Week 2 Flashcards
How many chromosomes are in most cells in the body
46
What cells do not have 46 chromosomes? and how many do these cells have?
Egg and sperms cells
23
What is the smallest unit of biochemical instruction in the DNA
gene
how many genes in 46 chromosomes
25,000
what percent of genes accounts for individual differences
less than 1%
Which chromosome determines sex
the 23rd
How does the inheritance of sex chromosomes work
males have XY, females XX
-you will inherit X from the mom and either for the dad
-dad determines gender of offspring
Genotype
Sum of all the genes a person inherits
Allele
different versions of a gene
-each person has 2 alleles per gene
Phenotype
Features that are actually expressed
Examples of single gene inheritance
-curly vs straight hair
-full head of hair vs baldness
-cheek dimples vs no dimples
-normal color vision vs red-green blindness
-type A vs type B vs type O
Sickle-Cell disease
Red blood cells are sickle-shaped
-cells cannot pass through small capillaries
-causes fatigue, acute pain, prone to infections
-10% die by age 20 and 50% by age 50
Allele is recessive
-heterogenous individuals will experience symptoms only under trama
Down Syndrome
DISTINIT PHYSICAL FEATURES
-almond eyes, fold over eyelids, smaller head, neck and nose
MENTAL & BEHAVIORAL DEVELOPMENT LAGS
MOTOR & MENTAL DEVELOPMENT SUBSTANTIALLY DELAYED IN CHILDHOOD
Def: Evolution
process of change in gene frequencies over many generations
-acts to select heritable traits that are adaptive
-changes occur to the species over generations
-evolution does not act on individuals
Natural selection
traits best adapted to current environment will be selected
Polygenic inheritance
-psychological traits are manifested through the activities of many genes and their interactions with the environment
- results is several possible genotypes and many distinct phenotypes
-results in a normal distribution of phenotypes
Evolutionary Theory of Development
-selected traits are adaptive for each stage of development
Genotype x Phenotype
Most psychological traits are governed by many genes
-phenotype depends on a combination of genes, but also an interaction with the environment
-genotype cannot change; phenotype can
Heritability
the extent to which differences in a trait can be attributed to inheritance
-a value of 0 to 1
-population level
-greater variability in environment = less heritability
Monozygotic twins
identical twins
-one zygote
-splits in first 2 weeks
Dizygotic Twins
fraternal twins
-two fertilized eggs develop in the uterus at the same time
