Exam 4 Flashcards
1
Q
What type of sugar is deoxyribose?
A
a pentose sugar
2
Q
In 1950, Erwin Chargoff reported that DNA composition varies from one species to the next.
True or False
A
true
3
Q
Nucleic acids are polymers specialized for what three things?
A
- storage
- transmission
- use of genetic information
4
Q
What is the monomer of nucleic acids?
A
nucleotides
5
Q
Are pyrimidines single rings or double rings?
A
single rings
6
Q
Which nitrogen bases are purines ?
A
adenine and guanine
7
Q
Are Purines single rings or double rings?
A
double rings
8
Q
What is the name of the rule that states that in any species there is an equal number of A and T bases, and an equal number of G and C bases?
A
Chargaff’s rule
9
Q
Pairing a purine with a pyrimidine results in a uniform width.
true or false?
A
true
10
Q
What three things together build a nucleotide?
A
pentose sugar+ N-containing base+ phosphate group
11
Q
What two pyrimidines are used in DNA ?
A
- Thymine
* Cytosine
12
Q
What did James Watson and Francis Crick (the buttheads) do?
A
Introduced an elegant double-helical model
Stole the information from Rosalind Franklin
13
Q
Who was responsible for taking DNA and crystalizing it to take an x-ray photograph?
A
Rosalind Franklin
14
Q
How did Rosalind Franklin determine that DNA was a double helix?
A
By MEASURING the xray crystallography that she had taken of DNA
15
Q
The Watson-Crick model helped explain Chargoff’s rule. true or false?
A
true
16
Q
Why can A not pair with C and G not pair with T?
A
Because of the amount of hydrogen bonds needed
17
Q
What does anti-paralell mean?
A
the two strands going in opposite directions, like two roads going in opposite directions
18
Q
The two strands of DNA are _____________, so each strand acts as a template for building a new strand in replication.
A
complementary
19
Q
In DNA replication, what does the enzyme helicase unwind?
A
the parent molecule
20
Q
Once the parent molecule unwinds, the two new daughter strands are built based on what?
A
base pairing rules
21
Q
What does a daughter DNA molecule consist of?
A
One parental strand and one new strand
22
Q
The new cell that will be made needs a copy of what?
A
the entire DNA
23
Q
What is a template?
A
An existing DNA strand that we can use to copy from or build off of
24
Q
What type of bond holds the two strands together?
A
Hydrogen bonds
25
What Model predicts that when a double helix replicates, each daughter molecule will have one old strand "conserved" from the parent molecule and one newly made strand?
Semiconservative Model
26
Is DNA synthesis anabolic or catabolic?
anabolic
27
What four things will the cell need to do DNA replication?
1. Energy
2. Template
3. Enzymes
4. Nucleotides (4 Nitrogen bases)
28
How many strands of DNA are there that must be copied?
48 strands, 24 pairs
29
DNA is short and thick.
| True or False?
Fasle, DNA is very thin and incredibly long
30
Does DNA synthesis require ATP (Energy)?
Yes, it's anabolic, it needs energy to build
31
Name the 4 nitrogen bases used to construct DNA
* Adenine
* Thymine
* Cytosine
* Guanine
32
Of the 4 bases, which ones are double rings?
Adenine and Guanine
33
What monomer is used to build into polymers in DNA replication?
Nucleotides
34
What is copulation?
the act of intercourse to introduce an egg cell to a sperm cell
35
DNA replication takes one strand and makes it into ___ _______.
two strands
36
In cells produced by mitosis, are all chromosomes alone or in pairs?
all chromosomes are in pairs
37
How many PAIRS of chromosomes are found in humans?
23 pairs
38
Are egg and sperm cells functional without fertilization (without eachother)?
no, they are not functional alone
39
When DNA first replicates, the two inner strands are still what?
Still attached to eachother, stuck together
40
During DNA replication, they speak of a "narrow waist" where there is a pinching of the two sister chromatids together, what is this area called?
centromer(e)
41
Where does the new strand replicate, on the outside or inside?
on the inside
42
What is the function of mitosis?
to pull apart the chromatids and allow them to complete and become two chromosomes.
43
If in Mitosis all chromosomes are in pairs, (one from mom, one from dad), what happens with Meiosis?
Meiosis= 1/2 of each chromosome pair
44
Which helps you repair, mitosis or meiosis?
Mitosis
45
What is made up of DNA and histone proteins?
Chromatin
46
Where are eggs and sperm produced?
in the ovaries and testes
47
How is asexual reproduction in humans done efficiently?
mitosis
48
How is asexual reproduction in bacteria done efficiently?
binary fission
49
Asexual reproduction means to what?
clone
50
Sexual reproduction is done through _______.
meiosis
| egg and sperm
51
Is DNA replication part of interphase or mitosis?
DNA replication is part of interphase
52
In which part of the stages of mitosis is most of the work done?
prophase/prometaphase
53
Once the chromosomes look like X's , they have been replicated (s phase) and are ready (for G2) and are ready for mitosis.
true or false?
true
54
The centrioles grow microtubules and attach to the chromosome at what part?
the centromer
55
What protein by the centromer can the microtubules attach to?
kinetochore
56
In what part of Interphase does DNA replicate?
