Exam 3 Chp. 7
mRNA vaccine
Covid vaccine consists of COVID-19 spike (coat) protein mRNA and lipids (similar to cell membrane lipids)
operator
a DNA sequence between the promoter and the protein-coding genes and serves as a regulatory region
operon
a clustered group of genes related to a specific function that can be turned on or off as needed
Transcrption
a gene's DNA is rewritten into messenger RNA(mRNA)
lac operon
a group of genes that function to break down lactose sugar but are expressed only in the presence of lactose sugar
In humans we have how many genes
25,000 spread across the 23 pairs
DNA is Duplicates during what?
Cellular division
gene
is a segement of dna thats contains instructions to make a specific protien or RNA molecule
mad cow disease
is caused by prions that occur from eating nervious tissues of previous infected cows
Function of a virus
is to replicate and propigate- make more of itself and infect new hosts
Prokaryotes
lack a nucleus so they have single circuar chromosomes
silent mutation
point mutations that do not change the protein's amino acid sequence
Nuclecic acids
polymers mde up of nucleotide monomers (Macromolecules)
Introns
segments removed from pre-mRNA- trash RNA
Caspases
stimulate cell death
Centeral dogma describes?
the flow of information from DNA to RNA to protien molecules
start codon
a specific codon that starts amino acid incorporation
Genome
all the DNA inside of a cell
Proteome
all the protiens in cells
homologous chromosomes encode the same RNA or protien products but may represent different forms known as ?
alleles
The strands are what to each other?
anti parallel but orientated in opposite directions
vaccines
antibodies do not work against viruses 2 options: supportive therapy (2 weeks) train the immune sstem to recognized the pathogen before actual infection occurs=vaccines
Mutagens
any external agent that induces mutations (radiation,chemicals, infectious agents)
Transfer RNA
are short RNA molecules that fold into a unique "t" shape - One end binds to a specific amino acid• The other end has 3 nucleotides that are complementary to the codon= anticodon
Pairs 1-22 are known as
autosomes- contains genetic instructions of general life processes
1 pre-mRNA molecule can?
be spliced in to numerous diffent mature mRNA's that can generate different protien types
Translation
converts the mRNA code into a polypetide(protien) sequence
DNA
deoxyribonucleic acid, 4 bases: adinine cytosine guanine thymine double stranded
ribosomes in translation
eads" mRNA 3 bases at a time= Codon
monomers are ?
bulding blocks
How many different amino acids are there?
20+
Alleles
Different forms of a gene. Allele a and allele B (think about ABO Blood typr)
How does DNA fit into the nucleus?
"nkaed" DNA condenses by first wrapping around proteins called histones, then coils into a super tight structure called chromosomes
Protiens can undergo post translational modifcations: what does this do
*can be modified in numerous ways AFTER they are translated they increase the functional outcome of protiens in an organism
regulating gene expression: eukaryotes (6 mechanisms)
-DNA Availibility -transcription factor availibilty -mRNA processing (alternative splicing) -mRNA transport from nucleus -RNA degradtion -protien processing and degration
Step 3 (Termination) of Transcription
-a specific termination sequence indicates the end of the gene RNA -Polymerase recognizes the termination sequence and relases from the DNA -mRNA molecule releases
Processing pre-mRNA
-add mRNA cap: modified nucleotide that serves as recognition signal for ribosome -Add a Poly-A tail:protects mRNA from degradation in cytoplasm -mRNA splicing-s egments of RNA are removed and the remaing segments are joined together
3 nucleotides equals
1 amino acid
Step 3 of Translation: Termination
1) "stop" codon reached- idicates where pritien ends 2) release factors (protein) cuts polypeptide from last RNA 3) ribosome dissociates
Viral Replication 5 stages
1. Attachment- virus binds to host cell surface receptors 2.Penetration- virus genome enters the host cell• Phagocytosis• Injection 3.Synthesis- the host cell is hijacked to produce millions of copies of the viral genome and viral proteins • Host cell provides all of the resources- ATP, ribosomes, nucleotides, amino acids, enzymes 4.Assembly- the viral particles assemble and the genetic information moves inside Release- the host cell releases the newly formed viral particles• Some viruses kill host cell during release (lysis) while others are released via exocytosis (vesicles)
Transcription Main Steps
1. initation 2. elongation 3. termination
How many karyotypes do humans have?
