UNIT 1 REVIEW Flashcards
(162 cards)
1
Q
If pangenesis were true:
A
hertiable info would be transmitted by somatic cells, not just germ cells in the gonads #gemmules
(Darwin proposed this theory)
2
Q
Drosophilia meanogaster
A
Fruit Fly
3
Q
Caenorhabditis elegans
A
Nematode
4
Q
Arabidopsis thaliana
A
Thale-Cress Plant
5
Q
Neurospora crassa
A
bread mold
6
Q
Zea mays
A
corn
7
Q
Danio reiro
A
zebra fish
8
Q
Xenopus laevis
A
clawed frog
9
Q
Preformationism
A
sperm or eggs contain a fully formed homunculus and thefore the traits of offspring were inherited from only one parent.
10
Q
homunculus
A
fully formed mini human
11
Q
Who Porposed the Theorgy of Pangenesis?
A
Darwin
12
Q
Who proposed the Germ-Plasm Theory?
A
Weissmann
13
Q
Germ-Plasm Theory
A
germline tissue in the reproductive organs contained a complee set of genetic info which is transferred directly to the gametes.
(Proposed by Weissmann)
14
Q
Inheritance of Acquired Characteristcs Theory
A
acquired traits become incorporated into hereditary info
(The theory is incorrect)
15
Q
What 3 Theories of Inheritance are Correct?
A
- Germ-Plasm Theory
- Cell Theory
- Mendelian Inheritance
16
Q
How many genes are in the human genome?
A
~20,500
17
Q
nucloside vs nucleotide
A
Nuclotide = 5 Carbon sugar + base + phosphate
Nucleoside = evereything but the phosphate (5 carbon sugar + base only)
18
Q
rNTP
A
ribose Nucleotide Tri Phosphosphate
19
Q
dNTP
A
deoxyribose Nucleotide Tri Phosphate
20
Q
Describe a Purine’s shape
A
hexagon connected to a pentagon
(A&G)
21
Q
Describe a Pyrimidine’s Shape
A
a hexagon
(T, C, U)
22
Q
A
A
purine
23
Q
G
A
purine
24
Q
C
A
pyrimidine
25
T
purine (found only in DNA)
26
U
purine
(found only in RNA)
27
What are the 2 Purines?
A & G
28
What are the 3 Pyrimidines?
T, C, U
29
What does it mean for nucleic acids to be antiparallel?
One strand is oriented 5' - 3' and the other strand is oriented 3' - 5'
30
What does it mean for nucleic acids to be complimentary?
pyrimidines align and hydrogen bodn with their corresponding purine and vise versa
31
4 Things that Genetic Material must do or be:
- contain complex coding info
- replicate faithfully
- must encode the phenotype
- have the capacity to vary
32
Fredrick Griffith
Discovered the principle of transformation
33
Who discovered the principle of Transformation using bacteria and mice?
Frederick Griffith
34
Explain How Frederick Griffith Discovered the Principle of Transformation of Bacteria?
- Live virulent bacteria killed the mice.
- Live non-virulent bacteria did not kill the mice.
- Killed virulent bacteria did not kill the mice.
- Killed virulent bacteria with with live non-virulent bacteria killed the mice.
Essenetially, virulent bacteria were able to share their genetic code for virulency with non-virulent bacteria which transformed them into virulent bacteria.
35
Griffith Discovered the Transforming Principle, but Who Identified the substances as being DNA?
Avery, MacLeod, & McCarty
36
What did Avery, MacLeod, & McCarty do?
Identified DNA is the substance which causes Transformatio in Bacteria
37
How did Avery, MacLeod & McCarty ID the Transforming Principle?
They 1) killed virulent bacteria
2) homogenized it into a mix of proteins, RNA, & DNA
3) Used DNAase, RNAase & Protease in different samples of the homogenized bacteria to kill the different componenens
4) examined which sampels allowed transformation into virulent bacteria
38
What did Alfred Hershey & Martha Chase discover?
DNA is the genetic material of phages
39
Briefly Describe How Hershy & Chase discovered DNA is the genetic material of phages?
E. coli was infected w/ bacteriophages in 2 separate test tubes. One test tube had radioactive S and the other had radioactive P.