S phase
57
In prophase, prophase I, and prophase II, chromatin is condensing into ___________.
Chromosomes
58
In Prophase (during mitosis), the nuclear envelope and the nucleolus are doing what?
breaking down
59
Does a replication of centrioles happen during mitosis?
yes
60
What does Helicase do?
unwinds the parent double helix at replication forks
61
What does a single-strand binding protein do?
Binds to and stabilizes single-stranded DNA
62
Which enzyme relieves "overwinding" strain ahead of replication forks by breaking, swiveling, and rejoining DNA strands
Topoisomerase
63
What is primase for?
synthesizing RNA Primer at 5' end of leading strand and of each Okazaki fragment of lagging strand
64
What makes new DNA strands by covalently adding nucleotides to the 3' end of pre-existing DNA strand or RNA primer
DNA pol III
65
What enzyme removes RNA nucleotides of primer and replaces them with DNA nucleotides?
DNA polymerase I
66
Which enzyme is responsible for joining the 3' end of DNA that replaces primer to the rest of the leading strand and joins Okazaki fragments of the lagging strand?
```
DNA ligase
(hint: ligands join things together)
```
67
Which enzyme works first, DNA pol I or DNA pol III?
DNA polymerase III
68
Replication begins at particular sites called what?
Origins of replication
69
What happens to the two DNA strands at the origin of replication?
the two DNA strands are separated, opening up a replication "bubble"
70
Where do origins of replication usually begin?
Where there are multiple A-T sequences in a row together.
71
Why are A-T sequences a good place for an origin of replication?
Because they are easier to break apart since A-T only have 2 hydrogen bonds
72
Are there multiple origins of replication or just one?
multiple, this helps it to happen quicker
73
A eukaryotic chromosome may have hundreds or even thousands of origins of replication.
true or false?
true
74
Replication proceeds in which direction from each origin, until the entire molecule is copied?
in both directions
75
The Daughter strand is the ___ strand while the Parental Strand is the ___ strand
new, old
76
Which strand is the template?
The parental strand
77
RNA can complimentary base-pair with DNA.
| true or false?
true
78
DNA polymerases can only ADD nucleotides to the 3' end, they cannot do what?
initiate synthesis of a polynucleotide
| they cannot start until a primer is added
79
We can only add new nucleotides to a 3' end becuase of the _____ of the enzyme.
shape
80
Which enzyme can start an RNA chain from scratch and add RNA nucleotides one at a time to the parental DNA template?
primase
81
When they refer to the RNA primer as short, how many nucleotides long is it?
5-10 nucleotides long
82
5' and 3' has to do with the orientation of what?
the carbons
83
The 3' end is continuous, while the bottom strand (lagging strand) has to wait for what?
* for it to unwind
* wait for a primer
* then add nucleotides
84
At the end of each replication bubble is a replication ____. A y-shaped region where new DNA strands are __________.
fork
| elongating
85
Does helicase untwist the double helix behind or ahead of the fork
ahead of the fork
86
Does topoisomerase correct "overwinding" behind or ahead of the fork?
ahead of the fork
87
What two things do most DNA polymerase require?
a primer
| a DNA template strand
88
What is the rate of elongation in bacteria and the rate of elongation in human cells?
```
bacteria= 500 nucleotides per second
humans= 50 nucleotides per second
```
89
DNA polymerases add nucleotides only to the free 3' end, therefore a new DNA strand can elongate only in the _' to _' direction
5' to 3'
90
To elongate the lagging strand, DNA polymerase must work in what direction?
in the direction away from the replication fork
91
The lagging strand is synthesized as a series of segments called what?
Okazaki fragments
92
Okazaki fragments are joined together by what enzyme?
DNA Ligase
93
The lagging strand can't add nucleotides continuously, it can only add to a 3' end so it has to wait for what to happen before it can add a primer?
for helicase to unwind it
94
What does DNA Polymerase I do to the RNA Primer?
It cuts out the RNA primer and replaces the RNA with DNA nucleotides
95
Ligase comes in after DNA Polymerase I and does what?
Connects it together so that we have a continuous strand of DNA
96
What does a DNA Polymerase proofreader do?
Goes down the newly made DNA strand, finds mistakes, cuts them out and replaces any incorrect nucleotides
97
What happens if a proofreader misses a mistake?
a mutation occurs
98
What do SOS enzymes do?
repair
99
What is another name for a mutagenic agent?
a carcinogen
100
What happens in nucleotide excision repair?
a nuclease cuts out incorrect nucleotide and replaces damaged stretches of DNA
101
Base pairs code for amino acids.
| true or false?
true
102
When is the only time that mutations can happen?
When DNA is replicating
103
What is Nuclease
an SOS repair enzyme
104
When is the only time that a mutation that occurs can effect your offspring?
If the mutation happens while making an Egg or a Sperm
105
Why do humans evolve so slowly?
they have a low reproduction rate
106
What are the chances that a mutation can occur?
