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134 Cards in this Set
- Front
- Back
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Anabolism is defined as
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biosynthesis a process that requires energy
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catabolism is defined as
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a process that breaks down a compound to produce energy
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what are some qualities of an electron carrier?
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Electron carriers repeatedly accept and release electrons and hydrogens
Facilitate the transfer of redox energy Most carriers are coenzymes Example: NAD |
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the parts of ATP
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A temporary energy repository
Three-part molecule Nitrogen base (adenine) 5-carbon sugar (ribose) Chain of three phosphate groups |
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what are the ATP production amount for aerobic respiration, anerobic respiration, and fermentation
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38-aerobic
2-36=anerobic 2-fermentation |
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what is the final electron acceptor for aerobic resp., anerobic resp., and fermentation.
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aerobic-O2
anderobic-non oxygen electron acceptors like SO4, NO3, and CO3 Fermentation-organic molecule like pyruvate, or acetaldahyde |
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what are the steps of aerobic respiration and what are the end products
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glycolysis-glucose to 2 pyruvates
krebbs cycle- pyruvate to CO2 reduction of NAD and FAD electron transport chain-FADH2 and NADH reduced with O2 final acceptor. |
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what are the steps of anerobic respiration and what are the end products
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same as for aerobic except O2 not the final acceptor
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where does glycolysis occur?
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in the cytosol
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what is the ATP net for glycolysis
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2 ATP
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what are the uses of pyruvic acid in the cell?
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production of amino acids
sugars and fat metabolites converted to acetyl CoA for use in Krebb cycle acetaldyhyde production in fermentation acids and gases |
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what are the end products of the TCA cycle(Krebbs)
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2 FADH2
6 NADH 2 ATP |
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what is the fatty acid catabolism
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acetyl coA is endpoint
also produces 1 NADH & 1 FADH2 explains why fats are such a storehouse of energy |
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what is the final stats for aerobic respiration
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Maximum yield of 38 ATPs
6 CO2 molecules generated in Krebs cycle 6 O2 molecules consumed during electron transport 6 net H2O molecules are produced |
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how does aerobic excersise work?
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Designed to allow muscles to continue using O2 (and not produce lactic acid)
Initially fueled by glycogen molecules in muscles then fueled by free fatty acids released by fat tissue the longer the exercise, the greater the fat dependency (after 20 min, 50% of calories from fat) |
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Amphibolism is?
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the property of a system to integrate catabolic and anabolic pathways to improve cell efficiency
Principal sites of amphibolic interaction occur during glycolysis and the Krebs cycle |
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what are the three photosynthetic pigments
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Chlorophyll is most common pigment
Carotenoids (yellow, orange, red) Phycobilins (red or blue-green) |
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what are the two major components of chlorophyll
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porphyrin ring—light absorption
phytol chain—hydrophobic to keep embedded in membrane |
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what is a photocenter
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Several hundred chlorophyll molecules act together as one unit
reaction-center chlorophyll other molecules act as antenna |
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what are the two parts of photosynthesis
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Light-dependent reactions
energy from sunlight is absorbed and stored as chemical energy in ATP & NADPH Light-independent reactions carbs are synthesized from CO2 using energy from ATP & NADPH |
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what occurs in the light dependent reaction
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Electrons travel from water to NADPH
8 photons are absorbed 1 O2 and 2 NADPH Produces proton gradient that is used to make ATP |
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what occurs in the light independent reaction
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Occur in the chloroplast stroma or the cytoplasm of cyanobacteria
Use ATP produced by the light rxs to synthesize sucrose also known as the calvin cycle |
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what are the differences btw eukaryotic and bacterial chromosomes
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Eukaryotic chromosomes
DNA + histone proteins Vary in number Diploid or haploid Linear Bacterial chromosomes DNA + histone-like proteins Single, circular chromosome |
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what are the three types of genes
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A segment of DNA encodes a protein or RNA molecule
Types: Structural genes RNA Regulatory genes |
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what are the sizes of genomes compared btw virus, bacteria and humans
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Vary greatly in size
Smallest viruses- 4 or 5 genes Escherichia coli- 4,288 genes Human cell- 20,000 to 25,000 genes |
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what are the characteristics of the nucleotides
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Basic unit: nucleotide
Phosphate Deoxyribose sugar Nitrogenous base Covalently bond to form a sugar-phosphate linkage 5’ end & 3’ end |
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what are the characteristics of the nitrogen bases
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Attach by covalent bonds at the 1’ position of the sugar
Pair with complementary bases from the other strand Hydrogen bonds Adenine(A) – Thymine(T) Guanine(G) – Cytosine(C) |
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how many enzymes are needed to to replicate DNA
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Requires the actions of 30 different enzymes
Separate the strands Copy its template Produce two new daughter molecules |
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what is the origin of replication
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Origin of replication
Short sequence Helicases bind to the DNA at the origin Untwist the helix Break the hydrogen bonds |
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what does DNA polymerase III
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Synthesizes new daughter strand using template
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what is required for DNA polymerase III to function
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Requires RNA primer (primase)
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What direction does DNA polymerase work in?
