Genetics and Molecular Biology Lecture Notes

Comprehensive vocabulary flashcards covering basic genetics, Mendelian inheritance, DNA structure, replication, protein synthesis, and mutations based on the lecture transcript.

Heredity

The passing of traits from parents to offspring.

Genetics

The scientific study of heredity and the variation of inherited characteristics.

Trait

A specific characteristic or quality of an individual.

Allele

Different forms or versions of a single gene.

Gene

A unit of heredity; a segment of DNA that codes for a specific protein.

Genotype

The genetic makeup of an organism, often represented by letter combinations like $RR$ or $RW$.

Phenotype

The physical appearance or observable traits of an organism, such as flower color.

Dominant

An allele that expresses its phenotype even when only one copy is present.

Recessive

An allele that only expresses its phenotype when two copies are present.

Codominance

A condition in which both alleles for a gene are fully expressed in the phenotype, such as in blood type $AB$.

Incomplete Dominance

A pattern of inheritance where the heterozygote has an intermediate phenotype, such as Red ($R$) and White ($W$) alleles producing Pink ($RW$) flowers.

Sex-linked Traits

Traits controlled by genes located on the sex chromosomes, typically the $X$ chromosome.

Polygenic Traits

Traits that are controlled by two or more different genes.

Gregor Mendel

The scientist known as the father of genetics whose experiments with plants led to the discovery of the basic principles of heredity.

Hemophilia

A rare blood disorder where blood doesn’t clot properly, inherited as an $X$-linked recessive trait.

$$X^H X^h$$

The genotype for a female carrier who does not have hemophilia.

$$X^h X^h$$

The genotype for a female with hemophilia.

$$X^h Y$$

The genotype for a male with hemophilia.

$$X^H Y$$

The genotype for a male without hemophilia.

Rosalind Franklin

A scientist whose X-ray diffraction images made significant contributions to understanding the double helix structure of DNA.

Nucleotide

The building block of DNA and RNA, consisting of a sugar, a phosphate group, and a nitrogenous base.

Base Pairing Rules

The rule in DNA that Adenine ($A$) always pairs with Thymine ($T$) and Cytosine ($C$) always pairs with Guanine ($G$).

Chargaff’s Rule

The rule stating that the percentages of Adenine equal Thymine and the percentages of Guanine equal Cytosine in DNA.

DNA Replication

The biological process of producing two identical replicas of DNA from one original DNA molecule.

Okazaki Fragments

Short, newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication.

Leading Strand

The DNA strand that is synthesized continuously in the $5'$ to $3'$ direction during replication.

Lagging Strand

The DNA strand that is synthesized discontinuously in small sections called Okazaki fragments.

Semi-conservative

The model of DNA replication where each new DNA molecule consists of one original parent strand and one newly synthesized strand.

Telomeres

Repetitive DNA sequences at the ends of chromosomes that protect them from deterioration and are linked to aging.

Central Dogma of Biology

The concept explaining the flow of genetic information from DNA to RNA to Protein.

Transcription

The process of copying a segment of DNA into messenger RNA (mRNA).

Translation

The process in which ribosomes use the mRNA sequence to assemble amino acids into a protein.

Splicing

The molecular process of removing non-coding introns and joining coding exons together to form a mature mRNA transcript.

Intron

A non-coding sequence within a gene that is removed during the splicing process.

Exon

A coding sequence of a gene that remains in the mRNA after splicing and is translated into a protein.

Alternative Splicing

A process that allows a single gene to code for multiple proteins by including different combinations of exons in the final mRNA.

Mutation

A change in the DNA sequence of an organism.

Substitution Mutation

A type of mutation where one nucleotide base is replaced by a different base.

Frameshift Mutation

A mutation caused by the insertion or deletion of a nucleotide, which shifts the reading frame of the genetic message.

Chromosomal Mutation

A mutation that involves changes in the number or structure of chromosomes.