HSCI 2216 - Final Exam Flashcards
Genes
- the basic functional and physical unit of heredity
- made of DNA and code for proteins
Chromatin
- organized complex of DNA and histones (proteins)
- humans have 23 pairs
- 22 somatic and 1 sex
Karyotype
a person’s full set of chromosomes
Genome
- entire set of DNA instructions in a cell
- every cell carries the body’s entire genome
- each type of cell only expresses the genes related to their structure/function
Alleles
- different forms of the same gene
- different alleles have different DNA sequences
- location of each gene on a chromosome is the locus of that gene
- humans have 2 alleles at each locus, one fro each parent
2 types of cell division
- Mitosis
- parent cell divides into 2 identical daughter cells
- ex) a haploid cell divides into 2 haploid cells - Meiosis
- parent cell divides twice into 4 daughter cells, each with half the original number of chromosomes
- only for sexually-reproducing organisms
- sperm and eggs
- ex) a diploid cell makes 4 haploid cells
Sources of Genetic Diversity
- Mutations
- Recombination
- Natural Selection
- Gene Flow
- Genetic Drift
Mutations
- random changes in the genetic code of an organism
- may refer to DNA mutations of chromosomal mutations
- may or may not have negative consequences
Types of DNA Mutations
- substitution
- insertion
- deletion
Recombination - 2 mechanisms
- independent assortment of chromosomes
- depends on whether a gamete gets a mixture of chromosomes from each parent (more likely) or if the gamete gets genes from just one parent or the other - crossing over
- when homologous maternal and paternal chromosomes exchange parts of their DNA sequences- enhances genetic diversity of the offspring
Epigenetics
- biomarkers that affect a gene’s expression
- compressing it to make it harder to read or expanding it, making it easier to read
Descent with Modifications
- the passing of the genetic code from parent to offspring with small hereditary changes
- the evolutionary mechanism that provides gradual changes in the genetic code of organisms
Four factors that could change allele frequencies in a population
- Mutation
- Natural selection
- Gene flow
- Genetic drift
Natural selection
determines which descendants survive to pass on their genes based on their environmental conditions and what is considered fitness
Genetic Drift
individual has more descendants and makes larger contribution to the gene pool - alleles with low frequency may not survive due to chance events
Gene Flow
geographic movement of an organism and their alleles - no genetic mixing, but allele frequency changes
surface-to-volume ratio
- Smaller S-V Ration: body saves heat
- Larger S-V Ratio: body loses heat through more surface area
Differentiation
the process by which cells become progressively more specialized
stages of pregnancy
- Fertilization
- Implantation
- Placenta Development
- Embryonic and Fetal Development
- Labour/ Childbirth
Fertilization
- process of combining gametes - egg and sperm
- happens in the fallopian tube
Steps:
1. Sperm binding - sperm binds to egg
2. Acrosomal reaction - acrosomal enzymes digest zona pellucida
3. Cortical reaction - sperm reaches plasma of membrane of egg - cortical enzymes prevent more sperm from binding
4. Genetic transfer - DNA of sperm enters egg
Implantation
attachment of egg to uterine lining
Placental Development
- starts at time of implantation
- placent connects fetus to uterine wall
Embryonic Membranes
- Amnion - fills with amniotic fluid in which the embryo is suspended for protection
- Yolksac - provides nutrient and gas exchange before placenta developed
- Allantois - stores urinary waste, helps with gas exchange
- Chorion - villi extend to form fetal portion of the placenta
Teratogenic Agents
- agents that cause abnormality following fetal exposure during pregnancy
- can include environmental exposures, drugs, medications, infectious agents, metabolic imbalances
Findings of the Dutch Famine
- First-trimester exposure: CVD, altered clotting, raised lipids, obesity
- Second-trimester exposure: more kidney and lung diseases
- Third-trimester exposure: metabolic disorders, decreased glucose tolerance
Fetal origin of adult disease - why it occurs
- adaptation
- survival
Findings of Project Ice Storm
Behaviour
- aggression - larger amygdala
- higher risk of autism
- lower motor and cognitive function and language ability
BMI
- increased risk of metabolic disorders s/a insulin resistance
- obesity due to dysregulation of energy and protein metabolism pathways
- higher BMI and central adiposity
- increased eating disorders
Immunity
- affects the immune system through methylation of immune-regulating genes - predicts asthma in girls
Puberty
- PNMS associated with increased childhood adiposity and obesity that have been associates with early menarche
- earlier puberty increases the risk of adverse physiological and psychological health outcomes in women
- childhood stress also known to be associated with earlier puberty
Sources of Carbon monoxide
burning fossil fuels
Sources of methane gas
- burned, digested (cattle), or rotten (landfills) vegetation
- main contributors: cattle farming, waste dumps, rice farming, oil and gas drilling, fracking
Sources of Nitrous Oxide
chemical fertilizers and burning fossil fuels