10^6 or 1 in a million
107
Cancer is a mistake in DNA replication.
| true or false?
true
108
How many errors occured for someone that gets sickle-cell anemia?
only one error
109
What does sickle-cell anemia protect from?
malaria
110
If there were no errors possible, we would never get cancer, but we would also never do what?
evolve
111
The chromosomes of prokaryotes are what shape?
circular
112
As DNA replicates, it gets _______.
shorter
113
Once you cut out the primer at the end, you cannot complete it. During the next round of replication, it will get ___ ___.
cut off
114
What are the ends of DNA that don't code for anything called?
telomers
115
Define Biological age
how many times your cells have divided
116
Define Chronological age
Age you are in numbers
117
Telomeres do not prevent the shortening of DNA molecules, but what do they do?
postpone the erosion of genes near the ends of DNA
118
It has been proposed that the shortening of telomeres is connected to what?
aging
119
define apoptosis
cell death
120
Each time DNA replicates, _______ gets cut off
telomer
121
What is the name of the enzyme that catalyzes the lengthening of telomeres in germ cells?
telomerase
122
define gametes
egg and sperm cells when they come together
123
what is another name for germ cell?
stem cell
124
As we age, what happens to the stem cells ability to produce new cells?
it goes down
125
Without telomerase, you lose the telomer, and what happend to the cell?
it dies
126
There is evidence of telomerase activity in cancer cells, which makes the cancer cells somewhat ________.
immortal
127
What helps condense DNA during cell division?
histone protein
128
Do normal cells have telomerase? If so when?
yes, but it turns off after gestational period
129
What is Cancer?
uncontrolled cell division
| cells get stuck in a part of the cell cycle
130
What does cigarette smoke do to the rates of mitosis?
speeds it up
131
Name some things that can speed up your biological time clock?
* cigarette smoke
* UV exposure
* substance abuse
* life style choices
132
What best distinguishes living things from non-living things?
the ability of organisms to reproduce
| also metabolism
133
Mitosis is cell division that takes place in what type of cells?
somatic cells
134
Meiosis produces non-identical daughter cells.
| true or false
true
135
What happens when unicellular organisms do cell division?
division of one cell reproduces the entire organism
136
What three things does cell division in multicellular organisms result in?
* Production of gametes (egg and sperm)
* Growth
* Repair
137
Name the two types of cell division in eukaryotes
Mitosis and Meiosis
138
define genome
all the DNA in a cell
139
A genome can consist of a single DNA molecule or a number of DNA molecules. Which is common in prokaryotes and which is common in eukaryotes?
single=prokaryotes
| multiple=eukaryotes
140
What are DNA molecules in a cell packaged into?
chromosomes
141
A Somatic cell is a non-reproductive cell.
| true or false?
true (non-sexual)
142
Is a Gamete a reproductive cell or a non-reproductive cell?
a reproductive cell (sexual)
143
Gametes have half as many chromosomes as Somatic Cells.
| true or false?
true
144
In Mitosis, Each duplicated Chromosome has __ sister chromatids, which separate during cell division.
2
145
What is the part of the duplicated chromosome where the two chromatids are most closely attached called
centromere (the waist)
146
Eukaryotic cell division consists of 2 parts, what are they?
Mitosis, and Cytokinesis
147
In cytokinesis when the contents of the cytoplasm are divided between the two new cells, is this an equal division?
No
148
The Mitotic (M) phase consists of what 2 things?
Mitosis and cytokinesis
149
Where does the cell "do it's job"?
Interphase
150
Where does about 90% of the cell cycle take place?
Interphase
151
Interphase can be divided into 3 subphases, name them
G1
S Phase
G2
152
The cell grows in all three subphases of interphase, but in which phase are the chromosomes duplicated and DNA replicated
s phase
153
In which subphase of interphase does the cell grow into its adult characteristics?
G1
154
Name the phases of mitosis
* prophase
* prometaphase
* metaphase
* anaphase
* telophase
* cytokinesis
155
In which phase do the microtubules pull apart the sister chromatids?
Anaphase and Anaphase II
156
Once sister chromatids are pulled apart they are no longer chromatids they are ___________.
chromosomes
157
In animal cells, cytokinesis occurs by a process known as ________.
cleavage, forming a cleavage furrow
158
What is the cleavage furrow made of?
microfilaments
159
A cell plate will eventually modify into what?
a cell wall
160
What major thing happens in metaphase?
microtubules attach at kinetochore and move the chromosomes to the middle (metaphase plate)
161
What is the name of the complex of DNA and protein, that eukaryotic cells have, that condenses during cell division?
chromatin
162
How many sets of chromosomes do somatic cells have?
2 sets
163
In comparison to somatic cells, how many chromosomes do gametes have?
1/2 as many
164
Each duplicated chromosome in eukaryotic cells, have 2 ______ __________, which separate during cell division
2 sister chromatids
165
define cytokinesis
the division of the cytoplasm
166
What type of cell division are gametes produced in?
meiosis
167
Meiosis yields nonidentical daughter cells. How many sets of chromosomes do these cells have?
only one set, half as many as the parent cell
168
What Phase of mitosis does cytokinesis take place during?
Telophase
169
What is the acronym that Mary used to help us remember the stages of mitosis?
PMAT
170
Can plant cells have more than one nucleolus?
yes
171
How big are the two new cells that have just been divided in telophase/cytokinesis?
half the size of the original cell
172
Where do the two new cells that have just been separated in telophase/cytokinesis need to go next?
