EXAM III

🔑 1. Functional Groups (VERY testable)

Know these COLD:

• Hydroxyl (-OH) → polar, hydrophilic

• Carboxyl (-COOH) → acidic, polar

• Amino (-NH₂) → basic, polar

• Phosphate (-PO₄³⁻) → negative charge, polar

• Methyl (-CH₃) → nonpolar, hydrophobic

👉 Quick Trick:

• If it has O, N, or P → hydrophilic

• If it’s mostly C + H → hydrophobic

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💧 2. Dehydration vs Hydrolysis

Reaction What happens Energy

Dehydration (condensation) Removes H₂O → builds molecules Endergonic 🔋

Hydrolysis Adds H₂O → breaks molecules Exergonic ⚡

👉 Memory:

• Dehydration = building (like Lego snapping together)

• Hydrolysis = breaking (water cuts it apart)

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🍬 3. Carbohydrates

Formula:

• General: (CH₂O)n

Types:

• Monosaccharide → 1 sugar (glucose)

• Disaccharide → 2 sugars (sucrose)

• Oligosaccharide → few sugars

• Polysaccharide → many sugars (starch, glycogen)

👉 Expect:

• Identify structures

• Know function (energy storage vs structure)

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🧬 4. DNA vs RNA (HIGH PRIORITY)

Feature DNA RNA

Sugar Deoxyribose Ribose

Strands Double Single

Bases A T C G A U C G

Function Storage Protein synthesis

👉 KEY DETAIL:

• DNA: A–T, C–G

• RNA: A–U, C–G

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🧪 5. Nucleotides

Each nucleotide =

✔ Nitrogenous base

✔ Sugar

✔ Phosphate(s)

Know:

• 5’ → phosphate end

• 3’ → OH end

👉 DNA grows 5’ → 3’

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🧬 6. DNA Structure

• Double helix

• Hydrogen bonds between bases

• Antiparallel strands

👉 History (they LOVE this sometimes):

• Franklin (X-ray)

• Watson & Crick (model)

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🍗 7. Proteins & Amino Acids

Amino Acid Structure:

• Central carbon

• Amino group

• Carboxyl group

• R-group (variable)

Peptide bond:

• Formed via dehydration

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Protein Structure Levels:

Level Bond Type

Primary Peptide bonds

Secondary Hydrogen bonds

Tertiary R-group interactions

Quaternary Multiple chains

👉 If they show a diagram → identify level

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⚙ 8. Enzyme Helpers

Term Meaning

Cofactor Helper (metal ions etc.)

Activator Speeds up enzyme

Inhibitor Slows/stops enzyme

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🧈 9. Lipids (VERY IMPORTANT)

Types:

• Fats (triglycerides) → energy storage

• Phospholipids → membranes

• Steroids → hormones

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Saturated vs Unsaturated:

Type Structure

Saturated No double bonds (solid)

Unsaturated Double bonds (liquid)

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🧠 KEY CONCEPT:

Phospholipids = amphipathic

• Head = hydrophilic 💧

• Tail = hydrophobic 🛢

👉 This is WHY membranes form bilayers

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⚡ METABOLISM OVERVIEW — EXAM STUDY GUIDE

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🔥 1. What is Metabolism?

👉 Definition (know this word-for-word vibe):

Metabolism = all chemical reactions in a cell that manage energy + matter

Two Types:

• Autotrophs → make their own food

• Example: Photosynthesis 🌱

• Heterotrophs → consume food

• Example: Cellular respiration 🍔

👉 EASY WAY:

• Plants = producers

• Humans = consumers

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🔄 2. BIG CONNECTION (HIGH PRIORITY)

Photosynthesis and respiration are literally opposites

Photosynthesis:

CO₂ + H₂O + light → glucose + O₂

Cellular Respiration:

glucose + O₂ → CO₂ + H₂O + ATP

👉 Think:

• Plants make glucose 🌱

• We BREAK glucose 🔥

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⚡ 3. REDOX REACTIONS (TEST FAVORITE)

