Sree Marella - Chapter 4: DNA & Gene Expression

Ahmed - 7th period

What is DNA

genetic material

What is DNA made up of

sugar phosphate backbone and nitrogenous bases

What shape is DNA

double helix

what is each nucleotide made up of

sugar phosphate backbone and bases

what is the backbone of DNA

deoxyribose sugar and phosphate

how are the rungs of the ladder connected together

hydrogen bonds

what are the four nitrogenous bases

adenine guanine thymine and cytosine

how do the nitrogenous pairs of DNA pair?

via hydrogen bonds

what do the sequences of bases code

genetic traits

how does biotech use DNA’s stability and reproducibility? 

for genetic testing and altering

what does understanding the structure of DNA allow?

allows to understand for genetic trait inheritance

when does DNA replication occur?

synthesis

what is semiconservative replication?

one strand original, one new 

how does the DNA double helix unwind?

via helicase

what is the replication fork?

origin of mRNA transcription

what is the leading stand

continuously transcribed

what is the lagging strand

transcribed in fragments

what type of DNA does bacteria have

circular

what is DNA polymerase?

creates the mRNA bases

what is the origin recognition complex?

initiation of replication

what is helicase

opens up (unwinds) DNA

what is the purpose of the template DNA

guides the rest of the DNA replication process

what is the replication bubble

where DNA replication occurs at multiple different locations

what is the replication fork

start of DNA replication 

what is topoisomerase

untangles / relieves tension 

what are single-strand binding proteins?

RNA proteins

what are RNA primers

mark the initiation of DNA replication

what is primase

the starting of DNA replication

what are okazaki fragments

small fragments that are then glued via ligase

what is DNA ligase

glues okazaki fragments

what are histone proteins

tightly coiled proteins

what are histones

positively charged molecules in which DNA coils to

what are nucleosomes

the small DNA molecules in the nucleus 

what is chromatin

the DNA material

what are euchromatin

less dense DNA

what are heterochromatin

more dense DNA

who discovered transformation

Griffith

when was transformation discovered

1928

what was the end conclusion of DNA transformation?

DNA is the genetic material responsible for heredity.

what is transcription

DNA replication into RNA

what is mRNA

messenger RNA

what is ribose phosphate backbone

backbone of RNA

what is a codon

three code sequence

what is polypeptide

the bonds made via ribosomes

what is an enzyme

lowers activation energy

what is the central dogma of molecular biology

DNA to RNA to protein

why is it important to understand the structure of RNA in biotechnology?

bcs it can used to transport DNA

how are RNA used to treat diseases and create new therapies

since RNA is temporary it can carry genetic info not permanently

what makes RNA unstable

the excess OH group

what is the ribose-phosphate backbone?

backbone of RNA

what makes DNA more stable?

absence of OH group

when does uracil pair with thymine

RNA

what are the three key differences between RNA and DNA 

ribose sugar, single stranded, uracil 

what is messenger RNA

the complementary replica of DNA

what is a codon

three base sequence — codes for amino acid

what are amino acids

the traits that code of a protein

what is an anticodon

ensures the amino acid is the right one and the codon sequence is true

what do tRNA molecules do

transport the amino acid to the ribosome

what does the cloverleaf shape of tRNA allow

bridge the gap between the genetic code in mRNA and the building of proteins

what is the small ribosomal subunit

the part of a ribosome that binds to messenger RNA (mRNA) and decodes the genetic information it carries

what is the large ribosomal subunit?

the larger of the two components that make up a ribosome

what do ribosomes do

make proteins

why is it important to understand transcription

because it is a basis fro biomelcularity

what is RNA polymerase

creates the RNA bases complementary to DNA

what is pre-mRNA

the RNA that includes the introns

what are exons

genes that don't code anything

what are introns

genes that are removed

what is the 5’cap

allows stability

what is a polyA tail

allows stability— made up of adenine

what percent of human genetic disorders are due to improper RNA splicing

15

what is the ribosomal complex

the inside of ribosmes

during translation, what happens at initiation

hooking /imitation of RNA molecules

during translation, what happens at elongation?

elongates via more and more bases being synthesized

during translation, what happens at termination?

a stop codon (UAA, UAG, or UGA) enters the ribosome's A site, triggering a release factor protein to bind to it

why is gene regulation important

it allows to see expression and the creation of useful enzymes

what is the regulator gene?

the gene that codes for the repressor protein

what is the operator region?

the site where the repressor protein binds to

what is an inducer

something that allows the operon to turn on

what is the repressor protein

protein that allows or not allows the transcription

what is the TRP operon

tryptophan-making operon

what happens when tryptophan is absent

operon makes more

what happens when tryptophan is abundant

operon stops transcribing

what is a point mutation?

changes one sequence in DNA

why is it important to understand point mutations?

because they can change the AA produced. 

What is polymerase chain reaction?

way to amplify DNA

How did PCR revolutionize medicine?

allowed scientists to make multiple copies of DNA

What is the starting material for PCR?

template DNA

how is PCR used in biotech

used to interpret genetic test results

What are PCR tubes?

thin-walled plastic tubes that contain rxn mixture

What are primers?

two short single stranded DNA oligonucleotides

Where does the forward primer bind?

the 3’ end

Where does the reverse primer bind?

5’ end

 What are dNTPs?

deoxynucleotides — building blocks for new DNA synthesis

What is Taq polymerase?

enzyme that synthesizes new DNA strands

 Where is Taq polymerase isolated from?

thermus aquaticus

What does thermostable mean?

survives repeated heating to 95 degrees C without denaturing

What are the three steps of PCR?

initialization, annealing, elongation

What temperature does denaturation happen at?

95 degrees C

 What happens during denaturation?

sample is heated to 95 degrees C

What temperature does annealing happen at?

55 degrees C