Cell Structure and Genetics Overview

Cell Structure and Function

Basic Unit of Life: Cell is the smallest unit of life.
Prokaryotic Cells: No nucleus; DNA is free-floating; examples include bacteria.
Eukaryotic Cells: Have a nucleus; membrane-bound organelles; examples include plant and animal cells.
Organelles:
- Nucleus: Contains genetic material (DNA).
- Mitochondria: Powerhouse of the cell; site of ATP (energy) production.
- Ribosomes: Protein synthesis.
- Endoplasmic Reticulum: Rough ER (with ribosomes) for protein synthesis; Smooth ER (no ribosomes) for lipid synthesis.
- Golgi Apparatus: Modifies, sorts, and packages proteins and lipids.
- Lysosomes: Contains enzymes for digestion of waste.

Genetics

DNA Structure: Double helix composed of nucleotides (A, T, C, G).
Genes: Segments of DNA that code for proteins.
Alleles: Different forms of a gene.
Mendelian Genetics:
- Law of Segregation: Alleles separate during gamete formation.
- Law of Independent Assortment: Genes for different traits can segregate independently.
Genotype vs. Phenotype: Genotype is genetic makeup; phenotype is the observable characteristics.

Evolution

Natural Selection: Process by which individuals with favorable traits are more likely to reproduce.
Adaptation: Traits that enhance survival and reproduction.
Speciation: Formation of new and distinct species in the course of evolution.
Common Ancestry: All life shares a common ancestor.

Ecology

Ecosystem: Community of living organisms interacting with their environment.
Biotic Factors: Living components, such as plants and animals.
Abiotic Factors: Non-living components, such as water, temperature, and soil.
Food Chains and Webs:
- Producers: Organisms that produce their own food (e.g., plants).
- Consumers: Organisms that consume others (herbivores, carnivores).
- Decomposers: Break down dead organisms (e.g., fungi, bacteria).

Human Biology

Body Systems:
- Circulatory System: Transports blood, nutrients, gases.
- Respiratory System: Responsible for gas exchange (oxygen and carbon dioxide).
- Digestive System: Breaks down food into nutrients.
- Nervous System: Controls body functions and responses to stimuli.
Homeostasis: Maintaining stable internal conditions despite external changes.

Plant Biology

Photosynthesis: Process by which plants convert light energy into chemical energy (glucose).
Plant Anatomy:
- Roots: Anchor plants and absorb water/nutrients.
- Stems: Support the plant and transport nutrients.
- Leaves: Main site of photosynthesis.
Reproduction: Can be sexual (seeds, flowers) or asexual (cuttings, runners).

Microbiology

Bacteria: Single-celled organisms; can be beneficial or pathogenic.
Viruses: Non-living entities that require a host to reproduce.
Fungi: Diverse group; can be unicellular (yeasts) or multicellular (molds, mushrooms).

Biochemistry

Macromolecules:
- Carbohydrates: Energy source (sugars, starches).
- Proteins: Made of amino acids; perform various functions.
- Lipids: Fats and oils; energy storage and cell membranes.
- Nucleic Acids: DNA and RNA; genetic information storage and transfer.

Biotechnology

Genetic Engineering: Manipulating genes for specific traits (e.g., GMOs).
CRISPR: Tool for editing genes with precision.
Cloning: Creating a genetically identical organism.

Evolutionary Biology

Fossil Record: Evidence of past life forms and evolutionary changes.
Phylogenetics: Study of evolutionary relationships among biological entities.

Cell Structure and Function

Cells are the fundamental units of life, responsible for all biological processes.
Prokaryotic cells lack a nucleus; their DNA is not enclosed, commonly exemplified by bacteria.
Eukaryotic cells feature a defined nucleus and membrane-bound organelles, including plant and animal cells.
The nucleus contains genetic material (DNA), directing cell activities.
Mitochondria are known as the cell's powerhouse, generating ATP, the main energy currency.
Ribosomes, either free-floating or attached to the rough endoplasmic reticulum, are crucial for protein synthesis.
The endoplasmic reticulum has two types: Rough ER synthesizes proteins, while Smooth ER focuses on lipid production.
The Golgi apparatus processes and dispatches proteins and lipids to their destinations.
Lysosomes contain digestive enzymes that break down waste and cellular debris.

Genetics

DNA is structured as a double helix, comprised of nucleotide bases: adenine (A), thymine (T), cytosine (C), and guanine (G).
Genes are specific DNA segments that encode for proteins, influencing traits.
Alleles represent different variations of a gene, contributing to genetic diversity.
Mendelian genetics' Law of Segregation states that alleles separate during the formation of gametes.
The Law of Independent Assortment indicates that genes for separate traits can segregate independently during gamete formation.
Genotype refers to the genetic composition of an organism, while phenotype describes the observable traits.

Evolution

Natural selection is a mechanism driving evolution, favoring organisms with advantageous traits to reproduce successfully.
Adaptation signifies traits that improve an organism's chances of survival and reproduction in a given environment.
Speciation occurs when new, distinct species arise through evolutionary processes.
All living organisms share a common ancestry, highlighting the interconnectedness of life.

Ecology

An ecosystem consists of living organisms interacting with each other and their environment.
Biotic factors are the living components of an ecosystem, including various species of plants and animals.
Abiotic factors encompass non-living elements like water, temperature, and soil, influencing ecosystem dynamics.
Food chains depict the flow of energy between producers, consumers, and decomposers.
Producers, primarily plants, synthesize their own food through photosynthesis.
Consumers rely on other organisms for energy; they can be classified as herbivores or carnivores.
Decomposers, like fungi and bacteria, recycle nutrients by breaking down dead organic matter.

Human Biology

The circulatory system is responsible for transporting blood, nutrients, and gases throughout the body.
The respiratory system facilitates gas exchange, delivering oxygen to the body and removing carbon dioxide.
The digestive system systematically breaks down food, allowing nutrient absorption.
The nervous system processes stimuli and regulates body functions.
Homeostasis is the process of maintaining stable internal conditions despite external variations.

Plant Biology

Photosynthesis converts light energy into glucose, essential for plant energy needs.
Roots anchor plants and absorb water and nutrients from the soil.
Stems provide structural support and facilitate the transport of nutrients and water.
Leaves are the primary sites for photosynthesis, maximizing light absorption.
Plants reproduce either sexually through seeds and flowers or asexually via processes like cuttings and runners.

Microbiology

Bacteria are single-celled organisms that can be beneficial (e.g., gut flora) or pathogenic, causing diseases.
Viruses are non-living, requiring a host cell for replication and propagation.
Fungi can exist as unicellular organisms (yeasts) or multicellular forms (molds and mushrooms), playing key ecological roles.

Biochemistry

Macromolecules include carbohydrates, which serve as energy sources; proteins, comprised of amino acids that perform various biological functions; lipids, which are used for energy storage and membrane formation; and nucleic acids (DNA/RNA) responsible for genetic information transfer.

Biotechnology

Genetic engineering involves altering genes to achieve desired traits, leading to the development of genetically modified organisms (GMOs).
CRISPR technology allows for precise gene editing, providing advancements in genetics and medicine.
Cloning is the method of creating genetically identical organisms, with applications in research and agriculture.

Evolutionary Biology

Fossil records provide crucial evidence for understanding historical life forms and the processes of evolution.
Phylogenetics examines the evolutionary relationships and lineage among different biological entities, helping to map the tree of life.