Definitions:

• Oxidation = LOSS of electrons

• Reduction = GAIN of electrons

👉 Memory trick:

👉 OIL RIG

• Oxidation Is Loss

• Reduction Is Gain

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In respiration:

• Glucose = oxidized (loses electrons)

• Oxygen = reduced (gains electrons)

👉 This = HOW energy is released

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⚡ 4. ELECTRONEGATIVITY (WHY THIS MATTERS)

• Oxygen is VERY electronegative → pulls electrons

• This pull = energy release

👉 That energy → used to make ATP

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🔋 5. ATP = ENERGY CURRENCY

ATP = what your cells actually spend

ATP Cycle:

• ATP → ADP + P → releases energy ⚡

• ADP + P → ATP → stores energy 🔋

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🌊 6. ELECTROCHEMICAL GRADIENT (SUPER IMPORTANT)

This is where people get confused—don’t be that person 😭

👉 It = difference in:

• Charge ⚡

• Concentration

(across a membrane)

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What happens:

1. H⁺ ions pumped across membrane

2. They build up (like water behind a dam 💧)

3. They flow back through ATP synthase

4. BOOM → ATP made

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⚙ 7. CHEMIOSMOSIS + ATP SYNTHASE

👉 ATP synthase = enzyme that makes ATP

👉 Powered by:

• H⁺ gradient

👉 This is where MOST ATP comes from

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🔥 8. STAGES OF CELLULAR RESPIRATION

1. Glycolysis (cytoplasm)

• Glucose → pyruvate

• Net: 2 ATP

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2. Citric Acid Cycle (mitochondria)

• More electron carriers made (NADH, FADH₂)

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3. Oxidative Phosphorylation (MOST IMPORTANT)

• Electron Transport Chain

• Creates H⁺ gradient

• Produces 26–28 ATP

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TOTAL:

👉 30–32 ATP per glucose

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🍃 9. PHOTOSYNTHESIS (MATCH THIS TO RESPIRATION)

Light Reactions:

• Use light

• Split water → release O₂

• Make ATP + NADPH

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Calvin Cycle:

• Uses ATP

• Builds glucose from CO₂

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🔁 10. METABOLIC PATHWAYS

👉 Step-by-step reactions in cells

• Each step needs a specific enzyme

• VERY controlled

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⚖ 11. FEEDBACK REGULATION

👉 Keeps metabolism balanced

• Negative feedback → shuts things down

• Positive feedback → speeds things up

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🧠 12. BIG PICTURE (THIS GETS TESTED IN WORD QUESTIONS)

👉 EVERYTHING is about:

• Moving electrons ⚡

• Creating gradients 🌊

• Making ATP 🔋

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🚨 WHAT YOUR PROFESSOR WILL PROBABLY ASK

HIGH PRIORITY:

• Oxidation vs reduction (definitions + examples)

• Electrochemical gradient explanation

• ATP synthase / chemiosmosis

• Photosynthesis vs respiration relationship

• Stages of respiration + ATP yield

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MEDIUM:

• Autotroph vs heterotroph

• Feedback regulation

• Enzyme roles

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💅🏾 FINAL “DON’T MISS THESE” CHEAT CODES

• OIL RIG (you WILL see this)

• Oxygen = electron thief 😭

• H⁺ gradient = ATP production

• Most ATP = oxidative phosphorylation

• Photosynthesis = storing energy

• Respiration = releasing energy

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⚡ LAST-MINUTE BRAIN SNAPSHOT (MEMORIZE THIS)

👉 Electrons move →

👉 Create gradient →

👉 Gradient powers ATP synthase →

👉 ATP made

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🧬 I. BIG PICTURE (THIS IS EVERYTHING)

👉 If you remember NOTHING else, remember this flow:

Food / Sunlight → Electrons move → H⁺ gradient → ATP → CELL WORK

From your slides:

