Chapter 7

alternative splicing

The production of different mRNAs (and proteins) from the same gene by splicing its RNA transcripts in different ways.

aminoacyl-tRNA synthetase

During protein synthesis, an enzyme that attaches the correct amino acid to a tRNA molecule to form a "charged" aminoacyl-tRNA.

Anticodon

a sequence of three nucleotides forming a unit of genetic code in a transfer RNA molecule, corresponding to a complementary codon in messenger RNA.

Codon

group of three nucleotide bases in mRNA that specify a particular amino acid to be incorporated into a protein

Exon

a segment of a DNA or RNA molecule containing information coding for a protein or peptide sequence.

Gene

a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.

Gene expression

process by which a gene produces its product and the product carries out its function

general transcription factors

Proteins that assemble on the promoters of many eukaryotic genes near the start site of transcription and load the RNA polymerase in the correct position.

Genetic code

set of rules that specify to the codons in DNA or RNA that corresponds to the amino acids in proteins

initiator tRNA

A special type of transfer ribonucleic acid (RNA) that initiates protein synthesis by binding to the amino acid methionine and delivering it to the small ribosomal subunit.

Intron

a non-coding, intervening sequence within a eukaryotic gene

Messenger RNA

RNA molecule that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell

Polyadenylation

the addition of multiple adenine nucleotides to the 3' end of a newly synthesized mRNA molecule

Promotor

DNA sequence where RNA polymerase attaches and initiates transcription

Protease

enzyme that breaks down proteins

Proteasome

an organelle responsible for destroying defective or degraded proteins within the cell

reading frame

On an mRNA, the triplet grouping of ribonucleotides used by the translation machinery during polypeptide synthesis.

Ribosomal RNA

RNA molecules that, together with proteins, make up ribosomes; the most abundant type of RNA

Ribosome

Cytoplasmic organelles at which proteins are synthesized.

Ribozyme

An RNA molecule that functions as an enzyme, such as an intron that catalyzes its own removal during RNA splicing.

RNA

A single-stranded nucleic acid that passes along genetic messages; ribonucleic acid

RNA capping

the modification of the 5' end of a maturing RNA transcript by the addition of an atypical nucleotide

RNA polymerase

enzyme that links together the growing chain of RNA nucleotides during transcription using a DNA strand as a template

RNA processing

Modification of RNA primary transcripts, including splicing out of introns, joining together of exons, and alteration of the 5' and 3' ends.

RNA splicing

The removal of introns and joining of exons in eukaryotic RNA, forming an mRNA molecule with a continuous coding sequence; occurs before mRNA leaves the nucleus.

RNA transcript

mRNA molecule formed during transcription that has a sequence of bases complementary to a gene.

RNA world theory

Life forms were thought to use RNA both to store genetic material and catalyze chemical reaction

small nuclear RNA (snRNA)

Small non coding RNA molecule found in the nuclei of eukaryotic cells; functions in the processing of pre-mRNA.

spliceosome

A large complex made up of proteins and RNA molecules that splices RNA by interacting with the ends of an RNA intron, releasing the intron and joining the two adjacent exons.

Transcription

(genetics) the organic process whereby the DNA sequence in a gene is copied into mRNA

Transfer RNA

type of RNA molecule that transfers amino acids to ribosomes during protein synthesis

Translation

(genetics) the process whereby genetic information coded in messenger RNA directs the formation of a specific protein at a ribosome in the cytoplasm

translation initiation complex

the union of mRNA, initiator tRNA, a small ribosomal subunit, and a large ribosomal subunit

What directs the synthesis of proteins?

Genetic information/DNA

A cell can express different _________ at different _______

Genes
Rates

Describe the chemical structure of RNA

Sugar ribose, base uracil, shorter, phosphodiester bond (phosphate)

Describe the structure of DNA

deoxyribose, phosphate group, nitrogenous base-adenine, guanine, thymine, cytosine; double stranded structure in a helical form

Uracil replaces what base pair in DNA and bonds with what base pair in DNA?

Replaces-thymine
Bonds with-adenine

RNA is single stranded but can fold into a specific structure thanks to ________ bonds.

Hydrogen

Transcription of a gene produces a ______ complimentary to one DNA strand

RNA

RNA polymerase function:

Transcribed DNA into RNA via enzyme

List the five types of RNA

1. mRNA
2. rRNA
3. miRNA
4. tRNA
5. Other non coding RNA

What type of RNA codes for proteins?
a) rRNA
b) mRNA
c) tRNA

b) mRNA or messenger RNA

What type of RNA form the core of the ribosome's structure and catalyze protein synthesis?
a) mRNA
b) miRNA
c) rRNA

c) rRNA or ribosomal RNA

What type of RNA regulates gene expression?
a) miRNA
b) rRNA
c) tRNA

a) miRNA or microRNA

What type of RNA serves as adaptors between mRNA and amino acids during protein synthesis?
a) miRNA
b) tRNA
c) mRNA

b) tRNA or transfer RNA

What type of RNA is used in RNA splicing, gene regulation, telomere maintenance, etc....
a) tRNA
b) other non coding RNA
c) miRNA

b) other non coding RNA

What tells RNA polymerase where to start and stop in transcription?

Signals in the nucleotide sequence

List the types of RNA polymerase (hint: there are 3)

1. RNA polymerase I
2. RNA polymerase II
3. RNA polymerase III

RNA processing proteins assemble in RNA Polymerase II because of ________ of the tail.

Phosphorylation

Protein coding sequences in eukaryotic genes are interrupted by ________ sequences known as introns

Non coding

Steps of RNA processing

1. Add a cap to the 5' end
2. Add a poly-A tail to the 3' end
3. splice out introns.

steps in splicing of pre-mRNA

primary transcript combines with snRNP's and other proteins to form a spliceosome
Lariat shaped loop generated
Lariat released to remove intron and join exons

Video review

https://youtu.be/8wAwLwJAGHs