Public Health Biology Midterm 1

What are the 4 components of risk assessment?

1. Hazard identification 2. Hazard characterization/Dose-response assessment 3. Exposure assessment 4. Risk characterization

Organisms are characterized by their method of metabolism, into heterotrophs and autotrophs. Describe each:

1. Heterotrophs: require organic compounds for energy 2. Autotrophs: don't require organic compounds; get their energy elsewhere (ex: photosynthesis) *autotrophs produce organic compounds & oxygen, so heterotrophs rely on autotrophs for energy

Hazard Identification

a step in risk assessment that looks at the health effects caused by a pollutant (is it bad for you?) -Does the agent cause adverse effects (harm)? *(based on laboratory & field studies)

single nucleotide polymorphism (SNP)

a variation in a single base pair in a DNA sequence

Public health microbiology focuses on:

infectious microbes that can cause human harm

DNA provides the blueprint for cell replication. How does it act as the control center of the cell?

it directs the synthesis of certain proteins that determines the specificity of the cell

An essential objective of microbiologists is not to eliminate all microbes, instead it is to:

manage the pathogens' impact on human safety & the burden of microbe- induced disease on public health

infection vs disease

-infection is when microbes enter and multiply -disease is when those bacteria produce signs and symptoms

transport vesicles

a membrane enclosed sac that transports proteins from the rough endoplasmic reticulum to the Golgi apparatus

communication strategy

a statement or document that expresses a planned process of assembling the components needed for an effective campaign

adaptive immunity

-immunity or resistance to a specific pathogen -slower to respond -has memory component -functional cells are lymphocytes

The goal of a vaccine is to stimulate T cells & B cells to:

-induce specific immunity -eliminate organisms that enter the host -neutralize bacterial toxins

Pyruvic acid is produced by glycolysis in the ____________, and is then transported into the _____________ where it is further broken down to form acetyl coenzyme A (acetyl CoA).

(a) cytosol (b) mitochondrial matrix

epigenetic modifications

-covalent modifications of the histone proteins or of the DNA itself -don't change the actual sequence of the DNA -can be passed down to future generations

negative feedback example with temperature:

-deviation in body temp -triggers shivering (response that opposes deviation) -this restores function in the opp. direction back to normal (homeostasis)

What can the human genome project be used for?

-diagnosing many diseases more accurately -identify people at risk for specific diseases (ex: breast cancer) -prescribe treatment w/ better efficacy & fewer negative outcomes

Nucleus

-double membrane containing DNA & specialized proteins -stores genetic material

Naming Bacteria

*binomial system -Every bacteria consists of two names, the Genus 1st & then the species, and both names are always italicized. -Many times the first named is abbreviated by its first letter and the second name is written out.

Cells make vital exchanges with the external environment via the internal environment. This exchange is possible b/c of extracellular fluid, which contains both:

- plasma & interstitial fluid

Mitochondria

- rod/oval shaped; have a double outer membrane, a folded inner membrane (cristae), & an interior (matrix) -major site of ATP (energy) production

plasma membrane

-A selectively-permeable phospholipid bilayer forming the boundary of the cells -regulates the passage of molecules in and out of the cytoplasm

Hazard

-Any agent (biologic, chemical, thermal, mechanical, psychosocial) that has the POTENTIAL to do harm -Hazards could, for example, be associated with energy (e.g., explosion, fire), material (toxic or eco-toxic), biota (pathogens) and information (panic communication)

law of independent assortment

-Mendel's second law -allele pairs separate independently from one another during gamete formation -2 unrelated traits (ex: pea-pod shape + flower color) separate independently when passed from parent to offspring

Endoplasmic Reticulum

-a network of fluid-filled tubules & flattened sacs -synthesizes proteins & transports materials through the cell *protein synthesizing factory -contain ribosomes

Cancer-promoting mutations include:

-activation of proto-oncogenes (stimulate cell proliferation) -deactivation of tumor suppressor genes (guard against too much cell proliferation)

immunization (vaccination)

-administration of a weakened pathogen to cause the immune system to create antibodies for future protection -prevents infectious disease

Describe how we use epigenetic changes to monitor the impact of the environment

-analyzing the epigenomes of people can help gain insight into past exposures b/c epigenetic patterns are maintained through cell divisions, long after the hazardous exposure is gone *epigenetic changes are BIOMARKERS of exposure

humoral immunity (B cells)

-antibody mediated immunity -Humor = fluids -Antibodies (Abs) flow through fluids (blood, lymph) -Abs bind to extracellular targets -Inactivates them and makes them for destruction

What factors control bacterial population size (keep bacteria from multiplying too much)?