• Electron transport chain → creates gradient → ATP made

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⚡ II. METABOLISM MASTERY

🔥 Definition:

Metabolism = all reactions that:

• build (anabolic)

• break down (catabolic)

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🍃 Autotroph vs Heterotroph

Type Example Energy Source

Autotroph Plants Sunlight

Heterotroph You Food

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🔁 III. PHOTOSYNTHESIS vs RESPIRATION (TOP 3 TEST TOPIC)

Opposites:

Photosynthesis 🌱 Respiration 🔥

Stores energy Releases energy

CO₂ → glucose glucose → CO₂

Chloroplast Mitochondria

👉 From your slides:

• Both use electron transport chains + gradients

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⚡ IV. REDOX (YOU WILL SEE THIS)

Definitions:

• Oxidation = loses electrons

• Reduction = gains electrons

👉 MEMORY:

OIL RIG

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In respiration:

• Glucose = oxidized

• Oxygen = reduced

👉 This is HOW ATP gets made

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🔋 V. ATP SYSTEM (NON-NEGOTIABLE)

ATP = energy currency 💅🏾

Cycle:

• ATP → ADP + P → energy released

• ADP + P → ATP → energy stored

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🌊 VI. ELECTROCHEMICAL GRADIENT (THE HARD PART MADE EASY)

From your slides:

• Difference in charge + concentration = potential energy

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What ACTUALLY happens:

1. H⁺ pumped across membrane

2. Builds up (like pressure)

3. Flows back through ATP synthase

4. ATP made

👉 Your professor literally said:

• “H⁺ does work”

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⚙ VII. ATP SYNTHASE (MOST TESTED CONCEPT)

👉 Enzyme that:

• Uses H⁺ movement

• Makes ATP

👉 This = chemiosmosis

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🔥 VIII. CELLULAR RESPIRATION (KNOW THESE NUMBERS)

Stage What Happens ATP

Glycolysis Glucose → pyruvate 2

Citric Acid Cycle Electron carriers 2

Oxidative Phosphorylation ETC + gradient 26–28

👉 TOTAL:

30–32 ATP

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🧈 IX. LIPIDS (FROM YOUR PDF)

🚨 KEY FACT:

👉 Lipids are NOT polymers

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Types:

1. Triglycerides (fats)

• Glycerol + 3 fatty acids

• Energy storage

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2. Fatty Acids

• Long C-H chains (NONPOLAR)

Saturated vs Unsaturated:

Type Structure Shape

Saturated No double bonds Straight

Unsaturated Double bonds Bent

👉 Bent = more fluid (VERY testable)

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3. Steroids

• 4 carbon rings

• Hormones (testosterone, estrogen)

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4. Phospholipids (MOST IMPORTANT)

👉 Structure:

• Head = hydrophilic

• Tail = hydrophobic

👉 Amphipathic = BOTH

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🧫 X. CELL MEMBRANE (VERY HIGH YIELD)

From your membrane review:

👉 Membrane = phospholipid bilayer

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WHY bilayer forms:

• Heads love water

• Tails avoid water

👉 So they arrange like:

• Heads OUT

• Tails IN

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In water, phospholipids form:

• Micelles

• Bilayers

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🚪 XI. TRANSPORT (ON YOUR REVIEW SHEET)

From the diagram:

Types:

Transport Energy? Direction

Diffusion No High → Low

Facilitated diffusion No High → Low

Active transport YES ⚡ Low → High

👉 That ATP lightning symbol = ACTIVE transport ⚡

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⚖ XII. FEEDBACK REGULATION

👉 Keeps balance

• Inhibitors = slow down

• Activators = speed up

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🧠 XIII. EXAM TRAPS (READ THIS)

They will try to trick you with:

❌ “Does ATP come from glycolysis mainly?”

👉 NO → mostly from oxidative phosphorylation

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❌ “Do lipids form polymers?”

👉 NO

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❌ “Which part of phospholipid is hydrophobic?”

