelle
• Made up 2 subunits
• Reads the DNA plans and assembles proteins
needed inside and outside the cell