Biology: Exploring the Fundamental Concepts and Topics

Cell Biology

The branch of biology that studies the structure, function, and behavior of cells, including organelles and molecular processes.

cells

the basic structural and functional units of life

Robert Hooke

who observed cork cells under a simple microscope and coined the term "cell."

Matthias Schleiden and Theodor Schwann

In the 19th century, __________ and __________ proposed the cell theory, which states that all living organisms are composed of cells, cells are the basic units of structure and function in organisms, and cells arise only from pre-existing cells.

Cell Membrane

Surrounds the cell, regulates substance passage, and is composed of a phospholipid bilayer with embedded proteins.

Cytoplasm

Gel-like substance filling the cell, where organelles are suspended. Contains various ions, enzymes, and other molecules necessary for cellular processes.

Nucleus

Houses the genetic material (DNA) of the cell and controls cellular activities. Surrounded by a nuclear envelope and contains the nucleolus, where ribosomal RNA is synthesized.

Mitosis and Meiosis

Processes of cell division crucial for growth, repair, and reproduction.

Organelles

Specialized structures within cells like mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes performing specific functions.

Metabolism

Sum of chemical reactions in a cell.

Cell Division

Process by which cells replicate and divide to produce new cells. (mitosis and meiosis)

Cellular Communication

Cells communicate with each other through signaling molecules, allowing coordination of physiological processes and responses to external stimuli.

Differentiation

Process by which cells become specialized in structure and function to perform specific roles within an organism. 

Microscopy

Techniques using microscopes to visualize cells and structures.

Cell Culture

Cells can be cultured in vitro under controlled conditions to study their behavior, growth, and responses to experimental manipulations.

Molecular Biology Techniques

__________________ such as polymerase chain reaction (PCR), gel electrophoresis, and DNA sequencing, are used to study cellular processes at the molecular level.

Medicine, Biotechnology, Regenerative Medicine, Environmental Science

Applications of Cell Biology

Ecosystem

Community of living organisms interacting with the environment.

Biotic Components of Ecosystems

Include all living organisms within an ecosystem, from microorganisms to plants and animals. These organisms interact with each other and with their environment, shaping the dynamics of the ecosystem.

Abiotic Components of Ecosystems

Consist of non-living factors that influence the structure and function of ecosystems. These include physical factors such as temperature, sunlight, soil composition, water availability, and topography.

Biodiversity

Variety of species within an ecosystem, indicating ecosystem health and resilience.

Ecological Interactions

Organisms within an ecosystem interact with each other in various ways, forming complex networks of relationships.

Predation

One organism (predator) consumes another organism (prey) for food.

Competition

Organisms compete for limited resources such as food, water, and habitat.

Mutualism

Both organisms benefit from the interaction (e.g., pollination by bees).

Parasitism

One organism (parasite) benefits at the expense of another organism (host).

Commensalism

One organism benefits while the other is unaffected (e.g., epiphytic plants growing on trees).

Ecological Succession

refers to the process by which an ecosystem undergoes predictable changes in species composition in an ecosystem over time.

Primary succession

occurs in newly formed habitats, such as bare rock or volcanic lava, where pioneer species colonize the area and gradually pave the way for more complex communities.

Secondary succession

occurs in habitats that have been disturbed or altered but still retain soil and some vegetation. It typically involves the reestablishment of vegetation following events like fires or clear-cutting.

Ecology

the scientific study of interactions between organisms and their environment. It encompasses the relationships between organisms, as well as their interactions with abiotic factors such as temperature, water, sunlight, and soil.

Innate Immunity

Non-specific defense mechanisms providing immediate protection against pathogens.

Individual, Population, Community, Ecosystem, Biome, Biosphere

Levels of Ecological Organization

Individual

The smallest level of organization, consisting of a single organism.

Population

A group of individuals of the same species living in the same area and interbreeding.

Community

All the populations of different species living and interacting in a particular area.

Ecosystem

A community of organisms and their physical environment, including biotic and abiotic components.

Biome

A large geographic area characterized by distinct climate, vegetation, and animal life.

Biosphere

The global sum of all ecosystems, encompassing the regions of the Earth inhabited by living organisms.

Habitat

The specific environment in which an organism lives and to which it is adapted.

Niche

The role or function of an organism within its ecosystem, including its interactions with other organisms and its use of resources.

Energy Flow

The transfer of energy through trophic levels in an ecosystem, from producers (plants) to consumers (herbivores, carnivores) to decomposers (bacteria, fungi).

Food Chains and Food Webs

Diagrams representing the transfer of energy and nutrients through feeding relationships in an ecosystem.

Nutrient Cycling

The movement and recycling of essential nutrients (such as carbon, nitrogen, and phosphorus) through biotic and abiotic components of ecosystems.

Biomes

are large-scale ecological regions characterized by distinct climate, vegetation, and animal life. Examples include tropical rainforests, temperate forests, grasslands, deserts, tundras, and aquatic ecosystems.

Structural adaptations

type of adaptation that involve physical features or body structures that enhance an organism's ability to survive (camouflage coloration, protective shells). 

