CELL METABOLISM (finals) Flashcards
The chemical processes that occur in a cell are collectively
referred to as its
metabolism
Two kinds of chemical reactions occur in a cell’s metabolism:
- Anabolic Reactions
- Catabolic Reactions
The processing of energy by cells involves a transfer of energy through the flow of electrons
Oxidation– reduction reactions
is a chemical process in which a
substance loses electrons
Oxidation
is a chemical process in which a
substance gains electrons
Reduction
Electrons associated with hydrogen
are transferred to
electron
acceptor molecules
usually involves the removal
of a hydrogen atom and its single electron from
a compound.
oxidation
usually involves a gain of a hydrogen
atom (and thus a gain in an electron)
Reduction
The electrons are transferred to an ————- ———–, which temporarily accepts them until they move along to the next acceptor molecule
electron acceptor molecule,
The shuttling of these electrons from one
acceptor to another is known as an
electron
transport chain
3 organisms capable of photosynthesis
plants
algae
certain prokaryotes
absorbing and converting light energy from the
sun to chemical energy
photosynthesis
end products of photosynthesis are
glucose/carbohydrates
water
oxygen
which is any organic
material used as fuel
biomass
which includes wood, agricultural
wastes, and fast-growing plants, contains
chemical energy that can be traced to solar
energy captured during photosynthesis
Biomass
makes up a small portion of the
electromagnetic spectrum
Light
a vast and continuous range of electromagnetic radiations propagated through space and matter
electromagnetic spectrum
is the distance from one wave
peak to the next
wavelength
portion of vicible light in the electromagnetic spectrum
from what nm?
380 and 760 nanometers
the electromagnetic spectrum that humans can see it
visible spectrum
Light is composed of small particles, or packets,
of energy called
photons
The lowest energy state an electron possesses
is called
ground state
When an electron is raised to a higher energy level than its ground state the electron is said to be
energized
where does chlorophyll mainly lie?
mesophyll
a layer with many
air spaces and a high concentration of water
vapor
mesophyll
the pigment that
initiates photosynthesis
chlorophyll a
an accessory pigent that also participates in photosynthesis
chlorophyll b
photosynthetic pigments which are yellow and orange
carotenoids
is the main photosynthetic pigment
Chlorophyll
an instrument that measures the relative abilities of different
pigments to absorb different wavelengths of
light. The absorption spectrum of a pigment is a
plot of its absorption of different wavelengths of
light.
spectrophotometer
is a graph of the relative effectiveness of different
wavelengths of light.
An action spectrum of photosynthesis
(light of one wavelength)
monochromatic light
To obtain an action spectrum, scientists
measure the rate of ——— for leaf cells or tissues exposed to
monochromatic light
rate of photosynthesis at each
wavelength
indicates the effectiveness of various wavelengths of light in powering photosynthesis
action spectrum of photosynthesis
The principal raw materials for photosynthesis
are
water and carbon dioxide
The energy that chlorophyll molecules absorb
from sunlight is expended to split
water
The energy that chlorophyll molecules absorb
from sunlight is expended to split water, which
releases
oxygen and hydrogen
what part of chloroplast are associated in light-dependent reactions
thylakoids
carbon fixation reactions produce
carbohydrates
these reactions “fix” carbon atoms from CO2 to existing skeletons of organic molecules
Carbon fixation
reactions
have no direct requirement for light
carbon fixation
referred to as the “dark” reactions
carbon fixation
most common carbon fixation pathway
Calvin cycle
Calcin cycle is named after
Melvin Calvin
are light-harvesting units of the light-dependent reactions
Photosystems I and II
the light-dependent reactions begins when these two absorbs light
chlorophyll a or accessory pigments
Chlorophyll molecules and accessory pigment
molecules are organized with pigment-binding
proteins in thylakoid membranes into units
called
antenna complexes
it absorbs light energy and transfer it to the reaction center
antenna complex
which consists of chlorophyll molecules and proteins that participate directly in photosynthesis
reaction center
Two types of photosynthetic units are involved in photosynthesis
photosystem I and photosystem II
it contains a pair of chlorophyll a molecules with an absorption peak of P700 nm
photosystem I
this reaction center is also known as P700
photosystem I
it contains of a pair of chlorophyll a molecules with an absorption peak of 680 nm and is referred to as P680
Photosystem II
a chain of alternatively oxidized and reduced compounds that links photosystems I and II
electron transport chain
a cyclic flow of electrons through photosystem I that produces ATP
cyclic electron transport
what photosystem is not involved in cyclic electron transport
Photosystem II
it occurs by chemiosmosis
ATP synthesis
ATP synthesis occurs
by
chemiosmosis
noncyclic and cyclic electro trasport is embedded in the ——-
thylakoid membrane
these photosynthesis units are involved in noncyclic and cyclic electron transport
photosystem I and photosystem II
\
does a greater concentration of H+ in the thyakoid interior decrease or increase the pH?
decrease/lowers the pH
an enzyme complex embedded in the thylakoid membrane
ATP synthase
an enzyme that forms a channel through which the accumulated protons leaves the thylakoids
ATP synthase
as protons pass through ATP synthase, some energy is used to form
ATP from ADP and
inorganic phosphate.
The synthesis of ATP by
first producing a proton gradient
chemiosmosis
uses the
energy released during electron transport
chemiosmosis
Photorespiration reduces the
efficiency of the
C3 pathway
it reduces the
efficiency of the c3 pathway
photorespiration
these plants lose more water by
evaporation from their surfaces than the roots
replace by drawing from the soil
Water-stressed plants
tiny pores in the
leaf surfaces through which CO2 enters and O2
exits during photosynthesis.
(stomata)
Once the stomata close, photosynthesis in the
chloroplasts rapidly uses up the —– remaining in
the leaf, and the —– produced in photosynthesis
accumulates in the chloroplasts.
CO2 AND O2
Occurs during intense daylight
PHOTORESPIRATION
requires oxygen and produces CO2 and H2O.
PHOTORESPIRATION
does not produce biologically useful energy.
PHOTORESPIRATION
what kinds of plants common using the c4 pathway
plants with tropical origins
3 examples of plants with tropical origins
crabgrass
corn
sugarcane
..
Many desert plants fix carbon
using what pathway?
CAM pathway
what does CAM pathway mean?
crassulacean acid metabolism
name comes from the stonecrop plant family, the Crassulaceae
CAM pathway
it is only one of the more
than 25 plant families that possess the CAM
pathway
Crassulaceae
