HSCI 2216 - Final Exam

Question 1

Genes

Answer 1

• the basic functional and physical unit of heredity

- made of DNA and code for proteins

Question 2

Chromatin

Answer 2

• organized complex of DNA and histones (proteins)
• humans have 23 pairs
  
  • 22 somatic and 1 sex

Question 3

Karyotype

Answer 3

a person’s full set of chromosomes

Question 4

Genome

Answer 4

• 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

Question 5

Alleles

Answer 5

• 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

Question 6

2 types of cell division

Answer 6

1. Mitosis
   - parent cell divides into 2 identical daughter cells
   - ex) a haploid cell divides into 2 haploid cells
2. 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

Question 7

Sources of Genetic Diversity

Answer 7

1. Mutations
2. Recombination
3. Natural Selection
4. Gene Flow
5. Genetic Drift

Question 8

Mutations

Answer 8

• random changes in the genetic code of an organism
• may refer to DNA mutations of chromosomal mutations
• may or may not have negative consequences

Question 9

Types of DNA Mutations

Answer 9

1. substitution
2. insertion
3. deletion

Question 10

Recombination - 2 mechanisms

Answer 10

1. 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
2. crossing over
   - when homologous maternal and paternal chromosomes exchange parts of their DNA sequences
   
   • enhances genetic diversity of the offspring

Question 11

Epigenetics

Answer 11

• biomarkers that affect a gene’s expression

- compressing it to make it harder to read or expanding it, making it easier to read

Question 12

Descent with Modifications

Answer 12

• 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

Question 13

Four factors that could change allele frequencies in a population

Answer 13

1. Mutation
2. Natural selection
3. Gene flow
4. Genetic drift

Question 14

Natural selection

Answer 14

determines which descendants survive to pass on their genes based on their environmental conditions and what is considered fitness

Question 15

Genetic Drift

Answer 15

individual has more descendants and makes larger contribution to the gene pool - alleles with low frequency may not survive due to chance events

Question 16

Gene Flow

Answer 16

geographic movement of an organism and their alleles - no genetic mixing, but allele frequency changes

Question 17

surface-to-volume ratio

Answer 17

• Smaller S-V Ration: body saves heat

- Larger S-V Ratio: body loses heat through more surface area

Question 18

Differentiation

Answer 18

the process by which cells become progressively more specialized

Question 19

stages of pregnancy

Answer 19

1. Fertilization
2. Implantation
3. Placenta Development
4. Embryonic and Fetal Development
5. Labour/ Childbirth

Question 20

Fertilization

Answer 20

• 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

Question 21

Implantation

Answer 21

attachment of egg to uterine lining

Question 22

Placental Development

Answer 22

• starts at time of implantation

- placent connects fetus to uterine wall

Question 23

Embryonic Membranes

Answer 23

1. Amnion - fills with amniotic fluid in which the embryo is suspended for protection
2. Yolksac - provides nutrient and gas exchange before placenta developed
3. Allantois - stores urinary waste, helps with gas exchange
4. Chorion - villi extend to form fetal portion of the placenta

Question 24

Teratogenic Agents

Answer 24

• agents that cause abnormality following fetal exposure during pregnancy
• can include environmental exposures, drugs, medications, infectious agents, metabolic imbalances

Question 25

Findings of the Dutch Famine

Answer 25

1. First-trimester exposure: CVD, altered clotting, raised lipids, obesity
2. Second-trimester exposure: more kidney and lung diseases
3. Third-trimester exposure: metabolic disorders, decreased glucose tolerance

Question 26

Fetal origin of adult disease - why it occurs

Answer 26

• adaptation

- survival

Question 27

Findings of Project Ice Storm

Answer 27

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

Question 28

Sources of Carbon monoxide

Answer 28

burning fossil fuels

Question 29

Sources of methane gas

Answer 29

• burned, digested (cattle), or rotten (landfills) vegetation
• main contributors: cattle farming, waste dumps, rice farming, oil and gas drilling, fracking

Question 30

Sources of Nitrous Oxide

Answer 30

chemical fertilizers and burning fossil fuels