unit 5 TEST

who discovered that harmless bacteria can turn into bacteria that can cause disease?

fredrick griffith

how did fredrick griffith discovered it?

by a factor in heat that killed disease causing bacteria

when did fredrick griffith discover his discovery?

1928

what did Oswald Avery determine?

determined that genes are made of DNA

when did Oswald Avery discover this?

1944

who verified Avery's results?

Hersey and Chase

how did hersey and chase verify this?

by using bacteriophages

when did hersey and chase discover this?

1952

what did Watson and Crick discover?

Developed the double helix model of DNA.

when did Watson and Crick discover this?

1953

genes are made of?

DNA

what 3 things must DNA do?

must transfer information from one generation to the next, must determine inheritable traits, dna must be easily copied

dna is made up of?

nucleotides

each nucleotide has how many parts?

3

what are the 3 parts in nucleotide?

5 carbon sugar, phosphate group, nitrogenous base

what is the 5 carbon sugar called?

deoxyribose

What forms the backbone of the DNA molecule?

sugar and phosphate group

what hangs off the side of the sugar molecule?

nitrogen base

what are the 2 groups of nitrogen base?

purine group and pyrimidine group

what does a purine group contain?

the bases of adenine (A) and guanine (G)

what are the 2 ringed structures?

A and G

what does a pyrimidine group contain?

the bases of thymine (T) and cytosine (C) and uracil (U)

what are 1 ringed structures?

T, C and U

when does nitrogen bases occur?

occurs in any order

what does the order of the nitrogen bases determined?

the specific amino acid sequence

a purine base will always pair with what base?

pyrimidine base to form complementary base pairs

what are the pairs in base pairing?

A always pairs with T and G always pairs with C

the number of A \=

the number of T

how does A and T connect?

with a double bond

the number of G \=

the number of C

how does C and G connect?

with a triple bond

what is the structure of a DNA

double helix

what are the 2 strands of DNA connected by?

hydrogen bonds between the nitrogen bases

DNA must make an exact copy of...

itself

semi-conservative replication

old strand of DNA is paired with a new strand

DNA template

each strand unwinds and is used as the template

pairing old with new DNA guarantees what?

an exact copy is made because of the base pairing rule

what is the end result of DNA replication?

2 copies of DNA, each made with one old strand and one new strand. total of 4 individual strands.

RNA

"decoded" DNA that make proteins

what are the 3 types of RNA?

messenger RNA, ribosomal RNA, and transfer RNA

messenger RNA (mRNA)

carries the copies of DNA to the rest of the cell

ribosomal RNA (rRNA)

makes up most the ribosome where proteins are made

transfer DNA (tRNA)

transfers amino acids to ribosomes during translation

What are the differences between DNA and RNA?

DNA: double stranded, has deoxyribose sugar, bases: adenine, guanine, cytosine, thymine

RNA: single stranded, has ribose sugar, bases: adenine, guanine, cytosine, uracil

why are dna sugars called deoxyribose

their 2' carbon does not have a hydroxyl group (-OH)

the "top" of the sugar is called what? what is it connected to?

5' end and is connected to the phosphate group

the "bottom" of the sugar is called what? what is it connected to?

3' end and is connected to the hydroxyl group

DNA nucleotides have which nitrogen bases?

A, G, T, and C

RNA nucleotides have which nitrogen bases?

A, G, U, and C

anti-parallel

The opposite arrangement of the sugar-phosphate backbones in a DNA double helix. For example, 3' end and 5' end is reversed to 3' and 5' end.

Why are the 3' and 5' ends important?

when the cells wants to add nucleotides to an existing strand, nucleotides can only be added to an existing strand of DNA on the strand's 3' end

helicase

job is to break the hydrogen bonds between nitrogen bases

gyrase

job is to reduce tension in unwinding DNA

primase

job is to create small RNA primers for DNA Polymerase to bond to

what's the purpose for DNA replication

so the cell can divide and give each daughter cell a correct DNA sequence

origins of replication

Sites where the replication of a DNA molecule begins.

replication fork

A Y-shaped region on a replicating DNA molecule where new strands are growing.

RNA nucleotides are what?

primers for DNA polymerase

primases move along what strand?

the existing strand's 3' to 5' direction.

DNA Polymerase I

removes RNA primers + inserts the correct DNA nucleotide; near completion of DNA replication

DNA Polymerase II

proof reading the new strand at end of DNA replication

DNA Polymerase III

attaches DNA nucleotides to make the new DNA strand

what must DNA Polymerase need/has to do?

must have RNA primers to start and travel from the 5' to 3' on the new strand

leading strand

a strand that is producing in a continuous manner

lagging strand

a strand that is built discontinuously

okazaki fragments

small segments of DNA found on the lagging strand

single stranded binding proteins (SSBP)

provide stability to keep the helix open

DNA Polymerase III will move where in the lagging strand?

move towards the origin of replication

DNA Polymerase III will move where in the leading strand?

moves away from the origin of replication

ligase

an enzyme that closes the gaps and connects the okazaki fragments into one continuous strand of DNA.

when does ligase happen?

after DNA Polymerase I

what are the DNA polymerase in chronological order?

III, I, II

are hydrogen bonds considered to be weak bonds or strong bonds?

weak

why is it useful for the base pairs of DNA to be held together by hydrogen bonds instead of covalent bonds?

hydrogen bonds are easier to break allowing for DNA copying

DNA is short for?

deoxyribonucleic acid

RNA is short for?

ribonucleic acid

when DNA polymerase III is added what happens to the primases?

moves away from helicases

Is RNA shorter than DNA? Which one is 1 gene long?

RNA is short, only 1 gene long. DNA is very long and contains many genes.

the information in DNA is in the form of what?

specific sequences of nucleotides along the DNA strands

the dna inherited by an organism leads to specific traits by

directing the synthesis of proteins

transciption and translation

the two stages that process by which DNA directs protein synthesis

central dogma

DNA -\> RNA -\> Protein

cells are governed by what?

a cellular chain of command

transcription

the synthesis of RNA under the direction of DNA

transcription produces what?

produces messenger RNA (mRNA)

transcription occurs where?

in the nucleus

translation

the actual synthesis of a polypeptide, which occurs under the direction of mRNA

where does translation occur?

occurs on ribosomes

RNA synthesis is based on information stored in?

DNA

transcription is started by?

RNA polymerase II

what does the RNA polymerase II do?

pries the DNA strands apart and hooks together the RNA nucleotides

mRNA goes from \____ to \____

pre-mRNA to mature-mRNA

RNA processing occurs when?

prior to leaving the nucleus before mRNA leaves through a nuclear pore.

how is the RNA copy of a gene converted into mature mRNA?

the cell adds a protective cap to one end, and a tail of A's to the other end. pre-mRNA is made of regions called introns and exons

introns

nonsense regions which need to be removed

exons

coding regions which need to stay put

splicing

the process of removing introns to produce mature messenger RNA (mRNA)

genetic information is encoded as a sequence of what?

nonoverlapping base triplets or codons

codons

3 bases on mRNA code for the production of a specific amino acid

3 nucleotides on mRNA \=

1 codon \= 1 amino acid