Chapter 3: Forming A New Life Flashcards
What is a Fertile Window?
A woman’s most fertile days
6th to the 21st days of the menstrual cycle
What is Fertilization/Conception?
The process by which sperm and ovum (male and female gametes) combine to create a single cell
What is a gamete?
Sex cells
What is a zygote?
A single cell created through fertilization or conception
What is Ovulation?
It happens when a mature follicle in either ovary ruptures and leads to the expulsion of the ovum
What is an Ovum?
An egg cell that is swept along by thee cilia through the uterus and finally, the womb.
What are sperm cells?
Cells that are produced in a males testicles at a rate of several 100,000 a day and are ejaculated in the semen at sexual climax
What is a Cervix?
It is the opening of the uterus
How do multiple births occur?
When the mother releases two eggs with a short time or when a single unfertilized ovum splits into two
When are Fraternal/Dizygotic Twins produced?
When the mother’s body releases two eggs at the same time.
When are Identical/Monozygotic twins produced?
When a single fertilized ovum splits into two
How are Triplets or Quadruplets produced?
Through either of thee two processes or a combination of both
What are Semi-Identical Twins?
They are a result of two sperm cells fusing with a single ovum. They are more genetically similar than dizygotic twins but less similar than monozygotic twins
What are the causes of the rise in Multiple Births?
Trend toward delayed childbearing
Increased use of fertility drugs
What is heredity?
Inborn factors inherited from one’s biological parents that affect development
What is a Genetic Code?
It is the basis of heredity.
What is Deoxyrionucleic Acid (DNA)?
It is a chemical which is the basis of heredity. It has a double-helix structure which resembles a long, spiraling ladder whose steps are made of bases
What are Bases?
These are pairs of chemical units which make up steps.
What are the letters of the Genetic Code which the cellular machinery “reads?”
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
What are Chromosomes?
These are coils of DNA that consist of genes. There are 23 pairs in a human body
What are Genes?
They are functional units of heredity, located in a definite position on its chromosome and contains thousands of bases
What do the Sequence of Bases do?
They tell the cell how to make the proteins that enable it to carry out specific functions
What is a Human Genome?
It is made up of a complete sequence of genes
What is Meiosis?
Type of cell division which the sex cells undergo when they are developing
What is Mitosis?
The process by which non-sex cells divide in half over and over again.
What are Autosomes?
These are chromosomes not related to sexual expression. There are 22 pairs in the body.
What are Sex Chromosomes?
23rd pair of chromosomes, one pair from the father and one pair from the mother, that govern the baby’s sex
What is the SRY Gene?
Gene for maleness
What combination of Chromosomes produce a Genetic Female?
XX or Ovum X + Sperm Y
What chromosomes produce a Genetic Male?
XY (Ovum X + Sperm Y)
What is Wnt 4?
A variant form of signaling molecules which can masculinize a genetically female fetus
Who was Gregor Mendel?
He laid the foundation and understanding of patterns of inheritance.
What are Alleles?
Genes that can produce alternative expressions of a characteristic
What does a person receive from his parents?
A pair of Alleles for a given characteristics, one from each parent
When is a person said to be homozygous for a characteristic?
When he possesses two identical alleles for a trait.
When is a person heterozygous for a characteristic?
When he possesses differing alleles for a trait
What is Dominant Inheritance?
It is a pattern of inheritance in which, when a child receives different alleles, only the dominant one is expressed.
When an offspring receives contradictory alleles for a trait, only one of them, the dominant one, will be expressed
What is Recessive Inheritance?
It is a Pattern of Inheritance in which a child receives identical recessive alleles, resulting in expression of a nondominant trait.
What is Polygenetic Inheritance?
It is a Pattern of inheritance in which multiple genes at different sites on chromosomes affect a complex trait.
What are the 23 pairs of chromosomes in a human’s body?
22 Pairs of Autosomes
1 Pair of Sex Chromosomes