Your AI study companion

Study PDFs like you have a personal tutor.

Upload any PDF — textbook, paper, lecture slides. Highlight what matters, ask questions, and let Pheynman explain, quiz, and help you remember. Reading becomes understanding.

Start studying freeSee how it works
pheyn
Library
Cell Biology
Organic Chemistry
Statistics
Generate
Flashcards
Quiz
Podcast
Chapter 3 — Cell Respiration
Pheynmanonline
"The mitochondria produces ATP through oxidative phosphorylation..."
Pheynman explains
Think of the mitochondria as a power plant. It converts glucose into usable energy (ATP) through a chain of chemical reactions called the electron transport chain.
Why is ATP important for the cell?

Used by students at universities worldwide · Free to start, no credit card required

The problem

Most students highlight.
Few actually understand.

There is a gap between reading and knowing. Between familiarity and fluency. Between a highlighted page and an idea you can explain.

Passive highlighting

You mark the page but not your memory. Colour-coded notes don't create understanding — they create the illusion of it.

Rereading without retention

You've read the same paragraph four times. The words go in. The meaning doesn't stay. Familiarity isn't the same as knowledge.

?

No way to test yourself

You don't know what you don't know until the exam reveals it. Passive study leaves too many gaps.

Lost in long PDFs

300 pages. No guide. Dense academic language with no one to ask when a paragraph stops making sense.

Pheyn closes the gap. It turns your PDF into an active conversation — one where you can ask, push back, test yourself, and actually walk away knowing the material.

How it works

From upload to understanding.

A learning loop designed to turn passive reading into active knowledge.

01

Upload

Drop in any PDF — textbook, paper, lecture slides, research article.

02

Read

Navigate with a clean, focused reading environment designed for deep study.

03

Ask

Highlight any passage and ask Pheynman to explain it in plain language.

04

Practice

Generate quizzes, flashcards, or mind maps from your highlights instantly.

05

Remember

Active recall builds understanding that lasts past the exam.

What Pheyn does

Every tool you need to understand what you read.

Not a collection of AI widgets. A single, coherent study environment.

AI Chat

Ask anything about what you're reading.

Highlight a confusing paragraph and ask Pheynman to explain it — in plain language, at your level, right in context. No tab switching. No Googling. Just understanding.

"Oxidative phosphorylation couples electron transport to ATP synthesis..."
Pheynman explains

Think of it like a turbine in a dam. Electrons flow along the protein chain, releasing energy that pumps hydrogen ions — and that pressure drives ATP synthesis.

So electrons are like the water driving the turbine?

Flashcards

Turn your highlights into a revision deck.

Every passage you highlight becomes a flashcard candidate. Review them with spaced repetition or export to your favourite tool. Memory-building starts the moment you highlight.

Flashcard 1 of 12

What drives ATP synthesis in oxidative phosphorylation?

Tap to reveal answer →

Quizzes

Test yourself before the exam does.

Generate a quiz from any section of your document. Multiple choice, short answer, or concept checks — Pheyn builds questions from the material you've been reading, so you know exactly what you know.

Which process directly produces ATP in cellular respiration?

Glycolysis
Oxidative phosphorylation
The citric acid cycle
Electron transfer
Mind Map

See how ideas connect.

Dense material becomes visual. Pheyn maps the concepts, arguments, and relationships in your document so you can see the whole picture — not just the paragraph you're stuck on.

Cell Respiration
Glycolysis
Krebs Cycle
ATP Yield
ETC
Podcast

Listen while you commute.

Pheyn turns any document into a conversational podcast summary. Two voices, back and forth, breaking down the key ideas. Study on the bus. Study in the gym. Study anywhere.

2:14
5:48

Chapter 3 summary · Cell Respiration

From students

Study sessions that actually work.

What students say after studying with Pheyn.

"Pheyn changed how I study for biochemistry. I highlight a section, ask Pheynman to break it down, and what used to take me an hour takes twenty minutes. My exam results have genuinely improved."

AR
Anika R.
Biomedical Science, Year 3

"I used to spend whole evenings making flashcards manually. Now I highlight what matters while I read and Pheyn turns it into a revision deck automatically. It's that simple."

DK
David K.
Pre-med, Second year

"Reading dense academic papers used to take me all day. Now I highlight what I don't understand and Pheynman explains it in plain English. I get through twice as much material."

MP
Marcus P.
PhD candidate, Sociology

"Pheyn changed how I study for biochemistry. I highlight a section, ask Pheynman to break it down, and what used to take me an hour takes twenty minutes. My exam results have genuinely improved."

AR
Anika R.
Biomedical Science, Year 3

"I used to spend whole evenings making flashcards manually. Now I highlight what matters while I read and Pheyn turns it into a revision deck automatically. It's that simple."

DK
David K.
Pre-med, Second year

"Reading dense academic papers used to take me all day. Now I highlight what I don't understand and Pheynman explains it in plain English. I get through twice as much material."

MP
Marcus P.
PhD candidate, Sociology
Meet Pheynman

More than a tool.
A thinking partner.

Pheynman is the AI tutor embedded in every reading session. Not a magic button — a patient, knowledgeable companion who helps you think through what you're reading.

Always in context.

Pheynman knows exactly which document you're reading and which passage you've highlighted. Every answer is grounded in your material.

Explains, doesn't just summarise.

There's a difference between restating a paragraph and helping you understand it. Pheynman explains concepts from first principles.

Patient by design.

Ask the same question five different ways. Pheynman never tires. Understanding is the goal — not speed.

Calibrated to your level.

Tell Pheynman how much you already know. Undergraduate, postgraduate, professional — the explanation adjusts.

Your textbooks deserve better than a highlighter.

Join students who study smarter — not just longer. Pheyn is free to start.

Start studying freeSign in

No credit card required · Free forever plan available