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New strand is always synthesized from 5’ to 3’
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What is difference btw leading and lagging strand
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leading strand is replicated normally but lagging strand must be broken into Okazaki fragments in order for DNA plymerase III to function in a 5 to 3 direction
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what does DNA polymerase I do?
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DNA polymerase I removes RNA primers and replaces them with DNA
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what is the central dogma of DNA flow and what is the exception?
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Genetic information flows from DNA to RNA to protein
Transcription Translation Exceptions: RNA viruses and retroviruses Recently shown to be incomplete Some RNAs are used for regulation Many of the genetic malfunctions that cause human disease are found in these regulatory RNA segments |
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what are the 5 stages of translation
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initiation, elongation, termination, protein folding, protein processing
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start codon?
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AUG
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termination codon
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uaa
UAG UGA |
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redundancy and wobble
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multiple codons code for each AA
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translation and transcription occurs...
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simultaneously
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splicosomes
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cut the introns out of pre-mRNA
occurs in nucleus |
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operons
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organized group of genes regulated as a single unit either repressed or induced
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regulator
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a gene that codes for a protein capable of repressing the operon
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control locus
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promoter
operator |
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promotor
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recognized by RNA polymerase
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operator
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- a sequence that acts as an on/off switch for transcription
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structural locus
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structural genes coding for a different enzyme
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lac operon
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regulates E.coli lactose metabolism
repressed in absence of lactose by repressor binding to operator lactose binds repressor to release it from operator |
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arginine operon
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repressor normally off but in excess of arginine, arginine binds repressor and activates it to bind
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nonsense mutation
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stop codon at random place
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missense mutation
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codes for different AA
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difference btw infection and disease
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Infection- a condition in which pathogenic microbes penetrate host defenses, enter tissues and multiply
Disease – if infection causes damage or disruption to tissues or organs |
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where is residencial flora not found
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Internal organs and tissues and fluids are microbe-free.
