Cells Unit Test and Concepts Review

Comprehensive vocabulary flashcards covering cell theory, organelles, prokaryotes vs. eukaryotes, plant vs. animal cells, transport, homeostasis, solutions, and the cell cycle based on biology review sheets.

Cell Theory

A fundamental biological theory stating that: 1. All living things are made of cells; 2. Cells are the basic unit of life; 3. All cells come from other preexisting cells.

Unicellular

An organism made up of only one single cell.

Multicellular

An organism composed of many cells that organize into tissues, organs, and organ systems.

Cellular Hierarchy

The structural organization of multicellular organisms: $\text{cell} \rightarrow \text{tissue} \rightarrow \text{organ} \rightarrow \text{organ system} \rightarrow \text{organism}$.

Organelle

Specialized structures within a cell that work together to help the cell function.

Prokaryotic Cell

A simple cell that lacks a nucleus and membrane-bound organelles, divides by binary fission, is unicellular, and includes bacteria.

Eukaryotic Cell

A complex cell with a nucleus and membrane-bound organelles that divides by mitosis; can be unicellular or multicellular (e.g., plants, animals, fungi, and protists).

Cell Membrane

A selectively permeable boundary that controls what enters and exits the cell.

Nucleus

The organelle that protects the DNA that controls the activities of the cell.

Nucleolus

A structure located inside the nucleus that makes ribosomes and RNA.

Ribosomes

Cellular organelles located on the rough ER or floating free in the cytoplasm that synthesize proteins.

Rough ER (Endoplasmic Reticulum)

An organelle covered with ribosomes that produces and packages proteins.

Smooth ER (Endoplasmic Reticulum)

An organelle lacking ribosomes that synthesizes lipids.

Golgi Apparatus

An organelle that receives, modifies, sorts, and packages proteins to be shipped out.

Vesicles

Small membrane-bound sacs that act like carts to transport proteins and other materials around the cell.

Cytoplasm

A jelly-like fluid that fills the cell and holds the organelles in place.

Cytoskeleton

A network of protein fibers that provides shape and structural support to the cell.

Mitochondria

The 'powerhouse' of the cell that breaks down sugar and food during cellular respiration to produce energy in the form of $\text{ATP}$.

Chloroplast

An organelle found in plant cells that performs photosynthesis, converting sunlight energy into sugar.

Cell Wall

A rigid outer protective layer found in plant and fungal cells that maintains cell shape.

Central Vacuole

A single, massive storage compartment found in plant cells primarily used for storing water.

Vacuoles (in Animal Cells)

Multiple small storage structures used for storing water, nutrients, and waste products.

Centrioles (Centrosomes)

Organelles found in animal cells that assist in cell division by pulling chromosomes apart.

Cilia

Short, hair-like projections that move fluid across the surface of the cell.

Flagella

A long, whip-like tail that acts to propel the entire cell.

Homeostasis

The need of an organism to stay stable by regulating its internal conditions.

Solute

The substance that gets dissolved in a solution (e.g., lemonade powder).

Solvent

The substance that does the dissolving in a solution (e.g., water).

Solution

A uniform mixture of two or more substances (e.g., prepared lemonade).

Concentration

The amount of solute that is dissolved in a given solvent.

Passive Transport

The movement of substances across a cell membrane that requires NO energy and moves molecules from HIGH to LOW concentration down the gradient.

Active Transport

The movement of substances across a cell membrane that requires energy ($\text{ATP}$) to move molecules from LOW to HIGH concentration against the gradient or transport large particles via vesicles.

Differentiation

A developmental process that creates specialized structures and functions, enabling specialized cells to form tissues and organs.

Stem Cells

Undifferentiated cells that have the ability to differentiate into one or more types of specialized cells.

Cell Cycle

A repeated pattern of growth, DNA duplication, and cell division that occurs in eukaryotic cells.

Chromosome

One long continuous thread of DNA that contains thousands of genes and regulatory information.

Gene

A section of DNA that holds the instructions for making a protein.

Sister Chromatids

Two identical copies of a chromosome that pull away from each other during cell division to become individual chromosomes.

Centromere

The pinched central region of a condensed chromosome where sister chromatids are held together.

Telomere

The protective structures located at the ends of DNA molecules.

Cancer

A disease characterized by uncontrolled cell division.

Metastasize

The spreading of disease or cancerous cells from one organ to other parts of the body.

Carcinogen

A substance capable of causing or leading to cancer.