-availability of resources -temperature -competition with other organisms

Environmental factors can cause somatic mutations in cancer genes. What are some characteristics of somatic mutations?

-caused by chemicals, radiation, & infectious agents -more common than germline mutations -result in cancers later in life -known as sporadic cancers

Citric Acid Cycle (Krebs Cycle)

-completes the breakdown of glucose -series of chemical reactions (8) in aerobic respiration -acetyl coA is completely degraded to CO2 & water with the release of metabolic energy that is used to produce ATP (2 more)

What is the importance of risk analysis?

-it allows us to determine the health & disease effects caused by diff. types of exposures & activities -can compare the effectiveness of new vs existing technologies in controlling risk -allows public health practitioners & policy makers to set risk management priorities

What are some examples of risk management?

-making recommendation -regulatory development -licensing laws -standard setting -control measures -monitoring & surveillance

Lysosomes

-membrane sacs containing hydrolytic enzymes -digest & eliminate cellular waste

Peroxisomes

-membrane sacs containing oxidative enzymes -detoxify the cell

What are some of the environmental stressors that are linked to adult diseases through epigenetic modification?

-nutrition in the fetal + early postnatal periods -chemical exposure during early development -intra-uterine cigarette smoke exposure (can alter developmentally approp. DNA methylation in fetal brain = neurologic damage) -phthalates exposure = endocrine disruptor

Vaults

-octagonal barrel shaped structures -may be involved in transport of mRNA or ribosomal units from the nucleus to the cytoplasm

Golgi complex

-organelle that modifies, packages, and transports material out of the cell -sets of flattened, curved sacs that are stacked in layers

What are some of the cons of direct-to-consumer testing?

-patients may misinterpret the results -patients may have a false sense of security --> make poor behavior choices -patients should have a discussion w/ a physician or genetic counselor about their results

innate immune system

-present from birth -1st & 2nd line of defense against pathogens -nonspecific barriers and cellular responses -is the same whether or not the pathogen has been encountered previously

X chromosome inactivation

-process that occurs in female mammals in which one of the X chromosomes is randomly turned off in each cell -to compensate for the diff. in the # of X chromosomes b/w males & females *all female mammals are mosaics -inactivation initiating factor = XIST (X-inactive specific transcript)

Examples of using microbes for human benefit:

-production of alcohol -yogurt, breads, cheeses -antibiotics, vaccines, pesticides, etc -bioremediation: using microorganisms to clean up polluted environments

epithelial tissue

-sheets of tightly packed cells that cover outside of the body and lines organs and cavities -specialized for the exchange of materials b/w the cell & its environment

What are some of the elements of a communication strategy?

-target audience -communication channels -key images -intended actions of audience -benefits audience will receive -ways to convince audiences of these benefits

histone methylation

-the addition of methyl groups to histone -condenses chromatin structure (heterochromatin), prevents transcription -suppresses gene expression

In determining what actions may be necessary to eliminate or reduce risk, the public health practitioner must take which things into account?

-the availability of resources to assist in management -the social, political, & economic consequences of taking, or not taking, action

Why do storms and floods cause common-source epidemics?

-there is an inc. risk of microbial outbreaks -transmission of water-borne diseases -contamination of drinking-water facilities -inc. human contact w/ contaminated drinking water sources

How are most microbes are beneficial and essential to the planet's ecosystem

-they are the foundation of the biosphere -many act as decomposers or scavengers, cleaning & recycling the planet's dead matter -they are the foundations of biogeochemical cycles, like carbon & nitrogen cycles

cell-mediated immunity

-type of immunity produced by T cells that attack infected or abnormal body cells -cytotoxic, helper, & suppressor T cells

Tumor suppressor genes can be divided into gatekeepers and caretakers:

1) Gatekeepers: imp. in cell cycle progression; prevent mutated cells from passing through cell cycle checkpoints (apoptosis vs stopping cell cycle until DNA repair) 2) Caretakers: involved w/ DNA repair mechanisms; help ensure that DNA mutations don't accumulate

Five Types of Vaccines

1) Live Attenuated: weakened form (ex: measles) 2) Inactivated Viruses: killed (ex: rabies, influenza) 3) Toxoid: treat bacterial toxins w/ formaldehyde so they become harmless but still stimulate Ab response 4) Subunit: selected epitopes or proteins from the organism instead of the entire antigen (ex: Hepatitis B) 5) Conjugate: use polysaccharide capsules + protein carrier (ex: HiB)

The WHO estimates that about 1/3 of cancer deaths can be attributed to these 5 major behavioral factors:

1) low fruit + vegetable consumption 2) high body max index 3) lack of physical activity 4) alcohol consumption 5) tobacco use

What are the 3 major strategies to defeat cancer?

