Note
Studied by 10 people
exam 3 cbg terms
The cell cycle – outline
🧠 MIND MAP STRUCTURE
1. Levels of Biological Organization
Atom → Macromolecule → Organelle → Cell → Organism
Cells → 2 cells (cell division)
2. DNA, Genes & Chromosomes
DNA Replication: Occurs in S phase
Transcription / Central Dogma happens anytime
Enough DNA in one human to stretch to the moon
Genes are coding regions in DNA
Chromatin = DNA + histones
Chromosomes → Sister Chromatids → Chromatin
G1 = Linear Chromosome
S = X-shaped Chromosome (2 sister chromatids)
G2 = Chromosome still in X-shape
22 pairs autosomes + 1 pair sex chromosomes
Y = male / No Y = female
Chromosome number varies by species but is consistent within a species
3. Cell Cycle
Phases:
Interphase (G1 – organelle growth, S – DNA synthesis, G2 – centrosomes form, G0 – cell leaves cycle and stops)
Mitosis (Prophase, Prometaphase, Metaphase, Anaphase, Telophase)
Cytokinesis
Mitosis Key Events:
Prophase: spindle forms, nuclear envelope disappears
Prometaphase: kinetochores form at centromeres
Metaphase: chromosomes align at metaphase plate
Anaphase: sister chromatids pulled apart
Telophase: nuclear envelope reforms, chromosomes decondense
Cytokinesis:
Animal: cleavage furrow (actin)
Plant: cell plate (vesicles)
Centrosomes: organize microtubules, contain centrioles
Binary Fission:
Prokaryotic cell division (origin replicates, moves to poles, cell divides)
Eukaryote: mitosis
Prokaryote: binary fission
Some unicellular eukaryotes divide in intermediate ways
Mitosis vs Meiosis: mitosis = diploid (1 division), meiosis = haploid (2 divisions)
4. Cell Cycle Regulation
Checkpoints:
G1: environment favorable, DNA damage
G2: DNA replication complete, damage repair
M: chromosomes aligned properly
Regulators:
Cyclins: cycle in abundance (e.g. Cyclin B accumulates in S & G2, degraded in anaphase)
CDKs: always present, need cyclin to activate
MPF = Cyclin B + CDK1 (phosphorylates proteins to move from G2 → M)
5. Cell Aging & Immortality
Telomeres: repeat sequences on chromosome ends that shorten with division
Telomerase: enzyme that restores telomeres (germ, stem, cancer cells)
Henrietta Lacks / HeLa Cells: immortalized line used in research
Cell Senescence: cell stops dividing due to telomere shortening
6. Cancer vs. Normal Cells
Normal:
Growth factors, density-dependent inhibition, anchorage dependence
Cancer:
Neoplasm (neo = new, plasm = growth): a new growth of cells that is abnormal
Malignant = cancer: when cells invade adjacent tissue they are considered cancer
Benign = non-cancerous: tumor cells do not invade, but can kill if it’s not possible to remove tumor due to location (brain)
7. Meiosis
Purpose: produces haploid gametes
Phases:
Prophase I: crossing over (chiasmata), spindle forms, envelope disappears
Metaphase I: homologous chromosomes line up
Anaphase I: homologous chromosomes pulled apart
Telophase I / Cytokinesis I: divide
Prophase II – Telophase II: like mitosis but with non-identical chromatids
Genetic Variation:
Crossing over (Prophase I)
Independent Assortment
Random Fertilization
8. Key Vocabulary / Concepts
Sister chromatids = identical halves of a duplicated chromosome
Homologous chromosomes = same genes, different alleles
Non-Homologous chromosomes: different traits
Locus = gene location
Diploid = full set of chromosomes
Haploid = half set of chromosomes
Karyotype = chromosomal makeup
Allele = version of a gene
9. Sex Chromosomes & Disorders
X = 1,100 genes
Y = 450 genes
Disorders:
Trisomy 21: Chromosome 21 fails to properly separate (Down Syndrome)
