Year 11 ATAR Biology - Cellular Processes Revision (Photosynthesis & Cellular Respiration)

A comprehensive set of practice flashcards covering photosynthesis, cellular respiration, and experimental design based on the provided lecture notes.

What is the purpose of photosynthesis?

A series of chemical reactions by which plants use light energy captured by chloroplasts to convert carbon dioxide and water into oxygen and glucose, with each step catalysed by enzymes.

What is the balanced chemical equation for photosynthesis?

6 CO2 + 6 H2O → C6H12O6 + 6 O2.

Where does the light-dependent stage occur?

On and across the thylakoid membranes of the chloroplast.

What happens to light energy during the light-dependent stage?

It is absorbed by pigments, energising electrons; it splits water into hydrogen ions (as NADPH) and oxygen gas, and ATP is formed.

What pigments are involved in photosynthesis in green plants?

Chlorophylls, carotenoids, and xanthophylls.

What wavelengths does chlorophyll absorb and what color does it reflect?

Absorbs blue and red light; reflects green light.

What are accessory pigments and what colors do they reflect?

Carotenoids reflect orange; xanthophylls reflect yellow (and both absorb blue-violet light).

Where does the light-independent stage take place and what are its inputs and outputs?

Occurs in the stroma; uses CO2, NADPH, and ATP from the light-dependent stage to produce glucose (C6H12O6) and polymers like sucrose, starch, and cellulose.

What limiting factors affect photosynthesis?

Light intensity, temperature, and carbon dioxide concentration.

How does light intensity affect the rate of photosynthesis?

Increases the rate with more light until another factor becomes limiting; the graph shows a steep rise at low light and then a plateau.

What is the typical optimum temperature range for photosynthesis in many plants?

About 25–35°C.

How does CO2 concentration affect the rate of photosynthesis?

Increasing CO2 raises the rate until another factor becomes limiting; the graph shows rapid increase at low CO2 then plateaus.

What is cellular respiration and where does it occur?

A biochemical process that metabolises glucose to release usable energy as ATP; occurs in the cytosol and mitochondria.

What is the balanced chemical equation for cellular respiration?

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ATP.

What are the main stages of cellular respiration listed in the notes?

Glycolysis, Citric Acid Cycle, and Electron Transport Chain (and anaerobic respiration as an alternative in the absence of oxygen).

Where does glycolysis occur and what is its net ATP yield?

In the cytoplasm; net gain of 2 ATP and production of 2 NADH.

What are the products and location of the Citric Acid Cycle per pyruvate?

Produces 3 NADH and 1 FADH2 and releases 2 CO2; located in the matrix of the mitochondria; yield listed as 2 ATP, 6 NADH and 2 FADH2.

Where does the Electron Transport Chain occur and what is its role?

On the cristae of the mitochondria; NADH and FADH2 donate electrons to drive ATP synthesis; oxygen is the terminal electron acceptor and water is formed.

What is anaerobic respiration and where does it occur in eukaryotes?

A form of respiration in the absence of oxygen, occurring in the cytosol; two forms: Alcohol Fermentation and Lactic Acid Fermentation.

Describe Alcohol Fermentation.

Glucose → ethanol + carbon dioxide + 2 ATP; occurs in plants, yeast, and bacteria.

Describe Lactic Acid Fermentation.

Glucose → lactic acid + 2 ATP; occurs in animals.

What is independent variable vs dependent variable in experimental design?

Independent variable is the factor changed by the experimenter; dependent variable is the factor measured.

What are control variables?

Factors kept the same throughout the experiment to ensure a fair test.

What does validity mean in experimental design?

The method fairly tests the hypothesis by controlling variables, using proper equipment, and repeating the experiment enough times to avoid random results.

What does accuracy mean in experimental results?

How close results are to the correct or expected value; assessed with percent error.

What does reliability mean in experimental results?

The consistency of results when the experiment is repeated under the same conditions.

What is a hypothesis design?

An if…then… statement that includes both the independent and dependent variables to predict outcomes.

How are Photosynthesis and Respiration related according to the notes?

They are interdependent processes: photosynthesis provides glucose and oxygen for respiration, while respiration provides CO2 and H2O used in photosynthesis.