Grade 11 Biology: Cell Transport, Photosynthesis, and Cellular Respiration

Flashcards testing knowledge on cell transport mechanisms, photosynthesis stages and step-by-step pathways, and cellular respiration stages based on Grade 11 Biology material.

What is cellular transport and why is it important for cells?

Cellular transport is the cell's traffic system describing how substances like water, nutrients, gases, and wastes move across the selectively permeable plasma membrane to maintain internal balance (homeostasis) and support life.

How do passive transport and active transport differ in terms of energy requirement and direction of movement?

Passive transport requires zero ATP and moves substances down a concentration gradient from high to low concentration. Active transport requires energy (ATP) to move substances against a concentration gradient from low to high concentration.

What defines simple diffusion and what are two examples of molecules that use it?

Simple diffusion is the passive movement of tiny, uncharged molecules directly through the lipid membrane without using cellular energy (ATP). Examples include oxygen ($O_2$) and carbon dioxide ($CO_2$).

What occurs to a cell when placed in isotonic, hypotonic, and hypertonic solutions during osmosis?

In an isotonic solution, solute concentration is equal inside and outside. In a hypotonic solution, the outside has fewer solutes, causing water to rush in and the cell to swell. In a hypertonic solution, the outside has more solutes, causing water to rush out and the cell to shrink.

How does facilitated diffusion function across the cell membrane?

Facilitated diffusion passively moves larger or charged molecules (such as sugar or ions) down their concentration gradient through special membrane proteins, such as protein channels or carrier proteins, without expending ATP.

What are the three main types of endocytosis?

The three types are Phagocytosis ("cell eating" of large particles or other cells), Pinocytosis ("cell drinking" of extracellular fluid), and Receptor-mediated endocytosis (using plasma membrane receptor proteins with specific binding affinity).

How do membrane protein disruptions relate to Cystic Fibrosis, Diabetes, and Cancer?

In Cystic Fibrosis, mutations cause a faulty CFTR membrane protein that disrupts ion transport and fluid balance. In Diabetes, insulin resistance impairs glucose transport into cells. In Cancer, faulty membrane signals and receptors constantly send "grow" messages leading to uncontrolled growth.

What is the key difference between catabolism and anabolism?

Catabolism is the breakdown of complex molecules into simpler ones to release energy (big to small, e.g., cellular respiration), whereas anabolism consumes energy to build complex molecules from simpler precursors (small to big, e.g., photosynthesis).

What three fundamental things do all cells require to survive?

1. Energy (sunlight for autotrophs, glucose for heterotrophs); 2. Nutrients (inorganic materials to build parts and enzymes); 3. Waste Removal (eliminating metabolic byproducts so they do not poison the cell).

What is the overall balanced chemical equation for photosynthesis?

$$6CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2$$

Where do the light-dependent reactions of photosynthesis occur, and what are their primary goals?

They take place in the thylakoid membranes of chloroplasts to convert sunlight into chemical energy stored in ATP and NADPH, releasing oxygen ($O_2$) as a byproduct.

What happens during the photolysis of water in Photosystem II (PSII)?

An enzyme at PSII (P680 reaction center) splits a water molecule according to $H_2O \rightarrow 2H^+ + 2e^- + \frac{1}{2}O_2$. The electrons refill PSII, protons ($H^+$) accumulate in the thylakoid lumen, and oxygen ($O_2$) is released.

How is ATP synthesized via chemiosmosis during the light-dependent reactions?

The buildup of $H^+$ ions in the thylakoid lumen creates a proton gradient. As $H^+$ flows back into the stroma through ATP synthase, this flow powers photophosphorylation to combine ADP and inorganic phosphate (Pi) into ATP.

Where does the Calvin Cycle occur, and how many turns are needed to build one full glucose molecule?

The Calvin Cycle (light-independent reactions) occurs in the stroma of chloroplasts and requires 6 turns (incorporating 6 $CO_2$ molecules) to produce one glucose ($C_6H_{12}O_6$) molecule.

What are the three main step-by-step phases of the Calvin Cycle?

1. Carbon Fixation: RuBisCO attaches $CO_2$ to 5-carbon RuBP, splitting into 3-PGA; 2. Reduction Phase: ATP and NADPH reduce 3-PGA into high-energy 3-carbon sugar G3P; 3. Regeneration of RuBP: Remaining G3P molecules are reshaped using ATP to reform RuBP.

What is the overall chemical equation for cellular respiration?

$$C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$$

What are the location, oxygen requirement, inputs, and outputs of Glycolysis?

Glycolysis occurs in the cytoplasm (cytosol) and is anaerobic. Inputs: 1 Glucose, 2 $NAD^+$, 2 ADP + 2 Pi. Outputs: 2 Pyruvate, 2 NADH, and a net gain of 2 ATP.

What are the location and chemical outputs after two turns of the Krebs Cycle?

The Krebs Cycle occurs inside the mitochondrial matrix (aerobic). After two turns, its outputs are 6 NADH, 2 $FADH_2$, 2 GTP, and 4 $CO_2$.

Where is the Electron Transport Chain (ETC) located in eukaryotic cellular respiration, and what is the role of oxygen?

The ETC is located in the inner mitochondrial membrane. Oxygen serves as the final electron acceptor, driving chemiosmosis to produce the majority of ATP.