Cell Structure and Genetics Overview

Cell Theory: All living organisms are composed of cells; the cell is the basic unit of life.
Types of Cells:
- Prokaryotic: No nucleus, smaller, simpler (e.g., bacteria).
- Eukaryotic: Nucleus present, larger, more complex (e.g., plant and animal cells).
Organelles:
- Nucleus: Contains DNA, controls cell activities.
- Mitochondria: Powerhouse of the cell, site of ATP production.
- Ribosomes: Protein synthesis.
- Endoplasmic Reticulum (ER): Rough ER (with ribosomes) synthesizes proteins; Smooth ER synthesizes lipids.
- Golgi Apparatus: Modifies, sorts, and packages proteins.
- Lysosomes: Digestive enzymes for waste processing.

DNA Structure: Double helix composed of nucleotides (adenine, thymine, cytosine, guanine).
Genes: Segments of DNA that code for proteins.
Chromosomes: Structures made of DNA and proteins; humans have 46 (23 pairs).
Mendelian Genetics:
- Law of Segregation: Alleles segregate during gamete formation.
- Law of Independent Assortment: Genes for different traits are inherited independently.

Natural Selection: Mechanism of evolution; organisms better adapted to their environment tend to survive and reproduce.
Speciation: Formation of new species through evolutionary processes.
Fossil Record: Evidence of past life and evolutionary changes over time.

Ecosystem: Community of living organisms and their physical environment.
Biomes: Large ecological areas (e.g., deserts, forests, grasslands) characterized by specific climate and vegetation.
Food Chains and Webs: Energy flow through ecosystems; producers (plants) → consumers (herbivores, carnivores) → decomposers.

Circulatory System: Transports blood, nutrients, gases; consists of heart, blood vessels, and blood.
Respiratory System: Facilitates gas exchange; includes lungs and respiratory passages.
Digestive System: Breaks down food into nutrients; includes stomach, intestines, and associated organs.
Nervous System: Controls body functions; includes brain, spinal cord, and nerves.

Bacteria: Single-celled prokaryotes; can be beneficial (e.g., gut flora) or pathogenic.
Viruses: Acellular entities that require a host to replicate; can cause diseases.
Fungi: Eukaryotic organisms, important for decomposition and nutrient cycling.

Photosynthesis: Process by which plants convert sunlight into chemical energy (glucose).
Plant Structures:
- Roots: Anchor and absorb water/nutrients.
- Stems: Support and transport nutrients.
- Leaves: Primary site of photosynthesis.

Innate Behavior: Instinctual, genetically programmed behaviors.
Learned Behavior: Acquired through experience or interaction with the environment.
Social Behavior: Interactions among individuals of the same species (e.g., mating rituals, territoriality).

Genetic Engineering: Manipulation of an organism’s DNA to create desired traits.
CRISPR: A tool for editing genomes, allowing scientists to alter DNA sequences and modify gene function.
Cloning: Producing a genetically identical copy of an organism.

Cell Theory: Fundamental concept stating all living things are made of cells; cells are the basic unit of life.
Types of Cells: Prokaryotic cells lack a nucleus and are simpler and smaller; eukaryotic cells possess a nucleus and are larger and more complex.
Nucleus: Main organelle that contains DNA, regulates cell activities and gene expression.
Mitochondria: Known as the powerhouse of the cell, responsible for ATP (energy) production through respiration.
Ribosomes: Sites for protein synthesis, can be found free in the cytoplasm or attached to the endoplasmic reticulum.
Endoplasmic Reticulum (ER): Composed of rough ER, which synthesizes proteins, and smooth ER, which is involved in lipid synthesis.
Golgi Apparatus: Processes and packages proteins for secretion or use within the cell.
Lysosomes: Contain digestive enzymes that break down waste materials and cellular debris.

DNA Structure: Consists of a double helix formed by nucleotide pairs (adenine with thymine, cytosine with guanine).
Genes: Defined segments of DNA that encode instructions for protein synthesis.
Chromosomes: Structures comprising DNA and proteins; humans have 46 chromosomes, arranged in 23 pairs.
Mendelian Genetics: Introduces key laws such as the Law of Segregation (allele separation during gamete formation) and the Law of Independent Assortment (inheritance of traits independently).

Natural Selection: A primary mechanism driving evolution; favors organisms that are better adapted to their environment, enhancing survival and reproduction.
Speciation: The evolutionary process that results in the formation of new species.
Fossil Record: Documents the history of life and illustrates evolutionary changes over geological time.

Ecosystem: An interactive network of living organisms and their physical environment.
Biomes: Major ecological regions defined by climate and vegetative characteristics, including deserts, forests, and grasslands.
Food Chains and Webs: Demonstrate the flow of energy through ecosystems, starting from producers (plants) to various levels of consumers and decomposers.

Circulatory System: Comprised of the heart, blood vessels, and blood; it circulates nutrients, gases, and waste products throughout the body.
Respiratory System: Key for gas exchange, primarily involving the lungs and associated airways.
Digestive System: Processes food, breaking it down into absorbable nutrients; includes the stomach and intestines.
Nervous System: Regulates and controls body functions, utilizing the brain, spinal cord, and peripheral nerves.

Bacteria: Single-celled prokaryotic organisms that can have beneficial roles (like gut flora) or cause diseases.
Viruses: Non-cellular entities that require host cells to replicate and can cause a variety of illnesses.
Fungi: Eukaryotic organisms that play critical roles in nutrient recycling and decomposition in ecosystems.

Photosynthesis: The process through which plants transform sunlight into chemical energy stored as glucose.
Plant Structures:
- Roots: Anchor plants and absorb water and nutrients from the soil.
- Stems: Provide structural support and transport nutrients and water.
- Leaves: Main site for photosynthesis, equipped with chlorophyll for capturing sunlight.

Innate Behavior: Instinctual actions that are genetically programmed in a species.
Learned Behavior: Behaviors acquired through interaction with the environment and experiences.
Social Behavior: Refers to interactions among members of the same species, including mating rituals and territorial displays.

Genetic Engineering: The intentional manipulation of an organism's DNA to create specific traits or alterations.
CRISPR: A revolutionary gene-editing tool enabling precise modifications of DNA sequences.
Cloning: The process of producing a genetically identical organism through cellular replication techniques.