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How to use this guide
                            ~1 minutes                        

Eukaryotic Cell Biology — Study Guide

This is a condensed review of the main Eukaryotic Cell Biology lesson. Use it to refresh on the essentials before a quiz, test, or class discussion.

You'll get the most out of this study guide if you have already worked through the main lesson. This guide is for review — not for first-time learning.

For each section: read the summary, study the diagram, and try the quick checks at the end.

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Reference intro
                            ~1 minutes                        

Section 1: Reference Infographics

Spend 2-3 minutes studying each infographic below. Cover the labels with your hand and try to name each organelle. Then check yourself.

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Animal cell
                            ~2 minutes                        

Animal Cell — Reference Infographic

Reference infographic of an animal cell showing its round, irregular shape bounded by a wavy blue plasma membrane. Inside: a large purple nucleus with a darker nucleolus; ribbons of rough endoplasmic reticulum studded with red ribosome dots; smooth endoplasmic reticulum; a pink stack of Golgi apparatus sacs; several orange oval mitochondria with internal folds; blue lysosomes; green peroxisomes; pink vesicles; purple free ribosomes; a yellow centriole bundle; and thin yellow cytoskeleton fibers radiating outward through the gel-like cytoplasm. Each labeled with a brief function description.

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Plant cell
                            ~2 minutes                        

Plant Cell — Reference Infographic

Reference infographic of a plant cell showing its rectangular, box-shaped form with a thick green cell wall surrounding a thinner plasma membrane. Inside: a very large light blue central vacuole filling much of the cell; a purple nucleus with a darker nucleolus pressed to one side; ribbons of rough and smooth endoplasmic reticulum; a pink Golgi apparatus stack; several green oval chloroplasts with internal grana; orange oval mitochondria; green peroxisomes; pink vesicles; purple free ribosomes; and a yellow cytoskeleton bundle suspended in cytoplasm. Each labeled with a brief function description.

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Section intro
                            ~1 minutes                        

Section 2: Organelle Cheat Sheet

Quick reference for every major organelle. Each one has a single sentence that tells you what it does.

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Boundaries
                            ~1 minutes                        

                💡
                The Boundaries            

Plasma membrane — controls what enters and exits the cell (in BOTH plant and animal cells) Cell wall — rigid outer layer made of cellulose; gives plants their shape (PLANT only)

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Information hub
                            ~1 minutes                        

                💡
                The Information Hub            

Nucleus — control center; holds the DNA; directs the cell's activities Nucleolus — small dark spot inside the nucleus; the ribosome factory Ribosomes — tiny machines that build proteins by reading mRNA

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Endomembrane
                            ~2 minutes                        

                💡
                The Endomembrane System (Protein Factory + Post Office)            

Rough ER — covered with ribosomes; builds and folds proteins Smooth ER — no ribosomes; makes lipids and detoxifies substances Golgi apparatus — stack of flat sacs; modifies, sorts, and packages proteins Vesicles — tiny membrane bubbles; transport materials between organelles Lysosomes — sacs of digestive enzymes; break down waste (animal cells) Peroxisomes — break down fatty acids and detoxify (both cell types)

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Energy organelles
                            ~1 minutes                        

                💡
                The Energy Organelles            

Mitochondria — the powerhouse; produce ATP through cellular respiration (BOTH cell types — yes, plants too!) Chloroplasts — capture sunlight to make glucose through photosynthesis (PLANT only)

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Support structures
                            ~1 minutes                        

                💡
                Support Structures            

Central vacuole — large fluid-filled sac; stores water and maintains turgor pressure (PLANT only) Cytoskeleton — protein fibers; the cell's "bones and highways" Centrioles — organize spindle fibers during cell division (mostly ANIMAL only) Cytoplasm — gel-like fluid that fills the cell

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Quick check
                            ~1 minutes                        

Question 1

Which organelle is found in plant cells but NOT in animal cells?

Mitochondrion
Chloroplast
Nucleus
Ribosome

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Organelle match
                            ~1 minutes                        

Question 2

Match each organelle to its primary function:

Nucleus

Ribosome

Mitochondrion

Golgi apparatus

Plasma membrane

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Cellular respiration intro
                            ~1 minutes                        

Section 3: Cellular Respiration — The Essentials

Cellular respiration is how cells break down glucose to make ATP. Most of it happens inside the mitochondria.

