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lecture 9 export & modifications Flashcards

(49 cards)

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1
Q

What is genetics?

A

Genetics is the scientific study of gene expression.

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2
Q

In genetics, what is replication?

A

Replication means DNA or RNA is manufactured from nucleotides and the code from DNA.

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3
Q

In genetics, what is transcription?

A

The key to protein synthesis. How RNA and DNA is replicated.

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4
Q

Where are DNA and RNA replicated?

A

In the cell nucleus.

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5
Q

How is the sequence of amino acids determined in the manufacturing of RNA?

A

By the DNA on the original gene.

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6
Q

review: What is the structure of DNA?

A

A double strand, helical nucleic acid with a backbone of deoxyribose sugar and phosphate, with four nitrogenous bases: adenine, guanine, cytosine, uracil

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7
Q

review: What is the structure of RNA?

A

A single strand nucleic acid with a ribose sugar and phosphate backbone, with four nitrogenous bases : adenine, guanine, cytosine, uracil

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8
Q

review: what are the three forms of RNA?

A

rRNA, tRNA, mRNA

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9
Q

review: Purine and pyrimidine make up what?

A
  • nitrogenous bases- purine has 2 nitrogenous rings- pyrimidine has 1 nitrogenous ring
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10
Q

review: a nitrogenous base bonded to a ribose or deoxyribose sugar is called what?

A

nucleoside

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11
Q

review: A nucleoside bonded with a phosphate group is called?

A

nucleotide

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12
Q

review: What is the backbone of DNA and RNA?

A

sugar phosphate backbone

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13
Q

review: nucleotides can hydrogen bond to form their specific couples. What are the base pairing rules for DNA and RNA?

A

DNA: Adenine & Thymine, Guanine & Cytosine
RNA: Adenine & Uracil, Guanine & Cytosine

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14
Q

What is transcription?

A

The writing of DNA genetic code into mRNA (nucleic acid to nucleic acid) by the RNA polymerase enzyme

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15
Q

What are chromatin?

A

the DNA tightly packed into a cell’s nucleus. Creates stability, organization, and protection for the cell’s storage of the genetic code. *only form when a cell is about to divide

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16
Q

What are Euchromatin?

A

less compacted, active chromatin that get transcribed regularly; available for replication (specifically exposed genes that need to be used in the moment)

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17
Q

what are heterochromatin

A

a genetic code that is conserved and almost never accessed for transcription, and is densely compacted in the nucleus (unexposed genes that are not being used at the moment)

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18
Q

What are histones?

A

histones are the chief protein components of chromatin which act as spools around which DNA winds, and they play a role in gene regulation

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19
Q

The DNA double helix wraps around a bundle of histone protiens, which wraps into a ball-like structure called a _____

A

nucleosome

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20
Q

What is the condensed fiber?

Study These Flashcards
A

This is what will bundle itself into Chromatin. It is the DNA double helix coiled around the histone proteins

21
Q

How is RNA transcribed?

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A

RNA polymerase finds the site of code on the DNA that is to be transcribed. It unzips the DNA, replicates the DNA using RNA nucleotides, and rezips the DNA. All RNAs are made this way.

22
Q

Is ATP used during the RNA polymerase’s enzymatic work?

Study These Flashcards
A

yes, copious amounts.

23
Q

what is the enzyme responsible for transcribing DNA code into RNA, allowing protein codes to get to the cytoplasm for protein manufacture

Study These Flashcards
A

RNA polymerase

24
Q

T or F, mRNA is produced by RNA polymerase like the othe rforms, and is spliced and processed in the nucleus

