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139 Cards in this Set

  • Front
  • Back

What is a gene? Where is it found in?

A linear sequence of DNA nucleotides; found in chromatin/ strands of DNA

What happens when a cell expresses a gene?

It makes proteins

A gene sequence changed, what is expected to happen to the protein product

Will not function properly

Overall flow of information during gene expression/ protein synthesis?

DNA➡️RNA➡️Amino Acids

3 forms of RNA; roles; which are involved with transcription/ translation?

1. mRNA: messenger, uses DNA as a template to polymerize RNA; transcription


2. rRNA: ribosome, acts as enzyme complex to polymerize amino acids into polypeptides; translation


3. tRNA: transfer, transfers amino acids from cytoplasm to ribosomes for polymerization; translation

What is a codon? What RNA is codon found in?

3-lettered word sequence used to make amino acids; found in mRNA

What is an anticodon? Which RNA is it found in?

3 lettered word sequence complementary to codon, found in tRNA

Transcription & where does it occur in?

Makes mRNA in nucleus

3 sequential processes of transcription & what happens in each step?

1. Initiation: RNA polymerase & transcription factors attach to promoter (@TATA) to unzip DNA helix


2. Elongation: RNA polymerase reads DNA template 3'➡️5' and polymerizes RNA 5'➡️3'. Forms 1° transcript


3. Termination: RNA polymerase detaches, releasing 1° RNA transcript

Promoter

Site on DNA that RNA polymerase can bind to, to initiate transcription

What must happen to mRNA after it is transcribed

Must be processed further

Transcribe this sequence into mRNA


TAC-ATA-AAA-GGC-CCG-ATC

AUG-UAU-UUU-CCG-GGC-UAG

What happens during RNA processing? ⭐️STEPS⭐️

⭐️SPLICESOMES HAPPEN⭐️


1. Introns are excised out


2. Exons are spliced together


3. Cap & tail is added to ends

Where does RNA processing occur?

Nucleus

What cellular components carry out RNA processing?

Splicesomes

What are Exons? Are the excised or spliced?

DNA nucleotide sequences used to make proteins; spliced together

What are introns? Are the excised or spliced?

DNA nucleotide sequences not used to make proteins; Excised out

What might happen if a secretion protein activates prematurely?

Can harm the cell

Besides intron excised and exons spliced, how else is mRNA modified in RNA processing?

Adds cap & tail for guidance & prevention of pre-degradation

Where does the mature mRNA that has been fully transcribed & processed go to?

Cytoplasm to be translated

Translation & occurs in?

Reads mRNA to make amino acids sequence of a polypeptide; occurs in cytoplasm

3 sequential processes of translation & happenings

1. Initiation:


a) mRNA bonds to small ribosome rRNA subunit


b) tRNA w/ methionine & UAC anti-codon joins @start codon (AUG) near ribosome P site


c) Large ribosome subunit joins to complete ribosome


2. Elongation:


a) 2nd tRNA amino acid joins at A site


b) 1st amino acid bonds with 2nd amino acid


c) mRNA moves through ribosome moving 1st tRNA (w/o A.A) to E site to exit & open up for new tRNA


d) APE cycle repeats; empty tRNA's reloaded w/ a.a


3: Termination:


a) release factor attaches to a stop codon( UAA, UAG, UGA)


b) Last tRNA releases polypeptide & exits ribosome


c) Ribosome subunits disassemble

Which tRNA (anti-codon) initiates translation ?

UAC

What amino acid does UAC (1st tRNA anti-codon) deliver?

MET

What does APE stand for? Recall what happens

Arrival➡️Polymerize➡️Exit

The 3 stop codons

UAA, UAG, UGA

Beyond folding, what 3 ways are proteins routinely modified?

1. Proteolysis: cut


2. Glycosylation: + sugars


3. Phosphorylation: + phosphate



What is the overall role that modification serves?

To activate a protein

Mutation is?

A change in the DNA polynucleotide sequence

What kind of mutations can be transmitted to offsprings

Mutations that occur in the germ cells

How do adaptive and maladaptive mutations differ?

Adaptive: evolve


Maladaptive: diseases

Do mutations occur spontaneously?

Yes

During which cellular process do mutations occur?

Replicating genetic material (Allele- crossover)

During which cellular process are mutations manifested into physical traits?

