Exercise 14: Mendelian Genetics Study Guide

Comprehensive vocabulary flashcards covering genetic terminology, Mendel's laws, monohybrid and dihybrid crosses, human ABO blood typing, and immunology concepts.

Chromosome

Structure of DNA and proteins carrying genetic info.

Fruit Fly Chromosome

Human Chromosome

Gene

DNA sequence coding for a functional protein/trait.

Allele

Alternative forms or variants of a specific gene.

Locus

Specific physical location of a gene on a chromosome.

Genotype

Genetic makeup of an organism (e.g., $Tt$, $YY$).

Phenotype

Observable physical expression of genotype.

Dominant

Allele expressed over recessive allele (e.g., $T$).

Recessive

Allele expressed only when homozygous (e.g., $t$).

Homozygous

Carrying identical alleles (e.g., $TT$ or $tt$).

Heterozygous

Carrying different alleles (e.g., $Tt$).

Multiple Allelic Trait

Trait controlled by a gene with more than two possible alleles in a population (e.g., ABO blood group alleles: $I^A$, $I^B$, $i$).

Law of Segregation (1st Law)

Allele pairs separate during gamete formation so that each gamete carries only one allele for each gene.

Law of Independent Assortment (2nd Law)

Genes for different traits assort independently during gamete formation (applies to genes on different chromosomes).

Monohybrid Cross (Heterozygous Parents, $Tt \times Tt$)

Tracks 1 trait, resulting in an expected phenotypic ratio of $3:1$ (Dominant : Recessive).

Monohybrid Test Cross

Crosses an individual with a dominant phenotype ($T?$) with a homozygous recessive ($tt$) to reveal genotype: if $100\%$ offspring are dominant, the parent was $TT$; if $1:1$ dominant to recessive, the parent was $Tt$.

Dihybrid Cross (Heterozygous Parents, $YyRr \times YyRr$)

Tracks 2 independent traits, resulting in an expected phenotypic ratio of $9:3:3:1$.

Type A Blood

Blood phenotype with genotype $I^A I^A$ or $I^A i$, RBC A antigen, plasma Anti-B antibodies, and can receive blood from types A and O.

Type B Blood

Blood phenotype with genotype $I^B I^B$ or $I^B i$, RBC B antigen, plasma Anti-A antibodies, and can receive blood from types B and O.

Type AB Blood

Blood phenotype with genotype $I^A I^B$, RBC A and B antigens, no plasma antibodies, and can receive from A, B, AB, and O (Universal Recipient).

Type O Blood

Blood phenotype with genotype $ii$, no RBC antigens, plasma Anti-A and Anti-B antibodies, and can receive only from O (Universal Donor).

Antigen

Surface molecule on cells that serves as an immunological identification tag.

Antibody

Y-shaped immune system protein in plasma that targets specific foreign antigens.

Agglutination

Clumping of red blood cells caused when plasma antibodies bind to corresponding antigens.

Blood Test Plate Interpretation

Clumping in Anti-A well only = Type A;
Clumping in the anti-B well only = Type B;
Clumping in both wells = Type AB;
Clumping in neither well = Type O.