Back into interphase to grow up
173
What happens to the chromatin in Prophase, Prophase I, and Prophase II ?
It begins condensing into chromosomes
174
During which phase of mitosis have the centrioles /centrosome replicated and gone to separate sides of the cell?
prophase/prometaphase
175
What do the microtubules of the mitotic spindle do?
They pull and push sister chromatids apart toward opposite spindle poles
176
What are aster, where are they found?
aster are microtubules emanating (sticking out of) the centrosomes
177
During which phase do the microtubules attach to the kinetochore and move the chromosomes to the middle?
Metaphase
178
What builds the mitotic spindle?
centrosomes
179
In anaphase, what do the microtubules attached to the kinetochore do to pull the sister chromatids apart and toward the opposite poles of the cell?
contract and shorten
180
In animal cells, cytokinesis occurs by the forming of a cleavage furrow that divides the cell into two parts, what is formed in plant cells that has a similar job?
cell plate
181
What is a homologous pair?
Both chromosomes of each pair carry genes controlling the same inherited characteristics
182
A genes specific location along the length of a chromosome is called what?
locus
183
When you say a cell is 2n it means it's what?
diploid, it has only 2 sets of information
184
Of the 23 pairs of chromosomes, the 23rd pair are sex chromosomes, what are the other 22 pairs called?
autosomes
185
In which one, meiosis or mitosis, do the Homologous Chromosomes pair up in the middle in a line?
meiosis
186
There are 2 cell divisions.
| during which one, mitosis or meiosis?
meiosis
187
During which phase in Meiosis are there four daughter cells produced?
Telophase II/ cytokinesis
188
An allele can be dominant or recessive.
| true or false?
true
189
If you have 12 chromosomes total, how many chromatids would you have?
24
190
Does DNA replication happen during meiosis?
no, its part of interphase and happens before
191
Do prokaryotes make a mitotic spindle?
no
192
How many chromosomes does a prokaryote have and what is their shape?
prokaryotes have 1 chromosome and it's circular
193
How many origins of replication does a prokaryote have?
only one
194
Right before a prokaryote splits into two during binary fission, it adds what to the other side before dividing?
another origin of replication (makes a copy)
195
Is binary fission simple or complex and why?
simple, there is so little DNA in prokaryotes
196
Mitosis probably evolved from binary fission since there were prokaryotes before eukaryotes.
true or false?
true
197
Different types of cells divide at different rates.
| true or false?
true
198
Bone marrow cells replicate _______.
quickly
199
Skin cells replicate _______.
quickly
200
The eukaryotic cell cycle is regulated by a molecular control system.
true or false?
true
201
Where are the chemical signals that drive the cell cycle located?
cytoplasm
202
Hormones are an example of a chemical molecule that does what?
tells cells what to do
203
In an experiment, what type of cells at different phases of the cell cycle, were fused to form a single cell with two nuclei?
mammalian cells
204
The sequential events of the cell cycle are directed by what?
cell cycle control system
205
The cell cycle control system is regulated by both ________ and ________ controls.
internal and external
206
What directs the cell cycle that is similar to a clock?
cell cycle control system
207
What is a checkpoint?
where the cell cycle stops until a go-ahead signal is received
208
A "go-ahead" signal is a chemical release signal.
| true or false?
true
209
Which checkpoint is the most important?
G1
210
If a cell receives a go-ahead signal at the G1 checkpoint, it will usually do what?
go on to complete the rest of the phases and divide
211
If a cell does not receive the go-ahead signal at the G1 checkpoint, it will exit the cell and switch into what?
a nondividing state called the G0 phase
212
Can neurons divide? yes or no and why?
no, because they do not have centrioles and can't do mitosis
213
Do you receive more neurons as an adult than you had when you were born?
no, what you have when you are born is what you've got
214
There are two types of regulatory proteins involved in cell cycle control, name them.
* cyclins
| * cyclin-dependent kinases (cdks)
215
What is a cyclin-dependent kinase?
a regulatory protein that's an enzyme
216
What is a cell guaranteed to be able to do if it gets past the G2 checkpoint?
mitosis
217
What does MPF stand for?
a maturation promoting factor
218
If spindle microtubules have not yet attached to the kinetochore, the kinetochore sends a molecular signal that delays anaphase. What is this an example of?
an internal signal
219
Some external signals are ______ _______.
growth factors
220
What are growth factors?
proteins released by certain cells that stimulate other cells to divide (do mitosis)
221
What are human fibroblast cells responsible for?
making your fibers
222
What does PDGF stand for?
Platelet-derived growth factor
223
What is PDGF used to stimulate?
the division of human fibroblast cells
224
Density-dependent inhibition is an external signal that does what?
stops crowded cells from dividing
225
In which phase of meiosis do the homologs move toward opposite poles, guided by the spindle apparatus?
Anaphase I
226
Which phase ends with two identical diploid cells being produced?
Telophase
227
In which phase do spindle fibers attach to ONE side of the kinetochore?
