lecture exam 2 Flashcards
what is metabolism
all chemical reactions in a cell
What’s Endergonic reactions?
also know as Anabolism; forms larger macromolecules from smaller molecules; requires energy input
what are the two types of chemical reactions?
catabolism and anabolism
what are exergonic reactions?
also known as catabolism; breaks the bonds of larger molecules forming smaller molecules
molecules that carry the electrons removed from glucose are called…
electron carriers
not carrying electrons; is the oxidized form of the molecule
NAD+ and FAD
is carrying electrons; is the reduced form of the molecules
NADH and FADH2
the energy currency of the cell; constant cycle in active cells
ATP
what are the 3 part molecules of ATP
adenine- a nitrogenous base
ribose- a 5-carbon sugar
3 phosphate groups
what is phosphorylation
when the 3rd phosphate group is put on ADP and it is accomplished with a kinase enzyme
ADP becomes ATP
when is ATP made in a cell?
a cell must always constantly make ATP and is made during cellular respiration. input energy comes from the oxidation (breakdown) of glucose
what is dephosphorylation?
when the 3rd phosphate group is removed from ATP. ATP becomes ADP. energy is released
what are enzymes?
biological catalysts that increase the rate of chemical reaction by lowering the energy of activation (the resistance to a reaction)
the chemical reactants to which an enzyme binds are called…
substrates
the location within the enzyme where the substrate binds is called the enzymes’s…
active site.
each enzyme binds to one specific substrate
name 7 enzyme characteristics
- biological catalyst
- protein in structure
- special three dimenional shape
- sensitive to changes in pH, temp, ionic concentration leads to denaturation
- reusable
- very specific
- usually has ‘ase’ ending
what is labile?
chemically unstable enzymes
what is denaturation?
weak bonds that maintain the shape of the protein are broken
what are 2 enzyme helpers?
cofactor and coenzyme
describe cofactor
smaller, inorganic
usually a metallic ion: copper, zinc, iron
are near or within the active site and participates directly in the chemical reaction
describe coenzyme
larger, organic
usually part of a vitamin
removes functional groups from a substrate; acts as a carrier
Ex: NADH+, FAD
what does enzyme regulation do?
enzymes can be regulated to promote or reduce their activity
what is competitive inhibitor?
a molecule similar enough to a substrate that competes with the substrate for the binding at the active site. concentration of both must be equal
ex. sulfa drugs kill bacteria by binding with the enzyme that makes folic acid
what is a noncompetitive or allosteric inhibitor
binds the enzyme at the allosteric site which is a location other than the active site
what are 3 catabolic pathways that convert glucose to CO2 and gives off energy?
aerobic respiration, anaerobic respiration and fermentation
what is anaerobic respiration
includes: glycolysis, krebs cycle, ETC
Energy produced= 5-36 ATPs
final electron acceptor:
nitrate (NO3-)
nitrite (NO2-)
sulfate (SO4^-2)
ferrous ion (FE+3)
carbonate (CO3-)
carbon dioxide (CO2)
NOT OXYGEN
What is fermentation?
uses glycolysis only (incomplete oxidation)
glucose–>pyruvic acid–>another molecule
the energy produced a small amount of ATP, 2-4 ATP
NO OXYGEN
production of ethyl alcohol by yeasts acting on glucose
formation of acid, gas, & other products by the action of various bacteria on pyruvic acid
what is aerobic respiration?
glycolysis, kreb’s cycle, ETC
oxygen is needed as the final electron acceptor
yields 38 ATPs total
what is the overall equation for aerobic respiration?
C6H12O6 + 6O2 + 38ADP + 38P —> 6CO2 + 6H2O + 38ATP
describe the pathway for glycolysis in aerobic respiration and where does it occur
1.) glucose is oxidized and split into 2 molecules of pyruvic acid and generates 2 ATP and 2 NADH
2.) occurs in the cytoplasm of prokaryotic/eukaryotic cell
3.) involves a energy investment phase and energy payoff phase
4.) NO OXYGEN NEEDED
Describe the pathway of the Krebs cycle in aerobic respiration and where does it occur
1.) processes 2 pyruvic acids and generates 6CO2, 2ATP, 8 NADH & 2 FADH2
2.) in cytoplasm of prokaryotic cell/mitochondrial matrix of eukaryotic cell
3.) bridge reaction (glycolysis) must occur first. 2 pyruvic acids (from glycolysis) converted to 2 Acetyl CoA—> enter krebs cycle
4.) 1 acetyl CoA is needed for each turn of wheel
5.) NO OXYGEN NEEDED
describe the ETC pathway in aerobic respiration and where does it occur
1.) accepts electrons from NADH and FADH; generates energy through sequential redox reactions called oxidative phosphorylation and generates 34 ATP
2.) In cell membrane of prokaryotic/inner mitochondrial membrane of eukaryotic cells
what are the exchange rate for coenzyme in ETC
1 NADH ields = 3 ATP
1 FADH2 yields = 2 ATP
what is photophosphorylation?