Trisomy 13 (Patau Syndrome)
Turner Syndrome (X): Female only receives 1 X; born with 45 chromosomes
Klinefelter Syndrome (XXY): reduced fertility
Jacob Syndrome (XYY): increased testosterone, tall, lean
(Aneuploidy: abnormal number of chromosomes)
10. Egg Meiosis / Arrests
Egg arrests in Prophase I after birth
After puberty → completes Meiosis I, arrests at Metaphase II
Fertilization → completes Meiosis II
📚 FLASHCARD STUDY LIST
Use flashcards for terms + definitions:
Atom, Macromolecule, Organelle, Cell, Organism
Chromatin, Chromatid, Chromosome
Gene, Allele, Locus, Karyotype
Homologous vs. Non-homologous Chromosomes
Diploid vs. Haploid
G1, S, G2, G0
Prophase, Prometaphase, Metaphase, Anaphase, Telophase
Cytokinesis
Centrosome, Centriole, Kinetochore, Centromere
Binary Fission
Cyclin, CDK, MPF
Telomere, Telomerase, Senescence
Crossing Over, Independent Assortment, Random Fertilization
Nondisjunction, Aneuploidy
Trisomy 21, 13, Turner, Klinefelter, Jacob Syndromes
🎥 DIAGRAM / VIDEO STUDY LIST
Use visual aids for these:
- The entire Cell Cycle and Mitosis process
- Meiosis I & II step-by-step with crossing over
- Binary Fission vs. Mitosis comparison
- MPF activation and Cyclin/CDK cycle
- Telomerase function & telomere shortening
- Chromosome alignment in meiosis and mitosis
- Genetic disorders and their karyotypes
- Egg Arrests: visual of stages and when they pause
- Cell Checkpoints and Regulation mechanisms
📌 Video links you saved:
Exam 3:
Mendel and the gene idea
🧠 MIND MAP STRUCTURE
🧬 1. Key Genetic Concepts
Genotype: genetic makeup
Phenotype: physical makeup
Allele: different versions of a gene (e.g., brown vs green eye color)
Heredity: transmission of traits from one generation to the next
Trait: a variant of a character
Character: a heritable feature that varies among individuals
Genetics: study of heredity
🧪 2. Historical Genetic Theories
Lamarck Inheritance: Acquired traits can be inherited (disproven by Mendel)
Example: Long necks in giraffes passed down if mother stretched her neck (proven false)
Gregor Mendel: Father of modern genetics
Pea plant experiments
Traits are inherited from one generation to the next
Disproved Lamarck
Discovered dominant vs recessive traits
Organisms inherit two gene copies (1 from each parent)
🌱 3. Mendelian Inheritance
Key Terms:
Homozygous dominant (BB)
Heterozygous (Bb)
Homozygous recessive (bb)
True breeding: Homozygous for alleles
P, F1, F2 generations
Dominance: Dominant alleles mask recessive
Punnett Squares used to determine inheritance
Example:
B= brown eyes
b= blue eyes
BB = homozygous dominant
Bb= heterozygous
bb= homozygous recessive
⚖ 4. Mendel's Laws
Law of Segregation: Alleles separate during meiosis
Lowercase = recessive
Uppercase = dominant
Law of Independent Assortment: Inheritance of one trait doesn't affect another
🧬 5. Dominance Patterns
Complete Dominance Disorders:
Recessive: Sickle Cell, Cystic Fibrosis, Tay-Sachs
Dominant: Huntington’s, Autosomal Polycystic Kidney Disease, Osteopetrosis
⚠ 6. Exceptions to Mendelian Genetics
Incomplete Dominance: Intermediate traits (e.g., wavy hair)
Codominance: Both traits expressed (e.g., calico cat, blood types A and B)
Epistasis: One gene affects another's expression (e.g., pigment in labs)
Polygenic Inheritance: Multiple genes affect a trait (e.g., skin color)
Epigenetic Inheritance: Environment affects DNA gene expression (e.g., identical twins differ)
Þ Codominance in humans:
- We have three alleles for blood type A, B and O blood.
- A and B are codominant, and O is recessive to both.
