Biology and Cell Structure: Key Concepts and Principles

What is biology?

The scientific study of life.

What are the 5 characteristics of life?

Organization, energy use, homeostasis, reproduction/growth/development, and evolution.

What is homeostasis?

The maintenance of stable internal conditions.

What is an emergent property?

A property that arises from interactions among parts of a system.

What is the basic unit of life?

The cell.

What is a hypothesis?

A testable explanation for an observation.

What is a scientific theory?

A broad explanation supported by extensive evidence.

What is the independent variable?

The factor manipulated by the researcher.

What is the dependent variable?

The factor measured in the experiment.

Why is a control group important?

It provides a comparison for the experimental group.

What are the levels of biological organization from smallest to largest?

Atom → Molecule → Organelle → Cell → Tissue → Organ → Organ System → Organism → Population → Community → Ecosystem → Biosphere.

What is an atom?

The smallest unit of an element.

Where are protons found?

In the nucleus.

What charge do electrons have?

Negative.

What are valence electrons?

Electrons in the outermost energy shell.

What is a covalent bond?

A bond formed when atoms share electrons.

What is an ionic bond?

A bond formed when electrons are transferred.

Why is water polar?

Oxygen pulls electrons more strongly than hydrogen.

What is a hydrogen bond?

A weak attraction between polar molecules.

What is pH?

A measure of hydrogen ion concentration.

What pH is neutral?

7.

What are carbohydrates used for?

Quick energy and structural support.

What are the building blocks of proteins?

Amino acids.

What are enzymes?

Proteins that speed up chemical reactions.

What are lipids used for?

Long-term energy storage, insulation, and cell membranes.

What are nucleic acids?

DNA and RNA.

What is the function of DNA?

Stores genetic information.

What are the three parts of cell theory?

All organisms are made of cells; the cell is the basic unit of life; all cells come from preexisting cells.

What are the two major cell types?

Prokaryotic and eukaryotic.

What is a prokaryotic cell?

A cell without a nucleus.

What is a eukaryotic cell?

A cell with a nucleus and membrane-bound organelles.

What do all cells have in common?

DNA, RNA, ribosomes, and a cell membrane.

What is an organelle?

A structure with a specific function inside a cell.

What is the function of the cell membrane?

Controls what enters and leaves the cell.

What is the function of the nucleus?

Stores DNA and controls cell activities.

What is the function of ribosomes?

Protein synthesis.

What is the function of mitochondria?

Produce ATP.

What is ATP?

The cell's primary energy molecule.

What is the function of the Golgi apparatus?

Modifies and packages proteins.

What is the function of the rough ER?

Produces and transports proteins.

What is diffusion?

Movement from high concentration to low concentration.

What is osmosis?

Diffusion of water across a membrane.

What is active transport?

Movement against a concentration gradient using energy.