Biology Basics: Cell Theory, Classification, and Molecular Structures

What is Biology?

The scientific study of life and living organisms.

What is homeostasis?

The ability to maintain stable internal conditions despite changes in the environment.

What is cell theory?

All living things are made of cells, and all cells come from pre-existing cells.

Name the classification system and human species classification.

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species; humans: Eukarya, Animalia, Chordata, Mammalia, Primates, Hominidae, Homo, sapiens.

Define science.

A way of knowing and understanding the natural world through observation and experimentation.

What are the two forms of science?

Discovery science and hypothesis-driven science.

What are the three domains?

Bacteria, Archaea, Eukarya.

Name the four kingdoms in Eukarya.

Protista, Fungi, Plantae, Animalia.

List properties of life.

Order, regulation, growth and development, energy processing, response to environment, reproduction, evolutionary adaptation.

What is a hypothesis?

A testable explanation for an observation.

What is a theory in science?

A broad explanation supported by evidence and experiments.

What is an atom?

The smallest unit of matter that retains the properties of an element.

What is an ion?

An atom with a positive or negative charge due to loss or gain of electrons.

What is an isotope?

Atoms of the same element with different numbers of neutrons.

Difference between atomic number and atomic mass?

Atomic number is protons; atomic mass is protons + neutrons.

What are the types of chemical bonds?

Covalent (strongest), ionic, and hydrogen (weakest).

Why is water important to life?

Its hydrogen bonds give it unique properties like heat retention, cohesion, and ability to dissolve substances.

Why does ice float?

Ice is less dense than liquid water because hydrogen bonds create an open lattice.

What is pH?

A measure of hydrogen ion concentration in a solution.

What is a macromolecule?

A large biological molecule such as carbohydrates, lipids, proteins, or nucleic acids.

Difference between simple and complex carbohydrates?

Simple: monosaccharides and disaccharides; Complex: polysaccharides.

Examples of carbohydrates?

Mono: glucose; Di: sucrose; Poly: starch, glycogen, cellulose.

Difference between saturated and unsaturated lipids?

Saturated: no double bonds, solid at room temp; Unsaturated: double bonds, liquid at room temp.

What is a phospholipid?

A lipid with hydrophilic head and hydrophobic tails that forms cell membranes.

What is a peptide bond?

The bond that links amino acids in proteins.

What factors affect protein folding?

Temperature, pH, and salt concentration.

Difference between DNA and RNA?

DNA: double-stranded, bases A-T-C-G; RNA: single-stranded, bases A-U-C-G.

Where is RNA made?

In the nucleus.

Where are proteins made?

On ribosomes.

Organelles containing DNA?

Nucleus, mitochondria, chloroplasts.

Difference between prokaryotic and eukaryotic cells?

Prokaryotic: no nucleus or membrane-bound organelles; Eukaryotic: has nucleus and organelles.

Difference between cilia and flagella?

Cilia are short and numerous; flagella are long and few, used for movement.