Chapters 3 & 4 Flashcards
______ holds that genes and environmental influences work hand in hand to eventually allow or prevent developmental behaviors.
Epigenetics
A gene is recessive when:
its influence can be hidden by a more powerful gene.
A sperm has ______ as many chromosomes as a normal body cell.
Half
Approximately how many genes are contained in the human genome?
20,000
Because most traits are polygenic, they are:
Produced by many genes
Human development begins when a sperm penetrates the membrane of:
An ovum
If one allele in a pair of genes differs in some way from the other, the genes are said to be:
Heterozygous
The sperm and the ovum are:
Gametes
A reflux is an
involuntary response to stimulus.
A teratogen is:
a substance or a condition that can increase the risk of prenatal abnormalities.
A total Apgar score of 3 indicates that a newborn is:
In critical condition
About eight weeks after conception, the embryo weighs ______ and is ______ long.
1 gram; 1 inch
Which period begins three weeks after conception?
the embryonic period
Synaptogenesis refers to an increase in the:
number of connections between neurons in the brain.
The age of viability refers to the point when the preterm newborn:
can survive outside the uterus.