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Three-stage flowchart
                            ~2 minutes                        

Cellular Respiration Three-Stage Flowchart

                
Cellular Respiration: The Three Stages
A horizontal flowchart of cellular respiration showing three connected boxes left to right. Stage 1 Glycolysis takes place in the cytoplasm, where one glucose molecule is split into two pyruvate molecules and produces two ATP. Stage 2 Krebs Cycle takes place in the mitochondrial matrix, where pyruvate is broken down further, producing two more ATP and releasing carbon dioxide. Stage 3 Electron Transport Chain takes place on the cristae of the inner mitochondrial membrane, using oxygen to produce about twenty-six ATP and releasing water. Below the boxes the overall equation is shown: glucose plus oxygen yields carbon dioxide plus water plus about thirty ATP.

Cellular Respiration: 3 Stages

1. GLYCOLYSIS
(in the cytoplasm)

Glucose
↓
2 Pyruvate
+ 2 ATP
(no oxygen needed)

2. KREBS CYCLE
(in mitochondrial matrix)

Pyruvate broken
down to CO₂
Releases CO₂
+ 2 ATP
(loads up NADH/FADH₂)

3. ELECTRON
TRANSPORT CHAIN
(on the cristae)

O₂ accepts
electrons → H₂O
+ ~26 ATP
Releases H₂O
(needs oxygen!)

  
  
  
  


Overall Equation:
C₆H₁₂O₆  +  6 O₂  →  6 CO₂  +  6 H₂O  +  energy (~30 ATP)
glucose + oxygen → carbon dioxide + water + ATP
            
Horizontal flowchart of the three stages of cellular respiration. Stage 1 Glycolysis in the cytoplasm: glucose splits into two pyruvate, producing 2 ATP, no oxygen needed. Stage 2 Krebs Cycle in the m...

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The 3 stages
                            ~2 minutes                        

                💡
                The 3 Stages — Memorize These            

Stage 1 — Glycolysis (in the cytoplasm) Glucose → 2 pyruvate; nets 2 ATP; no oxygen needed.

Stage 2 — Krebs Cycle (in the mitochondrial matrix) Pyruvate fully broken down; releases CO₂; nets 2 ATP; loads up electron carriers.

Stage 3 — Electron Transport Chain (on the cristae) Uses oxygen; produces ~26 ATP; releases water. This is where most ATP is made!

Total: ~30 ATP per glucose.

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The equation
                            ~1 minutes                        

                💡
                The Equation            

C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + ~30 ATP

Glucose + oxygen → carbon dioxide + water + ATP

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Quick check
                            ~1 minutes                        

Question 3

Which stage of cellular respiration produces the MOST ATP?

Glycolysis
Krebs cycle
Electron transport chain
All produce equal amounts

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Where glycolysis happens
                            ~1 minutes                        

Question 4

Where in the cell does glycolysis happen?

In the cytoplasm
In the matrix of the mitochondrion
On the cristae of the mitochondrion
In the nucleus

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Equation fill-in
                            ~1 minutes                        

Question 5

The overall equation for cellular respiration: glucose + ______ → carbon dioxide + ______ + ATP.

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Photosynthesis intro
                            ~1 minutes                        

Section 4: Photosynthesis — The Essentials

Photosynthesis is how plant cells convert sunlight into chemical energy stored in glucose. It happens inside the chloroplasts.

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Two-stage flowchart
                            ~2 minutes                        

Photosynthesis Two-Stage Flowchart

                
Photosynthesis: The Two Stages
A horizontal flowchart of photosynthesis showing two connected boxes. The first box is the light reactions, taking place in the thylakoid membranes of the chloroplast. Sunlight and water enter, oxygen is released as a waste product, and ATP and NADPH are produced. An arrow connects to the second box, the Calvin cycle, which takes place in the stroma of the chloroplast. The Calvin cycle uses ATP and NADPH from the light reactions plus carbon dioxide from the air to build glucose. Below the boxes the overall equation is shown: carbon dioxide plus water plus light energy yields glucose plus oxygen.

Photosynthesis: 2 Stages

1. LIGHT REACTIONS
(in thylakoid membranes)

☀
Sunlight in
H₂O
in (split apart)
Makes: ATP + NADPH
Releases: O₂ ↑
(the oxygen we breathe)

2. CALVIN CYCLE
(in the stroma)

Uses: ATP + NADPH
CO₂
from the air
Builds: Glucose (C₆H₁₂O₆)
(stored chemical energy
the plant can use later)

  
  

ATP +
NADPH

Overall Equation:
6 CO₂  +  6 H₂O  +  light energy  →  C₆H₁₂O₆  +  6 O₂
carbon dioxide + water + light → glucose + oxygen
            
Horizontal flowchart of the two stages of photosynthesis. Stage 1 the Light Reactions in the thylakoid membranes: sunlight and water enter, oxygen is released, ATP and NADPH are produced. Stage 2 the ...