1) prevention 2) early detection 3) targeted therapy

Epithelial tissue is organized into 2 types of structures:

1. Epithelial Sheets: cells that cover & line various parts of the body 2. Secretory Glands: specialized for secretion from the cell in response to a given signal (exocrine/endocrine glands)

Describe the difference between aerobes and anaerobes.

1. Aerobes: require O2 for their metabolic activity 2. Anaerobes: don't require O2 (a) Obligate Anaerobes: killed by O2 (b) Facultative Anaerobes: can grow in the absence of O2, but can use O2 if it's available

What are some of the current challenges to public health microbiology?

1. Antibiotic Resistance: gene mutations; antibiotic misuse (lack vs abundance of antibiotics); superbugs -healthcare-associated infections -antibiotics used in livestock 2. Biological Weapons: microbes deployed to grow in their target host; used to cause clinical disease w/ the intent of killing people 3. Modern Plagues: result of the lack of adaptation b/w humans & microbes

What are the 3 types of health literacy skills?

1. Clinical type: addressed aspects of the interaction process b/w doctors & patients, diagnosis & treatment, and clinical protocols 2. Prevention type: addressed the actions people take to maintain health (physical activity, nutrition, etc) 3. Navigation of the healthcare system type: addressed understanding of insurance & healthcare system procedures & patient rights

What are the first 4 factors of the internal environment that must be homeostatically controlled?

1. Concentration of Nutrients: needed for metabolic fuel for energy production 2. O2 & CO2 Concentration: need to maintain proper acidity level (pH) in the cell 3. Concentrations of Waste Products: buildup is toxic to cell environment 4. Concentrations of Water, Salt, & other Electrolytes: regulated to ensure proper cell volume & function

Describe the roles of the 3 types of RNA in protein synthesis

1. DNA is transcribed into mRNA which exits the nucleus & delivers the code to rRNA 2. rRNA translates code into a.a sequences 3. tRNA delivers sequences w/in cytoplasm to designated site of protein production w/in the cell

List four limitations with generalizing dose-response findings from animal studies to health effects in human beings.

1. Differences in dose delivery 2. Similarity of the animal model to the human system under study 3. Posture (four legs vs two legs) 4.

What are the 3 major factors that determine the chances of acquiring a particular infection & the severity of the accompanying symptoms?

1. Dose: the # of microbes the host has been exposed to 2. Virulence: degree of pathogenicity; factors that enable pathogen to overcome host defense mechan. 3. Resistance: the host's ability to defend itself against the immune system

The general regions of the bacteria cell include:

1. Envelope: capsule, cell wall, & cell membrane (site of energy production) 2. Cytoplasm: nucleoids, plasmids, spores 3. Appendages: flagella & pili; move due to detected changes via chemotaxis

What are some examples of exposure assessment?

1. Measurement/ characterization of water or air quality 2. The level of pesticides or other contaminants in produce 3. The clustering of fast food chains on a city block 4. The # of handguns owned in a community

What different characteristics do microbiologists use to differentiate b/w microbial species?

1. Metabolic Diversity (diff. ways to replenish their energy stores via biochemical reactions) 2. Oxygen Requirements (aerobes vs anaerobes) 3. The type of Genetic Information used (DNA) 4. Cell Type (eukaryotic vs prokaryotic)

Cycle of Microbial Disease

1. Pathogen 2. Reservoir: habitats for the pathogen (ex: animals) 3. Transmission: how a disease spreads (direct vs indirect) 4. Portal of entry: the opening through which microbes get into the body (ex: mouth, nose, ears) 5. Portal of exit: leave the host & start a new cycle

Muscle tissue is composed of cells specialized to contract & generate force. What are the 3 different types of muscle tissue?

1. Skeletal: move the skeleton; under voluntary control 2. Cardiac: innervated by the autonomic nervous sys. 3. Smooth: not under voluntary control; has 1 nucleus; responsible for exerting pressure/ moving contents forward (digestion or childbirth)

What are the two drivers of epigenetic modifications?