After growing, the protein coats were sheared off in a blender and separated using centrifugation. Radioactive S was seen in the fluid containing the virus coats and radioactive P was seen in the progeny phages.
40
Difference b/w Ribose and Deoxyribose
Ribose has an OH and Deoxyribose has just an H (no O) on the 2' Carbon.
41
Which Carbon in a pentose sugar determines if it is ribose or deoxyribose?
the 2' Carbon
42
Purines always pair w/ __________.
Pyrimidines
43
dAMP
deoxy Adenosine Mono Phosphate
44
What is adenine called when bonded with a sugar?
adenosine
(ose=sugar)
45
What are the 2 things sepcified by Chargaff's Rule?
- AT & GC are base pairs
- The variability of nucleotides is different in different species
46
According to Chargaff's Rule, if a genome is 20% adenine, what percent should be guanine?
30% Guanine
(20% A + 20% T = 40%
30% G + 30% C = 60%)
47
Who was a crystallographer and helped discovere the molecular structures of nucleic acids, including the helix?
Rosalind Elsie Franklin
48
What did Watson & Crick contribute to the study of Genetics?
Understanding the 2ndary structure (double helix) explains how DNA replciates
49
What two parts of the nucleotide form the backbone of a DNA strand?
sugar and phosphate held together by phosphodiester bonds
50
Which set of base pairs forms 3 hydrogen bonds and are therefore stronger?
G-C
51
What is the most common form of a right handed DNA helix?
B-Form
(the slightly uneven spacking forms mnor and major grooves)
52
To which Carbon in the sugar does the nitrogenous base bond to?
1'
53
To which carbons are the phosphates bonded to the sugar in nuclotides?
3' and 5'
54
What is the polarity of nucleic acids?
5' - 3'
55
What is the polarity of proteins?
N-terminus --> C-terminus
56
Tertiary Structure AKA
Globular Structure
57
What are the 4 main functions of DNA?
- store complex info
- replicate faithfully
- encode the phenotype
- capacity to vary
58
rRNA
ribosomal RNA
59
tRNA
translation RNA
60
Does the 3' or 5' end of a tRNA look longer?
3'
61
What prevents RNA from forming the B-Form double helix like DNA?
The extra OH group in RNA prevents it from forming the B-Form double helix. Instead, RNA forms the A-Form double helix.
62
What helical form is typical of DNA?
B-Form
63
What is the primary enzyme in DNA replication?
DNA polymerase
64
What is the primary enzyme in RNA replication?
RNA polymerase
65
What is the primary enzyme in translation from RNA --> proteins
ribosomes (ribozyme)
66
What is the difference b/w (+) and (-) sense RNA?
Positive Sense RNA can be translated or replicated
67
Which RNA is unique to prokaryotes?
crisprRNA
(crRNA)
68
List some RNAs unique to eukaryotes
pre-messenger,
small nuclear,
small nucleolar,
micro,
small interfering,
long noncoding
piwi-interacting
69
snRNA
snoRNA
small nuclear (sn)
small nucleolar (sno)
*Note: Both found in the nucleus
70
miRNA
micro RNA
71
siRNA
small interferring RNA
72
lncRNA
long noncoding RNA
73
piRNA
Piwi-interacting RNA
74
Difference b/w RNA Polymerase I, II & III
I: transcribes genes encoding rRNA
II: transcribes genes encoding mRNA (+sn & microRNAs)
III: transcribes genes encoing tRNAs
75
Which Polymerase transcribes genes encoding mRNAs
RNA Polymerase II
76
Which Polymerase transcribes genes encding tRNAs
RNA Polymerase III
77
Which Polymerase transcribes genes encoding rRNA
RNA Polymerase I
78
In which direction is DNA read?
3' - 5'
79
In which direction is RNA syntesized?
5' to 3'
80
Non-Template Strand AKA
Coding Strand
(this strand is idential to the RNA strand except T are replaced w/ U)
81
Template Strand AKA
Non-Coding Strand
82
What strand of DNA is actually being read during transcription?
The Non-Coding Strand
AKA the Template Strand
83
What is the Coding Strand?
The strand of DNA that will look ALMOST identical to the RNA transcribed. (The Coding Strand is not the strand being read).
