DEVPSYCH (LESSON 2)

Fertilization or conception

the process by which sperm and ovum—the male and female gametes, or sex cells— combine to create a single cell called a zygote

Zygote

duplicates itself again and again by cell division to produce all the cells that make up a baby

Dizygotic Twins

Monozygotic Twins

Causes Multiple Births

Dizygotic Twins

the union of two different ova (or a single ovum that has split) with two different sperm cells; also called fraternal twins; they are no more alike genetically than any other siblings.

Monozygotic Twins

Twins resulting from the division of a single zygote after fertilization; also called identical twins; they are genetically similar.

Deoxyribonucleic acid (DNA)

basis of hereditary is a chemical called _______.

Adenine (A)

Thymine (T)

Cytosine (C)

Guanine (G)

Four Chemical Units/Bases in DNA

Deoxyribonucleic Acid (DNA)

Chemical that carries inherited instructions for the development of all cellular forms of life.

Genetic Code

Sequence of bases within the DNA molecule; governs the formation of proteins that determine the structure and functions of living cells.

Chromosomes

Coils of DNA that consist of genes

Genes

Functional units of heredity

Human Genome

Complete sequence of genes in the human body.

23

How many pairs of chromosomes does every cell in the normal human body have?

Meiosis

A type of cell division in which the sex cells undergo when they are developing.

Zygote

It is produce when sperm and ovum fuse at conception.

Divorce

In many villages in Nepal, when a man’s wife has no male babies, he can take a second wife. What happens to the man and his first wife?

Father’s sperm

What genetically determines a child’s sex?

Autosomes

Twenty-two pairs of chromosomes are _________, chromosomes that are not related to sexual expression.

Sex chromosomes

The twenty-third pair are __________________ —one from the father and one from the mother.

Sperm

The sex chromosome of every ovum is an X chromosome, but ______ contain either an X or Y chromosome.

SRY gene

The Y chromosome contains the gene for maleness, called the ______.

Male

When an ovum (X) is fertilized by a Y-carrying sperm, the resulting zygote is XY, a genetic ______.

Female

When an ovum is (X) is fertilized by an X-carrying sperm, the zygote formed is XX, a genetic ______.

Male

_____ baby receives an X chromosome from the mother and a Y chromosome from the father

Female

______ baby receives X chromosomes from both mother and father.

Father

______ has an X chromosome and a Y chromosome.

Mother

______ has two X chromosomes

Recessive Inheritance

It is a pattern of genetic transmission in which a child can do what his/her parents can’t do.

Alleles

Two or more alternative forms of a gene that occupy the same position on paired chromosomes and affect the same trait.

Homozygous

Possessing two identical alleles for a trait.

Heterozygous

Possessing differing alleles for a trait

Recessive Inheritant

Pattern of inheritance in which, when a child receives identical recessive alleles, resulting in expression of a nondominant trait.

Dominant

Pattern of inheritance in which, when a child receives different alleles, only the ______ one is expressed.

Polygenic Inheritance

Pattern of inheritance in which, multiple genes at different sites on chromosomes affect a complex trait.

Mutations

Permanent alterations in genes or chromosomes that may produce harmful characteristics

Phenotype

Observable characteristics of a person.

Genotype

Genetic makeup of a person, containing both expressed an unexpressed characteristics.

Multifactorial Transmission

Combination of genetic and environmental factors to produce certain complex traits.

Epigenesis

Mechanism that turns genes on or off and determines functions of body cells.

Germinal Stage

Embryonic Stage

Fetal Stage

Stages of Prenatal Development

Germinal Stage

First 2 weeks of prenatal development, characterized by rapid cell division, blastocyst formation, and implantation in the wall of the uterus.

Embryonic Stage

Second stage of gestation (2 to 8 weeks), characterized by rapid growth and development of major body systems and organs.

Fetal Stage

Final stage of gestation (from 8 weeks to birth), characterized by increased differentiation of body parts an greatly enlarged body size.

Spontaneous Abortion

Natural expulsion from the uterus of an embryo that cannot survive outside the womb; also called misscarriage

Ultrasound

Prenatal medical procedure using high-frequency sound waves to detect the outline of a fetus and its movements, so as to determine whether a pregnancy is progressing normally.