1. Some are established as cells differentiate during development - cell gets specific identity + function 2. Others occur as adaptations throughput an organism's life in response to internal + external signals

Four categories of diseases

1. Sporadic: occurs occasionally & irregularly 2. Endemic: continually present at a steady level; pose little threat 3. Epidemic: sudden inc. in the morbidity & mortality above usual (a potential public health problem) 4. Pandemic: disease that can spread across continents & worldwide

Describe the three different types of horizontal gene transfer

1. Transformation: bacterial uptake of free fragments of DNA released by dead cells 2. Transduction: foreign DNA is introduced into the cell by a virus 3. Conjugation: direct cell-to-cell contact; genetic transfer through a sex pilus

viral replication cycle

1. adsorption (attachment) 2. penetration (entry) 3. replication (synthesis) 4. assembly 5. release (exit)

What are the two different shapes of bacteria?

1. bacilli = rod-shaped 2. spirilli = spiral

What are the 5 types of microbes?

1. bacteria 2. viruses 3. protozoans 4. fungi 5. unicellular algae

What are the benefits of genomics in public health?

1. deeper understanding of health risks 2. technology to monitor the public's health & investigate gene-environment interactions 3. timely identification of health threats 4. inform, educate, & empower people about health issues

What are the basic cell functions?

1. getting nutrients & O2 from the environment 2. converting them into energy 3. eliminating waste products from the conversions 4. synthesizing proteins for cell growth, structure, & function 5. controlling the exchange of materials in + out cell 6. moving materials around w/in the cell 7. monitoring the environ. surrounding the cell 8. reproducing

In multicellular organisms cells also perform a specialized function. What are some of these specialized functions?

1. muscle cell contractions for movement 2. elimination of waste by kidney cells 3. the secretion of digestive enzymes by specialized glands in the digestive system 4. nerve cell messages to the brain

Public health relies on health communication to relay in a timely manner important information about:

1. prevention 2. risk 3. crises (ex: disease outbreaks or natural disasters)

What are the four components of risk analysis

1. risk assessment 2. risk communication 3. health communication 4. risk management

Essential features of cancer cells:

1. the ability to divide in the absence of growth signals 2. the ability to ignore anti-growth signals 3. the ability to avoid apoptosis 4. the ability to divide indefinitely 5. production of signals to promote blood vessel growth (angiogenesis) 6. the ability to break away from tissue of origin & travel to other parts of the body to form secondary tumors = Metastasis

What three things does exposure assessment take into account?

1. the source of exposure 2. the level of exposure 3. how the exposure is absorbed into the body

Under aerobic conditions, what is the total yield of ATP per molecule of glucose?

36 ATP molecules per molecule of glucose

What are factors 5-7 of the internal environment that must be homeostatically controlled?

5. Temperature: narrow temp. range for proper cell function 6. Volume & Pressure: maintained to ensure the body-wide distribution of nutrients 7. Redox: in response to environmental stressors

The negative feedback loop is a common regulatory mechanism for maintaining homeostasis. What is it?

A feedback loop in which a system responds to a change by returning to its original state, or by decreasing the rate at which the change is occurring.

electron transport chain

A sequence of electron carrier proteins that shuttle high-energy electrons (from the Krebs cycle) during the redox reactions that release energy used to make ATP *imp. for intracellular respiration -occurs in the mitochondrial cristae

active immunity vs passive immunity

Active Immunity: the body produces its own antibodies against antigens (long-term protection) Passive Immunity: an individual does not produce his or her own antibodies, but rather receives them directly from another source, such as mother to infant through breast milk (short-term protection)

lag phase & exponential phase of bacterial growth

Lag phase: bacteria adapt to their new environment; they grow in size but do not increase in number Exponential phase: period of rapid growth (governed by the generation time)

Describe the structure of a neuron

Neurons have four regions: -cell body: containing the nucleus -dendrites: receive and sent messages to other cells (cell body + dendrites = Input Zone) -axon: relays info away from cell body towards cells n other parts of the body (Conducting Zone) -axon terminals: release chemical messages to other cells (Output Zone)

Koch's Postulates

Set of rules for proving that a microorganism causes a specific disease. (see picture) 1. Association 2. Isolation 3. Causation 4. Re-isolation

histone acetylation

The attachment of acetyl groups to certain amino acids of histone proteins.

p53

This tumor suppressor gene causes cell cycle arrest in G1, providing time for DNA repair. If repair is successful, cells re-enter the cycle. If unsuccessful, apoptosis *deregulation of p53 is common in most cancers

Retrotransposons

Transposable elements that move within a genome by means of an RNA intermediate, a transcript of the retrotransposon DNA. -repeat sequences *decrease in methylation at these areas is a hallmark of cancer

herd (community) immunity

Vaccination of a significant portion of a population provides protection for those not vaccinated due to interruption of disease transmission between susceptible hosts.

