AP Bio: DNA/RNA and Protein Synthesis (Part I)

is DNA or protein genetic material?

DNA!

transformation

one strain of bacteria takes on characteristics of another strain by taking in pieces of DNA

bacteriophage

virus that infects DNA

what is the role of DNA?

stores, copies, and transmits genetic information

how is genetic information expressed and used?

expressed + used as instructions for making proteins, which give cells their genetic traits

what is DNA made of?

nucleic acids

polymer name?

nucleic acid

monomer name?

nucleotides

what is deoxyribose?

5-carbon sugar

what are the three parts of a nucleotide?

deoxyribose, phosphate group (P+O), and nitrogen base (4 options)

what are the four nitrogen bases?

adenine, thymine, cytosine, guanine (a thyme cries guacamole)

A+G

purines

C+T

pyrimidines

how many strands are there in DNA nucleotides?

2

what is the overall shape and structure of DNA nucleotides?

strands are twisted + double helix

what is the backbone of DNA?

deoxyribose + phosphate alternative on the outsides

how are the base pairs held together?

H bonds (weaker)

how is the rest of DNA held together?

covalent bonds

A + T (how many H bonds?)

2

C + G (how many H bonds?)

3

how are the two strands facing

antiparallel

antiparallel

side by side, but facing in the opposite direction

Chargaff’s rule

in any sample of DNA %A=%T and %C=%G

Wilkins

made x-ray images of DNA, showed pictures to Watson+Crick

Franklin

made excellent image of DNA

Watson+Crick

built model for double helix

what is DNA replication

copying DNA

why does DNA replicate?

getting ready for cell division

when does DNA replicate?

during synthesis of interphase

where does DNA replicate?

in nucleus of eukaryotic cells

1st step in DNA replication

unwinding + unzipping of DNA within replication bubble

2nd step in DNA replication

new complementary DNA nucleotides added to both strands

3rd step in DNA replication

correcting + connecting all the nucleotides

what is the result of DNA replication?

2 identical DNA molecules (each one is 1/2 old and 1/2 new)

what do complementary nucleotides do?

match up according to base-pairing rules

what is the original strand used for?

a template for the new strand

semiconservative

description of the process that results in each molecule being 1/2 old + 1/2 new

topoisomerase

relaxes supercoiling in front of replication fork

helicase

unzips/separates 2 strands of DNA by breaking H bonds between bases

DNA polymerase

adds new complementary DNA nucleotides to each original strand; acts as proofreader

role of RNA primers

added to strands first to know where to add nucleotides, RNA primers are eventually converted to DNA nucleotides

ligase

connects fragments of DNA to each other on the lagging strand

leading strand

can be added to in 5’ to 3’ direction so DNA polymerase can work continuously

lagging strand

facing the other direction; has to be added to in segments b/c DNA polymerase only works in 5’ to 3’ direction

okazaki fragments

the pieces added to the lagging strand that have to be connected to each other by ligase at the end of the process

prokaryotic chromosome shape

circular

eukaryotic chromosome shape

linear (rods)

plasmids

extra pieces of DNA that are small and circular, commonly found in prokaryotic cells and some eukaryotic

DNA base pairs

A+T, C+G

RNA base pairs

A+U, C+G

how many strands are in RNA?

1

name of sugar in RNA?

ribose

full name of RNA

ribonucleic acid

overall role of RNA

involved in process of making proteins from instructions in DNA

mRNA

carry code (instructions from DNA) for protein synthesis

tRNA

brings a.a. to ribosomes according to information in mRNA

rRNA

component of ribosomes

transcription

process that makes all types of RNA

what type of RNA is mostly being made?

mRNA b/c it needs to made new each time to make a protein

what is transcription?

making any type of RNA using info. from DNA

why is there transcription?

to make proteins w/out DNA leaving the nucleus

when does transcription occur?

G1+G2

where does transcription occur?

nucleus

1st step in transcription

unwinding+unzipping part of DNA that will be transcribed

2nd step in transcription

new complementary RNA nucleotides added to one strand

3rd step in transcription

newly made molecule of RNA separates from DNA + DNA strands go back together

result of transcription

1 new piece of RNA + the original DNA

enzymes used in transcription

topoisomerase + helicase

RNA polymerase

adds RNA nucleotides

base pairs between DNA + RNA

A+U, T+A, C+G, G+C

polypeptide

chain of amino acids

protein

1 or more polypeptides that have folded into a specific shape + obtained a specific function

what is the folding of a protein effected by?

amino acid interacting with each other and the environment

central dogma

sequence of nucleotides in DNA (processes 1+2) determines sequence of nucleotides in mRNA ( process 3) determines sequence of a.a. in polypeptide

processes involved in central dogma

1=transcription, 2=RNA processing, 3=translation

promoter

area on DNA where RNA polymerase starts transcription

1st stage of transcription (part II)

initiation: RNA polymerase binds to the promoter

2nd stage of transcription (part II)

elongation: creation of RNA molecule (most often mRNA)

3rd step of transcription (part II)

termination: RNA polymerase reaches a stop sequence on the DNA which causes DNA, RNA, and RNA polymerase to separate (DNA goes back to normal)

what is the result of transcription (part II)

pre-mRNA

does DNA have intron and exons intermingled?

yes

introns

segments that don’t code for the protein

exons

segments that do code for the protein

what is the result of introns

they are cut out of pre-mRNA (spliced out)

what is the result of exons

put together to make final mRNA

where is the cap added on mRNA

5’ end

what does the cap modify

guanine nucleotide

what does the cap do

tells ribosome where to attach

where is the tail added on mRNA

3’ end

what does the tail help with

helps mRNA leave the nucleus and initiate translation

what does the tail maintain

mRNA stability (prevents it from falling apart)

poly-A tail

contains 150-200 adenine nucleotides

what is translation

putting together a.a. to make a polypeptide that will become a protein

why does translation occur

to make proteins

when does translation occur

G1+G2 of interphase

where does translation occur

on ribosomes in cytoplasm

how does translation occur

rRNA, mRNA, and tRNA work together to do translation

codon

3 nucleotides on mRNA

anticodon

3 nucleotides on tRNA (complementary to codon which allows correct tRNA to bring correct a.a.)

1st step in translation

initiation: mRNA, ribosome, first tRNA with first a.a. come together