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The 2 stages
                            ~2 minutes                        

                💡
                The 2 Stages — Memorize These            

Stage 1 — Light Reactions (in the thylakoid membranes) Chlorophyll absorbs sunlight; splits water; releases O₂; makes ATP and NADPH.

Stage 2 — Calvin Cycle (in the stroma — the fluid) Uses CO₂ from the air, plus ATP and NADPH from the light reactions, to build glucose.

Key fact: the oxygen released by photosynthesis comes from splitting WATER, not carbon dioxide!

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The equation
                            ~1 minutes                        

                💡
                The Equation            

6 CO₂ + 6 H₂O + light energy → C₆H₁₂O₆ + 6 O₂

Carbon dioxide + water + light → glucose + oxygen

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Light reactions location
                            ~1 minutes                        

Question 6

Where do the LIGHT REACTIONS of photosynthesis take place?

In the stroma
In the thylakoid membranes
In the cytoplasm
On the cristae

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Source of oxygen
                            ~1 minutes                        

Question 7

The oxygen released by photosynthesis comes from splitting water (H₂O).

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Equation fill-in
                            ~1 minutes                        

Question 8

The overall equation for photosynthesis: carbon dioxide + ______ + light → ______ + oxygen.

Word Bank:

                                                    water
                                                    glucose
                                                    oxygen
                                                    carbon dioxide
                                            

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Compare intro
                            ~1 minutes                        

Section 5: Photosynthesis vs. Cellular Respiration

The two energy processes work as partners. The products of one are the reactants of the other.

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Energy flow diagram
                            ~2 minutes                        

Energy Flow Between Photosynthesis and Respiration

Energy Flow: Photosynthesis and Cellular Respiration as Partners
A circular diagram showing how photosynthesis and cellular respiration work as complementary processes that cycle matter and energy through ecosystems. At the top, a sun radiates light energy down onto a plant on the left side. Inside the plant, photosynthesis takes in carbon dioxide and water, and using light energy makes glucose and releases oxygen. The plant or an animal that ate the plant then runs cellular respiration on the right side, which takes in glucose and oxygen and produces ATP for life processes, releasing carbon dioxide and water as waste. The carbon dioxide and water released by respiration return to the atmosphere where photosynthesis can use them again. Arrows make a complete cycle. Energy flows one direction from sun through plant through animal then is released as heat. Matter (carbon dioxide, water, oxygen) cycles continuously.

Photosynthesis & Cellular Respiration: Two Halves of One Cycle

☀
Light energy from the Sun

PHOTOSYNTHESIS
(in plant chloroplasts)

Inputs:
CO₂ + H₂O + light
Outputs:
Glucose + O₂
builds chemical energy

CELLULAR RESPIRATION
(in mitochondria of all cells)

Inputs:
Glucose + O₂
Outputs:
CO₂ + H₂O + ATP
releases usable energy

glucose, O₂

CO₂, H₂O

Plants do BOTH. Animals do only respiration (and eat plants for the glucose).
            
Circular diagram showing how photosynthesis and cellular respiration work as complementary processes. The sun radiates light energy to a plant, where photosynthesis takes in carbon dioxide and water a...

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Side-by-side
                            ~2 minutes                        

                💡
                Side-by-Side at a Glance            

PhotosynthesisCellular Respiration
WhereChloroplastsMostly mitochondria
Who does itPlants onlyEVERY eukaryotic cell
InputsCO₂ + H₂O + lightGlucose + O₂
OutputsGlucose + O₂CO₂ + H₂O + ATP
EnergyStores it (builds glucose)Releases it (makes ATP)
WhenDaytime onlyAll the time, day and night

	Photosynthesis	Cellular Respiration
Where	Chloroplasts	Mostly mitochondria
Who does it	Plants only	EVERY eukaryotic cell
Inputs	CO₂ + H₂O + light	Glucose + O₂
Outputs	Glucose + O₂	CO₂ + H₂O + ATP
Energy	Stores it (builds glucose)	Releases it (makes ATP)
When	Daytime only	All the time, day and night

Plants do BOTH! They photosynthesize during the day AND respire 24/7.