Metaphase I
228
What is a substratum?
another cell/something to attach to
229
What is it called when an animal cell must be attached to another cell in order to divide?
anchorage dependence
230
What must cells do to make a tissue?
anchor to another cell
231
Name the two things that control mitosis
* Anchorage dependence
| * Density-dependent inhibition
232
define metastasis
move to another location
233
Do cancer cells have anchorage dependence and density-dependent inhibition (controls)?
No, cancer cells take away controls
234
Do cancer cells make it through the G1 phase?
No, they don't grow up
235
Can cancer cells break off a tumor and become metastatic?
yes
236
Does cancer frequently start in Epithelial tissue? Why or why not?
yes, because Epithelial tissues have lots of replication and mitosis so more opportunity for mutations
237
Cancer cells have a normal cell cycle control system.
| true or false?
false, they have an abnormal cell cycle control system
238
What is it called when a normal cell is converted to a cancerous cell?
transformation
239
When is a lump called a benign tumor?
If abnormal cells stay at the original site and don't metastasize
240
What can malignant tumors do?
* invade surrounding tissues
| * metastasize
241
If the lymph node is sore and you have a fever, is it most likely cancer or an infection?
an infection
242
What happens during crossing over and what phase does it happen in?
DNA molecules of non-sister chromatids are broken by proteins and are rejoined to eachother.
Prophase I
243
Does any chromosome replication occur between meiosis I and meiosis II?
no
244
When chromosomes are still attached at the centromere, DNA replication is complete or not complete?
not complete
245
Genes are instructions to make proteins.
| true or false?
true
246
What is the information content of DNA in the form of?
sequences of nucleotides (ATCG)
247
Define genotype
what your genes say you are
| example: mary was born a blonde
248
Define phenotype
what you see, interaction between genes and the environment
| example: marys hair colored dark
249
What are the two stages of gene expression?
* transcription
| * translation
250
What is gene expression?
Making a protein and expressing it
251
During translation, what is the DNA nucleotide information changed into?
amino acids
252
Dominant traits and recessive traits are part of which one, your genotype or your phenotype?
genotype and phenotype, although recessive traits cannot be seen with regards to your phenotype
253
During transcription the DNA is ______ in it's nucleotide form
copied
254
During translation, the DNA nucleotides are changed or translated into _____ _____.
amino acids
255
RNA is the intermediate between genes and the proteins for which they code.
true or false?
true
256
Transcription produces which type of RNA?
messenger RNA (mRNA)
257
Translation is the synthesis of a ___________, which occurs under the direction of mRNA
polypeptide
258
What are considered the sites of translation?
Ribosomes
259
How does mRNA exit the nucleus to go find a ribosome so that it can do translation
through nuclear pores
260
In a eukaryotic cell, what separates transcription from translation?
the nuclear envelope
261
The cellular chain of command is
| DNA-------> RNA-----------> ________.
Proteins
262
In transcription, how many sides of the DNA are copied?
one side
263
In eukaryotes,Pre-mRNA is a single strand. For it to become mRNA what do you have to add to it to help protect it while it's being transported out of the nucleus?
a cap and poly-A tail
| cap to the 5' end, tail to the 3' end
264
_________ attach to the mRNA and translate, tells which amino acids it needs to build a specific protein.
Ribosomes
265
In bacterial cells, Transcription and translation are done very quickly. The single DNA strand is copied and the ribosomes attach immediately and translate.
true or false?
true
266
Ribosomes provide the translation for the mRNA transcript.
| true or false?
true
267
How many amino acids are there total?
| How many nucleotide bases are there total used in DNA?
20 amino acids
| 4 nucleotide DNA bases
268
Ribosomes translate the mRNA transcript in order to build what?
polypeptides (proteins)
269
How many nucleotide bases does it take to represent an amino acid?
3
270
DNA is in the code of a nucleotide, mRNA needs to change it into an _____ ____ ____.
amino acid code
271
What is a Codon?
the triplet code of nucleotide bases
272
What comes first in the process, transcription or translation?
transcription
273
In which direction are codons read?
5' to 3' direction
274
Each codon specifies which _____ ____ needs to be placed at a corresponding position along a polypeptide.
amino acid
275
Which side is the anti-parallel side?
the strand opposite the DNA Template strand
276
The Primary Transcript is done by mRNA, so what will you see that tells you it's RNA and not DNA ?
Uracil along the Primary Transcript strand
277
After mRNA gets the primary transcript from the one side of the DNA, what does the DNA then do?
reseals
278
One codon can tell us one amino acid, but one amino acid can have many codons.
true or false?
true
279
How many codons are there total?
64 triplets
280
How many of the codon triplets, are "stop" signals to end translation?
3 triplets
281
No codon specifies more than ___ amino acid.
one
282
How many different "start" codons are there?
1 triplet
283
What is the name of the "start" codon from our chart?
Methylamine
284
Which base of the three in a codon, holds the most importance? (if this base is changed, it changes the amino acid used entirely)
first base
285
Which base out of the three in a codon, is the least important? It is said to have wobble.
Third base
286
What is the first stage of gene expression?
