Final Exam Review Flashcards

DNA Structure: DNA consists of a sugar-phosphate backbone with base pairs (Adenine, Thymine, Cytosine, Guanine) acting as rungs. The sugar and phosphate form the side rails of the DNA structure, while the bases form the rungs.
Base Pairing in DNA:
- Adenine (A) pairs with Thymine (T).
- Guanine (G) pairs with Cytosine (C).
Full Names of Bases:
- A: Adenine
- T: Thymine
- C: Cytosine
- G: Guanine
- U: Uracil (found in RNA)
DNA Replication Steps:
1. Initiation
2. Elongation
3. Termination
Transcription and Translation:
- Transcription: DNA is transcribed into mRNA.
  1. Initiation
  2. Elongation
  3. Termination
  4. Processing
- Translation: mRNA is translated into protein.
  1. Initiation
  2. Elongation
  3. Termination
  4. Modification

Diploid vs. Haploid Cells:
- Haploid cells: Contain one set of chromosomes and are produced by meiosis.
- Diploid cells: Contain two sets of chromosomes and are produced by mitosis.
Homologous Chromosomes: These are pairs of one maternal and one paternal chromosome that pair up during meiosis.
Number of Chromosomes in Humans: Humans have $46$ chromosomes.
Sex Chromosomes: Chromosomes that determine an individual's sex.
Cancer: Results from genetic mutations that disrupt normal cell growth.

Genotype vs. Phenotype:
- Genotype: The unique sequence of DNA.
- Phenotype: The observable expression of the genotype.
Pure vs. Hybrid:
- Hybrids: Offspring resulting from a cross between two species, inheriting genes from both.
Heterozygous vs. Homozygous:
- Heterozygous: Having two different alleles for a trait.
- Homozygous: Having two identical alleles for a trait.
Dominant vs. Recessive:
- Dominant traits: Expressed when the connected allele is dominant.
- Recessive traits: Expressed only if both connected alleles are recessive.
Punnett Squares & Pedigrees:
- Punnett Squares: Used to predict the genotypes and phenotypes of offspring from a genetic cross.
- Pedigrees: Family trees tracing the inheritance of traits through multiple generations.
Pedigree Definition: A family tree that traces the inheritance of traits, genetic disorders, and other characteristics through multiple generations.

Producers vs. Consumers:
- Producers: Organisms that make their own food (e.g., plants).
- Consumers: Organisms that obtain energy by eating other organisms.
Types of Consumers:
- Herbivores
- Carnivores
- Omnivores
- Decomposers
Energy Flow in Energy Pyramid: Energy decreases as it moves up through the trophic levels.
Cycles in Nature:
- Water cycle
- Carbon cycle
- Nitrogen cycle
Ecological Relationships:
- Competition: Organisms compete for the same resources.
- Mutualism: Both species benefit from the interaction.
- Commensalism: One species benefits, while the other is neither helped nor harmed.
- Parasitism: One organism (the parasite) benefits at the expense of the other (the host).
Predator-Prey Relationship: The predator hunts, kills, and consumes the prey.
Food Chain: A sequence of organisms in which each one is a food source for the next.
Food Web: A visual representation of the feeding relationships between different organisms in an ecosystem.
Energy Pyramid: A diagram showing the flow of energy through different trophic levels in an ecosystem.

Pangea: A supercontinent that existed in the late Paleozoic and early Mesozoic eras.
Plate Tectonics and Fossil Evidence: The Earth's outer shell is broken into large rigid pieces (tectonic plates) that move and interact, supporting the idea that life on Earth has changed over time.
Law of Superposition: In layered beds, the lowest bed is the oldest, and the highest bed is the youngest.
Evolution vs. Natural Selection:
- Natural selection: The process by which advantageous traits increase in a population.
- Evolution: The broader change in genetic characteristics over time.
Importance of Species Evolution: Crucial for understanding the diversity and adaptability of life on Earth, shaping everything from individual traits to entire ecosystems.
Importance of Natural Selection: Crucial for understanding the diversity of life, the evolution of adaptation, and the origin of new species.
Human Impact on Species Evolution and Natural Selection: Humans impact species evolution and natural selection by creating artificial selection, altering environments, and introducing pressures on species.

Meiosis: Produces $4$ genetically different haploid cells (gametes).
Crossing Over: Increases genetic diversity during Prophase I.
Variation: Essential for evolution.
DNA: Contains instructions for proteins.
Transcription (nucleus): DNA → mRNA
Translation (ribosome): mRNA → protein
Protein Synthesis: Leads to cell specialization because only certain genes are turned 'on'.
Environmental Influence: The environment (like temperature, soil, diet) can influence gene expression.
Example: Siamese cats have darker fur in cooler areas due to temperature-sensitive gene expression.
Cancer: Occurs when cells lose control over cell division.

Camels: Originated in North America and spread due to tectonic plate movement and land bridges.
Fossil Distribution: Shows species like Mesosaurus and Glossopteris on different continents, supporting the idea of Pangaea and plate tectonics.
Species Evolution: Species like llamas and camels evolved differently on separate continents due to isolation (divergent evolution).
Natural Selection: Organisms with beneficial traits survive and reproduce.
Adaptation: A trait that increases an organism's survival chances.
Fitness: Ability to survive & reproduce.
Requires: Variation, competition, and reproduction.

Deforestation and Habitat Destruction: Major causes of biodiversity loss.
Pollution, Climate Change, and Invasive Species: Also reduce biodiversity.
Human Help: Humans can help by creating wildlife preserves, planting native species, and passing conservation laws.
Rising $CO_2$ Levels: Contribute to the greenhouse effect, trapping heat and raising global temperatures.
Climate Change: Causes habitat loss, species extinction, coral bleaching, and ocean acidification.
Indirect Effects: Include shifts in plant blooming, migration patterns, and food web disruptions.