UNIT 3 Flashcards
The process that converts solar energy into
chemical energ
Photosythasisi
interior tissue of the leaf and the
location of the chloroplasts
Mesophyll
are photosynthetic organs of plants
Leaves
organelles
in which photosynthesis occurs
Chloroplast
Photosynthesis is a
redox
6 CO2 + 12 H2O + Light energy C6H12O6 + 6 O2 + 6 H2O
Phtosythasis
Entire range of wavelengths produced is called the
ELECTROMAGNETIC SPECTRUM
main photosynthetic
pigmen
Chlropghyll a
Chlorophyll b and Carotenoid
are
Accessory Pigments
capturing energy
– Chlorophyll absorbs light and the energy is
captured
light reactions
Synthesis of sugar
– The captured energy is used for endergonic
reactions.
– Remember: synthesis is work and requires ATP
Calvin Cycle
in the thylakoids
Light Reactions
Split H2O
– Release O2
– Reduce NADP+ to NADPH
– Generate ATP from ADP by photophosphorylatio
Light Reactions
(in the stroma)
Calvin Cycle
with carbon fixation, adding inorganic CO2
to make an organic molecule
– Endergonic process, requires the energy captured earlier
Calvin Cycle
Occur in the grana
– (stacks of thylakoids
Light Reactions
a reaction center (a type
of protein complex
Part 1 of a Photosystem
ght-harvesting
complexes (pigment
molecules bound to
proteins) that transfer the
energy of photons to the
reaction center
Part 2 of a photosytem
Chlorophyll molecules
are bound to
particular proteins
light-harvesting complexes
funnel the
energy of photons
(units of light) to the
reaction cente
Light harvesting Complexes
One of its electrons
gets bumped up to a
primary electron
acceptor
1st STEP oif light reactions
the reactions center loses an electron and
the primary acceptor receives it, an enzyme
splits water to provide a replacement electro
Part 2 of light reactions
Electron from water replaces the one
handed to primary electron acceptor
– Oxygen atoms combine, O2 given of
Partt 3
Electron passed from Primary Acceptor
to a Transport chain
– ATP generated (via chemiosmosis
Part 4
functions first (the numbers
reflect order of discovery)
Photosyetem 11
best at absorbing a
wavelength of 680 nm
Photosystems 2
is best at absorbing a
wavelength of 700 nm and is called P700
Photosytem 1
primary pathway of energy transformation
in the light reactions
Non-cyclic or Linear Electron flow
photo-excited electrons
take an alternative path
Cyclic electric flow
Only ATP is produced (no NADPH, no release
of O2
Cyclic Electric Flow
Forms sugar from
carbon dioxide
– uses ATP for energy
– and NADPH for
reducing power
Calvin Cycle
uses ATP and NADPH to convert
CO2 to sugar
Calvin Cycle
Carbon fixation
– Reduction (of CO2)
– Regeneration of the CO2 accepto
Calvin Cycle
CO2 fixed by RUBISCO
– RuBP carboxylase
Calvin Cycle
t captures inorganic carbon (CO2 fixation)
– Only an autotroph can fix carbon and make organics
RUBISCO
is a function of
capillary action and evaporation
Transpiration
This conserves water but limits access to CO2
– Oxygen builds up and substitutes for CO2
* Rubisco binds to O2 instead of CO
hot, dry days, plants close their stomata
Photorespiration is the negative result
– Rate of photosynthesis is reduced
– Releases CO2 and consumes ATP
* Opposite goal of photosynthesis, less efficient
Closing stomata
move CO2 to cells deep in leaf (away from O2)
* Spatial solution to prevent photorespiration
C4 plants
pre-collect CO2 (when stomata are open at night)
* Temporal solution to prevent loss of water and photorespiration
CAM
Fix CO2 using different enzyme with less affinity
for oxygen, but then
C4
Fix CO2 when water loss is not a problem:
at night when stomata are open
CAM
A cell’s endowment of DNA
is called its
Genome
DNA molecules in cells are packaged
into
Chromosomes
Eukaryotic chromosomes are in the form of
Chromatinm
The process by which chromosomes
(DNA molecules) are copied is called
DNA replication
Chromatin condenses during
Cell Division
Chromatids are separated during cell
division
the phase during which the
cell is NOT dividing
Interphase
the phase during which the
cell is NOT dividing
Mitosis
Interphase (3 sub-phases) - Initial growth of the newly formed cell and
general metabolism
G1
Interphase (3 sub-phases) - DNA is replicated (synthesized) during this
phase
S phase
Interphase (3 sub-phases) - Final preparations for cell division
* Centrosomes divide
* Tubulin synthesis
G2
Chromatin condenses,
becomes visible
– (sister chromatids formed during
interphase)
* Mitotic spindle is formed
* Nucleolus disappears
* Nuclear envelope breaks down
Prophase
spindle arises
from the
Centrioles
Attach to the
kinetochores of
chromosomes
– Kinetochore is a protein
attached to the
centromere region
– Sister chromatid
attached from each side
prometaphase
Chromosomes are
moved and
aligned along the
‘equatorial plate
Metaphase
Centromere connection
released
* Sister chromatids
separate
* Chromosomes move
toward opposite ends of
the cell
Anaphase
Daughter nuclei
reform
– Nuclear envelope
reassembles
– Nucleolus reforms
– Chromosomes uncoils
and relaxes into
chromatin
* Cytokinesis occurs
Telophase
Prokaryotes (bacteria) reproduce
by a type of cell division called
Binary Fission
cell cycle is regulated by a
Molecular control system
Cell “decides” to divide.
* Primary point for external signal
influence
G1 /s checkpoint
Cell makes a commitment to mitosis.
* Assesses success of DNA replication
G2/ M checkpoint
Cell ensures that all chromosomes are
attached to the spindle.
Spindle checkpoint
Cyclins and
2. Cyclin-dependent Kinases (Cdks)
Regulatory protiens
enzymes that activate or
inactivate other proteins (by
phosphorylating them
Kinases
Dependent on CYCLIN to become active
Cyclin dependedn kinases
Proteins that fluctuate in concentration
– Accumulates during S and G2 phases
Cylcin
Active comples formed calledd MPF
Chemicals released by certain cells to stimulate
other cells to divide
– One type is released from platelets in blood
when tissue is damaged
* Cells in vicinity stimulated to divide
* Promotes healing of damaged t
Growth Factors
is a process by which a healthy cell
becomes a cancer cel
Transformation
Localized, non-invasive growth
Benign
Invasive, grows into surrounding tissues
Malignant
Malignant tumors invade surrounding
tissues and can metastasize
Cancer
usually
continue to divide well beyond a
single layer, forming a clump of
overlapping cells.
(b)
Cell mass similar
to tumor
Cancer Cells
