Unit 3 Exam Review: DNA, Cell Cycle, Meiosis & Gene Expression

Vocabulary practice flashcards generated from the Unit 3 Exam Review study guide covering DNA, mitosis, meiosis, mutations, biotechnology, and protein synthesis.

DNA

Deoxyribonucleic acid; a double helix-shaped molecule whose primary function is to store genetic information.

Nucleotide

The repeating structural unit that makes up DNA, consisting of a sugar, a phosphate group, and a nitrogenous base.

DNA Backbone

The structural sides of the DNA double helix formed by alternating sugars and phosphate groups.

Base Pairing Rules (DNA)

The specific pairing of nitrogenous bases where Adenine pairs with Thymine and Cytosine pairs with Guanine.

RNA

A nucleic acid that is comparatively single-stranded, contains the sugar ribose, and uses Uracil instead of Thymine (pairing Adenine with Uracil, and Cytosine with Guanine).

Gene

A segment of DNA that codes for a specific protein.

Chromatin

Loose, uncoiled DNA wrapped around proteins.

Chromosome

A highly condensed structure composed of chromatin; humans receive 23 from their father and 23 from their mother.

DNA Replication

The process occurring in the cell nucleus of copying DNA into two identical DNA molecules prior to cell division.

DNA Helicase

An enzyme that unzips the double-stranded DNA molecule during DNA replication.

DNA Polymerase

An enzyme that adds complementary nucleotides to the DNA template strand during replication (adds Adenine opposite Thymine, and Cytosine opposite Guanine).

Semi-Conservative Replication

The mechanism of replication where each newly formed DNA molecule contains one original (old) strand and one newly synthesized strand.

Gene Mutation

A change in the DNA sequence caused by errors during replication or exposure to mutagens, which can have harmful, beneficial, or neutral effects on an organism.

Binary Fission

Prokaryotic (bacterial) cell division in which a cell duplicates its single chromosome (not contained inside a nucleus) and splits.

Somatic Cells

Diploidal body cells, such as human body cells containing 46 chromosomes.

Gametes

Haploidal sex cells, specifically sperm and egg cells.

Diploid (2n)

Containing two complete sets of chromosomes (for example, fruit fly body cells with 8 chromosomes).

Haploid (n)

Containing a single set of chromosomes (for example, dog sperm cells with 39 chromosomes).

Interphase

The non-dividing phase accounting for about 80% of the cell cycle, consisting of G1, S, and G2 stages.

G0 Phase

The resting phase of the cell cycle where a cell is not dividing and is performing its normal cellular functions.

G1 Phase

The first growth phase of interphase characterized by cell growth and protein synthesis.

S Phase

The synthesis stage of interphase during which DNA replication occurs.

G2 Phase

The second growth stage of interphase involving final protein synthesis and cell growth preparation before mitosis.

Cancer

A condition characterized by uncontrolled, rapid mitosis.

Mitosis

Nuclear cell division taking up about 20% of the cell cycle that produces two genetically identical daughter cells for growth and repair.

Prophase (Mitosis)

The first phase of mitosis in which the nuclear membrane disappears and chromosomes condense into visible structures.

Metaphase (Mitosis)

The stage of mitosis where chromosomes line up along the equator (middle) of the cell.

Anaphase (Mitosis)

The phase of mitosis in which chromosomes separate into sister chromatids and move apart.

Telophase (Mitosis)

The stage of mitosis where separated chromatids reach opposite ends of the cell and nuclear membranes reform.

Cytokinesis

The division of the cytoplasm following telophase, yielding two separate identical cells.

Meiosis

A form of cell division that reduces chromosome numbers by half to produce four genetically different haploid sex cells (gametes).

Crossing Over

The exchange of genetic material between homologous chromosomes during Prophase I of meiosis, increasing genetic variation.

Homologous Chromosomes

Matching pairs of chromosomes that carry the same genes.

Independent Assortment

The random alignment of homologous chromosomes at the equator during Metaphase I of meiosis that contributes to genetic diversity.

Segregation

The separation of homologous chromosomes during Anaphase I of meiosis so that each resulting gamete receives one copy of each chromosome.

Polymerase Chain Reaction (PCR)

A technique used for copying DNA, diagnosing genetic conditions, detecting viral infections, analyzing forensics evidence, and studying ancient DNA.

CRISPR

A gene-editing tool used to edit and remove sections of DNA in order to genetically modify crops, treat human diseases, and analyze gene function.

Gene Therapy

A medical approach used to treat genetic disorders by inserting healthy genes into a patient's cells.

Gene Expression

The process by which genetic information stored in DNA is used to synthesize a protein that determines a physical trait.

Transcription

The process occurring in the nucleus where RNA polymerase reads a DNA template strand to create a complementary mRNA strand.

Codon

A sequence of three consecutive nucleotides on mRNA that codes for a specific amino acid.

Translation

The protein synthesis stage occurring at the ribosome where tRNA matches its anticodon to the mRNA codon to deliver amino acids.

Frameshift Mutation

A mutation caused by an insertion or deletion of a nucleotide base, shifting the reading frame and altering the amino acid sequence.

Silent Mutation

A substitution mutation that changes a base pair in DNA without changing the final amino acid sequence or resulting protein function.

Replicating Cell Cycle Diagram

A diagram illustrating the stages of a replicating cell cycle, including G1, S, G2, M (Mitosis), Cytokinesis, and the resting G0 state.

Genetic Code Chart

A standard reference chart listing mRNA codons and their corresponding amino acids (such as AUG coding for Methionine/Met).

Mitosis and Cell Cycle Steps Diagram

A diagram depicting the six key cell stages: 1 = Telophase, 2 = Interphase, 3 = Prophase, 4 = Cytokinesis, 5 = Anaphase, 6 = Metaphase.