central dogma

DNA

contains genes, code for all proteins in your body

proteins

structure + function of all the cells (examples of types of proteins, determine traits)

central dogma

flow of info in the cell (DNA --> RNA --> Protein)

Griffith's Experiment

the first experiment suggesting that bacteria are capable of transferring genetic information through a process known as transformation

Avery, MacLeod, McCarty

Proved that DNA is the hereditary material

Erwin Chargaff

Discovered that DNA composition varies, but the amount of adenine is always the same as thymine and the amount of cytosine is always the same as guanine.

the backbone of DNA is described as

Alternating sugar and phosphate groups

DNA replication

the process of making a copy of DNA

parent DNA molecule consists 2 polynucleotide chains together by bonds between

nitrogen bases

in DNA replication, an enzyme breaks the bonds and what?

pairs new nucleotide with two parental chains

what does DNA polymerase do?

adds new nucleotides

the DNA molecule does what during DNA replication?

unzips and separates

nucleotides attach to the unzipped portions using what?

base pairing rules

the original DNA strand serves as a pattern/template to do what?

make the new DNA molecule

the result of DNA replication

two identical DNA strands

Why is DNA replication is a semi-conservative process?

because half of the percent DNA molecule is conserved in each of the two daughter DNA molecules

what does helicase do?

Unzips/unwinds DNA

DNA ligase

connect pieces of DNA together

leading strand

continuously replicated/synthesized

lagging strand

replicated in pieces

DNA polymerase

proofreading

replication fork

where the 2 strands of DNA are separated

primase

adds the primer (short nucleotide strand)

the three important differences between RNA and DNA

1. uracil instead of thymine
2. single-stranded
3. sugar --> DNA has deoxyribose; RNA has ribose

functions of RNA

• working copy of a single gene
• controls how amino acids are made into protein

types of RNA

1. mRNA
2. rRNA
3. tRNA

messenger RNA

carries instructions for making proteins from nucleus to ribosomes in cytoplasm

ribosomal RNA

forms an important part of both subunits of the ribosome

transfer RNA

carries amino acids to the ribosome acid matches them to the coded mRNA message

ribosome

organelles that synthesize protein; they are made of protein and RNA

transcription

RNA molecules are produced that are complementary to the DNA sequences in genes

where does transcription occur in eukaryotes?

nucleus

the enzyme in transcription

RNA polymerase

promoters and transcription factors

signals where to begin making RNA

promoter

sequence in the DNA that "tells" the RNA polymerase where to start transcribing (before the gene)

transcription factors

proteins that bind to the promoter and help the RNA polymerase get started

RNA processing in eukaryotes

additional processing before mRNA leaves the nucleus

splicing

the process of removing introns and reconnecting exons in a pre-mRNA

5' cap

a modified form of guanine nucleotide added onto the 5' end of a pre-mRNA molecule

poly A tail

Modified end of the 3' end of an mRNA molecule consisting of the addition of some 50 to 250 adenine nucleotides.

spliceosome

A large complex made up of proteins and RNA molecules that splices RNA by interacting with the ends of an RNA intron, releasing the intron and joining the two adjacent exons.

exons

segments that stay in the RNA

introns

intervening sequence cut-out

proteins

long chains of amino acids

How many types of amino acids are there?

20

what does the amino acid sequence determine?

the shape and function of a protein

what do the bases in RNA determine?

the order of amino acids in proteins

codon

A specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid

start codon

AUG (methionine)

codon= mRNA

each codon:

• amino acid
• start
• stop

tRNA

has anti-codon on one side (two will complementary to a codon on the mRNA) carries amino acid on other side (determined by the genetic code)

ribosome

• large subunit / small subunit
• protein + rRNA
• tRNA docking sites

E

exit

P

where the peptide bond is formed

A

tRNA first binds

genetic code

each codon on the mRNA aligns with an anti-codon the tRNA --> brings the correct amino acid

initiation

• first stage of protein synthesis
• start codon AUG

what does the AUG (start codon) do in the initiation stage of protein synthesis?

attaches the mRNA to ribosome and puts the start codon in the P site; then the large subunit then binds

elongation

a series of repeated cycles that add amino acids one at a time to make a peptide

termination

when a stop codon (UAA, UGA, UAG) moves into A site it stops protein synthesis and they break the bond between the peptide and the tRNA in site P

what is being released in the cytoplasm in termination?

the peptide

what happens after the peptide is released into the cytoplasm?

the ribosome subunits then separate for reuse or are broken down

cells have different and ____

structure, function

gene expression

using a gene to make a given protein

regulation may occur at any point in the expression of a gene, from the start of transcription to…

processing of a protein after translation

all cells have the same DNA -->

each cell to making different proteins

mutations

change in the sequence of bases in DNA, which may be harmful, beneficial, or neutral; the ultimate source of changes in genes

types of mutations

germline and somatic

germline

sex cells

somatic

pertaining to the body

categories of mutations

• point mutations (substitutions; insertions or deletions)
• large scale (chromosomal alterations)

frameshift mutation

a genetic mutation that occurs when the number of base pairs inserted or deleted from a DNA sequence is not a multiple of three

substitutions

one base different (multiple codons--> amino acid)

substitution changes

1. nothing
2. changes the amino acid --> similar
3. changes " " " ---> different; change shape/function of the protein

sickle-cell anemia

disease causes red blood cells to deform

hemoglobin

point substitution, one amino acid is different

inherited in sickle-cell anemia

gene must be inherited by both parents

mutations can be caused by many factors including…

1. environmental insults (ex. radiation)
2. random chance events (ex. fault in replication of the gene)

mutagen

mutations in DNA

chromosomal mutations

change in the number or structure of chromosomes: deletion, duplication, inversion, translation

genes

area of the DNA that codes for a specific protein

purine bases

adenine and guanine

pyrimidine bases

cytosine, thymine, uracil