Biological and Environmental Influence on Development Flashcards
Genotype
the unique and complex blend of genes from both parents that determines our unique characteristics
Phenotype
the observable characteristics of your unique genetic make up
Genome
complete set of genes in a cell or organism
Gene
basic unit of heredity
Alleles
one or more alternative forms of a gene
Heterozygous
2 different alleles of same gene, carriers of the gene disorder
Homozygous
2 identical copes of the same gene
Chromosome
a structure of genetic information found in the nucleus that contains genes
Sex (gametes) cells
specific chromosomes that determines sex of organism (Male XY, Female XX)
Somatic (body) cells
all other cells in the body (besides sex chromosomes)
Autosome
genes located on chromosome pairs 1-22
Sex chromosomes
X and Y chromosomes, sex specific
Dominant
genes that are expressed when one copy is present
Recessive
genes that are expressed when two copies are present
Mitosis
cell replication, mother cell replicates into two daughter cells
Meiosis
sex cells replication, genetic variation
meiosis 1 ends with diploid cells containing 46 chromosomes
meiosis 2 ends with 4 different types of cells; haploid cells containing 23 chromosomes
Zygote
fertilized cell, 23 chromosomes from mother, 23 chromosomes from father, 46 chromosomes total
How is the sex of a child determined?
if fertilized by an X sperm, female fetus will form
if fertilized by a Y sperm, male fetus will form
Dizygotic (Fraternal)
occurs when released ova (egg) are fertilized individually by two different sperm; usually look different; genetically similar to siblings born separaretly
Monozygotic (Identical)
occurs when the same ovum is fertilized by one sperm, but splits during the fertilization process; looks the same; share the same exact genotype
Mendelian (simple) inheritance
inheritance of traits controlled by a single gene with two alleles; dominant and recessive
Patterns of Inheritance
autosomal dominant, autosomal recessive, x-linked (dominant and recessive)
Punnet Squares
determines the possible gene outcomes from mother and father genes
Dominant Genes
always expressed regardless of the gene they are paired with; homozygous or heterozygous (carriers)
Recessive Genes
only expressed if paired with another recessive gene; homozygous only
Autosomal Dominant Inheritance
located on non-sex genes (autosomal) and one requires one copy of the gene to display genetic condition
Marfan Syndrome
disorder of connective tissue
symptoms: tall, thin body, extremities disproportionately long for trunk, heart problems, skin and eye problems
Autosomal Recessive Inheritance
occurs in homozygous individuals only; affected individuals may or may not have an affected parent; offspring have 25% chance of having gene with 2 carrier parents
Cystic Fibrosis
disorder that causes buildup of thick, sticky mucus and affects the lungs and digestive system
symptoms: frequent lung infections, chronic cough, poor weight gain, bulky, greasy stools
X-linked Dominant
dominant gene on X chromosomes; affected males produce all affected daughters, cannot pass to sons; if mom is affected, 50% chance to either son or daughter
Fragile X syndrome
most common inherited cause of intellectual disability; affects males more severely
symptoms: large ears and head, ADHD, autism, language and learning delays
X-linked Recessive
usually expressed only in males, females are carriers
