FINAL EXAM SUMMARIES

πŸ”΅ CHAPTER 1 β€” CELLS

What all cells have

  • Plasma membrane

  • Cytoplasm

  • Genetic material (DNA)

  • Ribosomes

Cell Theory

  1. All living things are made of cells

  2. Cells are the basic unit of life

  3. Cells come from pre-existing cells

Prokaryotes vs Eukaryotes

  • Prokaryotes: No nucleus, small, no membrane-bound organelles

  • Eukaryotes: Have nucleus, larger, membrane-bound organelles

πŸ”΅ CHAPTER 2 β€” CHEMISTRY OF LIFE

4 Biological Macromolecules

  1. Carbohydrates – energy, structure

  2. Lipids – membranes, hormones, long-term energy

  3. Proteins – enzymes, structure, transport

  4. Nucleic acids – DNA/RNA, genetic info

Monomer β†’ Polymer

  • Carbs: monosaccharides β†’ polysaccharides

  • Lipids: fatty acids + glycerol β†’ triglycerides/phospholipids

  • Proteins: amino acids β†’ polypeptides

  • Nucleic acids: nucleotides β†’ DNA/RNA

Dehydration vs Hydrolysis

  • Dehydration: Builds polymers by removing water

  • Hydrolysis: Breaks polymers by adding water

Functional Groups determine behavior

  • Polar, nonpolar, acidic, basic β€” affects solubility & interactions

πŸ”΅ CHAPTER 3 β€” METABOLISM & ENZYMES

Thermodynamics

  • Ξ”G < 0: exergonic, releases energy, spontaneous

  • Ξ”G > 0: endergonic, non-spontaneous

  • Coupled reactions: Use exergonic to power endergonic

Entropy (disorder)

  • High entropy = more disorder

  • Systems naturally move toward higher entropy

Enzymes

  • Speed up reactions by lowering activation energy

  • Substrate: molecule acted on

  • Active site: where substrate binds

  • Affected by pH and temperature

Redox

  • Oxidation = loss of electrons

  • Reduction = gain of electrons

  • Oxidizing agent gains eβˆ’

  • Reducing agent loses eβˆ’

πŸ”΅ CHAPTER 4 β€” PROTEINS

Amino Acid Basic Structure

  • Amino group (NHβ‚‚)

  • Carboxyl group (COOH)

  • R-group

  • Central carbon

  • N-terminus: amino end

  • C-terminus: carboxyl end

  • Backbone = repeating Nβ€”Cβ€”C

Amino Acid Groups

  • Polar

  • Nonpolar

  • Charged (acidic/basic)

Protein Structure Levels

  1. Primary β€” amino acid sequence

  2. Secondary β€” Ξ±-helix/Ξ²-sheet (H-bonds)

  3. Tertiary β€” 3D shape (all bond types)

  4. Quaternary β€” multiple polypeptides

Phosphorylation

  • Adds phosphate β†’ increases energy β†’ changes shape β†’ activates proteins

  • Dephosphorylation removes it

πŸ”΅ CHAPTER 5 β€” DNA

Who discovered DNA?

  • Watson & Crick, 1953

Nucleotide Structure

  • Sugar

  • Phosphate

  • Nitrogen base

DNA vs RNA

  • DNA: deoxyribose, T, double-stranded

  • RNA: ribose, U, single-stranded

Base Pairing

  • A=T (2 H-bonds)

  • C≑G (3 H-bonds)

Chromosomes

  • Somatic: 46

  • Gametes: 23

πŸ”΅ CHAPTER 6 β€” DNA REPLICATION & REPAIR

Major Enzymes

  • Helicase: unwinds

  • SSBPs: stabilize

  • Topoisomerase: prevents supercoiling

  • Primase: makes RNA primers

  • DNA Pol III: synthesizes DNA

  • DNA Pol I: removes primers, replaces with DNA

  • Ligase: seals fragments

Leading vs Lagging

  • Leading: continuous

  • Lagging: discontinuous, Okazaki fragments (due to 5’→3’ rule)

Why chromosomes shorten?