DNA synthesis



What is a mutagen? And their impacts on mutation? + Examples

Agents that cause DNA mutation; Increases rate & severity of mutation as cells are exposed to mutagens;


EX: Ionizing radiation: UV, radioactive decay


Various chem agents: Arsenic, Benzene


Biological agents: Viruses like HPV

What is a point mutation

Changes in DNA base pairs

What is substitution mutation

When a single base pair is replaced by another base pair in the DNA sequence

What is a deletion or insertion mutation

Delete: 1 or more BP taken away


Insert: ! or more BP added

What is a frame shift mutation

The deletion or insertion of BP's in a DNA sequence

What is a silent mutation? Why is it considered silent?

Changes in BP's usually in the introns or 3rd position of a 3-lettered DNA sequence; Considered silent because they do not alter 1°

Silent mutation can be exploited for what practical purpose?

Used to identify people via finger prints ect.

What is a nonsense mutation?How much do they alter? What types of alleles are most-likely nonsensical?

One that causes a pre-mature stop codon; always alters 1° & 3°; Recessive alleles (r, i)

What is a missense mutation? How much do they alter? What types of alleles could be missensical?

One that changes the 1st or 2nd position; Always alters 1° and sometimes 3°; Co-dominant & Incomplete dominance (IA, IB- HbB, HbS)

Similarities and differences of nonsensical and missensical mutations?

Nonsense: Always 3°, stops reading, can't/ short protein


Missense: Sometimes 3°, change 1st or 2nd position, new protein


Similar: Always changes 1°, Both are Substitute mutations

What kind of mutation is Hemophilia A? (Xcl) What gene is altered? Which chromosome is it found in?

Nonsense; Factor 8; X sex chromosome

What is FVIII? What role does it play in our body?

1/13 factors; allows us to clot blood

Which cells normally express FVIII?

Liver cells & Blood vessels

Basic treatment for hemo A? Is there a cure?

Acute: Immediate


Prophylactic: Daily, prevention;


No Cure

What kind of mutation causes sickle cell anemia? (HbS) Which gene on which chromosome is mutated?

Missense; HbB- globin gene on homolouge 11

What is B-globin and what larger molecule does it help make? What role does the larger molecule then play in the body?

A subunit protein that makes hemoglobin protein; helps transport O2 throught the body

What cells normally express B-globin?

RBC's

What (or where) is the difference between B-globin & S-globin?

In the 6th amino acid

What happens to a RBC that makes S-globin? How does this impact a person?

Sickle- cell shaped; Person will have sickle cells, low oxygen transportation and immune system will attack RBC's

What is the basic treatment for SCA? Cure?

Limit exertion, manage pain & inflammation;


Cure: Bone marrow transplant

What is deletion mutation? What happens to the length of that gene?

When one or more BP's are taken away; Length shortens

What is insertion mutation? What happens to the length of that gene?

When one or more BP's are added; Length grows

What is frame shift mutation?

+ or - of 1 or more BP's in a DNA nucleotide sequence

What factor determines the severity of frame shift mutation?

Where the frame shift takes place on the sequence

Disease example of deletion/ frame shift mutation?

Cystic fibroses

What factor has prevented cure from genetic diseases?

The mutation occurs in all the cells

What is gene therapy? How might it overcome the barrier between genetic diseases and finding a cure?

Kills all cells inside a persons body and replaces them with cells that have the "healthy" allele. They will reproduce the healthy allele and person will not have disease anymore

What kind of cells can be cured by gene therapy? Why are such cells good candidates for gene therapy? What hurdles remain for gene therapy?

Cells that are still participating in the cell cycle (that reproduce still); Cells need to be able to replicate the good allele through out the body; Need to make sure gene is expressed at right time & perfect amount or else side effects

Are all mutations harmful?

No

What role does the environment have in determining if an allele is bad or good? What is the HbS example?

Depends on where the person lives if the allele will benefit them or not; Mild SCA is the best out of No or Full SCA in Malaria prone regions while No SCA is best in developed countries

What role does viruses play in gene therapy?

We need a virus with the "good" allele to introduce in the patient

Which geographic region does HbS increase in frequency and why?

Africa, people there are victims of Malaria & having Mild SCA that attacks the Malaria inside the sickle RBC's gives them a better survive rate than No or Full SCA.

