Flashcards in Chapter 3 - Genetics, Conception, and Prenatal Development Deck (32)
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1
Chromosomes
Physical structures of inheritance consisting of DNA and supporting proteins.
2
Deoxyribonucleic Acid (DNA)
Molecules that carry genetic code of a cell
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Genes
Units of hereditary information; each gene is a segment of DNA in a specific location on a chromosome
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Mitosis
A lifelong process of nuclear division involving the replication of chromosomes and their distribution into two identical nuclei, usually followed by cell division.
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Sex chromosomes
The pair of sex-determining chromosomes that each human possesses: XX in females and XY in males.
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Autosomes
Any of the chromosomes other than the sex-determining chromosomes; also referred to as somatic chromosomes
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Meiosis
The cell division process in which pairs of chromosomes exchange pieces of genetic material, producing chromosomes with new combinations of genes and traits in offspring.
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Congenital
A characteristic or condition present from birth
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Sex-linked inheritance
Transmission of characteristics via a sex chromosome.
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Down Syndrome
A syndrome, also referred to as Trisomy 21, in which there is an extra chromosome 21, resulting in distinctive facial features and other physical characteristics and mild to severe cognitive disabilities
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Multifactorial Transmission
The interaction of genes and the environment that produces most complex human characteristics.
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Ovum
Female sex cell
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Sperm
Male sex cell
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Zygote
The cell that results when an ovum is fertilized by a sperm cell
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Monozygotic Twins
Siblings resulting from a single egg; also known as identical
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Dizygotic Twins
Siblings resulting from two different eggs, also known as fraternal
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Infertility
The absence of pregnancy after 12 months of unprotected sexual intercourse
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Assisted Reproductive Technology (ART)
Fertility treatments in which both egg and sperm are handled
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Germinal Stage
The first prenatal stage, beginning at conception and lasting approximately two weeks
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Blastocyst
A hollow, spherical structure composed of approximately 100 identical cells, which are formed through mitosis during the first week of conception.
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Embryo
The tern for a blastocyst that has become implanted in the uterine wall
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Embryonic Stage
The second prenatal stage, lasting from 2 to 8 weeks after conception
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Teratogens
Substances such as alcohol, drugs, nicotine, and radiation that are known to cause harm to the developing embryo and fetus
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Cephalocaudal Principle
The pattern of growth in which development begins in the head and occurs later in the tail of the organism
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Proximodistal Principle
The pattern of growth in which development begins in the center of the body and moves toward the extremities
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Placenta
A network of blood vessels, formed from cells in the trophoblast and in the uterine lining, which conveys oxygen and nutrients to the embryo and carries away waste products
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Umbilical Cord
The structure through which the embryo is connected to the placenta
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Ectoderm
The outer layer of the developing embryo, which becomes the brain and spinal cord; sensory organs; and skin, nails, hair, and teeth
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Mesoderm
The middle layer of the inner cell mass, from which the circulatory and excretory systems, muscles, and skeleton develop
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Endoderm
The inner layer of the inner cell mass, from which the respiratory and digestive systems develop.
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Fetal Stage
The third prenatal stage, lasting from 8 weeks until birth
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