Hnrs Bio Knowledge Check 2

Transcription vs Translation

The process by which DNA is copied to RNA

vs

RNA is used to produce proteins

What are the differences between RNA and DNA?

* RNA has uracil, DNA has thymine
* RNA has a ribose (sugar), DNA has deoxyribose
* DNA is a double helix, RNA is a single helix

What are the main enzymes involved in DNA replication & transcription?

* DNA polymerase (DNA replication)
* RNA polymerase (transcription)

What are genes made of?

DNA

How is cell differentiation related to genes?

* cell differentiation is how unspecialized cells become specialized
* gene expression is the combination of genes turned on or off
* gene expression dictates how a cell functions

What is the central dogma of molecular biology?

DNA → RNA → Proteins

Which nitrogenous base is present in RNA and not in DNA?

Uracil

The three types of RNA

* mRNA - carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell
* tRNA - carries each amino acid to a ribosome during protein synthesis
* rRna - combines with proteins to form ribosomes

How many nucleotides make up a codon?

3

The **products and the locations** of transcription

* RNA
* nucleus

The **products and the locations** of translation

* protein
* ribosomes

What are the two ways mRNA is edited before leaving the nucleus?

* 5’ cap & poly-A tail: 5’ cap is added to the beginning of RNA transcript and a 3’ poly-A tail is added to the end
* Splicing: intron section of the RNA transcript are removed to join the exons back together

What is the purpose of the 5’ cap and poly-A tail?

* 5’ cap is added to protect RNA from degradation
* adenine nucleotides (where poly-A tail comes from) is added to the 3’ end to stabilize the molecule and allow it to leave the nucleus

Introns vs Exons

* Introns are noncoding sections of RNA transcript
* Exons code for proteins

What is the monomer for a protein?

amino acid

The importance of proteins

* Help determine all our physical traits
* Speed up the rate of reactions
* Reduce the amount of energy needed for reactions in cell

The __**start codons**__

* AUG ( codes for Methionine)

The steps of transcription

1. DNA is split apart
2. RNA polymerase binds to the template side with a promoter sequence
3. mRNA is transcribed from DNA template
4. pre-mRNA steps are take (5’cap, poly-A tail, splicing)
5. mRNA leaves the nucleus

The steps of translation

1. mRNA moves into the ribosome, the first tRNA meets the mRNA at the start codon
2. Amino acids are brought to the mRNA by the tRNA based off the mRNA codon
3. After the stop codon is read the final protein (polypeptide) is released in the cell

What is a mutation?

Any change in the sequence of nucleotides of DNA or RNA

What causes mutation?

* errors in DNA replications
* exposure to mutagens or viral infections

 **What a mutagen is**

* any chemical or physical agent that can change a sequence in DNA or RNA
* usually are harmful but sometimes can be beneficial

Protein structure order

1. Primary - order of amino acids
2. Secondary - sheets or helices formed by hydrogen bonding
3. Tertiary - 3D structure of one polypeptide
4. Quaternary - multiple tertiary structures linked together

**The different type of mutations**

* Frameshift
* Point
* Missense
* Nonsense
* Silent

Deletion

removal of one or more bases to the sequence

Insertion

insertion of one or more bases to the sequence

Frameshift mutation

a mutation that completely shifts the reading frame for the rest of the sequence

Point mutation

the changing/substitution of one single nucleotide

Silent Mutation

No change to the resulting amino acid

Nonsense Mutation

Change to one amino acid

Missense Mutation

A premature stop codon is created, making a shortened protein

Substitution

type of mutation in which one nucleotide is replaced by a different nucleotide

Enzymes

* increases the rate of reactions
* proteins that help speed up metabolism or chemical reactions in the body

How enzymes work?

* they bind to reactant molecules and hold them in a way that the chemical-bond breaking and bond forming process takes place more easily
* Their structure allows only certain reactants to bind to them

Epigenetics

the study of how your behaviors and environment can cause changes that affect the way your genes work

CRISPR

* Clustered Regularly Interspaced Short Palindromic Repeats
* Repetitive DNA sequences called CRISP
* bacterial defense system that forms the basis for CRISPR-Cas9 genome editing technology

Gel electrophoresis

method used to separate mixtures of DNA, RNA, or proteins

How mutations affect organisms (how mutations affect proteins)?

prevent one or more proteins from working properly

What the wobble hypothesis states?

some tRNAs can pair with more than one mRNA codon

Importance of the wobble hypothesis?

states that normal base pairing can occur between nitrogen bases in positions 1 and 2 of the codon and the corresponding bases 3 and 2 in the anticodon

Translation

* mRNA is read
* a protein is made from the genetic info read from the mRNA
* occurs in the ribosome

Transcription

* copies strand of DNA to produce a strand of mRNA
* product of RNA
* occurs in the nucleus
* requires RNA polymerese

Stop codons

* UGA, UAA, UAG

reading frame

the order in which you read the codons on a DNA or RNA sequence