BIOD102/ BIOD102 Module 6 – Essential Biology II (Portage Learning) 2026/2027 | Verified Q&A | 100% Correct Answers | A+

BIOD102/ BIOD102 Module 6 – Essential Biology II (Portage Learning) 2026/2027 | Verified Q&A | 100% Correct Answers | A+ Q: Natural history of a Disease Answer: Transmission, development, and outcomes of a given disease. Can inform treatment for those already impacted or help with development of therapies aimed at reducing morbidity and mortality. Q: Preventative model or therapeutic model Answer: Modes and measures of health care delivery Q: What is the goal of public health? Answer: Ultimately the goal of public health is to identify risk factors and intervene to reduce morbidity and mortality within a population. Q: Rates and proportions are descriptive metrics known as which of the following? Answer: Measures of association Q: Advantages of active surveillance include which of the following? Answer: Greater level of accuracy, quick identification of outbreaks, rapid intervention/prevention Q: After traveling throughout England and administering his vaccination protocol, what result did Edward Jenner find regarding smallpox infection? Answer: Jenner traveled throughout England following this protocol. The result was always the same: inoculation with cowpox followed by inoculation (exposure) with smallpox was protective and patients did not develop the wild-type disease. Q: How do observational studies differ from experimental studies? Answer: Observational studies differ from experimental studies, such as clinical trials, in that treatments are not applied by a researcher. Instead, groups of people with a defined exposure and without the exposure are monitored (a process called follow-up) to determine the incidence of a disease. Q: Which type of surveillance considers existing data or reportable illnesses? Answer: Passive Q: What is prevalence? Answer: Prevalence is defined as the number of persons, present within a defined population at a specific time, who have a particular condition. Q: A population can be defined using the following metrics? Answer: Person, time, place Q: Which of the following is a key characteristic of ecological studies? Answer: The population is the unit of analysis. Q: Differences in how an economic class or ethnic group receives or has access to healthcare services is called an ____. Answer: Disparity Q: True or false... Analytical studies determine the distribution of disease and potential determinants of the disease. Answer: False. Descriptive studies determine the distribution of disease and potential determinants of disease. Q: Vehicles and vectors are examples of ___ transmission. Answer: Indirect Q: As a measure of association , which of the following is incidence considered as? Answer: Rate Q: What is the most appropriate measure of association for case-control studies? Answer: Odds ratio Q: _______ denotes a system in which health officers or other public health officials execute procedures to gather pertinent health data. Answer: Active surveillance. Q: Etiology of a disease includes each of the following except... Answer: Treatment Q: Relative risk is defined by which equation? Answer: risk in exposed / risk in non-exposed Q: What is attributable risk? Answer: The attributable risk describes the risk of developing a disease, in the exposed group that can be attributed to the exposure. Q: Advantages of passive surveillance include each of the following except... Answer: Greater level of accuracy. Q: What are cross-sectional studies also known as prevalence studies? Answer: Cross-sectional studies are sometimes called 'prevalence' studies because they are designed to a snapshot that captures the relationship between disease and variables of net rest as they exist in a defined population in a specific time period. Q: True or False... mortality refers to symptoms or disabilities that occur from a disease. Answer: False, morbidity refers to symptoms or disabilities that occur from a disease. Or Mortality refers to the death of a person. Q: True or False... attack rates are actually proportions rather than rates. Answer: True. Q: Economic stability, education, social and community context, health and healthcare, and neighborhood and physical environment are considered which of the following? Answer: Social determinants of health. Q: During the 2020 COVID-19 pandemic, concerns over having enough PPE and ventilators addressed the ____ of the disease. Answer: Burden Q: How does case fatality differ from mortality rate? Answer: Mortality should not be confused with case fatality. Case fatality describes the percentage of people who have dies from a specific disease and is not a rate. Q: Smallpox develops from... Answer: Variola major or variola Minor Q: Smallpox is characterized by... Answer: Sudden high fever, body aches (especially in back muscles), abdominal cramping, vomiting, diarrhea, and body-wide rash. Rash begins as flat reddened spots that eventually expand and fill with fluid and then reupture before scabbing over and healing. Globally eradicated in 1980 by vaccination. Q: Epidemiologic Triad Answer: Interactions among the human host, mode of transmission, infectious agent, and the environmental factors that promote transmission. Q: Host Answer: For an illness or infection to occur , the host must be susceptible, but susceptibility to infectious disease is not universal. Humans are complex, and there are a variety of factors that can lead to being more or less susceptible to an illness. Age, gender, race, genetics, immmune status, health status, and previous health complications can all contribute. Q: Modes of transmission Answer: Direct or indirect Q: Direct transmission Answer: Involves human-to-human contact. Can occur through several routes - respiratory, fecal to oral, sexual or blood. Q: Indirect transmission Answer: May involve a common vehicle. Q: Vehicle Answer: Objects that are contaminated with an infectious agent. Air, water, soil, inanimate objects. Ex. Flu