Behavioral adaptations

type of adaptation that are actions or behaviors that organisms perform to increase their chances of survival (migration, hibernation).

Physiological adaptations

type of adaptation that are internal mechanisms or processes that help organisms cope with environmental challenges (temperature regulation, water conservation).

immune system

defends the body against pathogens through mechanisms such as phagocytosis, antibody production, and cell-mediated immunity.

Bacteria, Viruses, Fungi, Protists

Types of Pathogens

Bacteria

Single-celled prokaryotic organisms that can be beneficial or harmful. Pathogenic bacteria cause diseases such as tuberculosis, pneumonia, and food poisoning.

Viruses

Small infectious agents that require a host cell to replicate. Common viral diseases include influenza, HIV/AIDS, and COVID-19.

Fungi

Eukaryotic organisms that include yeasts, molds, and mushrooms. Fungal infections can affect the skin, nails, respiratory tract, and internal organs

Protists

Single-celled eukaryotic organisms that include protozoa and algae. Some protists, such as Plasmodium spp. (causative agents of malaria), can cause serious diseases

Innate Immunity

Non-specific defense mechanisms that provide immediate, generalized protection against pathogens. Examples include physical barriers (skin, mucous membranes), phagocytic cells (macrophages, neutrophils), and antimicrobial proteins (complement system).

Adaptive Immunity

Specific immune responses that develop after exposure to specific pathogens or antigens. Provides long-term immunity and immunological memory

Vaccination

is a preventive measure that stimulates the immune system to produce an immune response against a particular pathogen or antigen

contain weakened or inactivated forms of pathogens, antigens derived from pathogens, or genetic material (e.g., mRNA) encoding antigenic proteins.

Antibiotics

are drugs used to treat bacterial infections by inhibiting bacterial growth or killing bacteria

Energy

is vital for life processes, and organisms obtain and utilize energy through processes like photosynthesis and cellular respiration.

Bioenergetics

is the study of energy flow within living systems, focusing on how organisms acquire, transform, and utilize energy to sustain life processes.

Adenosine triphosphate (ATP)

is the primary energy currency of cells, storing and transferring energy for cellular activities.

consisting of adenine, ribose, and three phosphate groups, serving as the primary energy carrier in cells.

Cellular Respiration

The process of breaking down organic molecules to produce ATP, involving glycolysis, the citric acid cycle, and the electron transport chain.

Glycolysis, Citric Acid Cycl (Krebs Cycle), Electron Transport Chain (ETC)

Three main stages of cellular respiration:

Glycolysis

Occurs in the cytoplasm and involves the breakdown of glucose into pyruvate, producing a small amount of ATP and NADH.

Citric Acid Cycle (Krebs Cycle)

Takes place in the mitochondrial matrix and completes the oxidation of glucose-derived pyruvate to produce more ATP, NADH, and FADH2.

Electron Transport Chain (ETC)

Located in the inner mitochondrial membrane, the ETC uses electron carriers (NADH and FADH2) to generate a proton gradient, driving ATP synthesis through oxidative phosphorylation.

Photosynthesis

The conversion of light energy into chemical energy (glucose) by autotrophic organisms through light-dependent reactions and the Calvin Cycle.

Light-dependent Reactions, Calvin Cycle (Light-Independent Reactions)

Two main stages of photosynthesis:

Light-dependent Reactions

stage of photosynthesis that occur in the thylakoid membranes of chloroplasts, where light energy is captured by chlorophyll and used to generate ATP and NADPH.

Calvin Cycle (Light-Independent Reactions):

stage of photosynthesis that takes place in the stroma of chloroplasts and involves the fixation of carbon dioxide and the synthesis of glucose using ATP and NADPH generated during the light-dependent reactions.

Disorders Related to Bioenergetics

Health conditions like diabetes mellitus, mitochondrial diseases, and obesity resulting from disruptions in bioenergetic processes.

Diabetes Mellitus

Characterized by impaired glucose metabolism, resulting in high blood glucose levels (hyperglycemia).

Mitochondrial Diseases

Caused by mutations in mitochondrial DNA or nuclear genes encoding mitochondrial proteins, leading to defects in oxidative phosphorylation and ATP production.

Obesity

Resulting from an imbalance between energy intake and expenditure, leading to excessive accumulation of body fat and associated health risks.

Homeostasis

The maintenance of internal stability in response to external changes through regulation of factors like temperature, pH, and water balance.

Genetics

• explores how traits are passed from parents to offspring through genes located on chromosomes.

Variation

arises from genetic differences and environmental influences, leading to diversity within populations.

Evolution

as described by Charles Darwin's theory of natural selection, explains how populations change over time in response to environmental pressures.

Human Physiology

Study of organ systems like digestive, respiratory, circulatory, and nervous systems, crucial for maintaining homeostasis and overall health.

Biotechnology and Genetic Engineering

Involves manipulating living organisms for various purposes, including genetic engineering for agricultural, medical, and industrial applications, with ethical considerations.