Cell Biology and Genetics Quiz

Cell Theory: All living organisms are composed of cells; the cell is the basic unit of life; all cells arise from pre-existing cells.
Types of Cells:
- Prokaryotic: No nucleus, smaller, simpler (e.g., bacteria).
- Eukaryotic: Nucleus present, larger, more complex (e.g., plant and animal cells).
Cell Organelles:
- Nucleus: Contains genetic material.
- Mitochondria: Powerhouse of the cell, energy production.
- Ribosomes: Protein synthesis.
- Endoplasmic Reticulum: Synthesizes proteins (rough ER) and lipids (smooth ER).
- Golgi Apparatus: Modifies, sorts, and packages proteins.

DNA Structure: Double helix composed of nucleotides (adenine, thymine, cytosine, guanine).
Gene: A segment of DNA that codes for a protein or functional RNA.
Mendelian Genetics:
- Principles of segregation and independent assortment.
- Dominant and recessive alleles.
Genetic Variation:
- Mutations: Changes in DNA sequence.
- Crossing over during meiosis: Increases genetic diversity.
Modern Genetics:
- Biotechnology (e.g., CRISPR, gene therapy).
- Genomics: Study of the genome.

Ecosystem: A community of living organisms interacting with their environment.
Biotic and Abiotic Factors:
- Biotic: Living components (plants, animals, microorganisms).
- Abiotic: Non-living components (water, temperature, soil).
Trophic Levels:
- Producers (autotrophs): Make their own food via photosynthesis.
- Consumers (heterotrophs): Obtain energy by eating other organisms.
- Decomposers: Break down dead organic matter, recycling nutrients.
Population Dynamics:
- Factors affecting population size: Birth rates, death rates, immigration, emigration.
- Carrying capacity: Maximum population an environment can sustain.

Theory of Evolution: Change in the heritable traits of biological populations over successive generations.
Natural Selection: Mechanism by which individuals with favorable traits are more likely to reproduce.
Speciation: Formation of new and distinct species in the course of evolution.
Evidence for Evolution:
- Fossil record.
- Comparative anatomy (homologous structures).
- Molecular biology (genetic similarities).

Homeostasis: The maintenance of a stable internal environment in an organism.
Organ Systems:
- Circulatory System: Transports nutrients and oxygen (e.g., heart, blood vessels).
- Respiratory System: Gas exchange (e.g., lungs).
- Digestive System: Breaks down food for absorption (e.g., stomach, intestines).
- Nervous System: Controls body functions and responds to stimuli (e.g., brain, nerves).
Feedback Mechanisms:
- Negative feedback: Diminishes the output of a system (e.g., temperature regulation).
- Positive feedback: Enhances the output of a system (e.g., childbirth).

Cell Theory: Comprises three main components: all organisms consist of cells; cells are the fundamental units of life; cells originate from existing cells.
Types of Cells:
- Prokaryotic Cells: Lack a nucleus, are smaller and simpler in structure; exemplified by bacteria.
- Eukaryotic Cells: Contain a nucleus, are larger and more complex; include plant and animal cells.
Cell Organelles:
- Nucleus: Houses genetic information (DNA).
- Mitochondria: Known as the powerhouse, responsible for ATP production and energy metabolism.
- Ribosomes: Sites for protein synthesis, either free in the cytoplasm or bound to the endoplasmic reticulum.
- Endoplasmic Reticulum: Comprises rough ER (with ribosomes for protein synthesis) and smooth ER (lipid synthesis and detoxification).
- Golgi Apparatus: Processes, sorts, and ships proteins and lipids produced in the ER.

DNA Structure: Features a double helix composed of four nucleotides: adenine, thymine, cytosine, and guanine.
Gene Definition: Segment of DNA that encodes instructions for synthesizing proteins or functional RNA molecules.
Mendelian Genetics: Encompasses principles including segregation (distribution of alleles) and independent assortment (gene combinations), and concepts of dominant versus recessive alleles.
Genetic Variation Mechanisms:
- Mutations: Permanent alterations in the DNA sequence which can affect traits.
- Crossing Over: Genetic recombination during meiosis enhancing variability in offspring.
Modern Genetics:
- Uses biotechnological advances like CRISPR for precise genome editing and gene therapy to treat genetic disorders, along with genomics for comprehensive genome analysis.

Ecosystem Definition: System comprising living organisms interacting with their physical surroundings.
Biotic vs. Abiotic Factors:
- Biotic Factors: Include all living elements such as plants, animals, and microorganisms.
- Abiotic Factors: Encompass non-living elements like water, temperature, and soil composition.
Trophic Levels:
- Producers: Autotrophic organisms that generate food via photosynthesis (e.g., plants).
- Consumers: Heterotrophic organisms that derive energy by consuming other living entities.
- Decomposers: Organisms (e.g., fungi, bacteria) that decompose dead matter, recycling nutrients back into the ecosystem.
Population Dynamics:
- Influenced by birth rates, death rates, immigration, and emigration.
- Carrying Capacity: The maximum population size that an environment can sustainably support.

Theory of Evolution: Describes gradual genetic changes in populations over generations, leading to biodiversity.
Natural Selection: Process through which individuals with advantageous traits are more likely to reproduce and pass on those traits.
Speciation: Formation of new species due to evolutionary processes, such as geographic separation or ecological niche differentiation.
Evidence Supporting Evolution:
- The fossil record illustrates chronological changes in species.
- Comparative anatomy highlights structures with common evolutionary origins (homologous structures).
- Molecular biology reveals genetic similarities among diverse organisms.

Homeostasis: The regulatory process that maintains stable internal conditions despite external environmental changes.
Organ Systems:
- Circulatory System: Comprises heart and blood vessels, facilitating nutrient and oxygen distribution.
- Respiratory System: Responsible for oxygen intake and carbon dioxide expulsion through lungs.
- Digestive System: Breaks down food into absorbable nutrients via organs like the stomach and intestines.
- Nervous System: Centralized control for body functions and responsive actions, involving the brain and nerves.
Feedback Mechanisms:
- Negative Feedback: Stabilizes systems by reducing output (e.g., thermoregulation).
- Positive Feedback: Amplifies responses, often leading to a specific outcome (e.g., the process of childbirth).