Genotype-Phenotype Distinction

Topics: Pregnancy, Fetal alcohol syndrome, Mental retardation Pages: 12 (3331 words) Published: May 8, 2012
Chapter 2
Phenotype: an individual's directly observable physical and behavioral characteristics, which are determined by both genetic and environmental factors
Genotype: an individual's genetic makeup
Chromosomes: rodlike structures in the cell nucleus that store and transmit genetic information
DNA: are what chromosomes are made out of; long, double-stranded molecule that looks like a twisted ladder, each ladder consists of a specific pair of chemical substances called bases, joined together between two sides

Gene: a segment of DNA along the length of the chromosome Mitosis-meiosis
Mitosis: the process of cell duplication, in which each new cell receives an exact copy of the original chromosomes
Meiosis: the process of cell division through which gametes are formed and in which the number of chromosomes in each cell is halved Sex cells
Gametes: sex cells-sperm and ovum-combine; contains only 23 chromosomes; formed through a cell division (meiosis)
Zygote: when sperm and ovum unite at conception, will have 46 chromosomes
Autosomes: 22 of the 23 pairs of chromosomes are matching pairs
Sex Chromosomes: the twenty-third pair; females: XX males: X; Y is short and carries little genetic material, X is a relatively large chromosome
Fraternal/Dizygotic twins: most common type of multiple birth, resulting from the release and fertilization of two ova
Identical/Monozygotic twins: a zygote that has started to duplicate separates into two clusters of cells that develop into two individuals; same genetic makeup Dominant-recessive (including chart exercise done in class)

Allele: two forms of each gene occur at the same place on the chromosomes, one inherited from the mother and one from the father
Homozygous: alleles from both parents are alike and displays the inherited trait
Heterozygous: alleles differ and relationships between the alleles determine the trait that will appear
Dominant-recessive inheritance: occurs only one allele affects the child's characteristics; it is also called dominant; the second allele, which has no effect, is called recessive.
Carriers: heterozygous individuals with just one recessive allele can pass that trait to their children Polygenic
Polygenic Inheritance: a pattern of inheritance in which many genes influence a characteristic Reaction range
Range of Reaction: each person's unique, genetically determined response to the environment Three types of genetic-environmental correlation
Genetic-environmental correlation: our genes influence the environments to which we are exposed
Passive Correlation: the child has no control over it, being exposed to an "athletic environment" the children m ay have inherited their parent's' athletic ability; both genetic and environmental reasons

Evocative Correlation: children evoke responses that are influenced by the child's heredity, and these responses strengthen the child's original style
Active Correlation: children extends their experiences beyond the immediate family and are given the freedom to make more choices, they actively seek environments that fit their genetic tendencies

Niche-picking: tendency to actively choose environments that complement our heredity

Chapter 3
Fertilization process/locations
Zygote: As the zygote moves down the fallopian tube, it duplicates, at first slowly and then more rapidly
Blastocyst: By the fourth day it forms a hollow, fluid-filled ball, called a blastocyst. The inner cells, called the embryonic disk, will become the new organism. The outer cells, or trophoblast, will provide protective covering.

Implantation: At the end of the first week, the blastocyst begins to implant in the uterine lining. Periods of prenatal development
Zygote: Lasts about 2 weeks, from fertilization until the tiny mass of cells drifts down and out of the fallopian tube and attaches...
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