  • DNA polymerase cannot fully replicate the ends β†’ telomere shortening

DNA Repair (3 steps)

  1. Recognize

  2. Remove

  3. Replace

πŸ”΅ CHAPTER 7 β€” TRANSCRIPTION & TRANSLATION

Central Dogma

DNA β†’ RNA β†’ Protein

RNA Types

  • mRNA – message

  • tRNA – carries amino acids

  • rRNA – makes ribosome

mRNA Processing (Eukaryotes)

  1. 5’ cap

  2. Poly-A tail

  3. Splicing (remove introns)

Location

  • Prokaryotes: cytoplasm (no nucleus)

  • Eukaryotes: transcription in nucleus, translation in cytoplasm

Transcription Steps

  1. Initiation

  2. Elongation

  3. Termination

Translation Steps

  1. Initiation

  2. Elongation

  3. Termination

  • Use codon table to translate

πŸ”΅ CHAPTER 8 β€” GENE EXPRESSION

trp Operon (repressible)

  • Default ON

  • High tryptophan β†’ binds repressor β†’ shuts operon OFF

lac Operon (inducible)

  • Default OFF

  • Lactose present β†’ binds repressor β†’ turns ON

  • Low glucose β†’ high cAMP β†’ CAP activates transcription

Epigenetics

  • Modifying DNA or histones without changing sequence

  • Changes gene expression

πŸ”΅ CHAPTER 11 β€” CELL MEMBRANE

Components

  • Phospholipids

  • Cholesterol

  • Proteins

  • Carbohydrates

Fluidity Factors

  • More unsaturated fats β†’ more fluid

  • More cholesterol β†’ stabilizes (more fluid in cold, less in heat)

Proteins

  • Peripheral

  • Integral (transmembrane)

  • Functions: transport, receptors, enzymes

πŸ”΅ CHAPTER 12 β€” MEMBRANE TRANSPORT

What crosses easily?

  • Small nonpolar molecules (Oβ‚‚, COβ‚‚)

What cannot cross?

  • Ions, polar molecules (need help)

Passive Transport

  • Diffusion

  • Osmosis

  • Facilitated diffusion (channels/carriers)

Active Transport

  • Requires ATP (Na⁺/K⁺ pump)

Tonicity

  • Hypertonic: water leaves β†’ cell shrinks

  • Hypotonic: water enters β†’ cell swells

  • Isotonic: no net movement

πŸ”΅ CHAPTER 13 β€” CELL RESPIRATION

Purpose: Make ATP

Why oxidize food? Extract electrons.

3 Pathways

  1. Glycolysis

  2. Citric Acid Cycle

  3. Oxidative phosphorylation (ETC + Chemiosmosis)

Where COβ‚‚ made?

  • Pyruvate oxidation + Krebs

Where Oβ‚‚ used?

  • End of ETC (final electron acceptor)

Proton Gradient

  • High H⁺ in intermembrane space

  • Low H⁺ in matrix

Fermentation

  • Regenerates NAD⁺

πŸ”΅ CHAPTER 16 β€” CELL SIGNALING

Extracellular vs Intracellular Ligands

  • Extracellular ligands = polar/hydrophilic (can’t cross membrane)

  • Intracellular ligands = nonpolar/hydrophobic (cross membrane)

3 Receptors

  1. GPCRs

  2. RTKs

  3. Ion channels

GPCR Steps

  1. Ligand binds

  2. GDP β†’ GTP

  3. G protein activates target enzyme

  4. Second messengers produced

RTKs

  • Dimerize β†’ autophosphorylate

  • Partial vs full = one vs both receptors phosphorylated

Second Messengers

  • cAMP

  • Ca²⁺

  • IP₃

  • DAG

PLC produces:

  • IP₃ + DAG

Ca²⁺ location

  • High: ER lumen

  • Low: cytosol

πŸ”΅ CHAPTER 17 β€” CYTOSKELETON

Microfilaments (Actin)

  • Movement, shape, muscle contraction

  • Thinnest

Intermediate Filaments

  • Strength, stability

  • Keratin

Microtubules

  • Chromosome movement, vesicle transport, cilia/flagella

  • Made of tubulin

πŸ”΅ CHAPTER 18 β€” CELL CYCLE

Interphase: G1, S, G2

Mitotic phase: Mitosis + cytokinesis

G0 cells: Neurons, muscle cells

Definitions

  • Centromere: region where chromatids attached

  • Kinetochore: protein on centromere where spindle binds

  • Cohesin: holds chromatids together

  • Condensin: compacts chromosomes

  • Separase: cleaves cohesin

  • Securin: inhibits separase

  • Mitogen: signal that promotes division

  • Kinase: enzyme that phosphorylates

Checkpoints

  • G1: most important (decides division)

  • G2: DNA damage

  • M: spindle attachment

Cdk activation: requires binding to cyclin

πŸ”΅ CHAPTER 20 β€” CANCER

What is cancer?

Uncontrolled cell growth.

Benign vs Malignant

  • Benign: does not spread

  • Malignant: invades/spreads

Oncogenes

  • β€œGas pedal stuck ON”

  • Mutated version of proto-oncogenes

  • Gain-of-function

Tumor Suppressors

  • β€œBrakes fail”

  • Normally stop division

  • Loss-of-function causes cancer

Single-cell theory

  • A tumor comes from one mutated cell

Cell-kill theory

  • Need to kill % of cells each treatment