can remain on doorknobs for 24-48 hours. Vector Answer: Any living thing that aids in transmission of an infectious agent to the host. Ex. In the case of malaria, mosquitoes carries the plasmodium parasite from one human to the next. Infectious agents Answer: Anything that causes illness or injury in a human host. Can be living, biological microbes such as bacteria or parasites, but can also be non-living such as viruses, chemicals, or physical events. Nutritional status can also act as an agent. Environmental factos Answer: Temperature, humidity, physical crowding, air pollution, access to nutritional foods and clean water, and living conditions. Types of surveillance Answer: Passive and active Surveillance Answer: Is used as a tool for monitoring disease frequency or changes in risk factors for disease. Passive surveillance Answer: Denotes techniques in which data reporting is mandated or requested. In this system existing data are simply identified, counted and reported. Responsibility of health care practitioner or local health officer. The goal is to intervene and limit exposure to other people. Once the local and state health departments are notified the public health officer will work to identify WHO the infected patient had contact with, WHEN onset of infection occurred, and WHERE the patient spent his time after contracting the illness. Advantage of passive surveillance Answer: Inexpensive and uncomplicated - ease of international tracking and comparisons among different geographic areas. Disadvantage of passive surveillance Answer: Healthcare providers may not submit detailed reports. Local outbreaks may be missed - this is because small concentrated numbers of cases may not seem significant amid the total number of persons in the total population. Active surveillance Answer: A system in which health officers or other public health officials execute procedures to gather pertinent health data. Pursue new cases of disease or deaths that have occurred through a process called case finding. Common for assessing and controlling outbreaks of infectious disease in clinical and hospital settings. It is not defined by a specific list of diseases. Advantages of active surveillance Answer: Greater level of accuracy. Local outbreaks are quickly identified, rapid identification permits rapid intervention and prevention of spread. Disadvantage of active surveillance Answer: More costly and labor intensive. Require personnel time. Typically proponents of active methods must provide data that support improved health outcomes to maintain financial support. National Health Interview Survey (NHIS) Answer: Passive surveillance tool that has been in use since 1957 and continues to be used on an annual basis. Cross-sectional study. Seeks to obtain samples that are representative of the population. Objective of NHIS Identify changes in trends, barriers to accessing care, and to evaluate current healthcare programs deployed on the federal level. Extremely important to public health officials ; the data is used to drive public health research and implementation of policies. Types of Data NHIS seek Mental health, physical health, access to healthcare, health insurance coverage, general social demographics and determinants of health. Social determinants of health (SDOH) Physical and situational factors of a persons environment (home,work, school, or neighborhood) that affect physical health , mental health, quality of life, risks and health outcomes. Five main SDOH Economic stability Education Social and community context Health and healthcare Neighborhood and physical environment Disparity Differences in how an ethnic group or economic class receives healthcare services. Often shift the burden of disease, magnitude, and frequency of risk factors to a marginalized population. Rates Allude to how quickly a disease os occurring within a population. Proportions Provide a metric that describes the fraction of a population that is inflicted with a disease. Measures of association Rates and proportions. Allow researchers to evaluate the hypothesis that an exposure (preceding the disease) could be the cause of that disease. Morbidity measure... Measured by the rate (number of new cases that are identified) or as a metric of disability and time that is lost as a result of an illness. Incidence The number of new cases that occur in a specified time period among a population that is at risk for developing the condition or illness. Determining the number of new cases allows researchers to capture an event : a shift from a non-disease to a disease state. Incident rate equation Number of new cases occurring in a defined time period / Number of persons who are at risk of developing the illness in a defined time period X 1000 Cumulative incidence When all people have been observed to be at risk for an entire time period. Person-years Used when people in the same population are experiencing a risk at different times. Equation - Incident rate per 1,000 observed person-years at risk = Number of new cases / Observed number of person-years x 1000 Attack rates Unique set of incident rates that pertain to food borne illness. Tabulated in terms of single exposure. Therefore they are not really "rates", but rather proportions. Number of people who fell ill / Total number of people exposed Risk of disease Cases of disease per number of people at risk , this is a proportion rather than a rate and ha a possible range of 0-100% Rate of disease Defined as cases per person-years at risk (or other time metric) with a possible range of 0 to infinity. Prevalence Number of persons, present within a defined population at a specific time, who have a particular condition. Snapshot of current distributions and not a measure of change; it does not tell us when a condition developed and is not a rebate but a proportion. Equation - Prevalence per 1,000 = Numbers of cases of a disease present within a population at a specified time / Number of persons in the population at a specified time X 