BIO 150 EXAM 4

genes

proteins and RNA

DNA -> RNA -> Protein

Coupled and found in the cytosol

nucleus

cytoplasm or Rough ER

No mRNA processing and mRNA is polycistronic

mRNA codes for more than one protein. Found mainly in Prokaryotes.

monocistronic mRNA and mRNA processing

This means mRNA only codes for one polypeptide.

Only one strand is written but it is still a double helix

DNA-> coding strands-> templete strand-> transcript RNA-> adypeptide

Translated and nontranslated

mRNA

protein synthesis

Not made into a protein

tRNA and rRNA

transfer RNA; type of RNA that carries amino acids to the ribosome

ribosomal RNA; type of RNA that makes up part of the ribosome

small nuclear RNA, spliceosome

micro/small interfering RNA; binds to mRNA or DNA to block it, regulate gene expression, or cut it up

The human genome

3 billion

2 meters

76%

Promoter, transcribed region, terminator, regulatory sequences

specific region of a gene where RNA polymerase can bind and begin transcription

the region of DNA that gets copied to RNA

Marks the end of a gene.

controls gene expression

RNA polymerase

DNA is used as a templete, Primer not required, rNTP is added to 3OH'

ribonucleoside triphosphate

RATp, rUTP, rGTP, rCTP

initiation, elongation, termination

1. Recognition of the promoter or sigma factor(Bacteria)
2. RNA polymerase is recruited by sigma factor
3. RNA polymerase separates the DNA strands to form an open complex

1. TATA box
2. +1 site
3. Regulatory/ response element

2 base pairs upstream from transcriptional start site. Determines precise starting point for transcription

where transcription begins

Increases or decreases gene expression

RNA polymerase II & 5 different general transcription factors

Has the same job as the sigma factor

RNA polymerase synthesizes RNA 5' to 3'

provides a templete for ordering a sequence of complementary bases in an RNA transcript

the strand of DNA that is not used for transcription and is identical in sequence to mRNA, except it contains uracil instead of thymine

RNA polymerase reaches terminator sequence

Varies

5' to 3'

the modifications that occur to an mRNA transcript before it is exported from the nucleus as mature mRNA. Include: splicing of introns, addition of 5' cap, addition of poly-A-tail and rearranging of exons

1. 7 methylguanosine is added to 5' end of pre mRNA
2. Amino acids in mRNA exit nucleus
3. Binding site for ribosome
4, prevents degradation

Added to 3' end, not encoded in DNA, aids in exit from nucleons, and prevents degradation

removes introns and joins exons, creating an mRNA molecule with a continuous coding sequence

Noncoding segments of nucleic acid that lie between coding sequences.

Coding segments

Can result in different proteins made from same DNA gene

Splicesome

Amino acids

Peptide bonds

primary, secondary, tertiary, quaternary

sequence of amino acids

coiling or folding of a polypeptide due to H-bonding between amino acids

3D folding pattern of a protein due to side chain interactions

When protein subunits combine

three-nucleotide sequence on messenger RNA that codes for a single amino acid

Intermediary

Start codon

The ribosome binding site(RBS)

Downstream from RBS

MRNA, ribosomes, tRNA, & translation factors

proteins needed for the three stages of translation

Decode messages on RNA

secondary structure, cloverleaf form, anticodon

group of three bases on a tRNA molecule that are complementary to an mRNA codon

An enzyme that joins each amino acid to the appropriate tRNA on the 3' end

Energy is required

Protein and rRNA, small and large subunits

Nucelous

A site, P site, E site

Amino-acyl tRNA site; the site on a ribosome where a new amino acid is added to a growing peptide.

holds the tRNA that carries the growing polypeptide chain

the exit site, where discharged tRNAs leave the ribosome

initiation, elongation, termination

1. Initiation factors bind small subunit to mRNA and RBS or Shine-Dalgarno sequence(Bacteria)
2. TFs recruit initiator rNA(tRNA met) to p site
3. Large and small subunits are associated
4. GTP hydrolysis provides energy for synthesis

1. Ribosome trans locate with mRNA
2. Moves on codon down the message
3. Incoming tRNA binds to codon in A site
4. Uncharged tRNA leaves via E site
5. Elongation factors and GTP hydrolysis help

occurs when a stop codon in the mRNA reaches the A site of the ribosome & release factors are used

the sorting process in which the synthesis of certain eukaryotic proteins begins in the cytosol and then halts temporarily until the ribosome has become bound to the ER membrane

a sequence of about 6-12 amino acids that are predominantly hydrophobic and usually located near the N-terminus

A heritable change in genetic material

variation

harmful than helpful

A disease caused by genetic mutations

a genetic mutation where one nucleotide is changed

substitution and addition/deletion

silent, missense, or nonsense

frameshift

no change

change in one amnio acid

chnage in a normal codon to a stop codon

produces a different amino acid sequence

promoter, transcriptional regulatory element, splice sites, translational regulatory element, and intergonic region

may increase or decrease rate of transcription

may alter the regulation of transcription

may alter ability of pre-mRNA to be properly sliced

may alter the ability of mRNA to be translationaly regulated

not as likely to have an effect on gene expression

missence mutation in the HBB gene that encodes B-globin, changes gultamic acid to valine, and sticks cells together causing sickle shape

Time and location

passes mutations on to offspring through half of gametes, occurs in sperm/egg cell or gamete progenitor

body cells in which mutations occur during late development and are not passed down through gametes

muations that occur because of abonormal biological processes

1. error in DNA replication 2. toxic metabolic products/free radicals 3. changes in nucleotide structure, and insertion pf transposons

small segments of DNA that can insert at various sites in the genome

caused by mutagens

components of the envionment, food, or cells that can cause mutation

radiation, chemicals, infectious agents, and cellular response

deletion of damage and repair of damage

Direct repair, nucleotide excision repair, and methyl directed mismatched reapir

a repair enzyme recongizes incorrrect structure in the DNA and directly converts it back

portion od DNA strand containing an abonormal nucleotide is removed and replace

A Base pair mismatch is detcted and a strand of surrounding DNA is removed and replaced

uncontrollable cell divison

10%

90%

1%

a tumor that stays in its original location

when the tumor spreads to other parts pf the body

agents that increase the likelihood of devloping cancer

80%

a normal functioning gene that becomes an oncogene if mutated

promotes cancer by keeping the cell divison signaling pathway in a permanent position

maintain genome inegrity by by monitoring and repairing DNA damage & slows down and inhibits cell divison

turns on genes that repair DNa damage. If it is too severe, apoptosis is turned on

inhibits the E2F activation gene for G1 to S phase cell cycle, prevents cell divison