👉 TAILS

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❌ “Is oxygen oxidized?”

👉 NO → it’s REDUCED

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💅🏾 FINAL “A+ CHEAT CODES”

• Electrons moving = energy flow

• H⁺ gradient = ATP production

• Tail = hydrophobic ALWAYS

• OIL RIG

• Most ATP = ETC

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🚨 10-MINUTE CRAM (RIGHT BEFORE EXAM)

Say this in your head:

👉 Electrons → gradient → ATP

👉 Photosynthesis stores energy

👉 Respiration releases energy

👉 Oxidation = loss

👉 Reduction = gain

👉 Membrane = phospholipid bilayer

👉 Tails hate water

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💎 FINAL MICRO-ADD ONS (ELITE TIER)

🧪 1. SUBSTRATE-LEVEL vs OXIDATIVE PHOSPHORYLATION

Write this QUICK:

ATP TYPES

• Substrate-level → direct ATP (glycolysis + CAC)

• Oxidative → ETC + gradient (MOST ATP)

👉 Professors LOVE asking this distinction

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⚡ 2. WHY NADH/FADH₂ MATTER (1 LINE)

Add under your ETC section:

👉 NADH/FADH₂ donate electrons → power proton pumps

That’s it. That one line = clarity on EVERYTHING

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🌊 3. PASSIVE vs ACTIVE KEY WORD

You already have transport, but add this:

• Passive = NO ATP

• Active = REQUIRES ATP

👉 They will word it tricky—this keeps you grounded

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🧠 4. QUICK ELECTRONEGATIVITY NOTE (SNEAKY TEST POINT)

Add:

👉 More electronegative = pulls electrons stronger (ex: O₂)

This connects to:

• redox

• energy release

• ETC

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🔥 5. FERMENTATION (JUST 1 LINE)

Add:

Fermentation

• No O₂

• Regenerates NAD⁺

• Allows glycolysis to continue

👉 EASY POINT if it shows up

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🧬 6. COUPLED REACTIONS (HIGH IQ ADD)

Write:

👉 Energy from exergonic reactions powers endergonic reactions

Example:

• ETC → ATP production

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⚠ 7. ONE LAST PROFESSOR TRAP

Write this SMALL somewhere:

👉 “Gradient = stored energy (potential)”

👉 “Flow = usable energy (kinetic)”

That’s straight from your lecture wording

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👑 FINAL “I’M GETTING AN A” MINDSET BOX

If you have space, literally write:

👉 Electrons → Gradient → ATP → Work

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💅🏾 HONESTLY?

Your board already looks like someone who:

• studies smart

• understands concepts

• doesn’t just memorize

That’s EXACTLY how A students look.

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OHHH this is a CLASSIC exam question 😭🧬⚡—and it’s actually super easy once you see it right.

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🧬 5’ vs 3’ (DNA / RNA DIRECTION)

👉 THE RULE:

➡ DNA/RNA is built 5’ → 3’

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🧠 WHAT THAT MEANS:

• 5’ end = phosphate (P)

• 3’ end = OH group

👉 New nucleotides are ALWAYS added to the 3’ end

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💅🏾 EASY WAY TO REMEMBER:

👉 “3 = growing tree 🌱”

Growth happens at the 3’ end

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🔄 STRAND DIRECTION (VERY TESTABLE)

DNA strands are:

➡ Antiparallel

That means:

• One strand: 5’ → 3’

• Other strand: 3’ → 5’

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🧪 VISUAL IN YOUR HEAD:

5’ ---------> 3’

3’ <--------- 5’

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🚨 PROFESSOR TRAP

If they ask:

👉 “Which end does DNA polymerase add to?”

✔ Answer: 3’ end

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⚡ BONUS (A+ DETAIL)

• DNA polymerase can ONLY build 5’ → 3’

• It reads the template 3’ → 5’

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👑 ONE-LINE CHEAT CODE

👉 “DNA grows 5’ → 3’, adding to the 3’ end.”

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