2 - Biological Flashcards
Lessons 3-5
How many chromosomes in a cell?
46
How many genes per 46 chromosomes?
25,000
How many molecules of DNA per chromosome
1 (if you get this wrong u fuckin bozo istg)
Genotype
Sum of all genes a person inherits
Allele
Different versions of a gene
Phenotype
Visual expression of genes
Do genes lend themselves to the concept of race?
NOPE, spectrum not categorical
Roughly what percentage of DNA do 2 people differ by
0.1% of DNA
True or false, specific base pairs in DNA can cluster according to geographic origin?
True
Sickle-cell disease
cells cannot pass through small capillaries & block WBC
Sickle-cell geniology
- Recessive allele
- Heterozygous phenotype
- Protective trait against malaria, increased presence in places at high risk of malaria
Down-syndrome
Mental/motor delays, extra 21st chromosome
Evolutionary theory
Process of change in gene frequency over many generations
Natural selection
Environmental conditions allow certain members of a species to survive and pass genes to future generations
What do genes selected by evolutionary pressures depend on?
Environment our ancestors lived in
How does environment control genes?
Controls gene expression
Most psychological traits are manifested through…
Genes and environmental interactions
What kind of distribution does polygenic inheritance lead to?
Normal
Evolutionary theory of development
Selected traits may be maximally adaptive at that stage of development (i.e. clinginess in toddlerhood)
Heritability
Extent to which differences in a value can be e attributed to inheritance
Proportion of variance among population in trait results from ________
Genetic variability
How does greater variability in environment impact heritability?
Less heritability
Population level variance is explained by
evolutionary theories
Evolutionary theories CANNOT explain
Individual outcomes
Developmental systems theory
Development occurs within a system of interacting levels (environment, behaviour, neural activity, genetic activity)
Epigenesis
Functional change in the genome not involving alteration in DNA sequence
Structure and function of DNA
Structure: DNA sequence (blueprint)
Function: Gene expression (design)
How does experience lead to change in behaviour
Experience modifies chemistry of gene activity
Epigenetics - Skink Lizard
Mother exposed to snake (predator) = offspring has qualities that make them more difficult to become prey (i.e. Larger, longer tails etc.)
Outcome of the “good mothering” rat experiment (high grooming mothers)
Offspring have lower stress, will become HG mothers even if “adopted” by HG mother and not biologically related
Why do offspring of HG mothers have lower stress responses? (2)
- Demethylization -> allows for receptor formation -> better stress regulation (occurs by 6 days old)
- Handling (in general) increases cortisol receptors in hippocampus
3 effects of environment theory
- passive
- evocative
- active
Passive effects
Genetically related parents providing rearing environments (parents pick environment based on what suited them)
Evocative effects
Child elicits responses from others, child’s genotype is impacting their environment.
(Happy baby will grow to think everyone is happy because the baby wasn’t annoying)
Active effects
Child’s genotype influences the environments they select
Impact of your environment depends on your _____
genotype
Conduct disorder risk factors (4)
- Maltreatment
- Antisocial family members
- Deviant peers
- Inconsistent discipline/family stress/parental insensitivity
Conduct disorder treatment
CBT, family-oriented therapy best
Why don’t all mistreated children develop conduct disorder?
MAMO gene mediates effect of maltreatment on later antisocial behaviour (greatly decreases development of conduct disorder)
When does the neural tube form
18-24 days after conception
What can result from the neural tube not closing?
Birth defects (i.e. spina bifida)
When does neurogenesis occur
5-28 weeks after conception
Where does neurogenesis occur
One region in neural tube
What rate does neurogenesis occur at?
4000/s
When does migration occur?
By 7 months
What is migration?
Neurons move to permanent locations in brain via glial cells
What is faulty migration associated with?
Neural disorders (i.e. epilepsy)
What is differentiation? (2)
- Neurons become larger and produce dendrites/longer axons
- Neurons specialize
When do synapses form (synaptogenesis)
During differentiation
What is synaptic pruning?
Removal of neurons/synapses that aren’t being used
Why are synapses pruned?
Improves efficiency in remaining neural connections
When do neural connections peak?
≈7 years old
What does the level of harm caused by teratogens depend on? (3)
Dose, genetic predisposition to susceptibility, time of exposure
How much alcohol during pregnancy can cause fetal alcohol syndrome?
> 4oz/week
What is fetal alcohol syndrome?
Physical brain damage caused prenatally that leads to cognitive and growth defects
What does nicotine use during pregnancy do to the baby?
- Low birth weight
- Fetal/neonatal death
- Respiratory issues
- Shorter telomere length
Can a fetus hear what’s going on outside?
Sounds like Charlie Brown’s teacher, can likely only hear mother’s vocal patterns
Who’s voice to babies prefer?
Their mother’s voice
Can a fetus taste?
Seem to make facial expressions indicating they can taste bitter and sweer