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explain the fundamentals of microbial antagnoism
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Bacterial flora benefit host by preventing overgrowth of harmful microbes
acid fermentation of glycogen by lactobacilli in vagina prevents overgrowth of yeast Candida albicans E. coli protein in large intestine prevents the growth of pathogenic bacteria like Salmonella & Shigella Exceptions: Normal flora is beneficial only if host has a fully functioning immune system and flora present only in its natural habitat AIDS patients contract diseases from normal bacteria urinary tract infections if E. coli enters sterile bladder |
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when is initial exposure of newborn
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breaking of fetal membrane
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why is it better to breast feed
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Bifidobacterium species growth is favored by a growth factor from milk and becomes predominant flora of intestine
Bifidobacterium metabolizes sugars into acids that protect infant from infection from certain intestinal pathogens |
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true pathogen
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capable of causing disease in healthy persons with normal immune defenses
influenza virus, plague bacillus, malarial protozoan |
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opportunistic pathogen
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cause disease when the host’s defenses are compromised or when they grow in part of the body that is not natural to them
Pseudomonas sp & Candida albicans |
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explain infectous dose
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Minimum number of microbes required for infection to proceed
Microbes with small IDs have greater virulence Lack of ID will not result in infection. |
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three steps of becoming established
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portal of entry
adhesion surviving host defenses |
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Antiphagocytic factors
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used to avoid phagocytosis by microbes
Species of Staphylococcus and Streptococcus produce leukocidins, toxic to white blood cells. Slime layer or capsule – makes phagocytosis difficult Ability to survive intracellular phagocytosis |
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what are some ways that microbes cause disease
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Damage inflicted
directly with exoenzymes/toxins or indirectly with excessive or inappropriate host response Virulence factors endotoxins |
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Virulence factors
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traits used to invade and establish themselves in the host, also determine disease severity
Exoenzymes: Clostridium tetani collagenase; Ringworm keratinase Toxins: Staphylococci hemolysins, Clostridium tetanus & botulinum toxins |
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4 distinct stages of clinical infections
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incubation period - time from initial contact to appearance of first symptoms; (2-30 days)
prodromal stage – nonspecific complaints (malaise, aches) (1-2 days) period of invasion – multiplies at high levels, becomes well established; fever, cough, rashes, diarrhea; (variable length) convalescent period – symptoms decline |
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variations in transmission of disease can occur?
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incubation period (measles)
invasive period (Shigella) all periods (hepatitis B) |
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Patterns of Infection
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Localized infection– microbes enter body and remain confined to a specific tissue
boils, warts, fungal skin infections Systemic infection– infection spreads to several sites and tissue fluids usually in the bloodstream measles, rubella, chicken pox, anthrax, histoplasmosis Focal infection– when infectious agent breaks loose from a local infection and is carried to other tissues tuberculosis, scarlet fever |
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Types of Infection
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Mixed infection – several microbes grow simultaneously at the infection site
cooperate to break down tissue or one creates an environment that enables another to invade gas gangrene, wound infections, dental caries polymicrobial biofilms Primary infection – initial infection Secondary infection – another infection by a different microbe child with chicken pox scratches pox and infects them with Staphylococcus aureus Acute infection – comes on rapidly, with severe but short-lived effects (cold) Chronic infections –progress and persist over a long period of time (tuberculosis, periodontitis) |
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Persistence of Microbes and Pathologic Conditions
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Apparent recovery of host does not always mean the microbe has been removed
Latency Chronic carrier – person with a latent infection who sheds the infectious agent herpes, hepatitis B, HIV, syphilis, TB, malaria Sequelae – long-term or permanent damage to tissues or organs meningitis-deafness, strep throat-heart disease, lyme disease-arthritis |
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Where Pathogens Persist
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Reservoir – primary habitat of pathogen in the natural world
human or animal carrier, soil, water, plants Source – individual or object from which an infection is actually acquired Can be same or different syphilis primary reservoir & source same (human body) hepatitis A primary reservoir (human) & source (contaminated food) different |
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Living Reservoirs
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Carrier
Asymptomatic carrier incubation carriers – spread the infectious agent during the incubation period (HIV can be spread for years before first symptoms) convalescent carriers – spread during recuperation (diphtheria patients spread for 30 days after disease has subsided) Passive carrier – contaminated healthcare provider picks up pathogens and transfers them to other patient |
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Biological vectors
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actively participate in a pathogen’s life cycle
inject infected saliva into blood (mosquito) defecate around the bite wound (flea) regurgitating blood into the wound (tsetse fly) |
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Patterns of Transmission
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Communicable vs non-communicable