25
what is the difference between an mature mRNA and a tRNA or rRNA in regards to its transcription cycle?
the nuclear processing enzymes know mRNA is is destined to be an mRNA and therefore it is left as a strand that does not fold upon itself like tRNA or rRNA would
26
Is mRNA used to make protein more than once?
yes, it will pass through ribosome multiple times until enough of that protein has been created and the mRNA breaks apart from use and abuse. (negative feedback loop)
27
When is DNA replicated?
Only when a cell divides.
28
in the first step pf DNA replication, a _____ enzyme untwists the secondary helix structure
topisomerase
29
What does helicase do in DNA replication?
untwists the primary helix structure by relieving the hydrogen bonding between the bases. This separates the two strands.
30
What does DNA Primase do in DNA replication?
bonds free floating nucleotides into the deoxyribose chain
31
What does DNA Ligase do in DNA replication?
connects together the bits of newly created nucleotide chain
32
What does DNA polymerase do in DNA replication?
finishes the bonding of nucleotides and rezips the strands as two daughter strands.
33
What are proteins used for?
1) enzymes: catalyze biochemical processes 2) structure: muscles, tendon, skin, ligaments, glands, organs, etc 3) function: hormones and messengers, cell membrane transport, metabolism, etc.
34
What is the basic process of protein synthesis?
- TRANSCRIPTION: the protein code from DNA is copied, writing the code in mRNA. - TRANSLATION: the mRNA is moved out of the nucleus into the cytoplasm where it is TRANSLATED into an amino acid chain (polypeptide) by a ribosome
35
What is a codon?
a grouping of 3 nitrogenous bases that is read to indicate a specific amino acid
36
How does the codon function?
The mRNA strand that needs to be transcribed is a long chain of nucleic acids in groupings of three (codons) that will be read by the ribosome so that tRNA can attach the specific amino acids corresponding to that codon.
37
What other information does a codon provide?
various types of codons exist:- promotion codons- starter codons- termination codons (to tell the ribosome to begin translating mRNA, and telling when the protein code is over)
38
Before mRNA leaves the nucleus, it needs to be spliced. What are the codons called that designates what part of the mRNA is removed?
Introns are codons removed from the mRNA, and the sections of mRNA that are left are called exons. The remaining exons are spliced together and the resulting strand is a mature mRNA that will be moved out of the nucleus into the ribosome for translation into protein.
39
What does tRNA carry?
a 3-base anticodon (using the base pairing rules). tRNA is specific to codons and amino acids, and will carry the specific amino acid needed to attach to the corresponding codon on the mRNA.
40
Can a specific tRNA be used more than once?
Yes, an enzyme called aminoacyl tRNA synthetase recycles tRNA by reloading emptied tRNAs with their specific amino acid.
41
When a codon on mRNA enters the ribosome and tRNA brings the specific amino acid to it, what is this process called?
translation - since the aminos being brought by the tRNA are bonding together (by dehydration synthesis) and forming a new polypeptide. (transcription only occurs when DNA is being transcribed to RNA or DNA is being replicated)
42
in what form are ribosomes found and where?
as subunits 30 and 50, found in the RER or floating freely in the cytoplasm
43
when the mRNA is sensed by the ribosome, what happens?
a 30 subunit and a 50 subunit come together around the mRNA to form a protein factory
44
When the mRNA enters the ribosome, what do the tRNA's do?
loaded with their appropriate amino acid, tRNA enters the ribosome and match their anticodons to the codons on the mRNA
45
what kinds of bonds form between the amino acids from the A site to the P site by enzymatic action
peptide bonds
46
What are the A and P sites of the ribosome?
The tRNA are actively bonding their aminos here. The ribosome keeps moving the mRNA through so that the aminos can bond consecutively, forming a chain.
47
When does this action of the mRNA and the ribosome, and the forming of a polypeptide chain stop?
When the TERMINATION CODON reaches the active site, translation will stop
48
After the termination codon arrives at the active site and after the polypeptide chain is formed, what happens? Where?
The polypeptide chain moves out of the ribosome and folds or is modified into a protein. Often this happens in the Golgi Complex.
49
Where are vitamins and other cofactors inserted into the newly formed protein to create a holoenzyme for use or as a zymogen for storage?
in the ER or the Golgi Complex

Bio Chem (3 decks)

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