Photosynthesis and Cellular Respiration – General Biology 1 (2nd Grading)

Question-and-answer flashcards covering key terms and processes related to photosynthesis, cellular respiration, and associated cellular structures.

What is hydrolysis?

The process of breaking down bonds between phosphate groups (or other bonds) using water.

What is phosphorylation?

A biochemical process that involves the addition of a phosphate group to an organic compound.

What molecule is known as the energy currency of the cell?

Adenosine triphosphate (ATP).

Define chromatography.

A separation technique used to identify components of mixtures based on structural or compositional differences.

What are pigments?

Substances that absorb visible light; different pigments absorb light of different wavelengths.

What is photoexcitation?

Production of an excited state in a quantum system by photon absorption.

Where is chlorophyll located and which wavelengths does it absorb most?

In the thylakoid membrane of chloroplasts; it absorbs blue and red light and reflects/transmits green.

Name the pigment group abundant in purple grapes and berries.

Anthocyanins.

Which plant pigments give yellow, bright red, and orange colors?

Carotenoids.

What pigments are common in orange- and yellow-colored produce like pumpkins and carrots?

Xanthophylls.

Define a photosystem.

An aggregate of pigments and proteins in the thylakoid membrane that absorbs photons and transfers energy/electrons.

What is the light-harvesting (antenna) complex?

A group of pigments (chlorophyll a, chlorophyll b, carotenoids) that capture light and pass energy to the reaction center.

What composes the reaction-center complex?

A pair of chlorophyll a molecules and a primary electron acceptor.

Which photosystem acts first in the light reactions and what special chlorophyll does it contain?

Photosystem II; it contains P680 chlorophyll a.

Which photosystem was discovered first and what wavelength does its reaction center absorb best?

Photosystem I; its P700 chlorophyll a absorbs light at ~700 nm.

List the three main types of cellular work.

Chemical work, mechanical work, and transport work.

Give an example of chemical work in the cell.

Synthesis of polymers from monomers.

Give an example of mechanical work in the cell.

Beating of cilia or muscle contraction.

Give an example of transport work in the cell.

Pumping substances across membranes against their concentration gradient.

What is the function of the chloroplast outer membrane?

Compartmentalizes the chloroplast from the rest of the cell.

Why are grana (stacks of thylakoids) advantageous?

They maximize light absorption.

Why is the thylakoid space narrow?

To quickly build up a proton gradient.

Where does the Calvin cycle occur, and what does this compartment contain?

In the stroma of the chloroplast; it contains enzymes for carbon fixation.

State two key outcomes of the light reactions.

Formation of ATP via phosphorylation and production of NADPH while releasing O₂.

Describe non-cyclic electron flow.

Electrons are removed from water and pass through Photosystem II and Photosystem I before ending in NADPH.

Describe cyclic electron flow.

Electrons from Photosystem I are recycled back to the electron transport chain around PSI without producing NADPH.

What three molecules does the Calvin cycle return to the light reactions?

ADP, inorganic phosphate (Pi), and NADP⁺.

What does ATP stand for?

Adenosine triphosphate.

What does ADP stand for?

Adenosine diphosphate.

What does NADH stand for?

Nicotinamide adenine dinucleotide (reduced form).

What does FADH₂ stand for?

Flavin adenine dinucleotide (reduced form).

Define cellular respiration in simple terms.

The process by which cells convert sugars and other fuels into ATP, releasing waste products.

What is aerobic respiration?

Metabolic reactions that use oxygen to convert chemical energy into ATP.

What is anaerobic respiration?

Energy-producing cellular respiration that occurs without oxygen.

Summarize glycolysis.

Breaks one glucose into two pyruvate molecules, yielding 2 ATP and 2 NADH.

Per two pyruvate, what are the major products of the Krebs cycle?

4 CO₂, 6 NADH, 2 FADH₂, and 2 ATP.

What happens in the electron transport chain?

Electrons from NADH and FADH₂ pass through proteins, ultimately reducing O₂ to water and driving ATP formation.

Name the foldings of the inner mitochondrial membrane and their advantage.

Cristae; they increase surface area for reactions.

What is found in the mitochondrial matrix and what key cycle occurs there?

Ribosomes, DNA, and enzymes; the Krebs (citric acid) cycle occurs there.

Define chemiosmosis.

Movement of ions across a semipermeable membrane down their electrochemical gradient to drive ATP synthesis.

What does ATP synthase do?

Uses energy from H⁺ flow to bind ADP and Pi, producing large amounts of ATP.

What is the end product of alcoholic fermentation?

Ethanol (and CO₂) formation, common in fungi and plants.

What is the end product of lactic acid fermentation?

Lactic acid, occurring in mammalian muscles and some bacteria.

Which molecules enter the electron transport chain to yield about 34 ATP?

NADH, FADH₂, and O₂.