84
The best definition of a "gene" is
a transcription unit
85
Structural Gene
RNA coding region
86
At what end of the template is the terminator?
the 5' end
87
At what end of the template is the promotor?
the 3' end (in the negative region)
88
Does the promotor get transcribed?
No
89
Does the terminator get transcribed?
yes
90
What is the 5' UTR?
On an RNA molecule: located b/w the start of an RNA transcript and the AUG start codon. Allows the ribosome to bind and initiate translation.
91
What is the 3' untranslated region?
On an RNA molecule: starts at the stop codon and goes to the end of the transcript
92
In which direction is RNA synthesized?
5' - 3'
93
In which direction is RNA read?
5' - 3'
94
What are the 3 Phases of Transcription?
1) Initiation
2) Elongation
3) Termination
95
Step 1 of Transcription
INITIATION
DNA is unwound to create a transcription bubble and initiate RNA synthesis
96
Step 2 of Transcription
ELONGATION
RNA synthesis continues and the transcription bubble moves along
97
Step 3 of Transcription
TERMINATION
RNA stops synthesiszing and is released
98
Start Codon
AUG
(*A is at the START of the alphabet)
99
Stop Codon
UAG
(*U is near the end of the alphabet)
100
Where does Polymerase Bind?
at the promoter
101
Where is the promoter on DNA?
Towards the 5' end of the NONTEMPLATE strand, upstream from the transcriptions start site
102
What nucleotides are found in the Pribnow Box?
As and Ts
103
What are the locations of the two short sequences in prokaryotes' promoters that help initite transcription?
-35 and -10 (pribnow box)
104
Prokaryotes have a Pribnow Box in their promoters. Eukaryotes have a _________ Box
TATA
105
Consensus Sequence
the idealized sequence/most frequently occurring
106
sigma factor
a transcription factor that helps initiate transcription, by helping the core RNA Polymerase bind to the promoter.
Binds initially during transcription, but leaves once you get going.
107
sigma factor + core RNA polymerase =
holoenzyme
108
About how nucleotides long is the elongation bubble?
~18
109
Is sigma factor needed to intiate transcription?
Yes. It is necessary.
(only to initiate, but not to elongate)
110
sigma factors are found in prokaryotes or eukaryotes?
prokaryotes
111
What do Transcriptional Activator Proteins do?
bind to enhancer sequences upstream the promoter and cause the DNA to fold and create a large complex.
112
Rho Factor
helps termiate transcription in bacteria by unwinding the RNA from the DNA.
113
Where does Rho attach?
it attaches to the rut site on RNA
114
Explain how RNA synthesis is terminated in Bacteria
-Rho factor attaches to the rut site on the RNA then moves toward the 3' end
-When RNA polymerase encounters a terminator sequence, it pauses and Rho catches up.
-Rho uses helicase activity to unwide the RNA from the DNA
115
Explain Rho-Independent Termination
A sequence of inverted repeats in the terminator are transcribed into RNA and forms a hairpin loop.
The hairpin loop destabilizes DNA-RNA base pairing and the RNA is released.
116
What is the difference b/w T & U
a methyl group
117
How many hydrogen bonds form between G & C?
3
118
Does Rho Factor require ATP?
yes.
119
What must happen to end transcripition?
- RNA polymerase must stope synthesizing RNA
- RNA must be released from the RNA polymerase & DNA template and then dissociate
120
What do Inverted Repeats form?
Hairpin Loops
121
Polycistronic RNA
multiple genes share the same RNA molecule
122
Colinearity
direct correlation b/w DNA sequence and amino acid sequence in prokaryotes w/o exons and introns.
Prokaryotes have continueous genes and eukaryotes have disrupted genes.
123
During transcription, sequences of DNA containing introns will form ___.
loops
124
What is the Shine-Dalgarno Sequence?
ribosome binding site in prokaryotes
125
In prokaryotes, ribosomes can attach to the 5' end of mRNA and begin _______ while the 3' end is still being _________.
Translated
Transcribed
126
In eukaryotes, where does translation take place?
the cytosol
127
What are the 4 steps in pre-mRNA processing?
Introns are excised.
Exons are spliced back together.
5' Cap is formed.
Poly(A) Tail is formed (polyadenylation)
128
What is the purpose of the 5' Cap?
