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