Exam 2 Content (pt 1) Flashcards
(100 cards)
1
Q
where is the RNA exported to in eukaryotic cells?
A
cytoplasm
2
Q
which type of RNA becomes a proteins after translation?
A
mRNA
3
Q
where does translation occur in a eukaryotic cell?
A
cytoplasm
4
Q
proteins “zip” the mRNA together during translation
A
true
5
Q
what is the difference between nucleotides & nueclosides?
A
nucleotides have a phosphate group
6
Q
what type of bond forms between nucleotide bases?
A
phosphodiester bonds
7
Q
how many carbons are on a nucleotide?
A
5
8
Q
which carbon on a nucelotide attaches to the base?
A
1’
9
Q
what are the types of DNA bases?
A
- Adenine
- Guanine
- Cytosine
- Thymine
10
Q
what atom does the 2’ carbon on a nucelotide lack?
A
oxygen
11
Q
what part of the 3’ carbon will be used to form phosphodiester bonds?
A
OH (hydroxyl) molecule
12
Q
what is the 5’ carbon attached to in DNA?
A
phosphate group
13
Q
what are the characteristics that phosphates give to DNA’s backbone?
A
- acidity
- negativity
14
Q
what type of bond is a phosphodiester bond?
A
covalent
15
Q
what are the characteristics of a phosphodiester bond that make it strong?
A
it is resistant to both pH and temperature changes
16
Q
bases can only be added to the 3’ carbon
A
true
17
Q
DNA synthesis only occurs in the 5’ – 3’ direction
A
true
18
Q
what are the main characteristics of dsDNA?
A
- right handed
- antiparallel
19
Q
definition
antiparallel
A
going in opposite directions
20
Q
who are the scientists that conducted the x-ray crystallography of DNA?
A
- Rosalind Franklin
- Maurice Wilkins
21
Q
which base pairs did Erwin Chargaff discover to have equal percent ratios?
A
- %C = %G
- %A = %T
22
Q
what kind of bond forms between the deoxyribose sugar and the nucleotide bases?
A
glycosidic bond
23
Q
what kind of bond forms between the complementary base pairs?
A
hydrogen
24
Q
wha happens when uncomplementary bases pair?
A
they will repel each other, and cause genetic mutations
25
what is the angle between two bases that constitute a ***major*** *groove*?
**> 180˚**
26
what is the angle between two bases that constitute a ***minor*** *groove*?
**< 180˚**
27
***parental strands*** serve as *templates* for *daughter strands*
true
28
what are the *essential components* of each ***new double helix***?
* original parental strand
* newly synthesized daughter strand
29
which *enzyme* is utilized during **DNA replication**?
**DNA polymerase**
30
why is there a use for *complementary base pairing* in **DNA replication**?
to preserve fidelity
31
what causes ***DNA strands*** to be *stable*?
*hydrogen bonds* that are formed between the *bases*
32
DNA replication is ***antiparallel*** to the *template strand*
true
33
what is the chemical reaction that occurs to initiate **DNA synthesis** *(replication)*?
the ***3' end*** *hydroxyl group* _attacks_ the *3-phosphate bond* from incoming nucleotide
34
what happens to the ***3-phosphate group*** when it gets attacked by the *hydroxyl*?
it becomes a ***2-phosphate group*** *(pyrophosphate)*
35
what are the *base pairs* involved in ***transcription***?
| transcription: (DNA -> RNA)
* Uracil
* Thymine
* Adenine
* Cytosine
36
what constitutes **RNA synthesis**?
addition of next ***ribonucleotide*** to the 3' end of the growing subscript
37
*thymine* pairs with ***adenine*** from the *template strand of DNA*
true
38
*adenine* pairs with ***uracil*** from the *template strand of DNA*
true
39
what are the types of strands in **DNA**?
* coding *(template)*
* noncoding *(nontemplate)*
40
what are the steps in ***transcription***?
* initiation
* elongation
* termination
41
where on the DNA does ***transcription*** end?
**DNA terminator**
42
on what part of the DNA strand does transcription ***initiation*** occur?
**DNA promoter**
43
besides being the *initiation site*, what else is the purpose of **DNA promoter**?
recruits the machinery for transcription
44
what happens to **RNA** once it has been *transcribed*?
it dissociates from the DNA template & transported to the cytoplasm
45
what ***encourages*** *transcription* in DNA?
**DNA enhancer sequences**
46
what are ***transcription factors***?
these are proteins that turn genes "on" & "off"
47
what does the ***transcriptional activator proteins*** increase the likelihood of?
transcription of select genes
48
where do ***transcription factors*** bind to on the *DNA*?
**promoter**
49
where do ***activator proteins*** bind to on the *DNA*?
**enhancers**
50
*DNA* makes a loop in order for **transcription** to occur
true
51
what are the ***proteins*** that come in close proximity when *DNA* makes a loop?
* transcriptional activator proteins
* mediator complex
* RNA Pol II
* general transcription factors
52
what is the enzyme that catalyzes ***RNA polymerization***?
