Biology Chapter on Cell Structure and Genetics

Cell Types:
- Prokaryotic: Simple, no nucleus (e.g., bacteria).
- Eukaryotic: Complex, nucleus present (e.g., plants, animals).
Organelles:
- Nucleus: Contains genetic material (DNA).
- Mitochondria: Powerhouse, site of ATP production.
- Ribosomes: Site of protein synthesis.
- Endoplasmic Reticulum (ER): Rough (with ribosomes) for protein synthesis; Smooth (no ribosomes) for lipid synthesis.
- Golgi Apparatus: Modifies, sorts, and packages proteins.
- Lysosomes: Digestive organelles, breakdown waste.
- Cell Membrane: Selectively permeable barrier.

DNA Structure: Double helix made of nucleotides (A, T, C, G).
Gene Expression:
- Transcription: DNA to RNA.
- Translation: RNA to protein.
Mendelian Genetics:
- Law of Segregation: Alleles separate during gamete formation.
- Law of Independent Assortment: Genes for different traits can segregate independently.

Natural Selection: Process by which organisms better adapted to their environment tend to survive and produce more offspring.
Evolutionary Evidence:
- Fossil Record: Shows gradual changes over time.
- Comparative Anatomy: Homologous structures indicate common ancestry.
- Molecular Evidence: DNA sequencing shows genetic similarities.

Ecosystems: Interactions between living organisms and their environment.
Biomes: Large regions characterized by climate and flora/fauna (e.g., desert, rainforest).
Energy Flow:
- Producers (autotrophs): Convert sunlight into energy.
- Consumers (heterotrophs): Obtain energy by consuming other organisms.
- Decomposers: Break down dead organic matter, recycling nutrients.

Organ Systems:
- Circulatory: Transports blood, nutrients, gases.
- Respiratory: Exchanges oxygen and carbon dioxide.
- Digestive: Breaks down food, absorbs nutrients.
- Nervous: Transmits signals, controls responses.
- Immune: Defends against pathogens.

Genetic Engineering: Manipulation of an organism's DNA to achieve desired traits (e.g., GMOs).
CRISPR: A technology used for editing genomes with precision.
Cloning: Creating a genetically identical copy of an organism.

Homeostasis: Maintaining stable internal conditions (e.g., temperature, pH).
Metabolism: All chemical reactions occurring within an organism (catabolism and anabolism).

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

Bacteria: Single-celled prokaryotes; can be beneficial (gut flora) or pathogenic.
Viruses: Non-living entities that require a host to replicate; can cause diseases.

Innate Behavior: Instinctual, genetically programmed actions (e.g., reflexes).
Learned Behavior: Acquired through experience or observation (e.g., conditioning).

Biodiversity: Variety of life in a particular habitat/ecosystem.
Endangered Species: Species at risk of extinction due to habitat loss, climate change, etc.
Conservation Strategies: Protected areas, legislation, restoration ecology.

Prokaryotic cells are simpler organisms without a nucleus, exemplified by bacteria.
Eukaryotic cells have a complex structure with a nucleus, including plant and animal cells.
The nucleus houses genetic material (DNA) essential for cell function and reproduction.
Mitochondria are known as the powerhouse of the cell, producing ATP, the energy currency.
Ribosomes serve as the site for protein synthesis, crucial for cellular functions.
The Endoplasmic Reticulum (ER) exists in two forms: Rough ER for protein synthesis and Smooth ER for lipid synthesis.
The Golgi Apparatus modifies, sorts, and packages proteins for transport and secretion.
Lysosomes contain digestive enzymes to break down waste and cellular debris.
The cell membrane acts as a selectively permeable barrier, regulating the movement of substances in and out of the cell.

DNA is structured as a double helix, composed of nucleotide bases adenine (A), thymine (T), cytosine (C), and guanine (G).
Gene expression involves two key processes: transcription (DNA to RNA) and translation (RNA to protein).
Mendelian genetics includes the Law of Segregation, where alleles separate during gamete formation, and the Law of Independent Assortment, indicating genes for different traits segregate independently.

Natural selection is a fundamental process where organisms best adapted to their environment survive and reproduce more successfully.
Evidence for evolution includes the fossil record, which documents gradual changes over time.
Comparative anatomy highlights homologous structures that reveal common ancestry among species.
Molecular evidence, such as DNA sequencing, demonstrates genetic similarities that support evolutionary theory.

Ecosystems consist of interactions between living organisms and their physical environment.
Biomes are large ecological areas defined by distinct climate and characteristic flora/fauna, including deserts and rainforests.
Energy flow within ecosystems involves producers (autotrophs), consumers (heterotrophs), and decomposers, each playing a critical role in nutrient cycling.

The circulatory system transports blood, nutrients, and gases throughout the body.
The respiratory system facilitates the exchange of oxygen and carbon dioxide.
The digestive system breaks down food to absorb essential nutrients.
The nervous system transmits signals and controls bodily responses.
The immune system protects the body against pathogens and infections.

Genetic engineering involves altering an organism's DNA to create desired traits, such as in genetically modified organisms (GMOs).
CRISPR technology allows for precise editing of genomes, representing a significant advancement in biotechnology.
Cloning is the process of creating a genetically identical organism, raising ethical and biological considerations.

Homeostasis refers to the maintenance of stable internal conditions like temperature and pH vital for survival.
Metabolism encompasses all chemical reactions within an organism, divided into catabolism (breaking down molecules) and anabolism (building up molecules).

Photosynthesis is the process where plants convert light energy into chemical energy (glucose), predominantly using chlorophyll.
Plant structures include roots for anchoring and nutrient absorption, stems for support and transport, and leaves as the primary site for photosynthesis.

Bacteria are single-celled prokaryotes, some of which are beneficial for human health (e.g., gut flora), while others can cause disease.
Viruses are non-living entities that require a host for replication and can lead to various diseases.

Innate behaviors are instinctive and genetically programmed actions that organisms perform (e.g., reflexes).
Learned behaviors are acquired through experiences or observations, such as conditioning processes.

Biodiversity refers to the variety of life forms within a specific habitat or ecosystem.
Endangered species face extinction risks primarily due to habitat destruction, climate change, and human activities.
Conservation strategies include establishing protected areas, enacting legislation, and engaging in restoration ecology to sustain biodiversity.