👩🔬 7. Sex-Linked Traits
Men inherit X-linked traits more (no extra X to mask recessive traits)
Examples:
Duchenne Muscular Dystrophy: Muscle breakdown due to DMD gene mutation
Hemophilia: Blood doesn’t clot properly
Color Blindness
Genotypes:
o H = no hemophilia
o H = hemophilia
o XHY = make without hemophilia
o XhY = male with hemophilia
o XHXH = female without hemophilia
o XHXh = female without but is a carrier
🧬 8. Chromosomal Basis of Inheritance
Chromosome Theory: Genes have specific locations (loci) on chromosomes and undergo segregation and independent assortment
Genes on Chromosomes: Hundreds to thousands per chromosome
Model Organisms: Organism used to study biological processes (e.g., fruit flies)
Thomas Morgan: First evidence linking genes to chromosomes
Fruit fly red/white eye experiment → 3:1 ratio in F2 generation
📊 9. Genetic Mapping Tools
Pedigrees: Trace family lineage and inheritance
Linked Genes: Exception to Mendel’s Law of Indep. Assort.; Genes that are linked and are on the same chromosome will be inherited together.
Genetic Recombination (Crossing Over): Results in new phenotypes; Explains why linked genes sometimes separate
🧬 10. Chromosome Alterations
Deletion: Loss of a chromosome fragment
Prader-Willi (obesity, cognitive delay)
Angelman (ataxia, seizures, laughter)
Duplication: Extra gene copies
Charcot-Marie-Tooth (affects neurons)
Inversion: Chromosome segment flipped
Walker-Warburg syndrome (muscle and brain development issues)
Translocation: Part of a chromosome moves to another
Emmanuel Syndrome (growth and motor delays)
🔋 11. Organelle Genes
Non-nuclear DNA: Found in mitochondria and chloroplasts
Mitochondrial DNA (mtDNA):
Affects high-energy organs (muscles, brain)
Conditions: Mitochondrial Myopathy, Leber’s Hereditary Optic Neuropathy
🧫 12. Membrane Structure and Function
Plasma Membrane Functions:
Maintains cell shape and isolation from environment
Controls cellular interactions
Structure:
Lipids, Proteins, Carbohydrates (5–10% for cell communication)
Protein Types:
Peripheral: Associated via other proteins
Integral: Embedded in membrane
Protein Functions:
Transport
Enzymatic activity
Cell-to-cell recognition
Intercellular joining
Membrane Protein Mobility: Move laterally, not vertically
Membrane Fluidity Factors:
Unsaturated fatty acids (kinked tails = more fluid)
Cholesterol
Unsaturated fatty acids form kinks
Have double bonds that form bends causing tail to kink.
Phospholipids form kinks in tail that allows it to move more / more fluid, and prevents it from tightly packing.
Saturated fatty acids don’t have kinks so the phospholipids are tightly packed together making it less fluid / not able to move much.
Transport Types:
(Note: Incomplete in your notes—can add more here if you have them!)
Study Strategies (Flashcards vs. Visuals)
📇 Flashcard Material (Terms & Definitions)
Use flashcards for:
All vocabulary/definitions under Key Genetic Concepts
Dominant vs. Recessive Disorders
Mendelian terms (e.g., Homozygous, Heterozygous, P/F1/F2 Generations)
Types of dominance (Incomplete, Codominance, etc.)
All chromosome alteration types & their conditions (Deletion, Duplication, etc.)
Organelle Genes & mtDNA conditions
All sex-linked terms and genotypes
Membrane protein types and their functions
All laws (Segregation, Independent Assortment)
🧠 Visual Study Tools (Diagrams, Images, and Videos)
Use visuals/diagrams for:
Punnett squares (with genotype/phenotype outcomes)
Inheritance patterns (esp. sex-linked traits)
Linked genes and genetic recombination (crossing over)
All chromosome alteration types
Pedigrees and model organism experiments (fruit fly example)
Epistasis, Incomplete dominance, Codominance examples
Membrane structure and fluidity (lipid bilayer + protein movement)
Mitochondrial DNA inheritance and impact