1000 Reference group Typically the group that is not exposed to an agent or the group that has "Normal" levels of some biological metric, such as cholesterol, blood pressure or WBC count. This illustrates the risk that the exposed group would have if they had not been exposed to the agent. Risk Ratio Relative Risk (RR) = Risk in the exposed/Risk in the non-exposed Direction Direction of association describes the nature of the impact of the exposure on disease development. Relative risk greater than 1.0 suggest a positive association and determining causation would be wise. Less than 1.0 suggest a negative association and the exposure may have a protective effect against the development of disease. Magnitude Magnitude of the relative risk is also important because it illustrates the strength of the relationship between exposure and disease; the larger the value the stronger the association. Mortality RAte Describes severity of disease. Reflects the risk of dying from a disease. Several types of mortality rates - all-cause, cause-specific, age-specific All-cause mortality rates Equation Annual mortality (all causes) per 1,000 persons = Total number of deaths from all causes / Number of persons in the population at mid year X 1000 Cause-specific mortality rates Annual mortality rate from disease (per 1,000 persons) = Number of deaths from disease / Number of persons in the population at mid year X 1000 Age-specific mortality rate Annual mortality from all causes for children younger than age (per 1,000 persons ) = Number of deaths from all causes in one year in children under age / Number of children in the population younger than age at mid year X 1,000 Case fatality Percentage of people who have died from a specific disease and is not a rate. Helpful in determining the severity of a disease , as well as the benefits of new therapies. Equation Case fatality (percent) = Number of persons dying in a specified time period after disease onset or diagnosis / Number of individuals with the specified disease X 100 Observational studies Differ from experimental studies such as clinical trials in that treatments are not applied by a researcher. Instead , groups of people with a defined exposure are monitored (a process called follow-up) to determine the incidence of a disease. objectives cover a broader spectrum and include investigating the cause, prevention and treatment of a disease. Classification of observational studies Descriptive Analytical Descriptive observational studies Determine the distribution of disease and potential determinants of disease. Objective is to analyze patterns of disease according to characteristics of population: who are the cases? Where are the cases occurring? Is the disease changing over time? Ex. Case-series, cross-sectional, ecological studies Analytical observational studies Seek to determine risk factors and causes of a disease. Evaluate interventions to determine if and how they are changing the course of a disease. Ex. Cohort studies, case-control and specific subsets of clinical trials Case-Series descriptive Include only a small group of patients with a similar diagnosis. Does not include hypothesis testing or manipulation of any independent variables. Focus - review medical files and conduct interviews with patients to determine the possible links between exposure and outcome. Especially vulnerable to selection bias. INCLUDE ONLY A SMALL GROUP OF PATIENTS WITH A SIMILAR DIAGNOSIS Cross-sectional descriptive Also called prevalence studies. Designed to be a snapshot that captures the relationship between diseases and variables of interest as they exist in a defined population in a specific time period. Attempt to capture both disease and exposure prevalence. Investigates symptoms, conditions, specific diseases, attitudes/values, behavioral characteristics. Ecological studies Examine the rates of a disease in relation to a factor that is described at the population level. Units of measure are aggregates that summarize individuals in a population, environmental measures, or a geographic location. *key characteristic - population under study is the unit of analysis rather than the individuals. First step ins assessing a relationship between an exposure and outcome. Ecological Fallacy Occurs when it is falsely interpreted that individuals have the same risk as the risk among the aggregate group. Case-Control Analytical , major benefit of examining multiple exposures in relation to a single disease. Cases are recruited first, then controls are matched to cases, and then exposure history is investigated. No manipulations. EXAMINE MULTIPLE EXPOSURES IN RELATION TO A SINGLE DISEASE Case-control studies are useful epidemiological tools when... 1. The prevelance of a disease is low 2. Comparison of groups is necessary to complete the epidemiological investigation. Odds Ratio used in case-control study Ratio of the probability that an even occurs to the probability that the even does not occur. Once odds are determined for each group, we compare them with an odds ratio Cohort Reverse of case-control studies Use for for investigating multiple outcomes in relation to a single exposure. Participants are defined by exposure level (rather than disease) and they are followed over a time period to determine if disease occurs. INVESTIGATE MILTIPLE OUTCOMES IN RELATION TO A SINGLE EXPOSURE Attributable Risk Risk of developing a disease, in the exposed group that can be attributed to exposure. Equation: Attributable Risk (AR) = Incidence (risk) among exposed - Incidence (risk) among non-exposed What are the goals of public health and epidemiology? The goal of public health is to identify risk factors and intervene to reduce morbidity and mortality within a population. The basic objectives of epidemiology include: (1) identifying the cause of a disease and important risk factors, (2) determining the burden of disease, (3) studying the natural history of a disease, (4) evaluating preventative and therapeutic models, and (5) developing public policy. How does morbidity differ from mortality? Give an example of morbidity. Morbidity refers to symptoms or disabilities that occur from a disease, while mortality refers to the death of a person. Examples of morbidity include cancer, pain, disability, permanent shortness of breath, mental health conditions, brain injury, or hypertension Why is it essential to determine the burden of disease? Quantifying the burden of a disease is essential for public health planning to ensure there are adequate treatment facilities, services, prevention programs, and community education available to lessen the burden. Describe how Edward Jenner developed a vaccination for smallpox. Jenner tracked down one dairymaid, Sarah Nelms, who had fresh lesions on her hands and forearms in May of 1796. Jenner removed biological material from Sarah's lesions and introduced them subcutaneously to a young boy named James Phipps. The boy became mildly ill with a fever. Over the course of nine days, the little boy had chills and loss of appetite but recovered by the tenth day. In July 1796, Jenner encountered young James again, but this time he inoculated the boy with biological material from the lesions of a patient with smallpox; however, James Phipps never developed smallpox Explain the epidemiologic triad of disease. Diseases are described in terms of the epidemiologic triad, namely, interactions among the human host, mode of transmission, infectious agent and the environmental factors that promote transmission ____ surveillance denotes a system in which health officers or other public officials execute procedures to gather pertinent health data. ____ surveillance denotes techniques in which data reporting is mandated or requested. Active, Passive What is one advantage and one disadvantage of passive surveillance? There are both advantages and disadvantages to a passive reporting system. One advantage is that this type of surveillance is inexpensive and uncomplicated in its design. These two advantages result in a third advantage, which is the ease of international tracking and comparisons among different geographic areas. In contrast, passive surveillance has several disadvantages. First, health providers may not submit detailed reports. Second, local outbreaks may be missed. This is because a small, concentrated number of cases may not seem significant amid the total number of persons in the total population What is one advantage and one disadvantage of active surveillance? One advantage of active surveillance is a greater level of accuracy. Most health officers undertaking these procedures have been employed with the precise purpose of gathering the appropriate information. They are often knowledgeable about in-depth interviewing techniques, and their primary job is to collect the defined data and information. Additionally, local outbreaks are quickly identified with active surveillance methods. Rapid identification permits rapid intervention and prevention of further spread if the disease under investigation is infectious. The primary disadvantage of active surveillance is that it is more costly and labor intensive in comparison to passive methods What are social determinants of health (SDOH)? Social determinants of health are physical and situational factors of a person's environment (home, work, school, or neighborhood) that affect physical health, mental health, quality of life, risks and health outcomes. True or False... active surveillance is able to glean population-wide health outcomes. False. Active surveillance programs do not glean population wide-health outcomes, as passive surveillance such as the NHIS does. What metric describes the fraction of a population that is inflicted with a disease? Proportion Regarding relative risk, the ___ of the association describes the nature or the impact of the exposure on disease development , while the ____ illustrates the strength of the relationship between exposure and disease. Direction, Magnitude What are the two main ways observational studies are classified? Descriptive and Analytical What is an odds ratio? The odds ratio is the ratio of the probability that an even occurs to the probability that the event does not occur. What are the 2 phases of the cell cycle? Interphase and Mitotic phase What does interphase consist of? G1, S, G2 G1 and G2 the gap phases that are characterized by cellular growth such as protein and organelle production S phase the time during which chromosomes are duplicated and essential DNA information is replicated to be passed to daughter cells during mitosis Mitosis the division of genetic material; can be broken down into 5 subphrases (prophase, pro metaphase, metaphase, anaphase, and telophase) Cytokinesis the process of dividing the cell's cytoplasm Origin of Replication located along the strands of DNA are short nucleotides; the nucleotide sequence at each origin of replication encodes for a start signal at which the process of replication will be initiated by proteins that recognize and bind to those sequences Helicase an enzyme that has the role of untwisting and separating the helix parent strands at the replication fork Replication fork Y-shaped area where the DNA strands are beginning to untwist replication bubble as the helices begins to separate the double strands, a visible replication bubble forms that will expand as replication continues along the strand single stranded binding proteins act as a wedge to keep the parent strands separated and stabilized topoisomerase in the front of the fork and its function is to break the hydrogen bonds and the nucleotide bases and it plays a role in rejoining the DNA strands when replication is complete; it is able a stabilizing enzyme that reduces the strain in the strands that occur during replication RNA primers complementary to the parental DNA strand RNA single-stranded and contains sugar ribose and it does NOT have a thymine but a uracil primase enzyme that facilitates the synthesis of an RNA primer by