What role does mutation serve in the process of adaption and evolution?

It is the ultimate source of variation that can give beneficial phenotypes that allow a person to adapt and evolve better in their enviornment

What does Pathogenic mean?

They may cause diseases

Are viruses alive? Can they metabolize or proliferate on their own?

No

What are viruses and molecules that make them up?

Aggreate (combinations): 4-1,000 genes worth of nucleic acid encapsulated in a capsid

Capsid

A protein coat

Viral envelope? Do all viruses have it?

Stolen from host cell phospholipid and host glycoproteins that surround the virus giving it even more protection; only some have

3 factors that determine whether or not a virus can enter a host cell?

1. capsid 2. viral envelope 3. host cell receptors

Where do the enzymes necessary for a virus to replicate & build new capsids come from?

Comes from host cell and sometimes + viral cell enzymes if they have any

Viral lytic cycle compared to viral lysogenic cycle?

Lytic: Kills a host cell; Lyses


Lysogenic: Doesn't kill a host cell; replicates with host cell

What criteria are used to classify animal viruses?

1. Type of nucleic acid (DNA or RNA?)


2. 1 or 2 strands


3. Capsid shape


4. Has viral envelope or no?

Difference between a DNA & RNA virus?

dsDNA, ssDNA, dsRNA, & ssRNA (with more classification on ssRNA)

Group 'papovavirus, herpesvirus, & parvovirus' in dsDNA or ssDNA

I.dsDNA: Papovavirus, Herpesvirus


II.ssDNA: Parvovirus

DNA ONLY: Classify by viral envelope & not

I. Papovavirus: No, Herpesvirus: Yes


II.Parvovirus: No

Which general diseases/ conditions do we develop when infected by DNA viruses?

I. Papovavirus: Paoillomavirus (warts, cervical cancer), Herpesvirus: H.Simplex 1 (cold sores), 2 (genital warts), Shingles, chicken poxs


II.Parvovirus: mild rash

Group the following viral families/viruses of dsRNA or types of ssRNA: rotavirus, rhinovirus influenza,flavivirus, paramyxovirus, HIV

III. dsRNA: Rotavirus


IV:ssRNA for mRNA(+sense):Rhinovirus, flavivirus


V: ssRNA template for RNA(-sense): influenza, paramyxovirus


VI: ssRNA template for DNA synth: HIV

Additional ssRNA criteria + difference/ definitions of each?

IV: +sense, used as mRNA


V: -sense, used as template to make mRNA by host


VI: Retro, used as template to make DNA by reverse transcriptase



RNA viruses only: Which have a viral envelope or not?

III: Rotavirus: No


IV: Rhinovirus:No, Flavivirus: Yes


V:Influenza &Paramyxovirus: Yes


VI: HIV/AIDS: Yes

General diseases caused by RNA viruses in hoomans?

III: Reovirus- Rotavirus (diarrhea)


IV: Picornavirus- Rhinovirus (common cold), Flavivirus- West Nile, Yellow fever, Hep C


V:Orthomyxovirus- Influenza (Flu), Paramyxovirus (Measles & mumps)


VI: Retrovirus- HIV/AIDS

What kind of virus is HIV?

Retrovirus

What is the role of reverse transcriptase?

Reads viral RNA to make viral DNA. That viral DNA is incorporated into host genome

What is a provirus?

DNA of both virus & host combined

What cells can be infected with HIV?

WBC's (CD4 +T cells)

How is HIV transmitted from one individual to another?

Blood/ bodily fluids via sex, gestation/ breast feeding, sharing needles

What is AIDS?

When HIV infects WBC's causing serious immune system problems

Why do patients with AIDS take "cocktail" treatments?

Patiens cannot defend themselves against any other pathogens so must rely on medicine to defend for them

How do most antiviral drugs work?

Disrupt replication cycle of virus with competitive inhibitors

What is a competitive inhibitor?

Blocks enzyme active site directly

Which type of enzyme(s) would be competitively inhibited via an anti viral drug?

DNA polymerase

How can an antiviral drug apply selective pressure on a viral population?

Only kills some of the virus causing the survivors to all become adaptive to the chemical environment

If all of the viral partials are exactly the same can antiviral drugs apply selective pressure?

