Untitled Flashcard Set

BIO 101 — General Biology I

Study Guide: Test 2

Membranes & Transport · Energy & Enzymes · Photosynthesis · Cellular Respiration

How to Use This Guide

This guide prepares you for Test 2, which covers membrane structure and transport, energy and

enzymes, photosynthesis, and cellular respiration, and pulls questions from your labs as well as lecture.

Work through the topics in order:

• Fill in the vocabulary tables from memory first, then check your notes and slides for anything

you missed.

• Answer each Concept Check in complete sentences. The short-answer section of the test is

graded the same way.

• Try the Misconception Checks before looking at the explanation. These target the reasoning

errors the multiple-choice section is built to catch.

• Complete the Lab Connection sections with your lab notebook open next to you.

• Practice the five diagram self-checks. The real test includes a label-the-figure section.

• Finish with the Exam-Readiness Checklist on the last page.

Test Blueprint — What to Expect

Section Format Points

I Multiple Choice (20 questions) 40

II Short Answer (6 questions) 30

III Label the Figure (2 diagrams) 15

IV Data Analysis & Application 15

Total 100

Quick tip: Topics 1–5 below match the four lecture units, with membranes split into structure and

transport. Aim for one topic per study session.

BIO 101 Test 2 Study Guide | Page 2

TOPIC 1 — Membrane Structure

Learning Objectives

• Describe the fluid mosaic model and explain what “fluid” and “mosaic” each mean.

• Explain why phospholipids are amphipathic and how they self-assemble into a bilayer.

• Explain how fatty acid saturation and cholesterol affect membrane fluidity.

• Distinguish integral (transmembrane) proteins from peripheral proteins.

• List the major functions of membrane proteins.

• Explain why membranes have distinct inside and outside faces.

• Explain why the bilayer is selectively permeable and predict which molecules cross it unaided.

Vocabulary Self-Check

Cover the right column and write each definition from memory before checking your notes.

Term Write the definition from memory:

Selective permeability

Fluid mosaic model

Amphipathic

Phospholipid bilayer

Hydrophilic

Hydrophobic

Cholesterol

Integral protein

Transmembrane protein

Peripheral protein

Glycoprotein

Lateral movement

Concept Check — Answer in complete sentences

1. Describe the arrangement of phospholipids in a bilayer and explain what drives it. Why are the tails

in the middle?

__________________________________________________________________________________

2. Explain why oxygen crosses the membrane easily but a sodium ion does not.

__________________________________________________________________________________

BIO 101 Test 2 Study Guide | Page 3

3. A cell in a cold lake and a cell in a warm pond both need fluid membranes. Explain how fatty acid

saturation and cholesterol help each cell keep its membrane at the right fluidity.

__________________________________________________________________________________

Misconception Check

Read each statement. Decide if it is scientifically accurate or a common misconception, then explain why in

one sentence.

A. “The plasma membrane is a rigid wall with holes that molecules pass through.”

Misconception? ________ Why:

__________________________________________________________________________________

B. “Phospholipids constantly flip between the inner and outer layer, which is what makes the

membrane fluid.”

Misconception? ________ Why:

__________________________________________________________________________________

C. “Cholesterol makes a membrane more fluid at every temperature.”

Misconception? ________ Why:

__________________________________________________________________________________

(Answer key: All three are misconceptions. A is false: the membrane is flexible and fluid, and lipids and many

proteins drift sideways within the bilayer. B is false: lateral movement within one layer is rapid, but flipping

between layers is rare without help from enzymes. C is false: cholesterol is a fluidity buffer. It restrains

phospholipid movement when it is warm and keeps tails from packing tightly when it is cool.)

Diagram Self-Check #1 — Plasma Membrane

Sketch a section of the plasma membrane. Label: phospholipid head, fatty acid tails, cholesterol, an

integral (transmembrane) protein, a peripheral protein, a carbohydrate chain, the cytoskeleton, the

extracellular side, and the cytoplasmic side. The test uses a figure like this.

__________________________________________________________________________________

BIO 101 Test 2 Study Guide | Page 4

TOPIC 2 — Passive & Active Transport

Learning Objectives

• Compare simple diffusion, facilitated diffusion, and osmosis.

• Define tonicity and predict what happens to animal and plant cells in hypotonic, isotonic, and

hypertonic solutions.

• Explain turgor pressure, flaccid, turgid, and plasmolyzed cells.