ATP is formed using the energy of sunlight (photosynthetic organisms)
what is oxidative phosphorylation?
series of redox reactions occurring during respiratory pathway (occurs in ETC)
What is substrate-level phosphorylation?
transfer of phosphate group from a phosphorylated compound (substrate) directly to ADP (occurs during glycolysis and Krebs cycle)
the phosphorylation of ADP to mKE atp is accomplished with a kinase enzyme
what are 3 different ways ATP can be formed?
substrate-level phosphorylation
oxidative phosphorylation
photophosphorylation
what is the terminal step?
oxygen accepts 2 electrons from ETC & picks up 2 hydrogen ions from the solution to form a molecule of water. oxygen is the final electron acceptor
what is chemiosmosis
as electrons transport carriers move electrons, they actively pump hydrogen ions across the membrane setting a gradient of hydrogen ions- proton motive force. the hydrogen ions. Hydrogen ions diffuse back through the ATP synthase complex causing it to rotate, causing a 3-D change resulting in the production of ATP
In what circumstances will aerobic respiration not be possible
- cell lacks a sufficient amount of oxygen
- cell lacks genes encoding enzymes to minimize the damaging effects of dangerous oxygen radicals produced during aerobic respiration, such as hydrogen peroxide or superoxide
- cell lacks genes encoding an appropriate cytochrome oxidase for transferring electrons to oxygen at the end of ETC
what is genetics? name 7 things it involves
the study of the inheritance or heredity of living things. this involves:
*transmission of biological properties (traits) from parent to offspring
*expression and variation of those traits
*structure and function of genetic material
*How this material changes through time = EVOLUTION
*important molecules are DNA, RNA, and proteins
*DNA and RNA carry information
*Proteins carry out most cellular functions and are built using the information in DNA and RNA
what is vertical gene transmission?
the transfer of information from parent to daughter cells. accomplished by DNA replication
what is the function of DNA?
Stores the information needed to build and control the cell
what is a genome?
sum of total of genetic material of a cell
what is the genome of all cells?
DNA
what is the genome of viruses?
RNA or DNA
DNA complexed with _____ constitutes the genetic material as chromosomes
priotein
bacterial chromosomes are single circular loop found in the cytoplasm in a region called the….
nucleoid
eukaryotic chromosomes are multiple and linear found in the…
nucleus
what is the fundamental unit of heredity responsible for a given trait
gene; chromosome is subdivided into genes
what does a gene do?
provides information for a certain cell function
segment of DNA that contains the necessary code to make a protein, enzymes, or RNA molecules
the full collection of genes that a cell contains within its genome is called the
genotype
the expression of a set of genes that determines the cell observable characteristics is called
phenotype
what are two types of genes?
constitutive and nonconstitutive genes
describe constitutive genes
*genes that are always expressed
*sometimes called housekeeping genes
*ex. genes that are necessary for basic function of the cell
describe nonconstitutive genes
genes that are expressed due to environmental signals
give an example of nonconstituituve genes
*Streptococcus mutans produces its slime layer when sucrose is present
*Serratia marcescens makes its red pigment at 25oC and not 37oC
*Pathogens make their virulence factors when the infectious dose is present
chromosomes in eukaryotic cells are
diploids
chromosomes in prokaryotic cells are
haploid
Many interactions between human body and microorganism involve
Development of biofilms
Microbes most significant interactions?
*provide protection and stabilization effect on body surfaces
*involved in maturation of host defenses and development of immune system
*invade and grow in sterile tissues, causing disease
What is normal (resident) flora
Microbes engage in mutual or commensal associations.
(also known: indigenous flora, microbiota)
What is an Infection?
pathogenic microbes penetrate host defenses, enter tissues, and multiply
What’s an infection that cause damage or disruption to tissues and organs?
Disease
What’s Infectious Disease?
any disease caused by the direct effect of a pathogen
What is transients
microbes that occupy the body for only short periods
What is residents?
microbes that become established
What is Microbial antagonism?
It’s a type of resident flora. A bacterial flora benefit host by preventing overgrowth of harmful microbes
What’s another type of resident flora?
Endogenous infections - occur when normal flora is introduced to a site that was previously sterile.
Where are locations of Normal Flora
*Skin
*GI tract
*Respiratory tract
*Genitourinary tract
Flora of the Skin
Skin is the largest and most accessible organ.