No

If all of the viral partials are exactly the same can antiviral drugs apply selective pressure?

No

What does antiviral drug resistance mean?

The virus has grown a resistance/ immunity toward the drug

If all of the viral partials are exactly the same can antiviral drugs apply selective pressure?

No

What does antiviral drug resistance mean?

The virus has grown a resistance/ immunity toward the drug

Which enzyme was originally competitively inhibited by 3TC

HIV reverse transcriptase (cytosine analog)

How would you expect the frequency of viral particles that were & were not compatible inhibited by 3TC to change in patient who is administered 3TC

Were= virus already immune


Were not= Will die but will build immune system

Which class of viruses are herpesvirus classified? Envelope?

dsDNA (I.) , Yes

Which kind of human tissues do herpesvirus effect?

Epithelia (skin)

What results when herpes are expressed?

Ulcers: open wounds

How are herpesvirus transmitted from person to person?

Skin-to-skin contact

What part of the body does HSV-1 infect & cause ulcers to form?

On/ near lip

What does it mean that HSV-1 retrogrades? What nerve does it infect & become latent?

Goes backwards up the nerve; Ganglia of trigeminal nerve

Known triggers for HSV-1 to "anterograde" back into epithelium to cause users?

UV, illness, stress.

Is there a cure for herpes? Treatment?

No cure; Treatments: Docosanol (Abreva): Cell-binder inhibitor


Valacyclovior (Valtrex):DNA pol inhibitor

Which class of virus are HPV viruses classified? Envelope?

dsDNA, No envelope

What kind of human tissue do HPVs infect? Results of expression?

Keratinocytes, cells found in basal layer of stratified squamous epithelium (skin); warts/ cancer

How are HPV transmitted to people?

Skin-to-skin

HPV is "nessecary but not sufficient" to form cancer meaning?

Can't do it alone?

Cure for HPV? Treatment? Vaccine?

No cure; no treatment; Yes vaccines

What is a vaccination? Goals of vaccinating a person against pathogens?

Introducing pathogen antigens to invoke immunization against future infections

Which pathogens have we developed vaccines for, viruses or bacteria?

Both

Characteristics used to discern among prokaryotes & eukaryotes?

Pro's lack nucleus, internal membranes and membrane bound organelles

3 general morphologies (shapes) expressed by bacteria

Coccus, bacillus, spirilform

How are HPV transmitted to people?

Skin-to-skin

3 factors influence bacterial pathogenicity?

1. Cell wall


2. Outer membrane


3. Virulence factors

4 virulence factors

1. Flagella( +/- taxis)


2. Capsule


3. Fimbeane (bio films)


4. Sex pillus

Can virulence factors cause host inflammation?

Yes

How is a genome of a bacterium organized?

Single, circular

HPV is "nessecary but not sufficient" to form cancer meaning?

Can't do it alone?

Cure for HPV? Treatment? Vaccine?

No cure; no treatment; Yes vaccines

What is a vaccination? Goals of vaccinating a person against pathogens?

Introducing pathogen antigens to invoke immunization against future infections

Which pathogens have we developed vaccines for, viruses or bacteria?

Both

Characteristics used to discern among prokaryotes & eukaryotes?

Pro's lack nucleus, internal membranes and membrane bound organelles

3 general morphologies (shapes) expressed by bacteria

Coccus, bacillus, spirilform

What role does a bacterium a cell wall play?

1. Maintain cell wall


2. Protect


3. Prevents rupture in hypotonic environments

Which compound is used extensively to make bacterial cell walls?

Peptideglycan

Compare Gram + & -

+: thick peptideglycan


-: thin peptideglycan w/ an putee membrane

Plasmids

Smaller rings of self-replicated SNA that have few-10s of genes


Endoscope

Resistant packaging of cell genome when times are tough

How do bacteria reproduce?

Binary fission

Do bacteria transcribe/ translate genetic material? Do they undergo RNA processing?

Yes, No

Bacteria are haploid, meaning they lack...?

The ability to recombo genes

3 mechanisms (+ how they work) for horizontal gene transfer?

1. Transformation: DNA uptake from decomposing cohorts


2. Transduction: Transfer via viral bacteriophages (phages)


3. Conjunction: sex pillus exchange plasmids