MCAT Genetics Practice Flashcards

A set of practice flashcards covering key concepts in genetics for the MCAT, including Mendelian laws, population genetics, molecular biology, and chromosomal disorders.

Alternative forms of the same gene located at the same locus on homologous chromosomes are called what?

Alleles

The physical appearance resulting from a genotype and environmental influences is called what?

Phenotype

The genetic makeup of an organism is called what?

Genotype

Having two identical alleles for a trait is called what?

Homozygous

Having two different alleles for a trait is called what?

Heterozygous

An allele that masks the expression of another allele in a heterozygote is called what?

Dominant allele

An allele whose effects are masked by a dominant allele is called what?

Recessive allele

A chart used to predict offspring genotypes from parental crosses is called what?

Punnett square

A trait controlled by a single gene with two alleles exhibiting complete dominance is called what?

Mendelian inheritance

The principle stating that allele pairs separate during gamete formation is called what?

Law of Segregation

The principle stating that genes on different chromosomes assort independently during gamete formation is called what?

Law of Independent Assortment

Inheritance in which the heterozygote displays an intermediate phenotype is called what?

Incomplete dominance

Inheritance in which both alleles are fully expressed in the heterozygote is called what?

Codominance

The human blood type system demonstrating codominance is called what?

ABO blood group system

A trait controlled by multiple genes is called what?

Polygenic inheritance

A gene that influences multiple seemingly unrelated traits is demonstrating what?

Pleiotropy

When one gene affects the expression of another gene, this interaction is called what?

Epistasis

A chromosome other than a sex chromosome is called what?

Autosome

A trait carried on the X chromosome is described as what?

X-linked

A trait carried on the Y chromosome is described as what?

Y-linked

Disorders more common in males because only one recessive allele is required for expression are usually what type of inheritance?

X-linked recessive

The process by which homologous chromosomes exchange genetic material during meiosis I is called what?

Crossing over

The physical exchange points between homologous chromosomes during meiosis are called what?

Chiasmata

New combinations of alleles produced through crossing over are called what?

Recombinants

Genes located close together on the same chromosome tend to be inherited together and are called what?

Linked genes

The tendency of linked genes to be inherited together is called what?

Genetic linkage

The percentage of recombinant offspring used to estimate distance between genes is called what?

Recombination frequency

One percent recombination frequency equals what genetic map unit?

Centimorgan

Random separation of homologous chromosomes during meiosis I contributes to what source of variation?

Independent assortment

Random union of gametes during fertilization contributes to what source of variation?

Random fertilization

The equation describing allele frequencies in a population is what?

$$p + q = 1$$

The equation describing genotype frequencies in a population is what?

$$p^2 + 2pq + q^2 = 1$$

In Hardy-Weinberg, the frequency of the dominant allele is represented by what?

$$p$$

In Hardy-Weinberg, the frequency of the recessive allele is represented by what?

$$q$$

In Hardy-Weinberg, homozygous dominant frequency is represented by what?

$$p^2$$

In Hardy-Weinberg, heterozygous frequency is represented by what?

$$2pq$$

In Hardy-Weinberg, homozygous recessive frequency is represented by what?

$$q^2$$

Evolutionary equilibrium in a population is described by what principle?

Hardy-Weinberg Equilibrium

Random mating, no mutations, no migration, large population size, and no natural selection are assumptions of what model?

Hardy-Weinberg Equilibrium

A change in allele frequency over generations is called what?

Evolution

The flow of genetic information from DNA to RNA to protein is called what?

Central Dogma

Synthesis of RNA from a DNA template is called what?

Transcription

Synthesis of protein from an mRNA template is called what?

Translation

The enzyme responsible for DNA replication is called what?

DNA polymerase

The enzyme that synthesizes RNA during transcription is called what?

RNA polymerase

A sequence of three nucleotides that codes for an amino acid is called what?

Codon

The three-nucleotide sequence on tRNA complementary to an mRNA codon is called what?

