Bio Lab Exam II Study Guide

Page 1: Key Concepts in Genetics

Humans Cells: 46 chromosomes, organized into 23 pairs.
Homologous Chromosomes: Pairs of chromosomes that have the same genes at the same loci; similar structure and size.

White Blood Cells: Key players in fighting off infections.
Tay-Sachs Disease: Inherited in an autosomal recessive pattern. Both parents are carriers, passing on defective genes.

Nondisjunction: Failure of chromosome pairs to separate during cell division. Can occur in either meiosis. Leads to gametes with missing or extra chromosomes.
Aneuploidy: Condition of having an abnormal number of chromosomes (extra or missing).

Surface Area to Volume Ratio: As cells grow, volume increases faster than surface area, reducing the efficiency of nutrient transport and waste removal.
Single-celled Organisms: Remain small due to efficiency constraints related to surface area to volume ratios.

Sources of Variation: Mutations, crossing over, independent assortment.
Heterozygous Advantage: Example: Sickle cell trait provides protection against malaria.
Natural Selection: Mutations increase genetic variation, allowing selective pressures to favor certain traits.
Importance of Diversity: Vital for long-term population survival amid environmental changes.

Mitosis: Produces 2 diploid daughter cells, involved in growth and repair, occurs throughout body.
Meiosis: Produces 4 haploid cells, specialized for reproduction, occurs in ovaries and testes.

X-Linked Traits: Daughters inherit X-linked dominant traits from affected fathers (100% chance), while sons do not inherit from fathers (0% chance).
Karyotype Use: Analyzes chromosomal structure to determine biological sex and chromosomal abnormalities.
Genotype vs Phenotype: Genotype is the genetic makeup, while phenotype is the expression of those genes.
Homozygous vs Heterozygous: Homozygous: two identical alleles; Heterozygous: two different alleles.

Blood Type Analysis: Baby 1 (A) belongs to parents 2 (Carol and Derrek), Baby 2 (O) belongs to parents 1 (Jennifer and Thomas).
Thomas's Genotype: BO; Baby 2's Genotype: OO.

X-Linked Recessive Patterns: Daughters inherit the allele on X from the mother and X from the father; sons inherit Y from the father, with possible X from the mother.
X-Linked Dominant Patterns: Only daughters inherit X from affected fathers; mothers can pass the trait to both sons and daughters.

Interphase: Majority of cell life, focused on building proteins and replicating DNA.
Mitosis Phases:
- Prophase: Chromosomes condense; nuclear membrane disintegrates; spindle fibers form.
- Metaphase: Chromosomes align at the cell equator; spindle fibers attach.
- Anaphase: Sister chromatids pulled apart to opposite poles.
- Telophase: Chromosomes unwind; nuclear membranes reform.
- Cytokinesis: Cytoplasm divides; results in two identical daughter cells.

Haploid Cells: Contain one of each chromosome.
Trisomy vs Monosomy: Trisomy involves three copies of a chromosome; monosomy involves one copy.

Amniocentesis: A procedure for genetic testing in fetuses by extracting amniotic fluid.
CRISPR: Gene-editing technology for treating genetic disorders.
Natural Selection: Differential survival of organisms based on inherited traits.
Blood Composition: Plasma, erythrocytes, leukocytes, platelets, and antigens.
Genetic Screening: Testing for specific genes within an individual's genetic background.

Sickle Cell Anemia: Mutation on chromosome 11, leading to reduced oxygen-carrying capacity.
Cystic Fibrosis: Caused by mutations on chromosome 7, affecting respiratory tract secretions.
Down Syndrome: Trisomy 21, resulting in developmental delays.
Klinefelter's Syndrome: 47, XXY genetic condition, often results in male developmental issues.
Turner's Syndrome: 45, XO, results in female developmental differences due to missing X chromosome.
Jacobs Syndrome: 47, XYY, linked with behavioral issues, caused by an extra Y chromosome.
Patau Syndrome: Trisomy 13, associated with severe intellectual disabilities.
Edwards Syndrome: Trisomy 18, leads to growth problems before birth.
Phenylketonuria (PKU): Recessive disorder on chromosome 12, requires dietary management.
Neurofibromatosis: Dominant disorder on chromosome 17, characterized by skin spots.
Marfan Syndrome: Genetic disorder affecting connective tissue, linked to chromosome 15.
Duchenne Muscular Dystrophy: X-linked disorder causing muscle degeneration.
Cancer: Not typically inherited, results from uncontrolled cell division.