46 a total of 23 pairs
There are 20 different amino acids, but there are how many possible codons?
64
DNA pairs to RNA
A-U C-G G-C T-A
Chargaff's Rule
A=T and C=G
Making protiens uses a lot of energy. How much and what type?
ATP 90% of cell energy is spent on gene expression
Eukaryotic start codons are
AUG and it codes for the amino acid Methionine (Met) - all eukaryotic polypetide sequences have Met first
Step 2 of Translation elongation
After Met, the ribosome moves the mRNA down one codon • The next codon is read and the appropriate tRNA enters the ribosome • Ribosome makes covalent peptide bond between amino acids then kicks tRNA out as ribosome moves down one codon • Next codon is read, new tRNA enters, and next amino acid is added, etc...
what can increase the total number of protiens a cell can make?
Alternative splicing + post-translational modifications
regulating gene expression Prokaryotes
Bacteria can turn genes on or off depending on what resources are available
homologous chromosomes
Chromosomes that have the same sequence of genes and the same location
central dogma of biology
DNA is transcribe into RNA whec is then translated to a protien
EX: how mutation can occur
DNA polymerase can ocassionally add the wrong base when copying DNA
DNA polymerase
Enzyme involved in DNA replication that is used to produce a DNA molecule
EX: lactose present
Lactose physically binds to the repressor and the repressor falls off of the operator
Rungs
Paired nitrogen bases which are held together by hydrogen bonds
Adenine and Guaning are also known as
Purines
How to bases pair
Pyrimidine pair wirh Pyrimidines
cytosine and thymine are also known as
Pyrimidines
Step 2: Elongation
RNA polymerasre bgings to move along the DNA strand and "reads' the DNA template it adds complementary RNA nucleotides to a growing RNA molecule as it moves down the gene
EX: No lactose
Repressor proteins bind to the operator and physically stops RNA polymerase and operon gene expression
Rails
Sugar phosphate backbone
When ribosome "reads" the mRNA codon what happens
The appropriate tRNA enters the ribosome - Codon-anticodon base pairing (RNA-RNA base pairing: C-G; A-U) - The new amino acid is covalently bound to the previously-added amino acid in the growing polypeptide chain
Step 1 of Translation initation
The mRNA cap helps mRNAs associate with ribosomes but does not specify any amino acids
Certain bases occur in equal porportions
amount of g=c amount of a=t
Karyotype
an image showing all of the indivuals organisms chromeosomes
Mutation
can affect a single DNA base, a few bases, or large portions of chromosomes they can be silent or harmful
DNA point (substitution) mutations become permanent if not corrected during?
cell division
spontaneous point mutations occur durining what?
cell divison
operon genes
code the required proteins
Eukaryotes
have multiple linear chromosomes
Translation ocuurs where
in the cytoplasm (free ribosomes) or associated with the rough ER (bound ribosomes)term-53
In Eukaryotes, mRNA must be processed from Pre-RNA into mature?
mRNA before leaving the nucleus
DNA is made up of
nucleotides
Step 1 (Initiation) of Transcription
promoter regin acts as a signal for where the gene starts and what strand to use as template Protiens known as Transcription factors recruit the promoter and guide RNA Polymerase enzym to bind to templatr DNA Strand at the correct location
Prions
protein based infectious particles (zombie Protiens) -misfolded protiens that cause other protiens to misfold/ acumilation of misfolded protiens result in cell death
Lytic
rapid viral replication which causes infected cells to die -Massive release of new viral particles into the organism/ environment
RNA
ribonucleic acid 4 bases: adininde cytosine guanine uracil single stranded
Translation is performed by?
ribosomes
Exons
segments joined together to make mature mRNA
23 pais is known as
sex chromosomes- determines biological sex
other small scale mutations can causing diseases or even be leathal and example is
sickle cell
promoter
site where RNA polymerase binds
Chromosomes are arranged by
size and number
Semi-new DNA replication
split apart and the old dna is going to be incorportated into the new dna (Half-new, Half -Old)
Viruses
very small protein shells that contain genetic material made of either DNA or RNA
lysogenic (latent)
viral genome incorporated into host genome (prophage) -Viral genome maintained within host until conditions trigger entry into lytic phase• Stressful conditions can cause this transition• Sometimes host genes can be incorporated into viral genome