lec 16-20

im so cooked

dna (deoxyribose nucleic acid)

the blueprints of your own unique personal inherited traits

structure of dna

• two chains (double strand) of nucleotides

• twisted into a double helix

• joined by hydrogen bonds

dna nucleotides 3 different parts

1) deoxyribose sugar (5-carbon sugar)

2) phosphate group (backbone of DNA)

3) nitrogenous base (contains nitrogen)

dna nucleotides have 4 different types of nitrogenous bases

1) purines= adenine (a) guanine (g)

2) pyrimidines= thymine (t) cytosine (c )

complementary base pairing rule: (DNA)

ADENINE always joins THYMINE (A→ T)

GUANINE always joins CYTOSINE (G→ C)

RNA

ribo nucleic acid

structure of rna

• ONE chain (single strand) of nucleotides '

• joined by hydrogen bonds

3 parts of a RNA nucleotides

1) ribose sugar

2) phosphate group

3) nitrogenous base

4 different types of nitrogenous bases (RNA)

1) purines= adenine (a), guanine (g)

2) pyrimidines= uracil (U), cytosine ( c)

complementary base pairing RULE for RNA

adenine always joins to uracil (a→ u)

GUANINE always joins to CYTOSINE (g→ c)

types of RNA

messenger RNA (mRNA)

transfer RNA (tRNA)

ribosomal RNA (rRNA)

messenger RNA

carries RNA from the DNA (nucleus) to the ribosomes (cytoplasm) to make proteins

transfer RNA (tRNA)

transfers amino acids to the ribosomes (cytoplasm) to help make proteins

ribosomal RNA (rRNA)

the RNA that is part of the ribosome structure that helps make proteins

1) untwisting & unzipping DNA

• enzymes called DNA helicase separate DNA strands by untwisting and unzipping

• region where separation occurs= replication fork

• helicases break hydrogen bonds between bases

2) complementary bases added to new strand

• enzymes called DNA polymerase bond DNA strands back together again by adding complementary bases

• bases are complementary to original strand

• A→ T, G→C in complementary base pairing

3) results: two new strands of DNA

• DNA polymerase falls off after base pairing

• two new identical strands of DNA result

• Called semi-conservative replication

telomeres

• the tips of eukaryotic chromosomes

• the enzyme telomerase adds short, repeated DNA sequences to telomeres as the chromosomes are replicated

transcription

copying instructions from DNA into an RNA molecule (DNA→ RNA)

occurs in the nucleus

whats 1

DNA

whats 2

replication

whats 3

transcription

whats 4

RNA

whats 5

translation

whats 6

proteins

promoter

a specific location on DNA that RNA polymerase binds to in order to START transcription

RNA polymerase

an enzyme that forms RNA by using DNA as the original template (DNA→ RNA)

termination sequence

a specific location on DNA that signals the END of transcription

steps of transcription

1) DNA strands unwind and separate

2) RNA Polymerase binds to a Promoter

3) Using one of the DNA strands as a template, RNA Polymerase adds complementary RNA nucleotides to make an RNA chain

4) when RNA polymerase reaches the termination Sequence, Transcription ENDS

5)RNA Polymerase releases the DNA and forms a brand new RNA strand (DNA→RNA)

translation

the process of producing protein using the Genetic Code (nucleotides (RNA) → amino acids (PROTEIN) )

occurs in the ribosomes-mRNA brings the RNA from the nucleus to the ribosome

binding site

a region on tRNA that bonds to a specific amino acid

codon

a set of 3 nucleotides (letters) on mRNA that translate into a specific amino acid (3 nucleotides= 1 codon)

anticodon

a set of 3 nucleotides on tRNA that are complementary to the codons on mRNA

steps of translation

1) ribosome (rRNA) joins tRNA and mRNA together. the mRNA codon is paired with its tRNA anticodon

2) each codon (3 nucleotides) on the mRNA is translated into an amino acid using the Genetic Code

3) the amino acids are joined to a growing polypeptide chain, producing a protein

4) when the ribosome reaches a Stop Codon, the ribosome STOPS Translating

5) the resulting polypeptide chain (protein) falls off

the genetic code

when RNA from transcription is translated into amino acids using the genetic code

start codon

AUG

stop codons

UAG, UAA, UGA

dna identification

the repeating sequences in noncoding DNA vary between individuals and thus can be used to identify an individual (3 step process)

copying dna

polymerase chain reaction: * scientists isolate the DNA and copy it using the polymerase chain reaction (PCR)

cutting DNA- restriction enzyme

the DNA is then cut into fragments using restriction enzymes

restriction enzymes

recognize and cut specific nucleotide sequences

sorting DNA by Size-gel electrophoresis

the fragments are separated by size using gel electrophoresis.

dna fingerprint

the resulting patterns of bands

cloning vectors

researchers use restriction enzymes to insert DNA fragments into vectors

recombinant DNA

the resulting DNA from two different organisms

the human genome project

goal was to determine the nucleotide sequence of the entire human genome and to map the location of every gene on each chromosome

bioinformatics

uses computers to catalog and analyze genomes

proteomics

studies the identities, structures, interactions, and abundances of an organism’s proteins

dna microarrays

two-dimensional arrangements of cloned genes

gene therapy

refers to treating genetic disorders by transferring normal human genes into human cells that lack them, correcting a defect in a gene