Risk characterization refers to the question of

What is the estimated occurrence of the adverse effect in a given population? (likelihood of harm) *(derived from statistical modeling)

Exposure assessment refers to the question of

What types, levels, & duration of exposures are currently experienced or anticipated under different conditions? *(based on studies performed in the field)

Glycolysis

a chemical process that breaks down the glucose molecule into 2 pyruvic acid molecules to produce ATP *not very efficient - 1 molecule of glucose has a net yield of 2 ATPs

What is the major difference between basic cell functions and specialized functions?

basic cell functions are imp. for the survival of the individual cells, while specialized functions contribute to the survival of the system or whole body

Mechanism by which bacteria multiply

binary fission (splitting in 2) -produces 2 identical copies, or clones, of the original parent cell

The basic unit of life

cells (building blocks for tissue, organ, & whole body functions)

The body is organized progressively into 4 levels:

cells, tissues, organ, organ systems

Health marketing includes

creating, communicating, & delivering health information and interventions *uses a customer-centered approach and scientific basis

Organelles occupy ~50% of a total cell volume. The remainder of the cytoplasm not occupied by organelles comprises:

cytosol: semifluid portion of the cytoplasm

Law of Segregation

first law of heredity stating that pairs of alleles for a trait separate when gametes are formed -1 copy goes to each daughter cell

vertical gene transfer

flow of genetic information from one generation to the next

Microbial diversity is the result of:

gene mutation & gene recombination

Germline mutations in the tumor suppressor genes result in:

hereditary cancer syndromes -many members of a family through multiple generations will develop specific types of cancers (ex: breast & ovarian cancer)

Through a process called ____________, bacteria can exchange genetic information without reproducing.

horizontal gene transfer (transformation, transduction, & conjugation)

health literacy

how well individuals understand health communication messages in order to make appropriate health decisions

cell theory

idea that: -all living things are composed of cells -cells are the basic units of structure and function in living things -new cells are produced from existing cells *(doesn't apply to viruses - not considered living)

Vaccines attempt to stimulate the immune response by mimicking a natural infection. What are the two key elements that the success of a vaccine depends on?

immunological memory & specificity *allow the immune system to have a stronger response on the 2nd encounter w/ the antigen

What is the first step in the identification of bacteria?

microscopic determination of shape & pattern

What are the four different types of tissues in the body?

muscle, nervous, epithelial, connective

What is nervous tissue made up of?

neurons specialized for initiation & transmission of electrical impulses necessary to control the body

Viruses are

obligate intracellular parasites -which must infect a host cell in order to replicate

microbes that cause disease are called:

pathogens *(only a few microbes produce disease)

Homeostasis

process by which organisms maintain a relatively stable internal environment

Human Genome Project

project whose goal is to map, sequence, and identify all of the genes in the human genome

connective tissue

provides support for your body and connects all its parts

common source epidemic

rapid rise in cases suggests exposure to single source of pathogen

propagated epidemic

result of direct person to person contact (horizontal transmission) -the # of infected indiv. rises more slowly & decreases gradually

risk communication

stage in risk analysis that includes communicating information about risks to decision makers and the public

immunotherapy

targets unique antigens on cancer cells & marks them for destruction by the host immune system

Epidemiology also measures the transmission of a disease. What is an important measure of transmission?

the basic reproduction rate (Ro) = the mean # of secondary cases occurring in a non-immunized population in the wake of an infection

The cell is a more efficient energy converter when O2 is available. What occurs under anaerobic (w/out O2) conditions?

the breakdown of glucose can't go beyond glycolysis (pyruvic acid gets converted into lactic acid instead)

ED50 (effective dose)

the effective dose of a chemical that causes 50% of the individuals in a dose-response study to display an effect (TD50 = toxic effect) (LD50 = lethal effect)

Dose-response assessment in people are often hampered by:

the heterogeneity of response among humans (factors such as age, sex, body mass, disease status, etc. effect individual responses to uniform exposure)

Epidemiology

the investigative methodology designed to determine the source & cause of diseases & disorders that produce illness, disability, & death in humans

dose-response assessment

the measurement of the relationship between the amount of exposure and the occurrence of the unwanted health effects (what is the relationship b/w dose & response) (how much is bad for you?)

Risk

the probability an event will occur w/in a specified time period (the likelihood of a hazard causing harm)

Accurate communication of the risks associated with a given hazard is hampered by

the public's misunderstanding & misperception of risk

Risk Management

the strategies taken to eliminate risks or to lower them to acceptable levels

Health Communication

the use of communication strategies to inform and influence individual and community decisions that promote health & prevent disease