using the unwound DNA strand as a template; it binds to the 3' end of the parent strand and begins adding complementary RNA nucleotides as it moves toward the 5' end of the parent strand DNA polymerase enzymes that add nucleotides to the 3' end of the existing chain via dehydration reactions triphosphate tail three phosphate group; has a negative charge around it pyrophosphate will undergo hydrolysis reaction which splits the molecule into two inorganic phosphates and energy is released in the process leading strand if nucleotides can only be added to the 3' end of a parental strand this means that the (new) complementary RNA primer strand is being elongated in the 5' to 3' direction. ONE RNA is required for leading strand elongation and nucleotides are added continuously as the replication fork progresses along the length of the template strand. lagging strand the other template is oriented in a 3' to 5' direction. This requires the DNA polymerase to work backward, AWAY from the replication fork. The daughter strand that is synthesized in this direction is called the LAGGING STRAND. The lagging strand must be replicated in a series of fragments called Okazaki fragments rather than in one continuous strand DNA ligase an enzyme that facilitates the joining the Okazaki fragments Mismatch repair occurs when other proteins identify inappropriately mismatched nucleotides and replace them with the correct nucleotide Nucleotide excision repair DNA polymerases and mismatch repair proteins are helpful for identifying and remediating single-nucleotide errors but sometimes entire stretches of the newly synthesized strand may be erroneous; when this happens the cell will deploy the nucleotide excision repair mechanism Nucleases enzymes that cut DNA; cleave out a short stretch of DNA on the new strand and the template strand willl again be used to determine the correct complementary pairs to fill in the gap telomers specialized nucleotide sequences that serve as a protective tail on the ends of strands; can be thought of as placeholders, short, repeating sequences that do not hold any relevant genetic info; have a secondary function with proteins associated with telomers prevent the cell from deploying error repairs within the telomeric DNA Telomerases facilitate the lengthening of telomere and are crucial in preserving the original length of the leading strand gene the unit of heredity composed of DNA that is passed from parent to offspring and contain info about the characteristics of an individual genotype the precise sequence of genetic info phenotype the observable characteristics resulting from the geneotype gene expression the process through with an individual's unique DNA directs the synthesis of proteins transcription characterized by the process of synthesizing RNA from DNA and is the first step in protein synthesis what are the 3 stages of transcription initiation, elongation, termination mRNA RNA that is synthesized from a complementary DNA strand and this type of RNA contains the exact sequence of DNA that dictates how to build a protein and will take the info to ribosomes within the cell what is the flow of genetic info with in the cells DNA -- RNA -- protein triplet code a non-overlapping reading frame in which 3 bases encode for a single amino acid reading frame the phase in which successive nucleotides form the codons and is typically designated by the start (AUG) codon Initiation where transcription is initiated at a promoter region promoter region a control sequence on a gene that acts as a starting point for transcription; its specific nucleotide sequence that serves as a binding area for the RNA polymerase TATA box a promoter region that contains a DNA nucleotide sequence; its located ~25 nucleotide upstream from the point at which transcription will begin RNA polymerases a family of enzymes that are responsible for separating the DNA strands and chemical joining together complementary RNA nucleotides that are added along the length of the template DNA strand transcription factors assist with RNA polymerase binding and facilitate the initiation of transcription; they are responsible for controlling the rate of the mRNA transcription from the DNA template strand transcription initiation complex the association of these nucleotides' proteins what is the elongation process? o RNA polymerases glide down the DNA template strand in the 3' to 5' direction o The polymerase unwinds the DNA in small sections and builds a new complementary RNA strand to the DNA template strand o When the RNA strand continues to grow it pulls away from the DNA template allowing the DNA double helix to re-associate when does termination happen? after RNA strand has been elongated along the DNA template strand polyadenylation sequence a sequence spanning 6 nucleotides in length that signals the end of transcription 5' cap a guanine nucleotide that has been modified by the attachment of phosphates 20-40 nucleotides Poly-A-tail a series of 50-250 adenine nucleotides RNA splicing final modification of pre-mRNA that occurs within the nucleus; it involves the removal and rejoining of the RNA strand; the point of this removal and rejoining is to remove long stretches of nucleotides that don't code for amino acids introns non-coding regions; found among the segments that do encode for amino acids; spliced out during this phase exons nucleotide regions that do encode for amino acids and will be translated into a protein, rejoined together during this phase spliceosome RNA molecules and protein complexes what are the 3 stages of translation? initiation, elongation, and termination tRNA serves as translators that "read" the codon message along the mRNA molecule; its main role of transferring available amino acids from the cytosol to the growing polypeptide chain; they are transcribed from the DNA templates within the cell's nucleus and then transported to the cytoplasm where they will participate in the process of translation anticodon region consists of a nucleotide