Cell Biology Overview

Cell Biology

• Cells are the fundamental structural and functional units of life.
• Cells exhibit diverse shapes and sizes, yet share common characteristics.
• Unicellular organisms consist of a single cell.
• Multicellular organisms contain specialized cells that assemble into tissues, organs, and organ systems.
• All cells possess DNA, the genetic blueprint for building and maintaining the organism.
• Eukaryotic cells contain a nucleus and membrane-bound organelles like mitochondria and endoplasmic reticulum.
• Prokaryotic cells lack a nucleus and membrane-bound organelles.

Types of Cells

• Prokaryotic cells – simpler, smaller, lacking a nucleus, and possessing a single circular chromosome. Examples include bacteria and archaea.
• Eukaryotic cells – more complex, larger, with a nucleus housing chromosomes and membrane-bound organelles. Examples include plant cells, animal cells, fungi, and protists.

Cell Structure

• Cell membrane – surrounds the cell, controlling substance passage.
• Nucleus – houses the cell's DNA; regulates cellular activities.
• Cytoplasm – the fluid within the cell; holds organelles.
• Mitochondria – produce energy (ATP) for the cell.
• Ribosomes – synthesize proteins.
• Endoplasmic reticulum (ER) – transports proteins and other molecules.
• Golgi apparatus – processes and packages proteins.
• Vacuoles – store water, nutrients, and waste products.
• Lysosomes – contain enzymes for waste breakdown.
• Cell wall – a rigid outer layer, found in plant cells and some others, providing support and protection.

Cellular Processes

• Cellular respiration – cells break down glucose to release energy.
• Photosynthesis – plants use sunlight to convert carbon dioxide and water into glucose.
• Protein synthesis – creating proteins using DNA's instructions.
• Cell division – a cell divides into two or more daughter cells, including mitosis (somatic cells) and meiosis (sex cells).

Genetics

• DNA (deoxyribonucleic acid) – the hereditary material in most organisms.
• Genes – DNA segments encoding protein synthesis.
• DNA replication – copying a DNA molecule.
• Transcription – a gene's DNA sequence copied to a complementary RNA sequence (mRNA).
• Translation – mRNA's nucleotide sequence used to synthesize a polypeptide chain.
• Mutations – changes in DNA sequences, potentially altering encoded proteins. These changes can be neutral, harmful, or beneficial.
• Chromosomes – organized structures of condensed DNA within the cell nucleus.

Evolution

• Natural selection – a key evolutionary mechanism.
• Organisms with advantageous traits for survival are more likely to reproduce and pass on those traits.
• Evolution leads to new species development and environmental adaptations.
• Evolution – the gradual change in heritable traits over generations.
• Common ancestry underlies the concept of evolution.

Ecology

• Ecology – the study of interactions between organisms and their environment.
• Ecological organization – includes individuals, populations, communities, and ecosystems.
• Populations – groups of the same species in a particular area.
• Communities – different species populations interacting within an area.
• Ecosystems – encompass all living organisms (biotic) and non-living components (abiotic) interacting in a given area.
• Key ecological concepts – energy flow, nutrient cycling, and biodiversity.
• Organism interactions – include competition, predation, mutualism, commensalism, and parasitism.

Other

• Biochemistry – studies the chemical processes of living organisms.
• Physiology – studies the functions of living organisms and their parts.
• Microbiology – studies microorganisms like bacteria, viruses, and fungi.
• Zoology – the study of animals.
• Botany – the study of plants.