Regents Biology Review - Key Ideas 1-3

Introduction

Regents Biology Review series to help students with the Regents Living Environment Exam (New York State).
Can be used for general biology refreshers or other states' exam reviews.
Regents exam: Four-part, includes multiple choice, open-ended questions, and lab skills.
This video covers specific biology knowledge and content, focusing on key ideas 1-3.

Levels of Organization in Life:
- Population: Group of organisms of one species in one location.
- Trophic levels: Producers (autotrophs), Consumers (heterotrophs), Decomposers.
- Food Chains vs. Food Webs: Food chain shows one pathway, food web shows interconnected pathways.
- Autotrophs (Producers): Make their own food (e.g., plants).
- Heterotrophs (Consumers): Consume other organisms for food.
Trophic Pyramid:
- Energy transfer between levels, significant loss (90%) of energy with each level.
- More efficient to consume lower on the pyramid.
Ecosystem Factors:
- Biotic (living) and abiotic (non-living) factors interaction.
- Competition and interaction maintain stability.
- Carrying Capacity: Maximum population an environment can sustain.
- Human Impact: Complex interactions within human bodies; levels of cells, tissues, organs, systems maintaining homeostasis.

Homeostasis: Maintaining stable internal conditions (e.g., human sweating to cool down).
Cell Specialization:
- Organelle functions: Mitochondria (energy), Ribosomes (protein synthesis), Nucleus (DNA storage), Vacuole (storage), Cell Membrane (selective barrier), Cell Wall (support in plants), Chloroplast (photosynthesis).
- Differences between Eukaryotic and Prokaryotic cells:
  - Eukaryotic: Complex, membrane-bound organelles, DNA in nucleus.
  - Prokaryotic: Simpler, no membrane-bound organelles, DNA not enclosed, e.g., bacteria.
Cell Communication:
- Signaling pathways, hormone/receptor interactions.
- Disruption affects cell/organism stability (e.g., caffeine blocks adenosine).

Genes and Environment:
- Gene expression can be modified by the environment (e.g., identical twins in different environments).
- Traits often influenced by multiple genes.
DNA Structure and Function:
- DNA: Nucleic acid, composed of nucleotides (phosphate, sugar, base).
- Base Pairing: A-T, G-C; double helix structure.
- Genes code for proteins, different expression in different cells.
Protein Synthesis:
- Transcription (DNA to mRNA) and Translation (mRNA to protein).
- Universal genetic code shared by all organisms.
Genetic Engineering & Biotechnology:
- Selective Breeding: Artificial selection for desired traits.
- Genetic Engineering: Manipulating genes (e.g., Bt corn, modified bacteria).
- Gel Electrophoresis: DNA fingerprinting for analysis, paternity testing, studying evolutionary relationships.

Evolutionary Processes:
- Species evolve from earlier distinct species via gene mutations and inheritance.
- Adaptation to environments via natural selection (e.g., antibiotic-resistant bacteria).
Phylogenetic Trees (Cladograms):
- Diagrams showing evolutionary relationships, common ancestors.
- Traits appearing on branches show relatedness.
- Populations evolve, individuals don't.
Extinction and Fossil Record:
- Environmental changes can lead to species extinction.
- Most species that have existed are extinct, evidenced by fossil record.