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Energy vs. matter
                            ~1 minutes                        

                💡
                Energy flows; Matter cycles            

Energy ENTERS the system from the sun, gets stored in glucose, and eventually leaves as heat (one-way). Matter (carbon, oxygen, water atoms) RECYCLES between photosynthesis and respiration over and over (cyclical).

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Plants do both
                            ~1 minutes                        

Question 9

Plant cells have BOTH chloroplasts AND mitochondria.

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True statement
                            ~1 minutes                        

Question 10

Which statement about plants is TRUE?

Plants only photosynthesize; they never respire
Plants only respire when they cannot photosynthesize
Plants do BOTH photosynthesis and respiration
Plants do respiration only at night

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Process match
                            ~2 minutes                        

Question 11

Match each input or output to the right process:

CO₂ used as input

O₂ used as input

Glucose produced as output

ATP produced as output

Sunlight used as input

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Plant vs animal intro
                            ~1 minutes                        

Section 6: Plant vs. Animal Cell

A side-by-side comparison of the two main eukaryotic cell types you need to know.

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Side-by-side diagram
                            ~2 minutes                        

Plant vs. Animal Cell Comparison

Plant Cell vs. Animal Cell: Key Differences
Side by side comparison of a plant cell on the left and an animal cell on the right. The plant cell is rectangular with a rigid green cell wall surrounding a thinner plasma membrane, a large blue central vacuole filling much of the interior, several green oval chloroplasts, an orange mitochondrion, and a purple nucleus. The animal cell is round and irregular with only a plasma membrane around the outside (no cell wall), a smaller round nucleus, several mitochondria, blue lysosomes, and a yellow centriole structure. Below the cells is a comparison summary listing structures unique to each cell type and structures both share.

PLANT CELL
ANIMAL CELL

cell wall

central vacuole

nucleus

chloroplast

mitochondrion

plasma membrane
(no cell wall)

nuc.
nucleus

mitochondria

lysosomes

centrioles

Key Differences and Shared Structures
PLANT only:
cell wall, central vacuole, chloroplasts
ANIMAL only:
centrioles, lysosomes (more prominent)
BOTH have:
plasma membrane, nucleus, mitochondria, ribosomes,
RER, SER, Golgi, vesicles, peroxisomes, cytoskeleton, cytoplasm
Plant cells have BOTH chloroplasts AND mitochondria — they make food and use food.
            
Side-by-side comparison of a plant cell on the left and an animal cell on the right. Plant cell is rectangular with a thick green cell wall, a large blue central vacuole, several green chloroplasts, a...

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Differences and shared
                            ~2 minutes                        

                💡
                What's the same, what's different            

PLANT cells uniquely have:
• Cell wall (rigid outer layer, made of cellulose)
• Central vacuole (giant water-storage sac)
• Chloroplasts (for photosynthesis)

ANIMAL cells uniquely have:
• Centrioles (for cell division)
• More prominent lysosomes

Both cell types share: plasma membrane, nucleus, ribosomes, rough ER, smooth ER, Golgi, mitochondria, vesicles, peroxisomes, cytoskeleton, cytoplasm

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Cell wall fill-in
                            ~1 minutes                        

Question 12

The rigid outer layer of a plant cell, made of cellulose, is called the ______ ______.

Word Bank:

                                                    cell wall
                                                    plasma membrane
                                                    cytoplasm
                                                    central vacuole
                                            

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Quiz wrap-up
                            ~1 minutes                        

Section 7: Self-Quiz

Twelve quick checks to test your readiness. Try to answer without looking back. If you miss one, the related section above is where to review.

Learning Objectives

How to use this guide

Eukaryotic Cell Biology — Study Guide

Reference intro

Section 1: Reference Infographics

Animal cell

Plant cell

Section intro

Section 2: Organelle Cheat Sheet

Boundaries

Information hub

Endomembrane

Energy organelles

Support structures

Quick check

Organelle match

Cellular respiration intro

Section 3: Cellular Respiration — The Essentials

Three-stage flowchart

The 3 stages

The equation

Quick check

Where glycolysis happens

Equation fill-in

Photosynthesis intro

Section 4: Photosynthesis — The Essentials

Two-stage flowchart

The 2 stages

The equation

Light reactions location

Source of oxygen

Equation fill-in

Compare intro

Section 5: Photosynthesis vs. Cellular Respiration

Energy flow diagram

Side-by-side

Energy vs. matter

Plants do both

True statement

Process match

Plant vs animal intro

Section 6: Plant vs. Animal Cell

Side-by-side diagram

Differences and shared

Cell wall fill-in

Quiz wrap-up

Section 7: Self-Quiz