triplet oriented in the 3' to 5' orientation that base-pairs to a precise mRNA codon that is oriented in the 5' to 3' direction ribosomes protein machinery; functions to bring mRNA together with the tRNA carrying an amino acid; its composed of 2 subunits (1 small and 1 large) what does the small subunit have a binding site for? mRNA what are the 3 binding sites for the tRNA in the large unit? peptidyl-tRNA binding site (P-site) Aminoacyl-tRNA binding site (A-site) Exit site (E-site) Peptidyle-tRNA binding site (P-site) functions to hold the tRNA carrying the growing polypeptide chain firmly in place aminoacyl-tRNA binding site (A-site) serves to hold the tRNA carrying the amino acid that is to be added next to the growing chain exit site (E-site) permits the passage of the tRNA molecules out of the ribosome so that they can grab the appropriate amino acid for the next round of addition to the growing chain exit tunnel allows passage of the polypeptide chain which is continually growing in length as amino acids are added when its complete it is released through the exit tunnel initiation assembly go the translation initiation complex initiator tRNA adds the MET and small ribosomal subunits bind here translation initiation complex formed by the multi-unit complex amino end (N-terminus) the initial methionine located at the 5' N terminus carboxyl end (C-terminus) the final amino acid is said to be located at the 3' C-terminus elongation factors proteins that facilitate lengthening of the polypeptide chain what are the 3 steps termination of translation is broken down into? 1. binding of a releasing factor 2. liberation of the completed polypeptide chain 3. disassembly of the translation initiation complex releasing factors proteins shaped like aminoacyl-tRNA molecules that bind to the A-site when one of the stop codons is encountered disassembly the final step of translation initiation complex; it occurs in a a variety of steps and requires multiple protein facts what are the 3 types of mutation? point mutation, substitution, and insertion/deletion point mutations occur when a single nucleotide is changed within a gene; point mutations that occur in gametes give rise to the inheritance patters of some genetic diseases substitution mutations occur when a single nucleotide and its partner are substituted with another pair of nucleotides what are the 3 types of substitution mutations? silent substitution, missense, nonsense silent substitution occurs because of redundancy of the genetic code missense occur when one amino acid is replaced with another; can have a spectrum of effects on the resulting protein depending on where the mutation is located and which amino is changed nonsense occur when a point mutation turns the intended codon into a stop codon insertion/deletion occur from the gain and loss of nucleotides with a gene frameshift mutation the insertion/deletion of nucleotide bases in numbers that are not multiples of three differential gene expression the expression of different genes among different cells types of one organism acetylation the addition of acetyl groups to an amino acid of the histone tail which flips the switch ON; this induces transcription because the addition of the acetyl group alters the chemical structure and resulting interactions allowing the DNA to become more accessible to transcription machinery methylation the addition of methyl groups to the amino acid of the histone tail which flips the switch OFF; it induces further condensation of the chromatin and this tighter conformation inhibits transcription machinery from binding to DNA; direct methylation of cytosine resides on DNA instead of the histone tails which is another effective mechanism to inhibit transcription epigenetic inheritance occurs when chromatin modifications affect a trait and those effects are passed to future generations control elements non-coding regions of DNA and are responsible for the regulation of transcription proximal control elements control elements that are located close to the RNA promoter distal control elements located further away from the promoter region general transcription factors a broad group; these proteins are required for all genes that encode for proteins enhancers groups of distal control elements that can regulate the rate of transcription based on what type of protein binds to the region; they are specific to the gene they interact with activator proteins increase transcription by facilitating protein to protein interactions or binding to another regulatory regions; regardless of the mechanism the end result is enhanced transcription repressor proteins may bind to the DNA control element regions or block the binding of activator proteins; this causes gene transcription to decrease or completely stop alternative splicing a type of RNA processing that involves the splicing and rejoining of different regions from one primary transcript; the benefit of alternative splicing is the production of more than one kind of mRNA from a single primary transcript selective degradation a translated protein can act as a regulatory process What are the 2 phases of the cell cycle? Interphase and Mitotic phase What does interphase consist of? G1, S, G2 G1 and G2 the gap phases that are characterized by cellular growth such as protein and organelle production S phase the time during which chromosomes are duplicated and essential DNA information is replicated to be passed to daughter cells during mitosis Mitosis the division of genetic material; can be broken down into 5 subphrases (prophase, pro metaphase, metaphase, anaphase, and telophase) Cytokinesis the process of dividing the cell's cytoplasm Origin of Replication located along the strands of DNA are short nucleotides; the nucleotide sequence at each origin of replication encodes for a start signal at which the process of replication will be initiated by proteins that recognize and bind to those sequences Helicase an enzyme that has the role of untwisting and separating