Direct contact – physical contact or fine aerosol droplets (sneezing, coughing) portal of exit meeting portal of entry horizontal – person to person vertical – parent to offspring e.g. most STDs Indirect contact vehicle – inanimate material, food, water, biological products, (doorknobs, telephones, faucet handles, bedspreads) airborne – droplet nuclei, aerosols |
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Zoonoses
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An infection indigenous to animals but naturally transmissible to humans
Humans are accidental hosts for the pathogen At least 150 zoonoses exist worldwide; make up 70% of all new emerging diseases worldwide Impossible to eradicate the disease without eradicating the animal reservoir |
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Prevalence
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total number of existing cases with respect to the entire population usually represented by a percentage of the population
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Incidence
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measures the number of new cases over a certain time period, as compared with the general healthy population
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Mortality rate
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the total number of deaths in a population due to a certain disease
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Morbidity rate
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number of people afflicted with a certain disease
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Endemic
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disease that exhibits a relatively steady frequency over a long period of time in a particular geographic locale
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Sporadic
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– when occasional cases are reported at irregular intervals
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Epidemic
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when prevalence of a disease is increasing beyond what is expected
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Pandemic
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epidemic across continents
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what are the levels of defense
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first line of defense – any barrier that blocks invasion at the portal of entry – nonspecific
second line of defense – protective cells and fluids; inflammation and phagocytosis – nonspecific third line of defense – acquired with exposure to foreign substance; produces protective antibodies and creates memory cells – specific |
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The First Line of Defense
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Sebaceous secretions, lactic acid and electrolyte concentrations of sweat
Skin’s acidic pH and fatty acid content Lysozyme in tears HCl in the stomach Digestive juices and bile in the intestine Semen- antimicrobial chemical Acidic pH in the vagina cilia in lungs |
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Genetic Defenses
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Some hosts are genetically immune to the diseases of other hosts
humans can’t get distemper, cats can’t get mumps Some pathogens have great specificity. particularly true for viruses (specific host receptor) Some genetic differences exist in susceptibility severe skin burns blockages in salivary glands, tear ducts, etc. gene mutations |
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Immunology
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The study of the body’s second and third lines of defense
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Functions of a healthy functioning immune system:
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Constant surveillance of the body
Recognition of foreign material (self vs. nonself) Destruction of entities deemed to be foreign |
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White blood cells must distinguish self from nonself cells
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Evaluates cells by examining markers on their surfaces
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Four major subdivisions of immune system are:
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Reticuloendothelial system (RES)
Blood Extracellular fluid (ECF) Lymphatic system |
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Reticuloendothelial system (RES)
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Fibrous support network between cells within a tissue or organ
provides niche for WBCs to crawl between and within cells |
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Monocytes
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Discharged by bone marrow into bloodstream then differentiate into macrophages
Responsible for Many specific and nonspecific phagocytic and killing functions Processing foreign molecules and presenting them to lymphocytes Secreting biologically active compounds that assist, mediate, attract, and inhibit immune cells and reactions Dendritic cells, Neutrophils, Macrophages |
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Lymphocytes
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Key cells in the third line of defense/specific immune response
When stimulated by antigens, transform into activated cells that neutralize and destroy that foreign substance B cells Humoral immunity - produce specialized plasma cells which produce antibodies T cells Cell-mediated immunity: T cells modulate immune functions and kill foreign cells |
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Unique Characteristics of Leukocytes
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Diapedesis – migration of cells out of blood vessels into the tissues
Chemotaxis – migration in response to specific chemicals at the site of injury or infection |
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Lymphatic Vessels
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Along the lines of blood vessels
Similar to thin-walled veins Flow of lymph is in one direction only- from extremities toward the heart Lymph is moved through the contraction of skeletal muscles |
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Thymus
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high rate of growth and activity until puberty, then begins to shrink
site of T-cell maturation |
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Lymph nodes
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small, encapsulated, bean-shaped organs stationed along lymphatic channels and large blood vessels of the thoracic and abdominal cavities
filters material in the lymph, provides niche for immune reactions |
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Spleen
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structurally similar to lymph node
filters circulating blood to remove worn out RBCs and pathogens |
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The Second Line of Defense
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Non-specific response carried out by macrophages, neutrophils, dendritic cells, etc.
