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Flashcards in CH16 final Deck (25)
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0
Q

Define replication fork

A

At each end of replication bubble

1
Q

define origins of DNA replication

A

The replication of a chr begins at particular sites …

short stretches of DNA having specific sequence of nucleotides

2
Q

Define helicase

A

are enzymes tht untwist the dbl helix at the replication fork. separating the 2 parental strands and making them available as template strands.

3
Q

define okazaki fragments

A

the lagging strand is synthesized discontinuously, as a series of segments . these segments of the lagging strand are called okazaki fragments

4
Q

Define DNA polymerase

A

these enzymes catalyze the synthesis of new DNA by adding nucelotides to preexisting chains

5
Q

define DNA ligase

A

joins the sugar phosphate backbones of all the okazaki fragments into a continuous DNA strand

6
Q

Define leading strand

A

DNA polymerase III . this continuously adds nucleotides to the new complementary strand as a fork progresses . the DNA stand made by this is called the leading strand 5’ —> 3’ end tht is being made

7
Q

Define lagging strand

A

Is adding nucleotides towards the 5’ end.
this means primase primers the a 5’ end and DNA polymerase III synthesizes the okazaki fragment until it hits the next primer.
DNA polymerase I removes the primer and replaces it w/ nucleotides but the chain is not attached until DNA ligase connects the strand of nucleotides together

8
Q

Mismatch repair

A

other enzymes remove and replace incorrectly paired nucleotides tht have resulted from replication errors.

9
Q

excision repair

A

An area where there are damaged DNA it is cut out by nuclease and is filled in w/. new nucleotides

10
Q

describe how DNA becomes transcibed and translated into proteins tht run metabolism

A

Transcription- is the synthesis of RNA using info from DNA .

translation - is the synthesis of a polypeptide using info in the mRNA .

11
Q

mRNA

A

carries a genetic message from the DNA to the protein synthesizing machinery

12
Q

Triplet code

A

Genetic instructions for a polypeptide chain are written in the DNA as a series of nonoverlapping 3 nucelotide words

13
Q

codons

A

the mRNA nucleotides triplets are called codons

14
Q

reading frame

A

Reading the sequence of nucleotides triplets correctly

15
Q

Promoter

A

The DNA sequence where RNA polmerase attaches and initiates

AUG

16
Q

Transcription unit

A

The stretch of DNA downstream from the promoter tht is transcribed into an rna molecule

17
Q

Transcription factors

A

In ek a collection of proteins called “””” mediate the binding of RNA polymerase and the initiation of transcription

18
Q

RNA polymerase

A

Pries the 2 straands of DNA apart and joins together RNA nucleotides complementary to the DNA template strand

19
Q

Poly A tail

A

is attached to the 3’ end

20
Q

Introns

A

The noncoding segmetnts of nucleic acids tht lie between coding regions

21
Q

Exons

A

The are expressed usually by being translated into amino acid sequences

22
Q

Rybozymes

A

RNA molecules tht function as enzymes

23
Q

tRNA

A

the message is a series of codons along an mRNA molecule and the reanslator is called tRNA

24
Q

Anticodons

A

The paricular nucleotide triplet tht base paits to a specific mRNA codon