Midterm Exam 3 Study Guide: Modules 7, 8, and 9

Vocabulary practice flashcards covering fundamental terms from Module 7 (DNA and Gene Expression), Module 8 (Genes and Inheritance), and Module 9 (Biotechnology).

Ploidy

The number of complete sets of chromosomes present in a cell.

Homology

Similarity in characteristics or chromosome pairs resulting from shared ancestry.

Transcription

The enzymatic process of synthesizing an RNA molecule from a DNA template strand.

Translation

The biological process in which genetic information in mRNA is decoded by ribosomes and tRNA to synthesize a specific polypeptide chain.

mRNA

Messenger RNA; a single-stranded RNA molecule that conveys genetic information from DNA to the ribosome for protein synthesis.

tRNA

Transfer RNA; an adaptor RNA molecule that carries a specific amino acid to the ribosome matching an mRNA codon during translation.

Ribosome

A complex cellular macromolecular machine made of ribosomal RNA and proteins that catalyzes protein synthesis.

Transcription Factors

Proteins that regulate gene expression by binding to specific DNA sequences to promote or repress transcription.

Activator

A transcription factor that increases gene transcription by facilitating RNA polymerase binding to a promoter.

Repressor

A DNA- or RNA-binding protein that inhibits the expression of one or more genes by blocking RNA polymerase attachment or movement.

lac Operon

An inducible bacterial operon required for the transport and metabolism of lactose, consisting of structural genes, a promoter, an operator, and a regulatory gene.

Promoter

A specific sequence of DNA where RNA polymerase binds to initiate transcription of downstream genes.

Operator

A segment of DNA within an operon to which a repressor binds to prevent the transcription of adjacent structural genes.

Regulatory Gene

A gene that codes for a regulatory protein, such as a repressor or activator, controlling the transcription of other genes.

Epigenetics

The study of heritable changes in gene expression or cellular phenotype that do not involve changes to the underlying DNA sequence.

Mutation

A permanent alteration in the nucleotide sequence of the genome of an organism.

Genotype

The specific genetic makeup or allele combination of an individual organism.

Phenotype

The observable physical, biochemical, or physiological characteristics of an organism determined by both genotype and environment.

Simple Dominance

An inheritance pattern in which the dominant allele completely masks the presence of the recessive allele in the heterozygote.

Codominance

A non-Mendelian inheritance pattern where both alleles for a gene are fully and simultaneously expressed in heterozygous individuals.

Incomplete Dominance

An inheritance pattern in which neither allele is completely dominant, resulting in a heterozygous phenotype that is an intermediate blend of the two homozygous phenotypes.

Pleiotropy

A genetic phenomenon in which a single gene influences multiple, seemingly unrelated phenotypic traits.

Polygenic Trait

A phenotypic trait whose expression is governed by the additive effects of multiple independent genes.

Law of Segregation

Mendel's principle stating that two alleles for a heritable character separate during gamete formation and end up in different gametes.

Law of Independent Assortment

Mendel's principle stating that alleles of two or more different genes assort independently of one another during gamete formation, assuming they reside on separate chromosomes.

Test Cross

A breeding experiment in which an individual of unknown dominant genotype is crossed with a homozygous recessive individual to deduce the unknown genotype.

Linkage

The tendency of two or more genes positioned close together on the same chromosome to be inherited together during meiosis due to reduced crossing over.

Sex-Linked Trait

A trait governed by a gene located on a sex chromosome (typically the X or Y chromosome).

Biotechnology

The technical application of biological systems, living organisms, or their derivatives to make or modify products or processes for specific uses.

Transformation

A biotechnology and biological method by which a recipient cell takes up and incorporates foreign, naked DNA from its external environment.

Vector

A DNA vehicle (such as a plasmid or bacteriophage) used in molecular cloning to transfer foreign genetic material into another cell.

Antibiotic Selection

A laboratory technique using antibiotic-resistance genes on cloning vectors to identify and isolate host cells that successfully incorporated the vector DNA.

CRISPR

A specialized targeted genome-editing technology adapted from a bacterial defense system that directs an endonuclease to modify precise DNA sequences.

Recombinant DNA Technology

A set of molecular procedures used to artificially join DNA sequences from different biological sources into a single DNA molecule in vitro.

Genetic Engineering

The deliberate and direct modification of the genetic material of an organism using modern biotechnology techniques.

Loss-of-Function

A mutation or alteration that diminishes or completely abolishes the normal activity or expression of a gene product.

Gain-of-Function

A mutation or alteration that endows a gene product with an enhanced, novel, or inappropriately expressed biological activity.