Helps start translation.
CAP Binding Proteins Bind to the CAP then Ribosomes bind to the CAP Binding Proteins before moving along to the Start Codon
129
3 Fuctions of the 3' Poly(A) Tail
- Increases stability of the mRNA
- Aids in exporting the mRNA out of the nucleus in to the cytosol
- promotes attachment of the ribosome to the RNA
130
Where are the 5' and 3' splice sites located?
5' splice site is located at the beginning of an intron and the 3' splice site is located at the end of an intron.
131
snRNAs are located in what part of the cell?
the Nucleus
132
Explain how Introns are Removed
- snRNP (splicosome) cuts the RNA at teh 5' splice site (the beginning of the intron).
- The free 5' end loops and forms a lariat w/ the branch site in the middle of the intron through a transesterification rxn.
- the 3' splice site is cut to relase the intron with the lariat
- debranching enzymes release the lariat so the intron is a linear sequence again.
-exoribonucleases destroy the introns to make more RNAs with its nucleotides.
133
Alternative Splicing
exons can be included in the lariat and removed with the introns --> different proteins will be synthesiszed in eukaryotes
134
What is always the code for the Acceptor Arm in tRNA
CCA (5'-3')
135
Ribosome Size in Bacteria
70S (50S + 30S)
136
Ribosome Size in Eukaryots
80S (60S + 40S)
137
siRNA
pieces of double stranded RNA formed when Dicer chops up double stranded RNA
138
RISC
RNA Induced Silencing Complex
1 strand of siRNA + 1 argonaute
interferes with mRNA translation
139
Difference b/w microRNAs and siRNAs
both can be incorporated into RISC but mirocRNAs inhibit the translation of mRNA and siRNAs cleave and degrade mRNA
140
Where does transcription start?
The promoter
141
Where does translation start?
The start codon
142
Location of the Shine-Dalgarno sequence
5' UTR region of RNA in prokaryotes where the ribosome attaches
143
What are the two polarities on peptides?
N-Terminus and the C-Terminus
144
elements found in proteins
CHONS
145
Which amino acid is essential for children but not adults?
arginine
146
The 3 BCAAs are:
Leucine, Isoleucine, & Valine
147
How many Amino Acids are essential?
9
148
Marshall Nirenberg & Johann Matthaei
discovered which codons code for which amino acids
149
How many of the 64 codons are nonsense codons?
3
150
Start Codon
AUG
methionine
151
isoaccepting tRNAs
tRNAs with different anticodon sequences, but accept the same amino acid
152
The ___ position in a codon can sometimes pair with different nucleotides. ___ & ___ may sometimes be read by a G in the anticodon.
3rd position
U & C may be read by a G in the anticodon if in the 3rd position
#wobble
153
The Wobble Position
the 3rd position in the codon
(U & C may be read by G)
154
What are the 3 sites for tRNA on a ribosome?
A: Acceptor Site
P: Peptide Site
E: Exit Site
#APE
155
mRNA is read
5' to 3'
156
Initiation Factors which prevent ribosome subunits from closing before positioning around the mRNA
IF - 1 & 3
157
Initiation Factor which enables the attachment of tRNA carrying N-formylmethionine onto the P site at AUG
IF - 2
158
Explain how amino acids are added to a polypeptide chain
- IF-1&3 help the ribosome assemble around the mRNA.
- EF-Tu says "HEY YOU!" and joins w/ GTP to guide tRNA to the A Site
- EF-Ts stimulites the Tu and reenergizes it so it can keep working.
- Meanwhile, EF-G moves the ribosome down the mRNA so it can get Going and Growing
159
Where on the tRNA do amino acids attach?
The 3' end with the amino acid attachment site CCA
160
charging the tRNA
Aminoacyl tRNA Synthetases attach amino acids to the tRNA using ATP
161
Shine-Dalgarno vs Kozak Sequence
both are consensus sequences.
Shine-Dalgarno Sequence is found in BACTERIA UPSTREAM the start codon.
Kozak Sequence is found in EUKARYOTES AROUND the start codon.
162
Just as enhancers form loop and aid in transcription, _____ forms a loop and aids in __________.
Poly(A) tails form a loop and aid in translation.