the helix parent strands at the replication fork Replication fork Y-shaped area where the DNA strands are beginning to untwist replication bubble as the helices begins to separate the double strands, a visible replication bubble forms that will expand as replication continues along the strand single stranded binding proteins act as a wedge to keep the parent strands separated and stabilized topoisomerase in the front of the fork and its function is to break the hydrogen bonds and the nucleotide bases and it plays a role in rejoining the DNA strands when replication is complete; it is able a stabilizing enzyme that reduces the strain in the strands that occur during replication RNA primers complementary to the parental DNA strand RNA single-stranded and contains sugar ribose and it does NOT have a thymine but a uracil primase enzyme that facilitates the synthesis of an RNA primer by using the unwound DNA strand as a template; it binds to the 3' end of the parent strand and begins adding complementary RNA nucleotides as it moves toward the 5' end of the parent strand DNA polymerase enzymes that add nucleotides to the 3' end of the existing chain via dehydration reactions triphosphate tail three phosphate group; has a negative charge around it pyrophosphate will undergo hydrolysis reaction which splits the molecule into two inorganic phosphates and energy is released in the process leading strand if nucleotides can only be added to the 3' end of a parental strand this means that the (new) complementary RNA primer strand is being elongated in the 5' to 3' direction. ONE RNA is required for leading strand elongation and nucleotides are added continuously as the replication fork progresses along the length of the template strand. lagging strand the other template is oriented in a 3' to 5' direction. This requires the DNA polymerase to work backward, AWAY from the replication fork. The daughter strand that is synthesized in this direction is called the LAGGING STRAND. The lagging strand must be replicated in a series of fragments called Okazaki fragments rather than in one continuous strand DNA ligase an enzyme that facilitates the joining the Okazaki fragments Mismatch repair occurs when other proteins identify inappropriately mismatched nucleotides and replace them with the correct nucleotide Nucleotide excision repair DNA polymerases and mismatch repair proteins are helpful for identifying and remediating single-nucleotide errors but sometimes entire stretches of the newly synthesized strand may be erroneous; when this happens the cell will deploy the nucleotide excision repair mechanism Nucleases enzymes that cut DNA; cleave out a short stretch of DNA on the new strand and the template strand willl again be used to determine the correct complementary pairs to fill in the gap telomers specialized nucleotide sequences that serve as a protective tail on the ends of strands; can be thought of as placeholders, short, repeating sequences that do not hold any relevant genetic info; have a secondary function with proteins associated with telomers prevent the cell from deploying error repairs within the telomeric DNA Telomerases facilitate the lengthening of telomere and are crucial in preserving the original length of the leading strand gene the unit of heredity composed of DNA that is passed from parent to offspring and contain info about the characteristics of an individual genotype the precise sequence of genetic info phenotype the observable characteristics resulting from the geneotype gene expression the process through with an individual's unique DNA directs the synthesis of proteins transcription characterized by the process of synthesizing RNA from DNA and is the first step in protein synthesis what are the 3 stages of transcription initiation, elongation, termination mRNA RNA that is synthesized from a complementary DNA strand and this type of RNA contains the exact sequence of DNA that dictates how to build a protein and will take the info to ribosomes within the cell what is the flow of genetic info with in the cells DNA -- RNA -- protein triplet code a non-overlapping reading frame in which 3 bases encode for a single amino acid reading frame the phase in which successive nucleotides form the codons and is typically designated by the start (AUG) codon Initiation where transcription is initiated at a promoter region promoter region a control sequence on a gene that acts as a starting point for transcription; its specific nucleotide sequence that serves as a binding area for the RNA polymerase TATA box a promoter region that contains a DNA nucleotide sequence; its located ~25 nucleotide upstream from the point at which transcription will begin RNA polymerases a family of enzymes that are responsible for separating the DNA strands and chemical joining together complementary RNA nucleotides that are added along the length of the template DNA strand transcription factors assist with RNA polymerase binding and facilitate the initiation of transcription; they are responsible for controlling the rate of the mRNA transcription from the DNA template strand transcription initiation complex the association of these nucleotides' proteins what is the elongation process? o RNA polymerases glide down the DNA template strand in the 3' to 5' direction o The polymerase unwinds the DNA in small sections and builds a new complementary RNA strand to the DNA template strand o When the RNA strand continues to grow it pulls away from the DNA template allowing the DNA double helix to re-associate when does termination happen? after RNA strand has been elongated along the DNA template strand polyadenylation sequence a sequence spanning 6 nucleotides in length that signals the end of transcription 5' cap a guanine nucleotide that has been modified by the attachment of phosphates 20-40 nucleotides Poly-A-tail a series of 50-250 adenine nucleotides RNA splicing final modification of pre-mRNA that occurs within the nucleus; it involves the removal and rejoining