Campbell Biology: Chapters 8, 9, and 10 - Cellular Reproduction, Inheritance, and Molecular Biology

Comprehensive vocabulary flashcards covering the core concepts of cellular reproduction, Mendelian inheritance, and molecular genetics from Campbell Biology (Chapters 8, 9, and 10).

Asexual Reproduction

The creation of genetically identical offspring by a single parent without the participation of sperm and egg.

Clone

An organism or group of genetically identical offspring produced via asexual reproduction.

Binary Fission

A means of asexual reproduction in prokaryotes that literally means "dividing in half" to produce two daughter cells.

Chromatin

Thin, loosely packed fibers of DNA and proteins found in eukaryotic chromosomes that condense prior to cell division.

Sister Chromatids

Two identical copies of a duplicated chromosome joined together by a centromere before cell division.

Cell Cycle

An ordered sequence of events that extends from the time a cell is first formed from a dividing parent cell until its own division.

Centrosome

A structure found in the cytoplasm of animal cells that organizes microtubule arrangement and contains a pair of centrioles.

Mitotic Spindle

A football-shaped structure of microtubules and associated proteins that guides the movement of chromosomes during cell division.

Anchorage Dependency

The requirement that a cell must be attached to a solid surface in order to divide.

Density-Dependent Inhibition

A phenomenon in which crowded cells stop dividing to prevent the overproduction of cells.

Growth Factor

A protein secreted by certain body cells that acts as a chemical signal to stimulate other cells to divide.

Homologous Chromosomes

A pair of matching chromosomes in a body cell that carry genes controlling the same heritable characters at identical loci.

Locus

The particular site or position on a chromosome where a gene is located.

Diploid

A cell containing two homologous sets of chromosomes ($2n$), characteristic of somatic body cells.

Haploid

A cell containing a single set of chromosomes ($n$), such as an egg or sperm cell.

Crossing Over

The reciprocal exchange of corresponding segments between nonsister chromatids of homologous chromosomes during prophase I of meiosis.

Chiasma

The microscopically visible site where nonsister chromatids of homologous chromosomes cross over one another during prophase I.

Nondisjunction

An accident of meiosis or mitosis in which a pair of homologous chromosomes or sister chromatids fail to separate properly.

Karyotype

A photographic inventory and ordering of an individual's chromosomes used to detect chromosomal abnormalities.

Trisomy 21

A human chromosomal number abnormality involving an extra chromosome $21$, resulting in Down syndrome.

Polyploid

An organism that possesses more than two complete sets of homologous chromosomes, such as the tetraploid gray tree frog (Hyla versicolor).

Allele

An alternative version of a gene that accounts for variations in inherited characters.

True-Breeding

Varieties of organisms that produce offspring identical to the parent when self-fertilized.

Dominant Allele

The allele that determines the organism's physical appearance in a heterozygous individual.

Recessive Allele

An allele that has no noticeable effect on an organism's appearance when paired with a dominant allele in a heterozygote.

Law of Segregation

Mendel's principle stating that allele pairs separate during gamete formation so that a sperm or egg carries only one allele for each inherited character.

Law of Independent Assortment

Mendel's rule stating that the alleles of one gene pair segregate independently of other gene pairs during gamete formation.

Dihybrid Cross

An experimental mating between parental varieties that differ in two distinct characters.

Pedigree

A family tree diagram displaying the occurrence of heritable characteristics in parents and offspring across multiple generations.

Carrier

An individual who is heterozygous for a recessively inherited disorder and is phenotypically normal.

Incomplete Dominance

A type of inheritance where the appearance of $F_1$ hybrids falls intermediate between the phenotypes of the two parental varieties.

Codominance

An inheritance pattern in which both alleles are expressed in heterozygous individuals, such as the $I^A$ and $I^B$ alleles in type AB blood.

Pleiotropy

The control of multiple phenotypic characters by a single gene, as exemplified by sickle-cell disease.

Polygenic Inheritance

The additive effect of two or more genes on a single phenotypic character, such as human skin pigmentation.

Linked Genes

Genes located close together on the same chromosome that tend to be inherited together in genetic crosses.

Recombination Frequency

The percentage of recombinant offspring resulting from a genetic cross, used to map the relative positions of genes on a chromosome.

Sex-Linked Gene

A gene located on either sex chromosome, showing unique inheritance patterns predominantly observed in males when X-linked.

Nucleotide

The basic building block of nucleic acids, consisting of a five-carbon sugar, a nitrogenous base, and a phosphate group.

Sugar-Phosphate Backbone

The repeating alternating pattern of sugars and phosphate groups linked covalently in a DNA or RNA polynucleotide chain.

Semiconservative Model

The mechanism of DNA replication in which each newly formed double helix consists of one conserved parental strand and one newly assembled strand.

DNA Polymerase

The primary enzyme that assembles new nucleotides to the $3'$ end of a growing DNA strand during replication in the $5'$ to $3'$ direction.

Gene (Molecular Definition)

A region of DNA that can be expressed to produce a functional product that is either a polypeptide or an RNA molecule.

Codon

A three-nucleotide sequence in mRNA that codes for a specific amino acid or acts as a termination signal.

Transcription

The synthesis of an RNA molecule using a DNA strand as a template.

Translation

The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule.

Promoter

A specific nucleotide sequence in DNA that binds RNA polymerase to position and initiate transcription.

Terminator

A sequence of DNA bases that signals RNA polymerase to stop transcription and release the completed RNA transcript.

RNA Splicing

The cellular process of removing noncoding segments (introns) from a primary RNA transcript and joining together the coding regions (exons).

Ribosome

A cytoplasmic structure composed of ribosomal RNA (rRNA) and proteins that coordinates protein synthesis by providing binding sites for mRNA and tRNAs.

Mutagen

A chemical or physical agent that interacts with DNA and causes a genetic mutation.

Transformation

The uptake of foreign, naked DNA fragments from the surrounding environment into a bacterial cell.

Transduction

The transfer of bacterial DNA from one host cell to another mediated by a bacteriophage.

Conjugation

The direct transfer of genetic material between two bacterial cells connected temporarily by a cytoplasmic mating bridge.

Plasmid

A small, circular DNA molecule separate from the main bacterial chromosome that can replicate independently and carry genes for gene transfer.

Retrovirus

An RNA virus, such as HIV, that uses the enzyme reverse transcriptase to synthesize DNA from an RNA template, which subsequently inserts into the host genome.

Prion

An infectious protein that misfolds and induces abnormal folding of normal brain proteins, leading to degenerative neurological diseases in animals.