Chapter 2 Flashcards
gene
A microscopic structure made of thousands of links of chemical particles that combine to construct all the parts of a living being.
What is the function of the nucleus in a cell?
a) Synthesizing proteins
b) Storing genetic material
c) Facilitating cellular respiration
d) Regulating cell division
b) Storing genetic material
How many pairs of chromosomes are found in the nucleus of human cells?
a) 22
b) 23
c) 46
d) 48
23
Which of the following bases pairs with adenine in DNA?
a) Guanine
b) Thymine
c) Cytosine
d) Uracil
Correct Answer: b) Thymine
autosome
Any one of the 22 pairs of chromosomes shared by both males and females.
sex chromosome
The 23rd chromosome pair, containing the genes that determine biological sex characteristics of females (XX) and males (XY).
DNA
Deoxyribonucleic acid, the fundamental chemical of all genes that guide the construction of cells.
The arrangement of chromosomes by size is called a
karyotype
The most basic building blocks of heredity are
genes
Which term refers to the specific place of a gene on a chromosome?
A) Allele
B) Nucleotide
C) Locus
D) Chromatid
Correct Answer: C) Locus
An individual’s ________ determines the genetic potential and limitations of an individual, or the traits that genetically distinguish the individual from any other.
genotype
The observable characteristics of an individual that result from this gene–environment interplay are called the __
phenotype
The observable characteristics of an individual is the
phenotype
Normative variation between genes is called
allele
The quality of an allele that influences the expression of a trait is a
dominant
An allele that can only influence the expression of a trait in the absence of a dominant allele.
recessive
only about ___ ova mature and are expelled during a woman’s lifespan
400–450
A male or female cell that contains 23 chromosomes in their singular form is a
gamete
A female gamete containing 22 autosomes and 1 sex (X) chromosome is…
ovum
A male gamete containing 22 autosomes and 1 sex (X or Y) chromosome.
sperm cell
User
1. What female reproductive organ produces the ova?
- Where do sperm cells originate?
- After ejaculation, sperm cells travel from the ______ through the _______, into the ________, and along the _________ toward the awaiting ovum.
The female reproductive organ that produces ova (eggs) is the ovary.
Sperm cells originate in the testes.
After ejaculation, sperm cells travel from the testes through the vas deferens, into the urethra, and along the vagina/cervix/uterus toward the awaiting ovum. (The specific answer depends on whether you’re referring to the male or female reproductive system and the exact path the sperm takes.)
meiosis
The process by which cells containing 23 pairs of chromosomes divide into daughter cells containing one half of each chromosome pair.
mitosis
The process by which cells create an exact copy of themselves, including all 23 pairs of chromosomes.
cephalocaudal pattern
A pattern of physical growth that proceeds from the head down through the long axis of the body.
proximodistal pattern
A pattern of physical growth that proceeds from the centre of the body through the appendages.
organogenesis
The early development and differentiation of the internal organs such as the lungs, heart, and gastrointestinal systems.
stages of fetal development
The germinal stage
The embryonic stage
The fetal stage
The embryonic stage
In addition to the embryo itself, a support system for the embryo forms during the embryonic period. The amniotic sac, containing clear amniotic fluid, takes shape around the embryo to protect the developing organism from shocks and abrupt temperature changes. A thick organ called the placenta forms along the uterine wall. The placenta does the work that will eventually be taken over after birth by the baby’s lungs, digestive system, liver, and excretory organs. It allows nutrients to pass from the mother’s blood to the embryo, but it keeps the blood of mother and embryo separate. The embryo connects to the placenta through the umbilical cord, a vein-filled cord that serves as the embryo’s lifeline (Lamb, Bornstein, & Teti, 2002).
sensitive period
.
An interval of heightened plasticity, when environmental influences are most efficient at affecting an organism’s development: the prefrontal cortex has the earliest sensitive period, followed by the brain systems involved in vision and hearing.
critical period
A finite window of opportunity for development, outside of which environmental influences are said to have no effect
teratogen
An environmental agent that can adversely affect prenatal development and can have long-lasting effects on subsequent development
neural tube
In the developing embryo, the precursor to the central nervous system
Wilson’s six principles of teratogenic effects:
Susceptibility: The susceptibility of an embryo or fetus to teratogenic effects varies depending on the stage of development. Different organs and systems have different periods of susceptibility during gestation.
