Biology 103 Final
What is the process by which light energy is converted into the stored chemical energy of organic molecules?
Photosynthesis
Which photosynthetic unit consists of a pair of chlorophyll a molecules with an absorption peak of 700 nm?
Photosystem I
Which part of the chlorophyll molecule is responsible for absorbing light?
Porphyrin ring
Which list describes the correct sequence of events involved in cell signaling?
Signal transmission, reception, signal transduction, response
The region of the enzyme molecule that interacts with a substrate is called the ______.
active site
Some enzymes have a receptor site that is other than the active site. This is also referred to as a(n) ____ site.
allosteric
Select the phosphorylation reaction. a. Glucose + fructose → sucrose + H2O b. Glucose + ATP → glucose-P + ADP c. Glucose-P + fructose → sucrose + Pi d. Glucose + glucose → maltose e. Sucrose + H2O → glucose + fructose
b. Glucose + ATP → glucose-P + ADP
Land plants, algae, and certain prokaryotes are known as _______.
photoautotrophs
Substances that absorb visible light are called:
pigments
The process of receiving an incoming signal is known as _______.
reception
What refers to the alteration of an enzyme's shape due to binding of substrate?
Induced fit
What type of protein can transduce a signal in two directions?
Integrins
Which class of enzyme can catalyze the conversion of a molecule from one isomeric form to another?
Isomerases
As you climb a flight of stairs, what type of energy are your legs in motion using?
Kinetic Energy
Which refers to an organic, non-polypeptide compound that binds to the apoenzyme and serves as a cofactor?
coenzyme
What is the ultimate source of electrons for noncyclic electron transport, and thus photosynthesis?
water
Enzyme names are usually derived from the name of its substrate followed by which suffix?
-ase
How many electrons are needed to reduce one molecule of NADP+ to NADPH?
2 electrons
Overall reactions of photosynthesis:
6CO2 + 12H2O → C6H12O6 + 6O2 + 6H2O
What is typically the result of receptor upregulation?
A hormone's signal is amplified.
Thylakoid membranes are involved in ____ synthesis.
ATP
What happens in the second phase of the Calvin cycle?
ATP and NADPH are used to convert the PGA molecules to glyceraldehyde-3-phosphate
How are chlorophyll molecules attached to thylakoid membranes?
By a long hydrocarbon side chain
During photosynthesis, ____ is reduced and ____ is oxidized.
CO2 ; H2O
Which of the following are accessory photosynthetic pigments that expand the spectrum of light to provide energy for photosynthesis?
Carotenoids and chlorophyll b
Where are hormones produced in animals?
Endocrine glands
Why are enzymes considered important biological catalysts?
Enzymes lower the activation energy of a biochemical reaction
The reaction ATP + H2O → ADP + Pi is classified as an
Exergonic reaction
The hydrolysis of GTP to GDP deactivates the ____.
G protein
Which type of electromagnetic waves has the shortest wavelength?
Gamma waves
A group of thylakoid discs make up what part of the chloroplast?
Granum
Which local regulator is stored in cells of the immune system and released during an allergic reaction?
Histamine
What are the two phases of photosynthesis?
Light-dependent reactions and carbon fixation reactions
What transmits information electrically and chemically?
Neurons
What type of chemical compound diffuses across synapses?
Neurotransmitters
Select the hydrogen acceptor molecule that stores electrons in the process of photosynthesis.
Nicotinamide adenine dinucleotide phosphate (NADP+)
Which statement about G protein is false?
One subunit binds ATP.
Which chemical process occurs in which a substance loses electrons?
Oxidation
Which process not only yields electrons that replenish photosystems I and II, but also is the source of almost all Earth's oxygen in the atmosphere?
Photolysis
The energy of a(n) ____ is inversely proportional to its wavelength.
Photon
What type of cells must receive, relay, and respond to the information signaled?
Target cells
Under which of the following situations would receptor downregulation most likely occur?
The concentration of a hormone is too high
What would happen if you were to increase the temperature in an enzyme-catalyzed reaction?
The rate of reaction will increase and then decrease rapidly.
What is the ultimate source of energy for almost all living organisms?
The sun
Which statement about receptors is false?
They are also called ligands.
Where is the electron transport chain of photosynthesis located?
Thylakoid membrane
Chlorophyll and accessory photosynthetic pigments are associated with which part of the chloroplast?
Thyrakoid membranes
Most intracellular receptors are what type of protein?
Transcription factors
How are hormones produced by endocrine glands typically transported to target cells?
by blood
What is the function of the oxidoreductases?
catalyze oxidation-reduction reactions
ATP synthesis during the light-dependent reactions occurs by which process?
chemiosmosis
Animals, fungi, and most prokaryotes are known as ___.
chemoheterotrophs
Which of these absorbs light primarily in the blue and red regions of the visible spectrum and is the main pigment of photosynthesis?
chlorophyll
The action spectrum of photosynthesis best matches the absorption spectrum of
chlorophylls a and b
During enzyme-linked reception, signal molecules bind to two tyrosine kinase receptors. The receptor proteins move closer together in the plasma membrane and pair, forming a(n) ____.
dimer
Which best describes the energy of activation?
energy required to break existing bonds
What color does chlorophyll reflect?
green
ATP is formed when __________ the thylakoid lumen.
hydrogen ions leave
Many bacterial infections are treated with drugs, such as penicillin and sulpha drugs, that ____ the bacteria's enzyme activity.
inhibit
Typically, the gate of an ion channel remains closed until a(n) ____ binds to the receptor.
ligand
During which phase of photosynthesis is ATP and NADPH synthesized?
light-dependent phase
An electron absorbs a photon of light energy and becomes energized; the electron shifts from a ____ atomic orbital to a __________ atomic orbital.
lower energy ; higher energy
A chlorophyll molecule has a porphyrin ring containing a single atom of:
magnesium
The outer part of a G protein-linked receptor binds to a(n) ____, and its inner part binds to a(n) ____.
signaling molecule ; G protein
How is paracrine signaling different from other types of signaling?
signaling molecules are diffused through interstitial fluid and act on nearby cells
In which part of the chloroplast do the carbon fixation reactions take place?
stroma
What is the fluid-filled sac within the inner membrane of a chloroplast called?
stroma
Which is a major group of enzyme-linked receptors?
tyrosine kinases