Transcription
287
What is RNA synthesis catalyzed by?
| an enzyme that pries the DNA apart and hooks together the RNA nucleotides
RNA Polymerase
288
The DNA sequence where RNA Polymerase attaches is called the ________.
promoter
289
What is the promoter?
the start of the sequence
290
The stretch of DNA that is transcribed is called what?
the transcription unit
291
What is the sequence signaling the end of transcription (end of sequence) called?
terminator
292
Does RNA polymerase bind to a promoter?
yes
293
Once the RNA transcript is made, the copy _____ ___ and the DNA reseals (is rewound)
comes off
294
When does the terminator come into play?
Once the RNA transcript is completed
295
Name the three stages of transcription.
1. ) Initiation
2. ) Elongation
3. ) Termination
296
What happens during initiation?
Promoter initiates to start
297
What happens during elongation?
the addition of RNA nucleotides/ base pairing
298
What happens during termination?
Signal to stop
299
What's another work for the direction of transcription?
"downstream"
300
What is a complex composed of?
proteins and enzymes
301
What is the name of the promoter that is crucial in forming the initiation complex in eukaryotes?
```
TATA Box
(hint: start with the tatas)
```
302
The promoter binds to a site that has T-A-T-A, why is this a good place to open the strand?
It's easy to open because there are only 2 hydrogen bonds to break
303
What do transcription factors do?
mediate the binding of RNA Polymerase and the initiation of transcription
304
As RNA Polymerase moves along the DNA, it untwists the double helix __ to __ bases at a time.
10-20
305
Transcription progresses at a rate of __ nucleotides per second in eukaryotes.
40
306
Can more than one RNA Polymerase attach to the same promoter so that more than one of that specific type of protein can be made at the same time?
yes
307
Are the mechanisms of termination different in bacteria than they are in eukaryotes?
yes
308
Is it in bacteria, or eukaryotes, that the polymerase stops transcription at the end of the terminator and immediately falls off?
bacteria
309
In termination in eukaryotes, the polymerase continues transcription for a while after it's done being used and eventually falls off.
true or false?
true
310
Enzymes in the eukaryotic nucleus, modify pre-mRNA (edit the script, take out what's not needed) before the genetic messages are dispatched to the _________.
cytoplasm
311
Do Eukaryotic cells modify RNA after transcription?
yes
312
If I say during RNA processing, both ends of the primary transcript are altered, what am I referring to?
cap and poly-A tail being added
313
Another alteration that occurs to the RNA transcript after transcription is that usually some parts interior parts of the molecule are cut out and other parts spliced together.
true or false?
true
314
What is a poly-A tail composed of?
a bunch of adenine
315
Name the three things the cap and tail do for the mRNA
* help export out of nucleus
* protect it from hydrolytic enzymes (enzymes that will break it down before it's read)
* help ribosomes attach to the 5' end
316
What does the polyadenylation signal do?
signals that it's time to add the Poly-A Tail
317
Split genes and RNA Splicing does NOT happen in ___________.
prokaryotes
318
What are introns?
non-coding stretches of nucleotides, also known as intervening sequences
319
The part we dont want and need to get rid of, the intruders?
introns
320
If we want to get rid of the introns, what do we want to keep? The part that will eventually be EXpressed and translated into amino acids
Exons
321
What does RNA Splicing do?
Removes introns and joins exons creating a continuous coding sequence
322
What does Intron and Exon shuffling give you?
Different versions of the script
323
What do Spliceosomes do?
splicing, cutting out introns (intruders), sealing exons together, recognizing splice sites
324
Does the spliceosome bend the pre-mRNA transcript to cut the introns out?
yes
325
Enzymes are not the only catalytic molecule. Name the catalytic RNA molecule that functions like enzymes and can splice RNA.
ribozymes
326
What is it called when some genes can code for more than one kind of polypeptide (protein), depending on which segments are treated as exons during RNA splicing?
alternative RNA splicing
327
Because of alternative RNA splicing, the number of different proteins an organism can produce is much greater than it's number of _____.
genes
328
Exon shuffling may result in the evolution of new protiens.
| true or false?
true
329
A cell translates an mRNA message into protein with the help of what?
transfer RNA (tRNA)
330
What does tRNA transfer?
amino acid we need to make polypeptide (protein)
331
Each molecule or tRNA carries a specific amino acid on one end and an _________ on the other end.
anticodon
332
The anticodon on one end of the tRNA, base pairs with a complementary codon on ____.
mRNA
333
If each tRNA has to carry a different amino acid, what is the least amount of different tRNA we need
20 at least
334
Once the primary structure is complete, where does it go next?
to secondary -(beta pleated sheets, alpha helix)
tertiary- (folding, functional, disulfide bridges present)
some go to quaternary
335
What is the P site ?
peptide binding site, where the polypeptide is built
336
What is the E site?
the exit site
337
What is the A site?
The amino acid site, where the amino acid enters
338
What are spliceosomes made of?
proteins and small nuclear ribonucleoproteins (snRNP's)
339
What is the shape of tRNA?
