Chapter 3.2 - DNA Replication

semiconservative

the process of DNA duplication where the original double helix unwinds, and each strand serves as a template for a new, complementary strand

conservative

a hypothetical model of DNA replication where the original parental DNA double helix remains intact, and an entirely new double helix is synthesized separately. This would result in two daughter DNA molecules: one composed of the two original "old" strands, and the other composed of two completely "new" strands

dispersive

a hypothetical model of DNA replication where the original double helix breaks into fragments, and the new double helices are a mixture of both old and new DNA segments interspersed on each strand

semiconservative

how does DNA replicate? AKA which hypothesis was correct?

helicase

binds to the origin and unwinds the parental double helix to allow an access place for DNA polymerase to bind

binding proteins

make sure the two strands are actually separated and stay apart

primase

makes a short stretch of RNA on the DNA template; primes it for polymerase

DNA polymerase

proofreads activity checks and replaces incorrect bases

okazaki fragment

short DNA sequences synthesized on the lagging strand during DNA replication because DNA polymerase can only build new DNA in the 5′→3’ direction

because it is being created in 5’ to 3’

why is the leading strand continuous

because it’s going 3’ to 5’ and DNA polymerase can only make DNA in 5’ to 3’; it solves this by making fragments

why is the lagging strands discontinuous

ligase

seals up the sugar phosphate backbone

enzymes

what removes RNA primers?

1. helicase binds to origin and separates strands

2. binding proteins keep strands apart

3. primase makes a short stretch of RNA on the DNA template

4. DNA polymerase adds DNA nucleotides to the RNA primer

5. DNA polymerase proofreading activity checks and replaces incorrect bases

6. continuous strands synthesis continues in a 5’ to 3’ direction

7. discontinuous synthesis produces Okazaki fragments on the 5’ to 3’ template

8. Enzymes remove RNA primers and Ligase seals sugar-phosphate backbone

What are the steps to DNA replication? (8)

transcription, RNA processing, translation

what are the steps of protein synthesis?

transcription

production of mRNA

translation

production of protein using mRNA, tRNA, and rRNA

gene expression

taking the sequence of the purines and puramadines on DNA and using the info to synthesize a protein

nucleus

where is DNA replicated?

nucleus

where does transcription take place?

cytoplasm

where does translation take place?

RNA: single stranded, uses ribose, uses uracil

DNA: double stranded, uses deoxyribose, uses thymine

what are the three main differences between RNA and DNA

mRNA

carries information from DNA to ribosome

nucleus

where is mRNA produced?

ribosome

where is mRNA transported to?

codon

a three nucleotide ____ specifies a particular amino acid

rRNA

with associated proteins to make up ribosome; provide structural support

two

how many subunits does rRNA have?

tRNA

used to transfer amino acids to the ribosome to create the amino acid polypeptide chain

cloverleaf

what shape is tRNA

anticodon binding site

the site of tRNA that forms hydrogen bonds with the mRNA codon

thanks!

Here’s a picture showing the difference between mRNA and tRNA and how they interact with each other

RNA

____ is the bridge from DNA to protein

mRNA

____ is synthesized from the template strand of DNA

complementary strand

which strand of DNA is the coding strand?

RNa polymerase and transcription factors

what enzymes are required for transcription?

operons

in bacteria, these control gene expression

transcription factors

transcription factors

over 2,000

how many kinds of transcription factors exist?

True

True or False: there can be mutations in transcription factors

they bind to specific regions of DNA

what is the thing that is common between all types of transcription factors?

helix-turn-helix, zinc finger, leucine zipper

give 3 examples of transcription factors

initiation

promoter attracts transcription factors and RNA polymerase

elongation

RNA polymerase adds nucleotides to growing RNA

termination

sequences in the DNA prompt the RNA polymerase to fall off, ending the transcript

initiation, elongation, termination

what are the three steps of transcription in order?

promoter

a segment of DNA that binds to RNA polymerase to initiate the process of transcription

5’ to 3’

direction of transcription

False

True or False: you can only have one RNA polymerase on DNA at a time