Transients: influenced by hygiene
Residents: stable, predictable, less influenced by hygiene
Flora of the Genitourinary tract
sites that harbor microflora:
Females - Vagina, distal urethra, and external genitalia
Males - distal urethra, external genitalia
Flora of the upper Respiratory tract
*Nasal entrance, nasal vestibule, anterior nasopharynx: Staphylococcus aureus
*Mucous membranes of nasopharynx: Neisseria
*Tonsils and lower pharynx: Haemophilus
Flora of the lower Respiratory tract
Lower Respiratory sterile
*Larynx, trachea= flora
*Bronchi, bronchioles, lungs= sterile
Flora of the Gastrointestinal tract
GI tract is a long hollow tube, bounded by mucous membranes (tube exposed to environment)
*variations in flora distribution due to PH, oxygen tension, anatomy
*Oral cavity, large intestine, and rectum harbor appreciable flora
Flora of the Mouth (part of GI tract)
*Most diverse and unique flora of the body
-common species: Streptococcus mutans, S. salivarius, S. mitis, S. sanguis
*numerous adaptive niches
*bacterial count of saliva (5 x 10^9 per mL)
Flora of the Large Intestine (part of GI)
*complex and profound interactions with host
*10^8 - 10^11 microbes per gram of feces
*Intestinal bacteria contribute to intestinal odor and flatulence
*Intestinal environment favors anaerobic bacteria
-most common: Bacteriodes, Bifidobacterium, Clostridium
-smaller numbers: Coliforms= E.coli, Enterobacter, Citrobacter
Sterile areas of the body?
All internal tissues and organs:
*Heart and circulatory system
*Liver
*Kidneys and bladder
*Brain and spinal cord
*Muscles
*Bones
*Ovaries/testes
*Sinuses
*Middle and inner ear
*Glands (pancreas, salivary)
*Internal eye
Sterile areas of the body?
Fluids within an organ or tissue:
*Blood
*Urine in kidneys, ureters, bladder
*Cerebrospinal fluid
*Saliva prior to entering oral cavity
*Semen prior to entering the urethra
*Amniotic fluid surrounding the embryo and fetus
Maintenance of the Normal Resident Flora
*essential to health
*flora create an environment that prevent infections and can enhance host defenses
*Antibiotics, dietary changes, and disease may alter flora
*Probiotics - introducing known microbes back into the body
What is a Pathogen (true)?
any agent capable of causing disease in a healthy person with normal immune defenses
-(ex.): Influenza virus, plaque, bacillus, malarial protozoan
What is Opportunistic Pathogen?
one that invades the tissues when the body defenses are suppressed
-(ex.): Pseudomonas sp & Candida albicans
What’s the degree of pathogenicity of a parasite
virulence
What’s a virulence factor?
factor-characteristic or structure that contributes to the ability of a microbe to cause disease
What is Avirulent?
lacking the ability to cause disease
What are the 4 stages of pathogenesis
*Exposures (contact)
*Adhesion (colonization)
*Invasion
*Infection
What is Exposure?
An encounter with a potential pathogen but for it to cause disease it needs to access to the host tissue it prefers. It requires two things:
*Portal on entry
*Infectious dose
Portal of Entry
Site where the parasite enters the host, most microbes are adapted to a specific portal.
Exogenous - source outside the body
Endogenous - source on or inside the body
What are the 6 portals of entry?
*Skin
* GI tract
*Respiratory tract
*Urogenital tract (sexual)
*Transplacental (birth)
*Insect bite
Requirement for an Infectious Dose (ID)
minimum number of microbes required for infection to proceed
*microbes with small IDs have greater virulence
*lack of ID will not result in an infection
Adhesion
Pathogen finds target tissue and adheres to it
Include:
*Fimbrae, glycocalyx, and flagella for bacteria
*Cilia, barbs by protozoa
*Hooks and suckers by worms
*Spikes by viruses
Invasion
the pathogen may produce virulence factors to allow them to colonize, damage host tissues, and protect them from the immune system. Some remail local and other spread to other areas of the body.
Exoenzymes
extracellular enzymes that chemically break down or dissolve host’s barriers. promote the spread of microbes to deeper tissues. a wide variety of targets
(ex): Mucinase - dissolve mucus coating
*keratinase - dissolve keratin of skin & hair
*collagenase - dissolve collagen
*hyaluronidase - dissolve hyaluronic acid
What are microbial poisons that aid establishment and progress of disease?
Toxins
Exotoxin
*Protein secreted that goes to site of action = target tissue
*produced by Gram Positive and Negative
*very powerful and deadly
Examples:
*hemotoxins - lyse blood cells
*enterotoxins - affect intestinal mucosa
*neurotoxins - affect nerve tissue
*cytotoxins - affect general tissues
Endotoxin
*Composed of lipopolysaccharide (LPS), part of outer membrane of gram-negative species\
*Only released when microbe is damaged and is falling apart
*Lipid A (the lipid portion of endotoxin) is responsible for toxic properties
What happens if lipid A is low in the body?
inflammation, fever, diarhhea
What happens if lipid A is high concentrations?
hemorrhaging, blood coagulation, septic shock
True or False?
