Genes and Enviornment

Question 1

Which period in the lifespan is the most important in terms of growth, development, and potential effects of the environment?

Answer 1

The 9 months of the prenatal period

Question 2

what is a teratogen?

Answer 2

something that can cause or raise the risk for a birth defect in a baby

Question 3

what is a zygote?

Answer 3

• about first two weeks
• from fertilization to implantation into the wall of the uterus (does not allow teratogens to enter)

Question 4

what is the embryonic period?

Answer 4

from implantation to about 10 weeks

Question 5

what happens during embryonic period?

Answer 5

• major point of construction
• various support structures formed and all of the organ systems are laid down in at least a simple/basic fashion

Question 6

what period is greatest in vulnerability to outside agents?

Answer 6

embryonic period

Question 7

how big is the embryo at 14 days?

Answer 7

size of pinhead

Question 8

what happens to the embryo at 17-20 days?

Answer 8

develops along its dorsal surface a neural plate

Question 9

what is a neural plate?

Answer 9

is a sheet of cells that will ultimately
develop into the nervous system

Question 10

what happens to the neural plate during development?

Answer 10

Forms into a neural groove and then closes—the neural tube

Question 11

what happens if the neural tube doesn’t close?

Answer 11

Failure or ineffective closure of the neural tube causes neural tube defects

Question 12

most common neural tube defect?

Answer 12

spina bifida in which there is an opening somewhere in the spinal column

Question 13

cranial (head) of the embryo further differentiates by?

Answer 13

• Proliferation of cells
• migration of cells
• Travel in massive waves and accumulate in an “inside-out” sequence

Question 14

what is proliferation of cells?

Answer 14

An increase in the number of cells as a result of cell growth and cell division.

Question 15

what are nueronal migration disorders caused by?

Answer 15

Faulty migration

Question 16

Exogenous (vs endogenous) causes of faulty migration include?

Answer 16

nutritional deficiencies, viruses, chemicals, drugs/alcohol, medications, and exposure to radiation

Question 17

what is Synaptogenesis?

Answer 17

the formation of synapses, the points of contact where information is transmitted between neurons.
(“neurons that fire together wire together”)

Question 18

what is apoptosis?

Answer 18

“use it or lose it”
A type of cell death in which a series of molecular steps in a cell lead to its death.

Question 19

what do apoptosis and Synaptogenesis lead to?

Answer 19

increased selectivity and efficiency of transmission of neural signal

Question 20

what is the fetal period?

Answer 20

(the last 7 months) Mostly a process of finishing the organ systems and continued synaptogenesis/apoptosis of the nervous system

Question 21

what happens in the postnatal enviornment?

Answer 21

continues and expands upon what happened during the prenatal period

Question 22

what are the three core concepts in early development?

Answer 22

1. experiences build brain architecture
2. serve & return interaction shapes brain circuity
3. toxic stress derails healthy development

Question 23

when/ what happens during the brain growth spurt?

Answer 23

(about first 3 years) See dramatic synaptogenesis and neural pruning, Brain becomes increasingly specialized with experiences

Question 24

why are early years sensitive in brain development?

Answer 24

because certain experiences must occur for normal development to proceed

Question 25

examples of sensitivity in brain development?

Answer 25

visual perception in early infancy = cataract

Question 26

what do epigenetic factors attach to/mark ?

Answer 26

DNA

Question 27

what are epigenetics?

Answer 27

the study of how your behaviors and environment can cause changes that affect the way your genes work

Question 28

what do epigenetics act like?

Answer 28

They act as chemical tags, indicating what, where, and when genes should be turned on or off

Question 29

when is it likely we are seeing an epigenetic effect?

Answer 29

when an event or change in environment has biological consequences that continue far beyond the event itself

Question 30

what are the two important mechanisms by which epigenetic effects occur?

Answer 30

1. Methylation 2. Histone modification

Question 31

what is Methylation?

Answer 31

addition of a methyl group to the DNA strand which prevents transcription factors from binding and switches the gene off

Question 32

what is Histone modification ?

Answer 32

addition of an acetyl group to the histone tails which results in loose packing of the nucleosomes and allows the gene to be expressed

Question 33

Examples of epigenetic effects associated with disease?

Answer 33

- dutch hunger winter - Exposure to airborne benzene (found in gasoline) is associated with histone modification of a cancer-antigen gene - Chronic stress can cause methyl. of a gene which helps regulate stress hormone levels in brain - Children who experienced trauma or severe neglect/abuse at greater risk of depression as adults via methyl. of a gene which helps synthesize serotonin - The hydrocarbons in cigarette smoke cause methyl of a tumor suppressor gene

Question 34

genotype and environment?

Answer 34

Genes and environment are not separate factors that operate independently of each other — they are correlated

Question 35

what are the three ways that genotypes are correlated with environments?

Answer 35

1. passive 2. active 3. evocative

Question 36

what are passive gene interactions?

Answer 36

Occurs when biological parents contribute both genes and the environment

Question 37

what are evocative gene interactions?

Answer 37

Occurs when genetically influenced behaviors/traits evoke consistent reactions from other people

Question 38

what are active gene interactions?

Answer 38

Occurs when a person with a particular genotype creates or seeks out a particular environment (or niche)

Question 39

passive plays a bigger role in?

Answer 39

lifespan

Question 40

evocative plays a bigger role in?

Answer 40

nothing, fairly constant influence

Question 41

active plays a bigger role in?

Answer 41

nothing, gradually assumes a bigger/more important role overall

Question 42

genotype- environment interaction?

Answer 42

When the effect of the environment on a phenotype depends on the genotype; or, when the effect of the genotype on a phenotype depends on the environment

Question 43

genotype- environment interaction involves?

Answer 43

genetic sensitivity, or susceptibility, to different environments—greater effect of genetic risk in a high risk environment

Question 44

Diathesis is?

Answer 44

genetic vulnerability/susceptibility

Question 45

Stressor is?

Answer 45

adverse event/conditions in environment

Question 46

what is diathesis stress model?

Answer 46

people at genetic risk for psychopathology are especially sensitive to the effects of stressful environments