Recognition Inflammation Phagocytosis Other components Interferon Complement |
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microbe Recognition
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Toll-like receptors: Protein receptors within cell membrane of macrophages
Detect foreign molecules and signal the macrophage to produce chemicals which: stimulate an inflammatory response (nonspecific) promote the activity of B and T cells (specific) 10 TLRs in humans pathogen-specific molecules are shared among many, so small number recognizes large number of microbes |
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Inflammation chief functions
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Mobilize and attract immune components to the site of the injury
Start repair of tissue damage and localize and clear away harmful substances Destroy microbes and block their further invasion |
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Fever
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An abnormally elevated body temperature
Initiation of fever Pyrogen sets the hypothalamic “thermostat” to a higher setting Muscles increase heat production Peripheral arterioles decrease heat loss through vasoconstriction Pyrogens can be exogenous or endogenous |
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Benefits of Fever
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Inhibits multiplication of temperature-sensitive microorganisms
Impedes the nutrition of bacteria by reducing the availability of iron Increases metabolism and stimulates immune reactions/phagocytosis and naturally protective physiological processes |
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Phagocytosis
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General activities of phagocytes
Survey the tissue compartments and discover microbes, particulate matter, and injured or dead cells Ingest and eliminate these materials Extract immunogenic information (antigens) from foreign matter Three main types Neutrophils Monocytes/Macrophages Dendritic Cells |
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Interferon
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Used against viruses, other microbes, & in immune regulation and intercommunication
Bind to cell surfaces and induce changes in genetic expression Can inhibit the expression of cancer genes |
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Complement
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Consists of 26 blood proteins that work in concert to destroy bacteria and viruses
Complement proteins are activated by cleavage. Classical pathway – activated by antibody bound to microorganism Alternative pathway – begins when complement proteins bind to surface components of microorganisms (specific antigens |
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Cell receptors or markers confer specificity and identity of a cell.
Major functions of receptors are: |
To perceive and attach to nonself or foreign molecules
To promote the recognition of self molecules To receive and transmit chemical messages among other cells of the system To aid in cellular development |
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Major Histocompatibility Complex (MHC)
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Also known as human leukocyte antigen (HLA)
Plays a role in recognition of self by the immune system and in rejection of foreign tissue Class I – found on all nucleated cells (not RBCs) Class II – located primarily on macrophages and B cells; involved in presenting antigen to T-cells |
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B-cell receptors – bind
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free antigens
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T-cell receptors – bind
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antigen-MHC complex
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How can the receptors be varied to react with so many different antigens?
How can a cell contain enough DNA to respond to so many antigens? |
Clonal Selection Theory
stem cell replicates into many daughters each with different receptor those receptors are checked for responding to self, those that do are destroyed. |
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maturation cycle of B cell
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starts in bone marrow
differentiates in bone marrow developes Ig receptors migrates to lymph nodes |
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maturation cycle of T cell
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starts in bone marrow
differentiates in thymus developes T receptors migrates to lymph nodes |
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Development of lymphocyte Receptors
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An undifferentiated lymphocyte has ~150 different genes for light chains and ~250 genes for the heavy chain (variable areas)
During development, recombination causes only the selected V and D genes to be active in the mature cell. Once synthesized, immunoglobulin is transported to cell membrane and inserted there to act as a receptor Secreted Ig is an antibody |
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Specific B-Cell Receptor
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Immunoglobulin, antibody
Specific receptors of B cells 4 polypeptide chains: Y shaped arrangement |
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T-Cell Receptors
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Also formed by genetic recombination, with variable and constant regions
2 parallel polypeptide chains inserted into membrane unlike B cell because equivalent to one fork of B cell receptor never secreted |
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CD4
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T helper cells
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CD8
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T cytotoxic cells
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Characteristics of Antigens
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Perceived as foreign
Foreign cells and large complex molecules over 10,000 MW are most antigenic Antigenic determinant, epitope – small molecular group that is recognized by lymphocytes Antigen has many epitopes |
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Special Categories of Antigens
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Alloantigens – cell surface markers of one individual that are antigens to another of that same species (e.g. MHC, blood group)
Allergen – antigen that provokes allergy Autoantigens – molecules on self tissues that immune system sees as foreign Superantigens – potent T cell stimulators; provoke an overwhelming response (e.g. toxic shock protein of Staphylococcus) |
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T Cells & Cell Mediated Immunity
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Cell mediated immunity requires the direct involvement of T lymphocytes.
