2.7 DNA -> protein

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19 Terms

1
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why must DNA be replicated?
to prepare the cell for mitosis -> by making copy of the chromosones, to be passed to daughter cells
2
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during what phase of the cell cycle does DNA replication occur?
S-phase of interphase
3
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where in a cell does DNA replication occur?
Nucleus or nucleoid region
4
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summarize the process of DNA replication (6)
* DNA double helix is unwound → two strands are separated


* by enzyme helicase → breaking hydrogen bonds between bases


* new strands form on each of the two templates/parent strands
* nucleotides added to new strands using complementary base pairing
* A to T and G to C
* DNA polymerase add the nucleotides to the new strands
5
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6
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name the two enzymes involved in DNA replication and their roles
helicase → unwinds and separates the DNA double helix DNA polymerase →adds nucleotides to the new strands/proofreads the DNA
7
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explain what is meant by the phrase 'DNA replication is semi-conservative'
DNA replication produces two new molecules from one parent molecules
the newly formed DNA molecules each contains two strands
one of the strands is from the OG parent molecules, the other is new
8
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explain what is meant by the term 'complimentary base pairing' and discuss it's importance to DNA replication
* each base will pair with one other one (A to T, C with G)
* therefore the new strand of DNA formed using the parent strand as template will be identical to the other parent strands
* this means the process can continue forever wo ever changing the genetic material
9
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def: genes
short lengths of DNA that code for particular proteins
10
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def: protein synthesis
the production of polypeptide and proteins by cells involivng two processes, transcription and translation
11
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summarize transcription
* RNA polymerase binds to DNA at promoter site
* RNA polymerase unwinds and separates the double helix
* free RNA nucleotides pair with their complimentary bases on one strand of DNA
* RNA polymerase links the RNA nucleotides together by covalent bonds
* forming a strand of mRNA
* mRNA separates from the DNA and the double helix reforms
12
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names the enzyme involved in transcription and describes its role
RNA polymerase unwinds and separates the DNA double-helix and links together the RNA nucleotides to form the RNA strand
13
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where in a eukaryotic cell does transcription occur
nucleus
14
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where in eukaryotic cell does translation occur?
ribosomes in the cytoplasm
15
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def: codon
sequence of 3 mRNA bases, that codes for a particularly amino acid
16
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describe the genetic code
composes of mRNA codons, 64 in total
each codes for a particular amino acid to add to polypeptide
it is degenrate, more than one codon can code for a particular amino acid
it is universal the same in all living organisms
17
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def: anticodons
triplet of 3 bases on tRNA that are complementary to mRNA codons that determine the amino acid that is carried to the tRNA
18
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def role of tRNA
carry a particular amino acid that corresponds to its anticodon to a ribosome so it can be used to synthesize a polypeptide
19
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summarise the process of DNA translation
* ribosomes bind to the MRNA in the cytoplasm, move along the molecule in a 5’ to 3’3 direction until it reaches a start codon (AUG)
* anticodon on tRNA molecules align opposite appropriate codons according to complementary base pairing (e.g AUG = UAC)
* each tRNA molecule carries a specific amino acid (according to genetic code)
* ribosomes catalyze the formation of peptide bonds between adjacent amino acids (via condensation reactions)
* ribosome moves along mRNA molecule synthesizing a polypeptide chain until it reaches a stop codon
* at this point translation ceases, polypeptide chain is released