biology unit 2 Flashcards
1
Q
what experiments helped to discover the shape of DNA?
A
pauling (protein alpha helix), Wilkins and Frankline (x-ray crystallography), watson and crick (double helix)
2
Q
when one strand is used as a template for making a new complementary strand
A
DNA replication
3
Q
builds new DNA by conserving one old template strand
A
semi-conservative replication
4
Q
enzyme that matches complementary nucleotides to template, building new strand
A
DNA polymerase
5
Q
unzips DNA
A
helicase
6
Q
prevent bases from rebinding to each other
A
single strand binding proteins
7
Q
created when helicase unzips the DNA
A
replication forks
8
Q
specific DNA sequence where helicases and polymerases start replication
A
origin of replication
9
Q
prevent supercoiling by cutting strands, allowing them to unwind, and then rejoining them
A
topoisomerase
10
Q
what enzyme can only add bases to the 3’ end of an extant DNA/RNA strand
A
DNA polymerase
11
Q
enzyme that doesn’t need extant 3’ end to start
A
RNA polymerase
12
Q
build RNA primer
A
primase
13
Q
what enzyme joins the 2 replicated DNA forks
A
DNA ligase
14
Q
strand that chases the helicase
A
leading strand
15
Q
strand where replication keeps restarting
A
lagging strand
16
Q
generated by lagging strand
A
Okazaki fragments
17
Q
end of a linear chromosome that shortens with each replication, overhangs are more fragile, look like errors and are destroyed by the cell, only in eukaryotes
A
telomere
18
Q
solves the issue of telomeres by adding nucleotides to the template strand
A
telomerase
19
Q
lab method that amplifies part of a template DNA using dNTPs, heat, 2 single stranded
A
PCR
20
Q
transcription of single stranded mRNA from DNA template, translation of mRNA sequence into protein sequence at ribosome
A
DNA directed protein synthesis
21
Q
why mRNA?
A
amplification (make many mRNAs from 1 gene in DNA, make many proteins from 1 mRNA), control (can control when and how much mRNA made), evolution (earliest cells had RNA)
22
Q
theory that early cells had RNA not DNA
A
RNA world hypothesis
23
Q
first evidence that mRNA carries info from DNA
A
mRNA nucleotide content similar to DNA, if cell infected with virus DNA, mRNA nucleotide content becomes similar
24
Q
a region of DNA used as template for a type of mRNA, info where to start/stop contained
A
transcription unit
25
nucleotides linked by RNA polymerase and cofactors, where transcription begins
promoter DNA
26
where transcription ends
terminator DNA
27
bind specific DNA sequences, promote or inhibit transcription, general ones recruit RNA polymerase to promoter DNA
transcription factors
28
stored info for making proteins
genes
29
the promoter and terminator, doesn't have to include mutations
transcription unit
30
starts translation before transcription is finished
polyribosome
31
how does mRNA get from the nucleus to ribosomes
through nuclear pores in the nuclear envelope
32
how is RNA processed in eukaryotes?
ends of the primary transcript (premRNA) are modified to help stability, capping of 5' end by adding special nucleotide, 3' end cleaved and poly-A tail added, removal of noncoding introns
33
removed parts of RNA
introns
34
parts kept in the RNA
exons
35
proteins and small nuclear RNAs that remove introns, snRNA binds, recognize specific nucleotides, help splice ribozyme
spliceosome
36
binds promoter DNA, begins transcription at primary RNA, stops at terminator RNA
RNA polymerase and transcription factor proteins
37
what guides the spliceosome in the removal of introns
snRNAs
38
keeps different exons in different cells, leading to different RNAs and proteins
alternative splicing
39
have large and small subunits, made of ribosomal RNA and proteins
ribosome
40
codes for each amino acid, made of nucleotide in RNA
triplet codon
41
idea that adaptor binds mRNA using base pairings,
Crick's hypothesis
42
match specific amino acids with specific mRNA, form of transfer RNA
adaptor
43
bond between amino acid and RNA
aminoacyl tRNA
44
each transfer RNA has specific 3 nucleotide what
anticodon
45
how does tRNA get the correct amino acid
aminoacyl tRNA synthesases
46
starting and stopping translation depends on starting in the correct
reading frame
47
common start codon
AUG
48
what does a start codon have to match
initiator tRNA anticodon
49
where does translation stop
a nonsense stop codon
50
what binds when a stop codon is reached
release factor (protein)
51
what does mRNA have 5' to start codon or 3' to stop codon
untranslated region (UTR)
52
eukaryotic mRNA
usually only one protein coding sequence
53
prokaryotic mRNA
can code for several different proteins and have several start stop intervals,
54
the transcription unit of prokaryotes
operon
55
what does a DNA nucleotide change result in
mutations
56
what is the cause of inheritable genetic differences
mutations
57
causes of mutations
bad replication (missed proofreading), chemical damage to bases, selfish DNA (transposable element splices in and out)
58
change in or loss of a single base
point mutation
59
what can be created by a point mutation
synonymous/silent (no effect), missense (wrong AA), or nonsense (stop codon)
60
what can create frameshift mutations
deletions or insertions
61
do mutations in noncoding DNA effect cells
yes, can disrupt stop codon, promoter, terminator, splice sites, polyA site, and more
62
what are splice sites recognized by
snRNA
63
what can untranscribed DNA effect
gene expression
64
transcriptional regulation of gene expression uses what
transcription factor proteins
65
what is an example of prokaryotic transcription regulation
Lac operon DNA in e. coli, which involves a repressor transc. factor binding to operator DNA next to promotor, blocking RNA polymerase from transcription in the absence of lactose.