• Compare channel proteins and carrier proteins.

• Explain how active transport differs from passive transport, including the sodium-potassium

pump.

• Explain cotransport and how a proton or ion gradient can drive it.

• Compare exocytosis, endocytosis, phagocytosis, and receptor-mediated endocytosis.

Vocabulary Self-Check

Cover the right column and write each definition from memory before checking your notes.

Term Write the definition from memory:

Passive transport

Diffusion

Concentration gradient

Osmosis

Tonicity

Hypotonic

Isotonic

Hypertonic

Turgor pressure

Plasmolysis

Facilitated diffusion

Channel protein

Carrier protein

Active transport

Sodium-potassium pump

Cotransport

Exocytosis

Endocytosis

BIO 101 Test 2 Study Guide | Page 5

Concept Check — Answer in complete sentences

1. Compare passive and active transport. Give one example of each and state the direction of

movement relative to the gradient.

__________________________________________________________________________________

2. An animal cell and a plant cell are both placed in pure water. Explain what happens to each and why

the outcomes differ.

__________________________________________________________________________________

3. Explain how the sodium-potassium pump uses ATP, and how cotransport can then use the resulting

gradient to move a second molecule.

__________________________________________________________________________________

Misconception Check

Read each statement. Decide if it is scientifically accurate or a common misconception, then explain why in

one sentence.

A. “Osmosis is the movement of solute into or out of a cell.”

Misconception? ________ Why:

__________________________________________________________________________________

B. “In an isotonic solution, water stops moving across the membrane.”

Misconception? ________ Why:

__________________________________________________________________________________

C. “Facilitated diffusion is active transport because it uses a protein.”

Misconception? ________ Why:

__________________________________________________________________________________

D. “A hypertonic solution has more water than the cell does.”

Misconception? ________ Why:

__________________________________________________________________________________

(Answer key: All four are misconceptions. A is false: osmosis is the movement of water across a selectively

permeable membrane. B is false: water moves in both directions at equal rates, so there is no net movement (a

documented misconception in the diffusion and osmosis literature, e.g., Odom & Barrow, 1995). C is false:

facilitated diffusion uses proteins but moves substances down their gradient with no ATP, so it is passive. D is

false: hypertonic means more dissolved solute, which means relatively less free water, so water leaves the cell.)

Diagram Self-Check #2 — Tonicity

Draw an animal cell and a plant cell in each of three solutions (hypotonic, isotonic, hypertonic). Use

arrows to show the net movement of water and label what each cell looks like (lysed, normal, shriveled,

turgid, flaccid, plasmolyzed).

__________________________________________________________________________________

BIO 101 Test 2 Study Guide | Page 6

__________________________________________________________________________________

Lab Connection — Diffusion Lab

Pull out your completed lab and answer:

• What was the independent variable and the dependent variable in your lab?

• What was the control, and why was it needed?

• Which direction did water or solutes move in your setup, and how do your results show this?

• Explain your results using the terms gradient, selectively permeable, and tonicity.

BIO 101 Test 2 Study Guide | Page 7

TOPIC 3 — Energy & Enzymes

Learning Objectives

• Define metabolism and compare anabolic and catabolic pathways.

• State the first and second laws of thermodynamics and apply them to living cells.

• Define free energy (ΔG) and compare exergonic and endergonic reactions.

• Explain activation energy and how a catalyst changes it.

• Describe the structure of ATP and how ATP hydrolysis is coupled to endergonic reactions.

• Describe enzyme structure, the active site, and induced fit.

• Explain how temperature, pH, and substrate concentration affect enzyme activity.

• Compare competitive and noncompetitive (allosteric) inhibition, and explain feedback inhibition.

Vocabulary Self-Check

Cover the right column and write each definition from memory before checking your notes.

Term Write the definition from memory:

Metabolism

Anabolic

Catabolic

Entropy

Free energy (ΔG)

Exergonic

Endergonic

Activation energy

Catalyst

ATP

Coupled reaction

Enzyme

Substrate

Active site

Induced fit

Denaturation

Competitive inhibitor

Allosteric site

Feedback inhibition

BIO 101 Test 2 Study Guide | Page 8

Concept Check — Answer in complete sentences

1. Explain how a living cell can be highly ordered without violating the second law of thermodynamics.

__________________________________________________________________________________

2. Explain how ATP hydrolysis can drive an endergonic reaction that would not happen on its own.

__________________________________________________________________________________

3. Describe how a competitive inhibitor and a noncompetitive inhibitor each reduce enzyme activity, and

how feedback inhibition uses this to regulate a pathway.