L- shaped
340
When tRNA is flattened to reveal it's base pairing, it looks like what?
a cloverleaf
341
tRNA molecules consist of a single RNA strand and are only about __ nucleotides long
80
342
Name the two required steps in accurate translation
First: a correct match between tRNA and an amino acid, done by the enzyme
Second: a correct match between tRNA anticodon and an mRNA codon
343
What is it called when there is flexible pairing at the third base of a codon. This also allows some tRNA to bind to more than one codon?
wobble
344
What does ribosomal RNA (rRNA) do?
make up the structure of the ribosomes
345
Ribosomes facilitate specific coupling between ____ anticodon and ____ codons in protein synthesis
tRNA
| mRNA
346
Where are the A site, P site, and E site located?
in the ribosome (large unit)
347
Where is the mRNA binding site located at on the ribosome?
the small unit
348
Name the three binding sites for tRNA
* A site
* P site
* E site
349
The 3 stages of translation are the same as the 3 stages of transcription.
true or false?
true
350
Which provides less energy, ATP or GTP?
GTP
351
When elongating the polypeptide chain, _____ _____ are added one by one to the preceding _____ ____.
amino acids
| amino acid
352
Each addition of an amino acid to the elongation chain in translation, involves proteins called __________ _______ and occur in three steps.
elongation factors
353
During the elongation stage, amino acids are added one by one. Each addition of an amino acid occurs in 3 steps. Name the steps
1. codon recognition
2. peptide bond formation
3. translocation
354
What is the P sites job?
to hold onto the growing polypeptide chain
355
When adding the amino acids from the A site to the polypeptide chain in the P site, what type of bond is formed?
peptide bond
356
Once the amino acid from the A site joins onto the polypeptide chain in the P site, what does the ribosome need to do?
it needs to move/shift
357
Is energy needed to move the amino acid from the A site to the polypeptide chain in the P site?
yes
358
When do you know to stop doing the protein synthesis in the ribosome?
you'll come across the stop codon
359
Termination of translation occurs when a stop codon in the mRNA, reaches the __ ____ of the ribosome.
A site
360
When the A site accepts a protein called a release factor, what happens?
the release factor causes the addition of a water molecule instead of an amino acid. This releases the polypeptide
361
What carries release factors?
stop codon
362
What enables a cell to make many copies of a polypeptide very quickly?
polyribosomes
363
When there's a change in DNA, what is this called?
a mutation
364
Define point mutations
a chemical change in just one base pair of a gene
365
mRNA reads in the direction of 3' to 5' so that it can produce _' to _'
5' to 3'
366
What are the 2 types of point mutations that can occur within a gene?
* base-pair substitutions
| * base-pair insertions or deletions
367
What type of point mutation would produce a frameshift mutation?
one base pair insertion or one base pair deletion (insertions or deletions)
368
If there were a 3 base pair deletion, what would be missing?
one amino acid
369
What kind of mutation has no effect on the amino acid produced by a codon because of redundancy in the genetic code?
silent mutation (usually when the 3rd base has error)
370
What type of mutation almost always leads to a nonfunctional protein?
nonsense mutations
371
What happens in a nonsense mutation?
an amino acid codon is changed to a stop codon
372
Which type of mutation still codes for an amino acid, but not the right amino acid?
missense mutations
373
Which has a more disastrous effect on the resulting protein, substitutions or insertions and deletions?
insertions and deletions
374
A physical or chemical agent that can cause mutations is known as what?
a mutagen
375
Spontaneous mutations can occur during DNA replication, recombination, or repair.
true or false?
true
376
When an amino acid hooks up with a tRNA, this is called _____ ____ __________.
Amino acid activation
377
A gene can be defined as a region of DNA that can be expressed to produce a final functional product, either a ___________ or an ___ molecule.
polypeptide
| RNA molecule
378
What is nondisjunction?
If chromosomes don't separate correctly/ something goes wrong to cause the end cells to not be right. (Extra chromosomes X,Y)
379
What does trisomy 21 mean and represent?
They got three of the 21st chromosome.
| It is Down syndrome
380
Are there a high amount of genes in the 21 chromosome or a low amount?
Low
381
The 23rd set of chromosomes determines what?
The sex
382
Do people that have trisomy 21 often times have heart defects?
Yes
383
If the micro tubules don't all connect to the kinetochore completely, what could occur?
Nondisjunction
384
2n + 1 means what?
You have one too many chromosomes
385
Nondisjunction can happen at any age in egg or sperm.
| True or false?
True
386
Women are born with all the eggs they'll ever have.
| True or false?
True
387
Men produce new sperm every day from puberty until death, they continually do meiosis
True or false
True
388
Prices of your DNA in your cells can actually break off and attach to another chromosome.
True or false
True
389
What is someone that has XXX?
Super female
390
What is someone that has XYY
Super male
391
What does someone with Klines Felters syndrome have?
XXY, male with an extra X
392
A YO will never _____.
Grow
393
XO represents someone with what disease?
Turner's syndrome
394
Males are much more likely to be colorblind because they need only one _________ _____.
Recessive trait
395
Both men and females have estrogen and testosterone, what is the only difference?
The levels of each hormone in their bodies
396
Which has less genetics in it, a Y chromosome or an X?
A Y chromosome has less genes
397
Who is the father of genetics?
Mendel
398
Mendel discovered the basic principles of heredity by breeding what?
garden peas
399
Most genetic traits in humans are _________.
polygenic
400
Which trisomy has the most severe impact on the health of an individual human?
