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