Dose-response relationship: The severity and frequency of teratogenic effects are often related to the dose or level of exposure to the teratogenic agent. Higher doses or more prolonged exposures tend to result in more severe effects.
Threshold effect: Below a certain threshold dose, a teratogenic agent may not produce any observable effects. However, once the threshold is exceeded, the likelihood and severity of teratogenic effects increase.
Specificity: Different teratogenic agents may produce specific types of birth defects or abnormalities. The type of defect or abnormality may be characteristic of the particular teratogen involved.
Time of exposure: The timing of exposure to a teratogenic agent during embryonic or fetal development can influence the type and severity of the resulting abnormalities. Critical periods exist during which specific organs or systems are particularly vulnerable to damage.
Maternal factors: Maternal factors such as genetics, nutritional status, overall health, and exposure to other environmental agents can influence the susceptibility of the fetus to teratogenic effects. Maternal factors may interact with teratogens to increase or decrease their harmful effects.
What is the sensitive period for the effects of alcohol consumption on prenatal development?
2 weeks after conception to birth
mutation
An abnormality that occurs during genetic transmission and that may affect the entire chromosome or specific genes.
autosomal recessive trait
A trait that requires the presence of both paternal and maternal genes for the phenotype to be expressed.
autosomal dominant trait
A trait that requires the presence of only one parental gene for the phenotype to be expressed.
sex-linked gene
A gene located on one of the sex chromosomes (X or Y).
An example of a sex-linked disorder is
colour-blindness
three common prenatal tests
Ultrasound, amniocentesis, and chorionic villus sampling
User
During what stage of prenatal development can an ultrasound be performed?
a. germinal stage
b. embryonic stage
c. fetal stage
d. all of the above
c. fetal stage
amniocentesis
The process of removing fluid from the amniotic sac of a pregnant woman and surveying the genome under a microscope
bloody show
A plug of thick, blood-tinged mucus that is discharged from the cervix shortly before labour begins.
maternal mortality rate (MMR)
The number of maternal deaths per 100,000 live births.
4 stages of labour
1) dilation
2 )descent and birth (when cervix reaches dilation of 10 cm) - baby is born
3) delivery of placenta (followed by skin to skin)
4) postpartum = 6 weeks
infant mortality rate (IMR)
The number of infant deaths occurring in the first year of life per 1,000 live births.
electronic fetal monitoring (EFM)
A technology for monitoring the heart rate of a fetus with electrodes attached to the mother’s abdomen or placed internally on the scalp of the fetus.
Apgar scale
A scoring system that assesses the health of newborns based on five key areas: activity and muscle tone, heart rate, reflexes, skin colour, and respiration. Apgar scores are calculated at one minute and five minutes after the baby is born
Neonatal Behavioral Assessment Scale The NBAS focuses on the baby’s
(1) ability to regulate his or her breathing, (2) ability to control body movement, (3) levels of arousal from fully awake to sleep, and (4) social interaction with parents and others
low birth weight (LBW)
A birth weight of less than 2,500 g.
preterm
An infant born earlier than the full gestational period, usually less than 37 weeks.
small for gestational age (SGA)
A birth weight of less than 2.5 kg for an infant with a gestational age that is normal (37+ weeks).
very low birth weight (VLBW)
A birth weight of less than 1,500 g.
full term is considered
39 weeks
postpartum depression (PPD)
Clinical depressive symptoms such as apathy, sadness, and detachment associated with late pregnancy and the period of time following the birth of an infant - can occur in fathers too - breastfeeding and social support are protective factors
la cuarentena refers to the
cuarenta días (40 days) of recovery for Mexican women after the birth of a child
Gametes are formed through the cell-division process of
meiosis
After conception, the zygote grows through the process of
mitosis
8.A disorder caused by a defective gene on the X chromosome is called _________.
a. a sex-linked disorder
b. an autosomal recessive disorder
c. an autosomal dominant disorder
d. a chromosomal disorder
a. a sex-linked disorder
- After ejaculation, sperm cells travel from the ______ through the _______, into the ________, and along the _________ toward the awaiting ovum
After ejaculation, sperm cells travel from the vagina through the cervix, into the uterus, and along the fallopian tubes toward the awaiting ovum (egg).
Chronologically, the process of _______ occurs before the process of _______
meiosis mitosis
The single-celled zygote becomes a multicelled blastocyst through the process of _________
mitosis
morula
post zygote collection of cells that continue to divide before creating a more complex cell