Anticodon

A change in a DNA sequence is called what?

Mutation

A mutation that changes one amino acid to another is called what?

Missense mutation

A mutation that creates a stop codon is called what?

Nonsense mutation

A mutation that does not alter the amino acid sequence is called what?

Silent mutation

Insertion or deletion mutations that alter the reading frame are called what?

Frameshift mutations

The process by which cells control when and how much a gene is expressed is called what?

Gene regulation

DNA wrapped around histone proteins forms what structure?

Nucleosome

Tightly packed, transcriptionally inactive DNA is called what?

Heterochromatin

Loosely packed, transcriptionally active DNA is called what?

Euchromatin

Addition of methyl groups to DNA generally causes what?

Gene silencing

Heritable changes in gene expression without altering DNA sequence are called what?

Epigenetics

Noncoding DNA sequences removed from pre-mRNA are called what?

Introns

Coding DNA sequences retained in mature mRNA are called what?

Exons

Removal of introns and joining of exons is called what?

RNA splicing

Production of multiple proteins from a single gene through different exon combinations is called what?

Alternative splicing

The region where RNA polymerase binds to begin transcription is called what?

Promoter

A DNA sequence that increases transcription levels is called what?

Enhancer

A protein that binds DNA to regulate gene expression is called what?

Transcription factor

The inheritance pattern of mitochondrial DNA is called what?

Maternal inheritance

Organelles containing their own circular DNA and inherited from the mother are called what?

Mitochondria

The random inactivation of one X chromosome in female mammals is called what?

Lyonization

The inactive X chromosome visible in the nucleus is called what?

Barr body

The chromosomal condition characterized by trisomy $21$ is called what?

Down Syndrome

A chart used to track inheritance patterns through multiple generations is called what?

Pedigree

A trait appearing in every generation is most characteristic of what inheritance pattern?

Dominant inheritance

A trait that can skip generations is most characteristic of what inheritance pattern?

Recessive inheritance

An unaffected individual carrying one copy of a recessive disease allele is called what?

Carrier

If affected fathers pass a trait to all daughters but no sons, the inheritance pattern is most likely what?

X-linked dominant

If affected fathers pass a trait to all sons, the inheritance pattern is most likely what?

Y-linked inheritance

Cell division producing genetically unique haploid gametes is called what?

Meiosis

Cell division producing genetically identical daughter cells is called what?

Mitosis

Homologous chromosomes separate during which meiotic division?

Meiosis I

Sister chromatids separate during which meiotic division?

Meiosis II

Failure of chromosomes to separate properly during meiosis is called what?

Nondisjunction

An abnormal chromosome number resulting from nondisjunction is called what?

Aneuploidy

Having three copies of a chromosome is called what?

Trisomy

Having only one copy of a chromosome is called what?

Monosomy

Monosomy X is known as what syndrome?

Turner Syndrome

XXY karyotype is known as what syndrome?

Klinefelter Syndrome

Trisomy $18$ is known as what syndrome?

Edwards Syndrome

Trisomy $13$ is known as what syndrome?

Patau Syndrome

The DNA strand used as a template during transcription is called what?

Template strand

The DNA strand that matches the RNA sequence except T replaces U is called what?

Coding strand

Addition of a modified guanine to the 5' end of mRNA is called what?

5' cap

Addition of adenine nucleotides to the 3' end of mRNA is called what?

Poly-A tail

The process of making RNA from DNA is called what?

Transcription

The process of making protein from RNA is called what?

Translation

The cellular structure where translation occurs is called what?

Ribosome

The start codon AUG codes for which amino acid?

Methionine

UAA, UAG, and UGA are collectively called what?

Stop codons

A mutation involving replacement of one nucleotide with another is called what?

Point mutation

A purine replacing a purine or pyrimidine replacing a pyrimidine is called what mutation?

Transition mutation

A purine replacing a pyrimidine or vice versa is called what mutation?

Transversion mutation