of the RNA strand; the point of this removal and rejoining is to remove long stretches of nucleotides that don't code for amino acids introns non-coding regions; found among the segments that do encode for amino acids; spliced out during this phase exons nucleotide regions that do encode for amino acids and will be translated into a protein, rejoined together during this phase spliceosome RNA molecules and protein complexes what are the 3 stages of translation? initiation, elongation, and termination tRNA serves as translators that "read" the codon message along the mRNA molecule; its main role of transferring available amino acids from the cytosol to the growing polypeptide chain; they are transcribed from the DNA templates within the cell's nucleus and then transported to the cytoplasm where they will participate in the process of translation anticodon region consists of a nucleotide triplet oriented in the 3' to 5' orientation that base-pairs to a precise mRNA codon that is oriented in the 5' to 3' direction ribosomes protein machinery; functions to bring mRNA together with the tRNA carrying an amino acid; its composed of 2 subunits (1 small and 1 large) what does the small subunit have a binding site for? mRNA what are the 3 binding sites for the tRNA in the large unit? peptidyl-tRNA binding site (P-site) Aminoacyl-tRNA binding site (A-site) Exit site (E-site) Peptidyle-tRNA binding site (P-site) functions to hold the tRNA carrying the growing polypeptide chain firmly in place aminoacyl-tRNA binding site (A-site) serves to hold the tRNA carrying the amino acid that is to be added next to the growing chain exit site (E-site) permits the passage of the tRNA molecules out of the ribosome so that they can grab the appropriate amino acid for the next round of addition to the growing chain exit tunnel allows passage of the polypeptide chain which is continually growing in length as amino acids are added when its complete it is released through the exit tunnel initiation assembly go the translation initiation complex initiator tRNA adds the MET and small ribosomal subunits bind here translation initiation complex formed by the multi-unit complex amino end (N-terminus) the initial methionine located at the 5' N terminus carboxyl end (C-terminus) the final amino acid is said to be located at the 3' C-terminus elongation factors proteins that facilitate lengthening of the polypeptide chain what are the 3 steps termination of translation is broken down into? 1. binding of a releasing factor 2. liberation of the completed polypeptide chain 3. disassembly of the translation initiation complex releasing factors proteins shaped like aminoacyl-tRNA molecules that bind to the A-site when one of the stop codons is encountered disassembly the final step of translation initiation complex; it occurs in a a variety of steps and requires multiple protein facts what are the 3 types of mutation? point mutation, substitution, and insertion/deletion point mutations occur when a single nucleotide is changed within a gene; point mutations that occur in gametes give rise to the inheritance patters of some genetic diseases substitution mutations occur when a single nucleotide and its partner are substituted with another pair of nucleotides what are the 3 types of substitution mutations? silent substitution, missense, nonsense silent substitution occurs because of redundancy of the genetic code missense occur when one amino acid is replaced with another; can have a spectrum of effects on the resulting protein depending on where the mutation is located and which amino is changed nonsense occur when a point mutation turns the intended codon into a stop codon insertion/deletion occur from the gain and loss of nucleotides with a gene frameshift mutation the insertion/deletion of nucleotide bases in numbers that are not multiples of three differential gene expression the expression of different genes among different cells types of one organism acetylation the addition of acetyl groups to an amino acid of the histone tail which flips the switch ON; this induces transcription because the addition of the acetyl group alters the chemical structure and resulting interactions allowing the DNA to become more accessible to transcription machinery methylation the addition of methyl groups to the amino acid of the histone tail which flips the switch OFF; it induces further condensation of the chromatin and this tighter conformation inhibits transcription machinery from binding to DNA; direct methylation of cytosine resides on DNA instead of the histone tails which is another effective mechanism to inhibit transcription epigenetic inheritance occurs when chromatin modifications affect a trait and those effects are passed to future generations control elements non-coding regions of DNA and are responsible for the regulation of transcription proximal control elements control elements that are located close to the RNA promoter distal control elements located further away from the promoter region general transcription factors a broad group; these proteins are required for all genes that encode for proteins enhancers groups of distal control elements that can regulate the rate of transcription based on what type of protein binds to the region; they are specific to the gene they interact with activator proteins increase transcription by facilitating protein to protein interactions or binding to another regulatory regions; regardless of the mechanism the end result is enhanced transcription repressor proteins may bind to the DNA control element regions or block the binding of activator proteins; this causes gene transcription to decrease or completely stop alternative splicing a type of RNA processing that involves the splicing and rejoining of different regions from one primary transcript; the benefit of alternative splicing is the production of more than one kind of mRNA from a single primary transcript selective degradation a translated protein can act as a regulatory process