Comprehensive Notes on DNA, Genetics, Evolution, and Animal Kingdom

DNA, Genetics, Evolution, and Animal Kingdom Overview

DNA:
- Deoxyribonucleic Acid.
- Function: To store genetic information and instructions for building proteins.
Nucleotide:
- Parts: A phosphate group, a deoxyribose sugar, and a nitrogenous base.
Deoxyribose:
- Sugar in DNA.
Nitrogenous bases in DNA:
- Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
Chargaff's Rule:
- A = T and C = G; base pairs are always in these ratios.
Hydrogen bonds:
- A-T has 2 bonds.
- C-G has 3 bonds.
- C-G bonds are stronger and more stable due to having more hydrogen bonds.
Sugar-phosphate backbone:
- The outer structure of DNA made of alternating sugar and phosphate groups.
Importance of weak hydrogen bonds:
- They allow DNA strands to separate for replication and transcription.
Shape of DNA:
- A double helix.

Topoisomerase:
- Relieves tension in the DNA strand.
Helicase:
- Unzips the DNA double helix.
Single-strand binding proteins:
- Keep DNA strands apart during replication.
DNA polymerase:
- Adds new nucleotides to form a new DNA strand.
Okazaki fragments:
- Short DNA fragments on the lagging strand during replication.
Reason for Okazaki fragments:
- DNA polymerase can only build 5' to 3', requiring fragments on the lagging strand.
Direction of DNA replication:
- 5' to 3' direction.

DNA \rightarrow RNA \rightarrow Protein.
Transcription:
- Location: In the nucleus.
- Job: To create mRNA from DNA.
- Enzyme: RNA polymerase.
Translation:
- Location: On ribosomes in the cytoplasm.
- Job: To assemble proteins using mRNA.
- Performer: Ribosome (not an enzyme).

Fitness in biology:
- The ability of an organism to survive and reproduce.
Somatic cell mutation:
- Affects the individual.
Gamete mutation:
- Affects offspring.
Types of mutations:
- Hurtful: reduce fitness.
- Beneficial: increase fitness.
- Neutral: no effect.
- Deletion: A base is removed.
- Inversion: A DNA segment flips and reinserts.
- Duplication: A DNA segment is copied.
- Frameshift insertion: A base is added, altering the reading frame.
- Frameshift deletion: A base is removed, altering the reading frame.
- Missense: A change that results in a different amino acid.
- Nonsense: A change that creates a stop codon.
- Silent: A change that does not alter the amino acid.

Early Earth conditions:
- It lacked oxygen, had extreme temperatures, and frequent meteor impacts.
Oparin's proposal:
- Life began from simple organic compounds in Earth's early oceans.
Primordial soup:
- A mixture of organic molecules from which life began.
Protocell:
- A simple membrane-bound structure that may have led to life.
Organic molecules:
- Can form from inorganic substances under early Earth conditions.
Autotrophs:
- Make their own food.
Heterotrophs:
- Consume others.
Oxygen in the atmosphere:
- Allowed complex life and aerobic respiration.
Spontaneous generation:
- Life arises from non-living matter.
- Disproved by:
  - Francesco Redi (meat and maggots experiment).
  - Louis Pasteur (swan-neck flask).
Leeuwenhoek's contribution:
*Observed cells.
Hooke's contribution:
*Named 'cells.'

Theory in science:
- A well-tested explanation for a broad set of observations.
Species:
- Group that can breed.
Population:
- All individuals in one area.
Lamarck's theory:
- Traits acquired during life are inherited (Law of Use and Disuse).
Darwin's adaptations:
- Traits that help organisms survive.
- Examples: Camouflage, mimicry, sharp teeth, hibernation, migration, etc.
Darwin's six points of evolution:
- Overproduction, competition, variation, adaptation, natural selection, speciation.
Fossils:
- Rare because they need specific conditions to form.
- Five types: Petrified, mold/cast, carbon film, trace, preserved remains.
Tiktaalik:
- A transitional fossil showing features of fish and amphibians.
Homologous structures:
- Same structure, different function.
Analogous structures:
- Same function, different structure.
Vestigial structures:
- Structures with no current function.
Embryo similarities:
- Suggest common ancestry.
DNA similarities:
- Suggest relatedness among species.
Six mechanisms of evolution:
- Natural selection, mutation, gene flow, genetic drift, non-random mating, artificial selection.
Genetic drift:
- Random changes in gene frequencies.
- Bottleneck effect: A disaster reduces population.
- Founder effect: A small group starts a new population.

Three domains of life:
- Bacteria, Archaea, Eukarya.
Bacteria shapes:
- Coccus (spherical), bacillus (rod), spirillum (spiral).
Archaea:
- Extremophiles - live in extreme environments.
Eukarya kingdoms:
- Protista, Fungi, Plantae, Animalia.
Plantae:
- Use chlorophyll for photosynthesis.
Mnemonic For Taxonomy
*Dear King Philip Came Over For Great Spain (Domain -> Species).

Macroevolution:
- Large-scale evolutionary changes over time.
Four types of macroevolution:
- Extinction, adaptive radiation, convergent evolution, coevolution.
Cambrian Explosion:
- A rapid increase in animal diversity ~540 million years ago.

Properties of all animals:
- Multicellular, heterotrophic, eukaryotic, no cell walls.
Bilateral symmetry:
- Two sides.
Radial symmetry:
- Circular symmetry.
Direct development:
- Mini adult form.
Metamorphosis development:
- Dramatic change.
Porifera traits:
- No symmetry, filter feeders, spicules.
Cnidaria traits:
- Radial symmetry, nematocysts, medusa/polyp forms.
Platyhelminthes traits:
- Parasitic, hermaphroditic, flatworms.