Unit 4 Exam Review: Cell Cycle, Differentiation, and DNA Structure

Comprehensive vocabulary review flashcards for Unit 4, covering the cell cycle, checkpoints, cancer and apoptosis, cell differentiation and stem cells, and the structure of DNA and nucleotides.

Interphase

The phase of the cell cycle during which cell growth and metabolism take place.

Synthesis ($S$-Phase)

The specific stage of interphase during which DNA replication occurs.

$G_2$ Checkpoint

The regulatory checkpoint in the cell cycle that checks the cell for DNA damage before division proceeds.

Cancerous Cells

Cells that have stopped responding to the normal checkpoints of the cell cycle.

Apoptosis

Programmed cell death that serves as one of the two possible outcomes (along with cancer) when cell cycle checkpoints fail.

Contact Inhibition

A regulatory mechanism that stops cell division upon cell-to-cell contact; the loss of contact inhibition leads to uncontrolled cell growth and tumor formation.

Tumor

An abnormal mass of cell growth that develops when cells lack contact inhibition and divide uncontrollably.

Cell Differentiation

The process by which unspecialized stem cells develop into specialized cells with specific functions.

Stem Cells

Unspecialized cells whose specialization is influenced by environmental signals, gene activation, and gene expression.

Gene Expression / Gene Activation

The mechanism in stem cells that is influenced by environmental signals to determine how a cell becomes specialized.

Nitrogenous Base

The component of a nucleotide responsible for carrying the genetic code that determines traits in an organism.

Nucleotide

The fundamental monomer of DNA consisting of three components: a phosphate group, a deoxyribose sugar, and a nitrogenous base.

Complementary DNA Strand

The matching sequence of paired bases corresponding to a DNA template strand; for the template $\text{TTCAGCATAGG}$, the complementary strand is $\text{AAGTCGTATCC}$.

What are the 3 components of a nucleotide

The three components of a nucleotide are a phosphate group, a deoxyribose sugar, and a nitrogenous base.

What is component of the nucleotide is responsible for a person’s physical traits

nitrogenous bases