__________________________________________________________________________________

Misconception Check

Read each statement. Decide if it is scientifically accurate or a common misconception, then explain why in

one sentence.

A. “Enzymes are used up by the reactions they catalyze.”

Misconception? ________ Why:

__________________________________________________________________________________

B. “Because living things are so ordered, they violate the second law of thermodynamics.”

Misconception? ________ Why:

__________________________________________________________________________________

C. “A reaction with a negative ΔG will happen quickly.”

Misconception? ________ Why:

__________________________________________________________________________________

(Answer key: All three are misconceptions. A is false: an enzyme is not changed or consumed and is reused. B is

false: cells maintain order by taking in energy, and the energy transformations increase the entropy of the

surroundings (for example, by releasing heat), so total entropy still rises. C is false: negative ΔG means a reaction

is spontaneous, not fast. How fast it goes depends on the activation energy, which is what enzymes lower.)

Diagram Self-Check #3 — Energy Diagram

Sketch an energy-versus-reaction-progress graph for an exergonic reaction. Label reactants, products,

activation energy, and ΔG. Then draw a second curve showing the same reaction with an enzyme, and

state what changed and what did not.

__________________________________________________________________________________

BIO 101 Test 2 Study Guide | Page 9

Lab Connection — Enzymes Lab

Pull out your completed lab and answer:

• What was the enzyme and what was the substrate?

• Identify the independent and dependent variables, and the control.

• What happened to enzyme activity as conditions changed, and what is the evidence from your

data?

• Explain your results in terms of protein shape and the active site.

BIO 101 Test 2 Study Guide | Page 10

TOPIC 4 — Photosynthesis

Learning Objectives

• Write the overall equation for photosynthesis and identify what is oxidized and what is reduced.

• Describe chloroplast structure: thylakoid membrane, grana, stroma.

• Explain how pigments absorb light, and compare chlorophyll a, chlorophyll b, and carotenoids.

• Describe the light-dependent reactions: photosystems II and I, the electron transport chain,

water splitting, and chemiosmosis.

• Identify the inputs and outputs of the light reactions.

• Describe the three phases of the Calvin cycle and the role of rubisco.

• Explain photorespiration and why it is a problem in hot, dry conditions.

• Compare C3, C4, and CAM photosynthesis (spatial vs. temporal separation).

• Name factors that affect the rate of photosynthesis.

Vocabulary Self-Check

Cover the right column and write each definition from memory before checking your notes.

Term Write the definition from memory:

Autotroph

Chloroplast

Thylakoid

Granum

Stroma

Chlorophyll a

Carotenoid

Absorption spectrum

Photosystem II (P680)

Photosystem I (P700)

Photophosphorylation

Chemiosmosis

NADPH

Calvin cycle

Rubisco

Carbon fixation

Photorespiration

C4 plant

CAM plant

BIO 101 Test 2 Study Guide | Page 11

Concept Check — Answer in complete sentences

1. Compare the light-dependent reactions and the Calvin cycle: where each occurs, what each needs,

and what each produces.

__________________________________________________________________________________

2. Explain why the Calvin cycle stops in the dark even though it does not use light directly.

__________________________________________________________________________________

3. Explain photorespiration, and how C4 plants and CAM plants each reduce it.

__________________________________________________________________________________

Misconception Check

Read each statement. Decide if it is scientifically accurate or a common misconception, then explain why in

one sentence.

A. “Plants get most of their mass from the soil.”

Misconception? ________ Why:

__________________________________________________________________________________

B. “The O₂ released in photosynthesis comes from CO₂.”

Misconception? ________ Why:

__________________________________________________________________________________

C. “Plants photosynthesize, and animals respire, so plants do not do cellular respiration.”

Misconception? ________ Why:

__________________________________________________________________________________

D. “The Calvin cycle can run just as well without the light reactions.”

Misconception? ________ Why:

__________________________________________________________________________________

(Answer key: All four are misconceptions. A is false: most plant mass is carbon fixed from atmospheric CO

₂ (plus

water), not from soil. B is false: the O

₂ comes from the splitting of water at photosystem II. C is false: plants have

mitochondria and carry out cellular respiration all the time, and photosynthesize in the light. D is false: the Calvin

cycle depends on ATP and NADPH made by the light reactions, so it stops without them. These ideas match the

photosynthesis and respiration misconceptions reported by Brown & Schwartz (2009).)

