Chap 2 - Gene & Environment Found.

Question 1

What are the two main sources that influence human development?

Answer 1

The genetic component and the environment

Question 2

What is the phenotype?

Answer 2

An organism’s observable characteristics (i.e. color of hair/eyes)

Question 3

What is the genotype?

Answer 3

An organism’s genetic information inherited from parents’ gene, which influence one’s phenotype.

Question 4

How can genes be defined?

Answer 4

Molecular hereditary unit of a living organism that stores the DNA.

Question 5

Where are located the DNA molecules?

Answer 5

On chromosomes within the cell nucleus

Question 6

What is the utility of genes?

Answer 6

They provide boundary for development (i.e. if your parents are short, chances are you’ll be short too)

Question 7

What does it mean when we say that development is polygenic?

Answer 7

Idea that multiple genes contribute to an individual’s development.

Question 8

How many pairs of chromosome does a person have? How many comes from the mom/dad? What are the two different types of chromosomes?

Answer 8

23 pairs (total of 46), one chromosome from each pair comes from mom, other from dad. Autosomes & sex chromosomes

Question 9

What are the sex chromosomes of a female? Male?

Answer 9

XX, XY

Question 10

What does the DNA double helix contain?

Answer 10

Nucleotides (A,T,G,C)

Question 11

What is the definition of an allele?

Answer 11

Different form of the gene at the same place on the chromosome, one inherited by the mom and one by the dad

Question 12

Every cell is composed of:

Answer 12

2 chromosomes (1 pair) and 2 alleles for a particular gene

Question 13

What is the difference between a recessive and a dominant gene?

Answer 13

Dominant: allele that has a strong effect –> you only need one dominant allele for the genotype to be expressed in the phenotype
Recessive: less powerful allele –> you need both alleles in order to get the phenotype

Question 14

What are the different types of genotypes? (3)

Answer 14

Homozygous recessive: 2 recessives alleles (recessive phenotype, aa)
Homozygous dominant: 2 dominant alleles (dominant phenotype, AA)
Heterozygous dominant: 1 recessive and 1 dominant allele (dominant phenotype, Aa)

Question 15

What are the two processes of cell division?

Answer 15

Mitosis and Meiosis

Question 16

What is the process of mitosis? What is an example?

Answer 16

Cell division that starts with one cell that divides into 2 identical cells. Skin cells are replaced through mitosis continuously .

Question 17

What is the process of meiosis? What is an example?

Answer 17

Meiosis is the cell division creating sex cells (egg or sperm cells). Starting with one cells that divides into 4 different cells

Question 18

What is another word for sex cells?

Answer 18

Gametes (sperm and ovum)

Question 19

What is the name to describe the union of two gametes?

Answer 19

Zygotes

Question 20

What is the difference in the conception of two MZ twins vs. two DZ twins?

Answer 20

MZ twins: 1 ovum is fertilized, which creates 1 zygote that then divides into 2 cells clusters, which then creates 2 individuals sharing 100% of DNA
DZ twins: 2 ovums are fertilized, which create 2 zygotes, and so 2 individuals sharing 50% of their DNA

Question 21

What are the 4 different patterns of inheritance?

Answer 21

1. Autosomal recessive inheritance
2. Autosomal dominant inheritance
3. X-linked recessive inheritance
4. X-linked dominant inheritance

Question 22

What is the autosomal recessive inheritance? What is an example?

Answer 22

When two recessive alleles are combined and you are homozygous recessive (i.e cystic fibrosis)

Question 23

What is the autosomal dominant inheritance? What is an example?

Answer 23

Can either be when two dominant alleles are combined or when one recessive allele is combined with a dominant allele. When a condition is on a dominant gene, as soon as you have an affected gene or allele, you’ll be affected by the condition (i.e. Huntington’s disease)

Question 24

What is the X-linked recessive inheritance? What is an example?

Answer 24

It is a condition that is expressed in the X chromosome. Since it is recessive, both X chromosome must be affect. You can be a carrier without being affected. If son gets mom’s affected X, then he is affected by the condition. If daughter gets mom’s affected X, she can be just a carrier since her dad’s X is safe.

Question 25

What is the X-linked dominant inheritance? What is an example?

Answer 25

It is a condition that is expressed in the X chromosome. Since it is dominant, you only need one of the X to be affected in order to suffer from the condition. **ask prof

Question 26

What is an incomplete dominance or "codominance"?

Answer 26

It is a pattern of inheritance in which 2 alleles are expressed in the phenotype, resulting in a combined trait or one that is intermediate between 2 alleles (i.e. curly hair + straight hair = wavy hair)

Question 27

What different types of problem/disease that may emerge from defective genes?

Answer 27

1. Down syndrome (trisomy on 21st pair) = having 3x the 21st chromosome 2. Turner syndrome (missing (partly or completely) an X sex chromosome on 23rd pair) 3. Triple X syndrome (trisomy on 23rd pair)

Question 28

What are the main symptoms of Down Syndrome?

Answer 28

Physical growth delay, facial features, intellectual disability (mild to severe).

Question 29

What are the main symptoms of Turner Syndrome?

Answer 29

Short but wide neck, facial features, lowered ears, puberty processes inhibited (need hormonal treatment), potential infertility

Question 30

What are the main symptoms of Triple X Syndrome?

Answer 30

Potential learning disabilities, normal fertility, may be difficult to detect

Question 31

What are the three different models of heritability and the environment?

Answer 31

1. Diathesis stress-model 2. Gene-environment correlational model 3. Epigenetic "inheritance" of behavior

Question 32

What is the diathesis-stress model?

Answer 32

The idea that diathesis, being one's genetic vulnerability, is triggered by environmental influences. In other words, diathesis itself is not enough to develop a condition, it needs to be stressed enough by the environment. If the diathesis is absent, the chances of developing a disorder are very low. But if present, and if stressed by the environment, chances are you will develop the disorder.

Question 33

What is shown in Capsi's study about serotonin transporter gene and depression?

Answer 33

It examines whether the serotonin transporter gene predicts depression, and shows that having a S allele predisposes you to depression, and your chances are enhanced when triggered by environmental stressors.

Question 34

What is the focus of the Gene-Environment Correlational Model? What is an example of it?

Answer 34

It looks at the association between individual's genetic propensities and environmental niche the individual selects. In other words, the genetics correlate with environmental exposure. For instance, parents with history of antisocial behavior are more likely to maltreat their children, which makes their children more susceptible to have conduct problems and develop loneliness.

Question 35

What is the genetic inheritance of behavior model? What is another name for it? What is an example of it?

Answer 35

Also called "Epigenetic programming" It looks at the dynamic gene expression that changes under environmental influences. For instance, baby rats coming from anxious mothers but raised by calm mothers grew up with low levels of anxiety (regardless of their predisposition).