Trisomy 21
or Trisomy 4
Trisomy 4
401
What is the main factor that makes it difficult to study a humans genetics?
humans traits are polygenic
402
What does polygenic mean?
multiple sets of alleles at many different loci (locus)
| more than one set of alleles
403
define true breeding
when the parent organisms only produce offspring with the same traits (same phenotype) as them
404
When Mendel was doing his research, was this before or after we knew about replication, cell division, mitosis/meiosis, chromosomes, genes?
before
405
Humans are called diploid organisms because they have ___ _______ at each genetic locus, one inherited from each parent.
two alleles
406
How many locus and how many sets of alleles does a pea plant have?
1 locus
| 1 set of alleles
407
Character varients are called ______.
traits
408
Each flower has sperm-producing organs called what?
stamens
409
Each flower has an egg-producing organ called what?
carpel (ovary)
410
define cross-pollination
fertilization between two plants
411
In the results from Mendel's study of pea plants, F1 represents the first set of children. What does F1 stand for?
first filial generation
412
Is a recessive gene still a gene, and does it still make a protein, even when being masked by a dominant gene?
yes
413
A recessive gene is still expressed while the dominant overrides it.
true or false
true
414
How can a pea plant do true breeding on it's own?
it has both male and female parts (they can self-pollinate)
415
When Mendel mated two contrasting, true breeding varieties? What was this process called?
hybridization
416
Who are the true breeding parents of the hybrid offspring?
P generation
417
What are the hybrid offspring of the P generation called?
F1 generation
418
When F1 individuals self-pollinate or cross-pollinate with other F1 hybrids, what is produced?
F2 generation
419
What is Mendel's ratio in purple to white flowers in the F2 generation?
3 to 1
420
What Mendel called a "heritable factor" is what we now call a ____.
gene
421
What is the name for an alternative version of a gene?
alleles
422
A pair of homologous chromosomes has 2 alleles, one from mom and one from dad, located where?
on the same locus
423
If two alleles at a locus differ, then out of dominant and recessive, which one determines the organisms appearance and which one has no noticeable effect.
dominant determines appearance
| recessive has no noticeable effect
424
during the production of gametes the two copies of each hereditary factor segregate so that offspring acquire one factor from each parent. What law is this?
Law of Segregation
425
A diagram for predicting the results of a genetic cross between individuals of known genetic makeup is called what?
a Punnett square
426
A capital letter represents what kind of allele?
dominant
427
An organism with two identical alleles for a character is said to be what?
homozygous
| for the gene controlling that character
428
An organism that has two different alleles for a gene is said to be what?
heterozygous
| for the gene controlling that character
429
Unlike homozygotes, _____________ are not true breeding.
heterozygotes
430
If a genotype is pp, what is it?
homozygous recessive
431
If a genotype is Pp, what is it?
heterozygous
432
How can we tell the genotype of an individual when we only know the dominant phenotype?
carry out a testcross
433
Breeding the mystery individual with a homozygous recessive individual, if any offspring display the recessive phenotype , then the mystery parent must be heterozygous. What is being done here?
a testcross
434
define monohybrid
heterozygous for one character
435
What is the law of assortment?
each pair of alleles segregates independently of each other pair of alleles during gamete formation.
436
What is another word for gamete formation?
meiosis
437
Alleles/genetic traits on the same chromosome travel together and dont independently assort.
true or false
true
438
Being somewhere between the phenotypes of the two parental varieties (blended equally) is referred to as __________ _________.
incomplete dominance
439
When two dominant alleles are both expressed, this is called ___________.
codominance
440
What occurs when phenotypes of the heterozygote and dominant homozygote are identical?
complete dominance
441
List the 3 degrees of dominance
* Complete dominance
* Incomplete dominance
* Codominance
442
Alleles are simply variations in a gene's nucleotide sequence.
true or false?
true
443
A dysfunctional enzyme causes an accumulation of lipids in the brain. What disease is this and is it dangerous?
Tay-Sachs disease
| yes it is fatal
444
define polydactyl
extra digits
445
Are Dominant alleles always more common in populations than recessive alleles?
no.
446
Is having 5 digits a dominant trait or a recessive trait?
recessive (homozygous recessive)
447
How many different alleles express bloodtype. What are they?
3 different alleles
* IA
* IB
* i
448
Why is O- the universal donor?
it has no RH antigens, so it won't react with other blood types
449
The enzyme encoded by the IA allele, adds which carbohydrate?
the A Carbohydrate
450
The enzyme encoded by the i allele adds which carbohydrate?
it doesn't add a carbohydrate
451
IAi is the genotype for which blood group?
A
452
IBIB is the genotype for which blood group?
B
453
ii is the genotype for which blood group?
O
454
Most genes have multiple phenotypic effects? This is called what?
pleiotropy
455
What are responsible for the multiple symptoms of certain hereditary diseases, such as cystic fibrosis and sickle-cell?
pleiotropic alleles
456
Skin color in humans is a good example of _________ ___________.
polygenic inheritance
457
What is Polygenic Inheritance?
Many genes that control the same trait
| example: eye color, skin color
458
Hydrangea flowers of the same genotype range from blue-violet to pink, depending on soil acidity. What is this an example of?
Environment controlling/effecting genes