Diagram Self-Check #4 — Chloroplast

Sketch a chloroplast and label the outer membrane, inner membrane, stroma, thylakoid, and granum.

Mark where the light-dependent reactions occur and where the Calvin cycle occurs, and draw arrows

showing which molecules move between them (ATP, NADPH, ADP, NADP⁺).

__________________________________________________________________________________

BIO 101 Test 2 Study Guide | Page 12

__________________________________________________________________________________

Lab Connection — Photosynthesis Lab

Pull out your completed lab and answer:

• What was the independent variable and the dependent variable in your lab?

• What was the control, and what did it show?

• How do your results show how the factor you tested affects the rate of photosynthesis?

• Connect your results to the light-dependent reactions or the Calvin cycle.

BIO 101 Test 2 Study Guide | Page 13

TOPIC 5 — Cellular Respiration

Learning Objectives

• Write the overall equation for cellular respiration and identify what is oxidized and what is

reduced.

• Compare substrate-level phosphorylation and oxidative phosphorylation.

• Describe glycolysis: location, inputs, outputs, and net ATP.

• Describe pyruvate oxidation and the Krebs (citric acid) cycle: location, inputs, and outputs.

• Describe the electron transport chain and chemiosmosis, and explain why O₂ is required.

• Compare lactic acid and alcohol fermentation and explain why cells ferment.

• Explain how fats and proteins enter respiration.

• Summarize the approximate ATP yield per glucose.

Vocabulary Self-Check

Cover the right column and write each definition from memory before checking your notes.

Term Write the definition from memory:

Cellular respiration

Oxidation

Reduction

NAD⁺ / NADH

FAD / FADH₂

Glycolysis

Pyruvate

Acetyl CoA

Krebs (citric acid) cycle

Electron transport chain

Chemiosmosis

ATP synthase

Oxidative phosphorylation

Substrate-level

phosphorylation

Fermentation

Lactic acid fermentation

Alcohol fermentation

Mitochondrial matrix

Cristae

BIO 101 Test 2 Study Guide | Page 14

Concept Check — Answer in complete sentences

1. Name the four stages of aerobic respiration in order. For each, give where it occurs and its main

products.

__________________________________________________________________________________

2. Explain how the electron transport chain and ATP synthase produce ATP, and what happens to the

chain when O₂ is absent.

__________________________________________________________________________________

3. Explain why fermentation is necessary when O₂ is not available, and why it yields so little ATP.

__________________________________________________________________________________

Misconception Check

Read each statement. Decide if it is scientifically accurate or a common misconception, then explain why in

one sentence.

A. “Cellular respiration is the same thing as breathing.”

Misconception? ________ Why:

__________________________________________________________________________________

B. “The CO₂ we exhale is made from the O₂ we inhale.”

Misconception? ________ Why:

__________________________________________________________________________________

C. “Cells store large amounts of ATP to use later.”

Misconception? ________ Why:

__________________________________________________________________________________

D. “Fermentation makes more ATP than aerobic respiration because it works faster.”

Misconception? ________ Why:

__________________________________________________________________________________

(Answer key: All four are misconceptions. A is false: breathing exchanges gases at the organism level, while

respiration is the cellular process that extracts ATP from food (Songer & Mintzes, 1994, document this confusion).

B is false: the carbon in exhaled CO

₂ comes from glucose (released in pyruvate oxidation and the Krebs cycle),

and the O

₂ ends up in water at the end of the electron transport chain. C is false: cells hold only about a few

seconds’ worth of ATP and store energy long-term in fats and carbohydrates. D is false: fermentation yields only

the 2 ATP from glycolysis, compared with about 30–34 ATP from aerobic respiration.)

Note: There is no separate lab for cellular respiration in this unit, so questions on it come from lecture.

Diagram Self-Check #5 — Mitochondrion and the Four Stages

Sketch a mitochondrion and label the outer membrane, intermembrane space, inner membrane

(cristae), and matrix. Then write where each of the four stages of aerobic respiration occurs, and the

ATP and electron-carrier yield of each. The test uses a figure like this.

BIO 101 Test 2 Study Guide | Page 15

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