Fundamentals of Biology

• Biology is the science that studies living organisms, their interactions with each other, and their environment.
• It attempts to describe and understand the nature of the universe.
• Biology encompasses many branches.
• All living organisms share key properties, including order, response to stimuli, reproduction, growth and development, regulation, homeostasis, energy processing, and adaptation.

Order

• Organisms are highly organized, even down to single-celled organisms.
• Inside each cell, atoms form molecules, and these molecules make organelles.
• In multicellular organisms, cells form tissues, tissues form organs, and organs form systems.

Sensitivity to Stimuli

• Organisms respond to diverse stimuli.
• Examples of responses include plants bending towards light, climbing fences or walls, or responding to touch.
• Bacteria can move towards or away from chemicals (chemotaxis) or light (phototaxis).
• Positive responses involve movement towards a stimulus.
• Negative responses involve movement away from a stimulus.

Reproduction

• Single-celled organisms reproduce by duplicating their DNA and then dividing it equally to form two new cells.
• Multicellular organisms reproduce by producing sex germline cells that will form new individuals.
• DNA contains genes that pass from parents to offspring.
• This ensures that offspring belong to the same species and share similar characteristics.

Growth & Development

• Genes in the DNA contain the instructions for growth and development in all organisms.

Regulation

• Regulation refers to the coordination of internal functions, such as nutrient transport, blood flow, waste removal, and body cooling.

Homeostasis

• Homeostasis is the ability of an organism to maintain constant internal conditions.
• Cells need to maintain optimal conditions like temperature, pH, and ion concentration for proper function.
• Organisms maintain internal conditions within a narrow range despite environmental changes.
• Organisms living in cold climates, like polar bears, have body structures such as fur, feathers, blubber, and fat to withstand low temperatures.
• In hot climates, organisms use methods such as perspiration in humans and panting in dogs to shed excess body heat.

Energy Processing

• All organisms use a source of energy for their metabolic activities.
• Plants capture sunlight energy and convert it into chemical energy. Animals then use this chemical energy.

Levels of Organization

• Atoms
• Molecules
• Cells
• Tissues
• Organs
• Systems
• Organism
• Populations
• Communities
• Ecosystems
• Biosphere

Chemical Foundation of Life

• Elements in various combinations comprise all matter, including living things.
• Abundant elements in living organisms include carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus.
• These elements form the protients, carbohydrates, lipids, and nucleic acids
• The four elements common to all living organisms are oxygen (O), carbon (C), nitrogen (N), and hydrogen (H).
• Oxygen constitutes 65% of human composition, 21% of the atmosphere, and 46% of Earth's crust.
• Carbon makes up 18% of human composition, with trace amounts in both the atmosphere and Earth's crust.
• Hydrogen constitutes 10% of human composition, with trace amounts in the atmosphere and 0.1% in Earth's crust.
• Nitrogen accounts for 3% of human composition and 78% of the atmosphere, with trace amounts in Earth's crust.

Biological Macromolecules

• Macromolecules are large polymers made up of monomers.
• Organisms obtain nutrients from food to survive.
• The four major classes of macromolecules are carbohydrates, lipids, proteins, and nucleic acids.
• These classes are organic, containing carbon, and may contain hydrogen, oxygen, and nitrogen.
• Macromolecules also make up the majority of the cell's dry mass, while water makes up the majority of the complete cell mass.

Dehydration Synthesis

• Monomers combine with each other using covalent bonds to form large polymers when water molecules are released.

Hydrolysis

• Polymers are broken down into monomers using water molecules.
• Two components result from the breakdown of one polymer: one part gains a hydrogen atom (H+), and the other part gains a hydroxyl molecule (OH-).

Protein Types and Functions

• Digestive Enzymes: Amylase, Lipase, pepsin, trypsin helps the digestion of food into monomers
• Transport: Hemoglobin, albumin helps transport oxygen & nutrients in blood & lymph
• Structural: Actin, tubulin, keratin forms the Cytoskeleton
• Hormones: Insulin, thyroxin coordinate body functions
• Defense: Immunoglobulins aid in immunity
• Contractile: Actin, myosin aids in muscle comtraction
• Storage: Legume storage proteins and egg white albumin provides nourishments to the embryo in early development