Honors Bio Unit 4 (DNA)Study Guide

Cell Cycle

Sequence of events in which a parent cell splits into 2 daughter cells.

G0 Phase

Period in the interphase where the cell is in a quiescent (resting) phase.

G1 Phase

1st phase in interphase where all nutrients and components (except from DNA) are replicated.

S Phase

2nd phase in interphase where DNA in the cell is replicated.

G2 Phase

Cell grows and replenishes energy while checking for errors in DNA replication before mitosis.

M Phase

Mitosis phase that occurs after all regulations are met in G1, S, and G2 checkpoints.

Prophase

Phase in which DNA condenses to form chromatin, and the nuclear membrane diffuses.

Metaphase

Spindle fibers align chromosomes across the middle of the cell.

Anaphase

Spindle fibers change in length, to pull the chromosomes apart, resulting in 2 sets of chromatids on opposite poles.

Telophase

Nuclear envelope forms around each set of chromatids, which decondense into chromatin.

Cytokinesis

Final phase in the cell cycle that involves the splitting of the parent cell into 2 daughter cells.

Interphase

Phase where the cell grows, matures, and replicates organelles, including G1, S, and G2 phases.

Binary Fission

Process of splitting a cell into 2 identical cells with the same DNA as the mother cell.

Sexual Reproduction

Process using DNA from 2 different organisms to create a new cell with equal DNA from each parent.

Asexual Reproduction

Process that duplicates DNA from one parent cell and splits it into 2 new daughter cells.

G1 Checkpoint

Primary checkpoint that decides if the cell is committed to division, regardless of damage.

G2 Checkpoint

Checks for DNA damage and proper replication; can lead to cell pause for repair.

M Checkpoint

Checks if all sister chromatids are attached to spindle fibers before proceeding.

Chromosome

X-shaped DNA molecule formed by merging 2 sister chromatids with a centromere.

Chromatin

Complex of DNA formed when DNA strands are condensed in the nucleus.

Centrioles

Organelles that form spindle fibers used to separate the parent cell into daughter cells.

Centromere

Region at the center of the chromosome where sister chromatids are joined.

Telomere

Nucleotide-repeating caps placed at the ends of chromosomes.

Chromatid

Half of a replicated chromosome, created during anaphase.

Spindle Fibers

Structures formed by centrioles that divide chromosomes into chromatids.

Kinetochores

Protein patches on centromeres that help sister chromatids stick together and attach to spindle fibers.

Microtubules

Components of centrioles that assist in the creation of spindle fibers.

Cancer

A disease caused by mutations in cells leading to rapid division and DNA errors.

Benign

Abnormal cells that multiply uncontrollably but do not invade surrounding tissue.

Malignant

Cancerous cells that grow and divide rapidly without responding to growth signals.

Tumor

A clump of benign, malignant, or cancerous cells that multiplies in a certain area.

P53

A negative cell regulator that prevents further cell cycle progression and leads to apoptosis.

Cyclins

Proteins that regulate the cell cycle and are essential for progression through checkpoints.

Apoptosis

Programmed cell death that occurs when a cell has irreversible damage.

Stem Cells

Cells that can self-renew and differentiate into various cell types.

Differentiate

The process by which stem cells become specialized cells.

DNA

Deoxyribonucleic acid, the hereditary material in organisms.

DNA Nucleotide

Building block of nucleic acids, consisting of a nitrogenous base, a sugar, and phosphate groups.

Phosphate

Component of DNA nucleotide that bonds to sugar in nucleic acids.

Deoxyribose Sugar

Sugar in DNA nucleotides, bonded to phosphate and nitrogenous base.

Ribose Sugar

Five-carbon sugar in RNA that alternates with phosphate groups in the RNA backbone.

Nitrogenous Base

Organic molecule containing nitrogen used as a base for hereditary information in DNA and RNA.

Adenine

A nitrogenous base that pairs with Thymine in DNA.

Thymine

A nitrogenous base that pairs with Adenine in DNA.

Cytosine

A nitrogenous base that pairs with Guanine in DNA.

Guanine

A nitrogenous base that pairs with Cytosine in DNA.

Uracil

A nitrogenous base that substitutes for Thymine in RNA.

Purines

Nucleotide bases with 2 rings, including Adenine and Guanine.

Pyrimidines

Nucleotide bases with 1 ring, including Cytosine and Thymine.

Phosphodiester bonds

Covalent bonds linking phosphate groups to sugar molecules in nucleic acids.

Hydrogen bonds

Special bonds that link nucleotide bases together in DNA.

Double Helix

The structure of DNA, consisting of 2 strands that twist around each other.

3’ End & 5’ End

Ends of the DNA strand identified by the number of carbon atoms in the deoxyribose sugar.

Anti-Parallels

Refers to the orientation of DNA strands running in opposite directions for accurate pairing.

Chi-Square Test

Statistical analysis to determine significance between observed and expected data.

Null Hypothesis

Hypothesis stating no difference exists between groups being compared.

Alternate Hypothesis

Hypothesis stating that a difference exists between the groups being compared.

Critical Value

Statistical threshold used to determine significance in chi-square tests.

Degrees of Freedom

The number of independent values that can vary in an analysis, calculated as n-1.