molecular genetics

what does DNA do

it stores the information to build all of the body’s structural and functional proteins

how is the information carried in DNA

it is in the form of a code

how many subunits is DNA consist of

3 smaller subunit molecules

what does the D in DNA stand for

Deoxyribose

What does the N in DNA stand for

Nucleic

What does the A stand for in DNA

acid

double ring nitrogenous bases

Purine

single ring nitrogenous ring

Pyrimidines

Phosphodiester

The bond between the sugar of one nucleotide and phosphate of another nucleotide are strong covalent bonds.

the 5 referred to in a strand of nucleotides

the end of the strand that is a phosphate group

the 3 referred to in a strand of nucleotides

the end of the strand that is a deoxyribos.

what differs from one DNA molecule to another DNA molecule

The nitrogenous bases

what does the order of nitrogenous bases on a DNA do

they act as a code determining the order of amino acids in a protein molecule

howe many strands of nucleotides are bonded together to form DNA

2

what needs to happen so that the nitrogenous bases form hydrogen bonds.

the two strands have two be antiparallel

Antiparallel

two strands run in opposite directions.

what order are the strands in when they are parallel

one strand runs 5” to 3” and the other strand runs 3” to 5”

entire DNA ladder shaped

it is twisted into the form of a ladder.\

what are the nitrogenous bases

they are complementary.

purpose of mRNA

to carry a copy of a code for a single gene to the ribosome.

where is DNA found

only found in the nucleus

Where is RNA found

found in the nucleus and the cytoplasm

Transcription

the process by which a single gene of DNA is copied unto an RNA molecule

First step of transcription

RNA polymerase attaches to the promoter region in front of a gene.

Second step of transcription

DNA in front of the enzyme unwinds and opens.

Third step of transcription

RNA polymerase moves along one strand of DNA and adds complimentary RNA nucleotides

Fourth step of transcription

polymerase functions until it reaches a termination signal

Fifth step of transcription

RNA polymerase detaches and releases the mRNA

Sixth step of transcription

DNA closes and winds back up

Codon

3 nucleotides on an mRNA molecule that code for a specific amino acid

what is a mutation

any change in the sequence of bases in a DNA molecule.

what does a mutation DO

changes the DNA code, changing the protein that is produced by that code.

what does a mutated/changed protein do

alter the functions of a cell.

what is a point mutation

any mutation that alters the DNA code by one nucleotide either through a substitution addition or removal of a nucleuotide

what is a base substitution

when one nucleotide is replaced by another nucleotide

what is a frameshift mutation

when a nucleotide is either added or deleted from the DNA sequence

what is translation

converting mRNA code into an Amino Acid sequence

what is a ribosome

large subunit and a small subunit put together.

what are ribosomes made of

different types of RNA

what is tRNA

a type of RNA who carries amino acids

what does tRNA do

it brings the correct amino acid to the ribsome, it matches its anticodon to a codon on mRNA, making sure the amino acids are in the correct sequence to build a protein.

what is an anti codon

it pairs with a codon on mRNA during protein synthesis, this matching makes sure the correct amino acid is added to the growing protein.

where are anticodons located

found on a molecule called tRNA

what is the first step in Translation

small subunit of the ribosome attaches to the mRNA molecule lining the initiation codon in the p-site

what is the second step of translation

the first tRNA molecule lines up withs it anticodon hydrogen bonding with the start codon

what is the third step of translation

the large subunit of the ribosome attaches to the small unit of the ribosome

what is elongation

the middle stage of translation where the amino acid chain is being built.

what is the fourth stage of translation

a tRNA molecule attaches to the codon in the A site

what is the fifth stage of translation

a bond between the the amino acids form starting the chain of the amino acid chain.

what is the sixth stage of translation

the entire mRNA molecule shifts by 1 codon with the codon in A going to P and P going to the E site.

what is the seventh stage of translation

The tRNA in the E site leaves the ribosome and a new tRNA enters the A site.

what is the eighth stage of translation

steps 4-7 repeat until a stop codon enters the A- site

what is the ninth stage of translation

the ribosome reaches a stop codon which tells it to release the finished protein then the ribosome fall apart into large subunit and small subunit again.

what is peptidyl transferase

linking the amino acids together by forming peptide bonds during translation.

what is translocation

when the ribosome shifts one codon making the anticodon in A go to P then go to E

what is DNA replication

the process by which DNA makes an exact copy of itself

what is the first step of DNA replication

The DNA molecule unzips and unwinds at multiple replication origins.

What is the enzyme responsible for opening up the DNA molecule

Helicase

what is a replication origin

location where the helices attaches to the DNA molecule

what is a replication fork

where helices separates DNA into 2 single strands.

what is a replication bubble

2 replication forks going in opposite directions

what happens in the second stage of replication

a short RNA primer is formed along each strand of DNA.

What does RNA primer do

it acts as an anchor pointer the DNA polymerase to attach to the DNA molecule so that it can begin adding nucleotides.

what does Primease do

it builds a short RNA segment called a primer.

What does polymerase 3 do

it runs along the DNA strand adding new nucleotides with their compliments on the original DNA structure.

After polymerase 3 adds the nucleotides what does polymerase 1 do

it goes back and changes the RNA primer with new nucleotides

what happens in stage 5 of replication

ligase runs along the new backbone and creates bonds between the DNA segments formed by different DNA polymerase

what does ligase do

on the lagging strand it adds “glue” to the Okazaki fragments so that the thing is one whole strand.

what are Okazaki fragments

in a strand of DNA there are fragments of nucleotides

what happens in the sixth stage of replication

DNA polymerase 2 runs along the new backbone and repairs mismatched pairs of nitrogenous bases.

what does polymearse 2 do

it repairs mismatched nitrogenous bases.

what happens in the seventh stage of replication

the new DNA coils into a double helix as it is being copied