Most pathogens have the ability to prevent or slow down phagocytosis by WBCs.
True
What is a slime layer or capsule
engulfment is more difficult because the WBC cannot get a good grip on the pathogen
-ex. Streptococcus pneumoniae
What do Proteases (enzymes that digest protein antibodies) do?
prevent the antibody from binding to the pathogen
-ex. Neisseia gonorrhea
What are Mycolic acids
prevents the pathogen from being digested once inside the WBC
-ex. Mycobacterium tuberculosis
Leukocidins
digest holes in phagocytes
-ex. Streptococcus and Staphylococcus species
Describe Antigen variation?
ability of the pathogen to change its surface proteins so it can’t be recognized by the immune system
-ex. Borrelia burgdorferi
Define Antibiotic Resistance
*Microbe genes that allows it to avoid destruction by an antibiotic; will add to its virulence
*Pathogen makes an enzyme or membrane protein that helps the inactivation of abx
Portal of Exit
(same as Entry)
*Skin scales
*Fecal
*Urogenital
*Blood
*Insect bite
*Respiratory and salivary
-respiratory droplets
-mucus
-nasal drainage
-sputum
-saliva
What’s the difference between Sign and Symptoms
Signs are objective and measurable (ex. vitals, temp, HR, BP)
Symptoms are subjective and are felt or experienced; not confirmed or measured (ex. nausea, loss of appetite, pain)
What are the 5 stages of Infectious disease
1) Incubation period
2) Prodromal period
3) Period of Illness
4) Period of Decline
5) Period of Convalescence
Which stage is when the number of pathogen particles begin to decrease, signs & symptoms start to decline
Period of Decline
Define Incubation period
time from initial contact with the infectious agent and appearance of first symptoms (2-30 days); agent is multiplying but damage is insufficient to cause symptoms; several hours to several years
What stage is when the host experiences general signs & symptoms of illness with vague feelings of discomfort and nonspecific complaints.
(include: headache, fatigue, nausea, fever, muscle aches)
Prodromal Period
Define Period of illness
Microbe multiplies at highest rate, shows greatest toxicity and is well established in target tissue; specific symptoms of particular disease
Define Period of Convalescence
patient’s immune system begins to overcome the microbe, symptoms begin to fade, patient’s strength returns and body system comes back to normal
What concerns distribution, occurrence, and frequency of disease
Epidemiology
Define Science of Epidemiology
includes etiology-study of the causes of disease and investigation of disease transmission
size of genomes in viruses are
4-5 genes
size of genomes in E.coli are
4,288 genes
total length of DNA= 1mm (1000x longer than cell)
Eukaryotic cells have 3 or more levels of coiling accomplished by
topisimerases that supercoil the DNA
size of genome in humans
31,000 genes
total length of DNA= 6ft (180,000x longer than the cell)
DNA in eukaryotic cells are wrapped around ___ proteins to package it
histone
what do prokaryotic cells package their circular chromosomes with?
DNA gyrase and histone like proteins
what are 2 essential functions of DNA?
DNA replication
direct and regulate the construction of proteins via protein synthesis
what is DNA replication and what happens?
DNA replication- DNA is copied
strands of the double helix are separated and new complementary strands are along side the parental strands
what is semiconservative replication
when new complementary strands are constructed along side the parental strands in DNA replication
how are chromosomes replicated?
replicon (during binary fission)
how are plasmids replicated?
rolling circle (during conjugation)
bacterial genome contain 2 pieces of DNA to replicate:_____and ______
chromosome and Plasmid
what are the replicon steps
initiation, elongation, termination
what happens in the initiation step of the replicon mechanism (4 THINGS)
DNA gyrase uncoils DNA
helicase separates 2 parental starnds
RNA primer is synthesized by primase
DNA polymerase III adds nucleotides to make a new strand of DNA
What happens in the elongation step of the replicon mechanism?
DNA nucleotides are added along parental strands around the circular bacterial chromosome
new DNA- continuous/segmented piece
DNA POLYMERASE I- replace RNA primers with DNA, fills in gaps of spotty strand, connects DNA fragments
what happens in the termination step of the replicon mechanism?
daughter chromosomes are separated
a heritable change in phenotype due to a change in genotype is called___
mutation
a natural, nonmutated characteristic is known as a ____
wild type
what is beneficial mutation
creates an advantage for microbe (retained by population)
what is a neutral mutation
no significant change
what is a harmful mutation
created a disadvantage for microbe
what is lethal mutation
kills the microbe