**RNA polymerase**
53
what does the **elongation phase** of *transcription* require?
| (3)
* template DNA
* ribonucleotides
* RNA polymerase
54
what kind of bond does the **RNA polymerase** form during *elongation phase*?
the ***phosphodiester bond*** between the last nucleotide in the *mRNA* strand and the new one
55
what part of the DNA does the **RNA polymerase** reach in order to release the *mRNA transcript*?
the *terminator sequence*
56
what are the tasks of **RNA polymerase**?
* separate DNA's two strands
* allows pairing between DNA & RNA
* polymerization
* releases the mRNA transcript
57
what are the regions on the ***primary mRNA transcript*** that will be *spliced*?
**introns**
58
which region on the ***primary mRNA transcript*** will be removed during *transcription*?
**extrons**
59
what are the steps that *modify* the mRNA transcript?
| (3)
* 5' capping
* 3' polyadenylation
* intron splicing
60
what does the **5' cap** do for the *mRNA transcript*?
* provides protection from degradation
* recruits ribosomes for translation
61
what does the **5' cap** consist of?
a modified base with its 5' carbon ***linked to the 5' end of the primary transcript*** with a *3-phosphate bridge*
62
where does the **poly-A tail** in *3' polyadenylation* attach to?
the *3' end* of the transcript
63
what is the result of **alternative splicing of mRNA**?
different transcripts that code for different proteins from mRNA transcripts from the same gene
64
what does it mean when an *RNA* is **noncoding**?
it is not involved with *transcription*
65
what do **noncoding RNAs** become if they are not transcripted?
* ribosomal RNA
* transfer RNA
* small nuclear RNA
66
# definition
**ribosomal RNA**
RNA that attaches to *ribosomes* that *perform translation*
| they are the MOST abundant type of RNA
67
# purpose
**transfer RNA**
carries individual amino acids that are involved with *translation*
68
# purpose
**small nuclear RNA**
aid in splicing of *introns* from mRNA
69
what are the types of **amino acids**?
* hydrophilic
* hydrophobic
70
what are the types of ***hydrophilic*** **amino acids**?
* polar *(o)*
* basic *(+)*
* acidic *(–)*
| neutral; positive; negative
71
how are the charges of an amino acid determined?
based off ***R-groups***
72
what kind of *bond* forms between **amino acids**?
**peptide bond**
73
what kind of *bond* is a **peptide bond**?
**covalent**
74
*amino acids* are the building blocks of **protein**
true
75
the ***carbon*** in one amino acid's *carboxyl group* binds to which *atom* of the next amino acid?
**nitrogen**
76
what kind of *reaction* results from a *peptide bond formation*?
**dehydration reaction**
| byproduct is water
77
on what part of the *amino acid* is a new one attached?
**C-terminus**
| it contains the ***carboxyl***
78
the **N-terminus** of one amino acid is attached to the **C-terminus** of the next
true
79
which **protein structure** dictates a protein's way of folding and function?
**primary structure**
80
what happens when a *protein* starts forming its **secondary structure**?
**hydrogen bonding** within the polypeptide
81
what are the components involved in the **hydrogen bonding** of the *secondary structure*?
* amino group
* carboxyl group
82
how many *nucleotides* are in one **codon**?
**3**
83
what do the ***3 nucleotides*** determine in *translation*?
which *amino acid* will be translated
84
what is the ***initiation codon***?
**AUG**
85
how many *possible* ***codons*** are there?
**64**
86
what are the *cellular components* required for ***translation***?
* mRNA
* ribosome *(small & large subunit)*
* tRNA
* initiation factors
* elongation factors
* release factors
* aminoacyl tRNA syntheses
87
what are the *binding sites* located in the **large ribosome subunit** for translation?
* **E**xit site
* **P**eptidyl site
* **A**minoacyl site
88
what does the **small ribosomal subunit** decode?
**mRNA**
89
# purpose
**large ribosomal subunit**
joins the newly formed amino acids to form ***polypeptides***
90
the **E site** is where *empty tRNA* exits the ribosome
true
91
what does the **A site** accept?
the new **tRNA**
92
where on the **large ribosome** does the *peptide bond formation* occur?
**P site**
93
what is the role of **tRNA** in translation?
they function as *adaptors* between ***ribonuleotides*** & newly synthesized ***amino acids***
94
what are the *characteristics* of **tRNA**?
* anticodon *(5' – 3')*
* single stranded
95
how does *tRNA* join with the *amino acid*?
the tRNA's anticodon recognizes the codon in mRNA
96
on what part of the amino acid is the **3' end** of *tRNA* bound to during translation?
the **carboxyl group**
97
**tRNA** is in charge of *how* amino acids will form polypeptides
true
98
where does **3' end** of *anticodon* bind to _before_ it binds to the new amino acid?
**5' end of codon**
99
what are the roles of **initiation factors**?
* recruit the *small ribosomal subunit* & *tRNA*
* scans the mRNA for *AUG*
100
what happens when the ***small ribosomal unit*** reaches AUG on the *mRNA*?
* the **large ribosomal unit** joins *(makes a "sandwich")* the unit
* initiation factors are released