T cells act directly against Ag and foreign cells and only reacts against Ag if it is in association with MHC II. T cells secrete cytokines that act on other cells. Sensitized T cells proliferate into long-lasting memory T cells. |
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T helper cells (CD4 or TH)
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most prevalent type of T cell (65%)
regulate immune reaction to antigens, including other T and B cells stimulated by MHCII-antigen complex on APCs also involved in activating macrophages and improving opsonization accounts for immunopathology of AIDS |
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Cytotoxic T cells (CD8 or TC)
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stimulated by MHC I-antigen complex on any cell
destroy foreign or abnormal cells by secreting perforins that punch holes in target cell membrane and granzymes that attack target cell proteins -> leads to cell death |
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Natural killer cells
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lack specificity
circulate through the spleen, blood, and lungs first cells to attack cancer cells and virus-infected cells |
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Major Histocompatibility Complex (MHC)
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Class I & Class II
Plays a role in recognition of self by the immune system and in rejection of foreign tissue |
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Antibody Structure
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Immunoglobulins
Large Y-shaped protein Consist of 4 polypeptide chains Fab with ends that bind to specific antigen Fc binds to various cells and molecules of the immune system C and V regions |
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antibody function
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tagging
opsinization-make it able to be engulfed neutralization-surrounding microbe blocks binding agglutination-forms a cross linkage compliment fixation- precipitation-aggregates antigens |
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Functions of the Fc Fragment
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Binding of Fab to specific antigen exposes the Fc component
Fc fragment binds to immune cells – macrophages, neutrophils, eosinophils, mast cells, basophils, and lymphocytes effect depends on cell’s role |
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5 classes of Ig
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IgG-long term immunity memory antibody
IgA- secretory antibody on mucous membrane IgM- produced at first response to antigen can serve as B-cell receptor IgD- receptor on B-cell IgE- antibody of allergy/worm |
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Primary and Secondary Responses to Antigens
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Primary response – produces IgM and a gradual increase in the production of IgG
Secondary response – after second contact with the same Ag, immune system produces a more rapid, stronger response due to memory cells – anamnestic response |
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difference btw T cell and B cell
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T cell- matures in thymus
B cell - matures in marrow T cell- specific surface marker- T cell receptor B cell specific surface marker- immunoglobulin T cell - high ciruculation in blood B cell - low circulation in blood T cell always requires MHC B cell sometimes requres MHC T cell product of antigen stimulation is sensitized T cells and memory cells B cells product of antigen stimulation is plasma cells and memory cells T cells synthesize cytokines, B cells produce antibodies |
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Artificial active immunity
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deliberately exposing a person to material that is antigenic but not pathogenic
Stimulates a primary and secondary anamnestic response to prepare the immune system for future exposure Response to a future exposure will be immediate, powerful, and sustained. |
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Most vaccines are prepared from:
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Killed whole cells or inactivated viruses
Live, attenuated cells or viruses Antigenic molecules derived from bacterial cells or viruses |
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Killed or Inactivated Vaccines
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Cultivate the desired strain, treat it with formalin or some other agent that kills the agent but does not destroy its antigenicity
Because microbe is not multiplying, often require a larger dose and more boosters to be effective |
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Live Attenuated Cells or Viruses
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Process that substantially lessens or negates the virulence of viruses or bacteria – eliminates virulence factors
Advantages of live preparations are: organisms can multiply and produce infection (but not disease) like the natural organism They confer long-lasting protection. usually require fewer doses and boosters Disadvantages include: require special storage, can be transmitted to other people, can conceivably mutate back to virulent strain |
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Herd Immunity
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Immune individuals will not harbor it, reducing the occurrence of pathogens – herd immunity.
Less likely that an nonimmunized person will encounter the pathogen Less herd immunity today because many parents won’t immunize their children |
