DNA review Flashcards by Mandy McDaniel

How does DNA molecule determine who I am?

These elements compose all nucleotides (phosphate, sugar, base).
the order of nitrogen bases
determines traits.

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mRNA function

single strand that carries info to ribosomes from DNA

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tRNA function

carries AA’s to the ribosomes

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ribosomes

location of protein synthesis; marker for tRNA

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protein function

structures and enzymes

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A certain protein is composed of 500 amino acids. How many nitrogen bases does the gene that is responsible
for making this protein contain? Show how you know.

3 N.bases = 1 AA

So 500 AA are composed of 1500 N.bases (500 x 3)

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Draw a picture of a small DNA molecule that contains 8 total nucleotides. Simplify your drawing by using the

letters S (for sugar), P (for phosphate), and A, T, G, C. When finished circle one nucleotide.

S -- A T--- S 
P               P
S—G   C---S
P               P
S—G   C---S
P               P
S—A    T---S
P                P

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Explain the base pairing rules.

B.p. rules are determined by the # of Hydrogen bonds that each base can
form.
A=T ( 2 H bonds)
C_G (3 H bonds)

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DNA

4 facts

deoxyribose,
thymine,
double stranded,
stays in nucleus

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RNA

4 facts

ribose,
uracil,
single stranded,
can leave nucleus

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Purines

Double ring N. Base –
Adnenine, Guanine
“Pure As Gold”

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Pyrimidines

Single ring N. base-
Cytosine, Thymine, Uracil
“Cut The Py”

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5’

The fifth carbon is facing up so that is the 5’ end.

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3’

The 3rd carbon is at the bottom so that is the 3’ end.

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Describe the role of an intron and exon within a gene

Right after transcription, during “RNA processing”, the newly mRNA strand splices out the introns and connect the remaining exons together before the mRNA leaves the nucleus.

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DNA helicase –

Unzips the DNA by breaking the Hydrogen bonds

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DNA polymerase –

Adds free DNA nucleotides during replication

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RNA polymerase–

Adds free RNA nucleotides during transcription

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Introns are

Introns are the non-coding part of a gene. They are not used to make a protein.

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Exons are

Exons are the coding parts of a gene that are expressed and result in the production of a protein.
Exons= Expressed gene

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One thing that DNA must be able to do is duplicate its structure in preparation for cell division. This duplicating
process is called.

replication

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During replication the DNA molecule unzips between the _________________
found in the nucleus fill in according to the
proper base pairing so that upon finishing, two identical molecules are synthesized

nitrogen bases and free nucleotides

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If DNA is the molecule that controls all the cell’s activities it must be able to transmit its base sequence code out
to the _____________1.
Since we know that DNA never leaves the nucleus, it has a messenger molecule
which is _____2.

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ribosomes .

2. mRNA .

Transcription

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mRNA is formed when DNA opens and FREE nucleotides

mRNA will take the base sequence code out to the small round organelles in the cytoplasm called ------------.

ribosomes

Ribosomes

organelle where protein synthesis takes place

Proteins are

These molecules that are synthesized are long chains of amino acids that determine the structure of the cell and also be enzymes control all of the chemical reactions that take place inside the cell.

-1- is formed in the nucleus by a process called -2- in which the DNA opens and the free nucleotides align themselves by -3-, thus picking up the base sequence code from the DNA. This molecule will then pull away from the DNA and take its information to the -4-in the cytoplasm. There it will be used to determine the sequence of -5- in the protein.

1. mRNA 2. transcription 3. base pairing 4. ribosomes 5. amino acids

Translation

process by which bases of mRNA is converted to sequence of aa via tRNA

Codon

sequence of 3nitrogen bases

Ribosomes

in cytoplasm

tRNA

bring proper aa for protein being made

mRNA

codes for the ORDER of the aa

amino acids

building blocks of protein

mutation

change in DNA of cell which are errors in the nitrogen base sequence and result in protein molecule errors because of an incorrect sequence of amino acids in the protein.

Sickle cell anemia

mutation that results in red blood cells that do not carry oxygen properly.

DNA: T A C C C A C T A A C C C G T G G T C C C A A A T T T A A C mRNA: AUG GGU GAU UGG GCA CCA GGG UUU AAA UUG

tRNA: UAC CCA CUA ACC CGU GGU CCC AAA UUU AAC Amino Acid sequence: met -- gly -- Asp acid - Try -- Ala --- Pro --- Gly ---- Phe --- Lys ----L

amino acids connected by

peptide bond

polypeptide chain function determined by

folding of the chain.

peptide chain folding determined by

order of aa

Substitution mutation-

mutations that change ONE nucleotide

Silent mutation

change one nucleotide but do not change the amino acid sequence

Insertion mutation

Insertion mutation- mutations that insert a nucleotide (frameshift)

Deletion mutation

Deletion mutation- mutations that delete a nucleotide (frameshift)

Frame shift caused by

Insertion or deletion of nucleotide

Which is worse deletion of 1 base or 3 bases?

Deletion of one base causes a greater change because it shifts all the bases which in turn will change many AA. While a deletion of 3 sequential bases will only delete one AA.

Give an example of a mutation in the DNA sequence that would result in no change in the protein for which the gene coded.

DNA: AGA DNA: AGT mRNA : UCU mRNA: UCA AA: Serine AA: Serine

Chargaff’s Rule

A always pairs with T | C always pairs with G

Define antiparallel

One side is “right side up” and other is “upside down”

Who discovered the double helix of DNA?

Watson and Crick proposed it and Rosalind Franklin xray shows the Dna twisting

double helix is like a?

ladder

what are the backbones and the steps of the double helix

Backbone: alternating sugars & phosphates Steps: pairs of nitrogen bases (A, T, G, C)

Normally, DNA is in what state

chromatin (unwound)

What is a gene

segment of DNA that instructs the cell to make a specific protein

What makes people DNA different from others

the order of nitrogen bases

DNA review Flashcards

(55 cards)