Development and Genetics

Question 1

What is the end product when a sperm and ovum combine?

Answer 1

Zygote

Question 2

When a zygote is formed, it splits. When there are 8 cells, they each have equal potential. What does this mean?

Answer 2

They can all become everything a person needs for a body; if a cell is lost, a person can still fully develop from the 7 remaining cells

Question 3

Term for inner cell mass (embryo) and trophoblast (placenta).

Answer 3

Blastocyst

Question 4

What are the three germ layers?

Answer 4

1. Ectoderm
2. Mesoderm
3. Endoderm

Question 5

Germ layer that becomes the skin and nervous system

Answer 5

Ectoderm

Question 6

Germ layer that becomes the muscles and bones

Answer 6

Mesoderm

Question 7

Germ layer that becomes the GI tract

Answer 7

Endoderm

Question 8

Occurs during organogenesis; time where organs are particularly susceptible to injury, cells are rapidly dividing, cells are migrating, and important interactions between cells are occurring

Answer 8

Critical periods

Question 9

When do most critical periods occur?

Answer 9

First 3 months of pregnancy

Question 10

Fetal RBC contain fetal Hb which are replaced by adult Hb after birth. What is the difference between the two Hb’s? Why does it make the switch after birth?

Answer 10

Fetal Hb has a higher affinity to O2; because of the higher affinity, it is also harder for the O2 to get to the baby’s body tissue

Question 11

What is the importance of surfactant and gestational age?

Answer 11

Surfactant isn’t produced by the baby’s body until later pregnancy; premies don’t have enough surfactant to aid with breathing when born

Question 12

Where are fetal RBC’s made?

Answer 12

Liver

Question 13

Study of birth defects

Answer 13

teratology

Question 14

Anything that can produce a birth defect?

Answer 14

teratogen

Question 15

What are physical teratogens?

Answer 15

1. X-rays

2. Other forms of irradiation

Question 16

What are chemical teratogens?

Answer 16

1. Alcohol
2. Illegal drugs - cocaine
3. Thalidomide - limb deficiencies
4. Diethylstilbestrol (DES) - reproductive tract abnormalities and cancers

Question 17

What are microbial teratogens?

Answer 17

• Direct effects:
  1. Toxoplasma (cat and cat litter)
  2. Other
  3. Rubella
  4. Cato megalovirus
  5. Herpes virus
• Indirect effects:
  Weakening of the mother cause fetal weight reduction, growth retardation, premature birth

Question 18

The DNA sequence determines the sequence of proteins

Answer 18

DNA base pair

Question 19

All of the DNA that determines a protein, along with the regulation of the synthesis of that protein

Answer 19

Genes

Question 20

Structures that contain multiple genes and DNA regulatory regions

Answer 20

Chromosomes

Question 21

What are the types of chromosomal abnormalities?

Answer 21

1. Structural
2. Numerical
3. Sex aneuploidy

Question 22

Structural chromosomal abnormality where there is a loss of part of a chromosome

Answer 22

Deletion

Question 23

Structural chromosomal abnormality where part of a chromosome is moved to another chromosome; may be moved to regulatory elements and turn expressions on or off

Answer 23

Translocation

Question 24

What are 2 common diseases that are examples of structural chromosomal abnormalities?

Answer 24

1. Fragile X

2. Philadelphia chromosome (associated with myelogenous leukemia)

Question 25

Numerical chromosomal abnormality that has the wrong number of chromosomes

Answer 25

Aneuoploidy

Question 26

Numerical chromosomal abnormality where where there is a loss of one chromosome; incompatible with life

Answer 26

Monosomy

Question 27

Name the numerical chromosomal abnormality where there is a gain of one chromosomes; most are lethal, but some will result in birth defects if they survive. Which chromosomes result in abnormalities, not death?

Answer 27

Trisomy; 13, 19, and 21

Question 28

Numerical chromosomal abnormality where there is a loss of an X chromosome (OX)

Answer 28

Turner's syndrome; females only

Question 29

Numerical chromosomal abnormality where there is a gain of an X chromosome (XXY)

Answer 29

Klinefelter's syndrome; males

Question 30

Changes in DNA sequence that produce a change in function

Answer 30

Gene mutation

Question 31

Different versions of the same gene; code for different characteristics

Answer 31

Allele

Question 32

Alleles on different chromosomes are the same

Answer 32

Homozygous

Question 33

Alleles on different chromosomes are different

Answer 33

Heterozygous

Question 34

The genetic make up of a person's DNA; the alleles in their DNA

Answer 34

Genotype

Question 35

How the genes are expressed in the individual; what you see

Answer 35

Phenotype

Question 36

Trait that is expressed water homozygous or heterozygous; overshadow recessive genes

Answer 36

Dominant

Question 37

True or false: Not all people with an autosomal dominant gene will have the same S&S.

Answer 37

True; relates to penetrance and expressivity

Question 38

Measure of whether the gene is expressed; a person may have the gene but not the disorder

Answer 38

Penetrance

Question 39

Measure of how well the trait is expressed; how severe the disease is

Answer 39

Expressivity

Question 40

Trait where both alleles are expressed

Answer 40

Codominant (blood types - AB)

Question 41

Trait where only expressed of dominant alleles are not present; need to be homozygous

Answer 41

Recessive

Question 42

What are 4 examples of recessive trait diseases?

Answer 42

1. Cystic fibrosis (1 in 25 whites are carriers) 2. Tay-sachs disease 3. Sickle cell anemia 4. Thalassemia

Question 43

Disorders not linked to a single gene; involve several genes and exogenous factors

Answer 43

Multifactorial inheritance

Question 44

Effect where persons with a more severe form of the disease have a greater chance of transmitting the disease

Answer 44

Dose effect