66
what is the lac operon an example of
regulation of gene expression
67
when there is a lot of glucose, what blocks the breakdown of lactose
cyclic AMP and an activator transcription factor (CRP)
68
less glucose means
more cAMP
69
a nonprotein second messenger, used to carry info
cAMP
70
what does adenylyl cyclases catalyze
ATP---> cAMP + 2pi
71
what binds with transc. factors to stimulate transcription
binding with enhancer DNA
72
what binds with transc. factors to repress transcription
silencer DNA
73
can silencer and enhancer DNA be distant and sill effect transcription
yes
74
change wrapping of DNA by histone proteins, less direct change of transcription
chromatin remodeling
75
another way to modify DNA by adding methyl side group to bases
DNA methylation
76
changes in transcription factors, histone modifications, DNA methylation, etc.
epigenetic
77
do epigenetic changes alter the nucleotide sequence
no, but can last for many cell divisions
78
can eukaryote gene expression be controlled after transcription
yes, through mRNA destruction
79
non-protein coding DNA, particular classes of
transposable elements
80
can noncoding sites still regulate epigenetic change
yes
81
can change promoter, enhancer, silencer DNA that binds transc. factors
mutations
82
how can expression of a gene change
mutation of a transcription factor
83
process of getting mRNA and proteins to the right place
trafficking
84
contains chromatin, a strand of chromosomes made of DNA, histones, and transcription factors
nucleus
85
site of mRNA synthesis, assembly of ribosomal subunits, non membrane bound
nucelolus
86
made of 2 lipid bilayers, perforated by nuclear pores
nuclear envelope
87
complex transporter in nuclear envelope
nuclear pores
88
part of protein has to bind lock and key to specific structure
signal sequence
89
in trafficking, proteins have what to bind amino acids to importin protein
internal nuclear localization (import) signal sequence
90
shuttles back and forth in nuclear pores to import proteins bound to it
importin
91
network of membrane bound tubes and discs, continuous with outer nuclear envelope, rough and smooth
endoplasmic reticulum
92
part of ER with ribosomes
rough ER
93
binds to SRP the receptor and channel in ER, inserts protein through pores, and cleaved off, secretes things out of cell
secretion signal sequence
94
where are proteins that are secreted out of the cell made and inserted
rough ER
95
how are proteins secreted
exocytosis
96
how are proteins secreted
packaged into transport vesicles, sent to Golgi apparatus, then packaged into secretory vesicles that are exocytozed
97
what sequence is left in the membrane during secretion
signal anchor sequence
98
stack of flattened membrane bound disks. secretes proteins out of cell
golgi apparatus
99
when proteins are covalently linked to carbs
glycosylation
100
has digestive enzymes, kept acidic with proton pump, transport proteins in membrane export digested molecules into cytoplasm
lysosome
101
how do vesicles move
using elements of the cytoskeleton
102
thickest diameter, made of a and b tubulin proteins, move by lengthening and shortening, kinesin/dynein motor proteins, or slide past each other
microtubules
103
thinnest, double helix made of proteins, use myosin motor proteins, used for rapid cell shape changes and movements, splitting of cell
microfilaments
104
intermediate thickness, mostly structural uses, meshwork, shape cell and organelles
intermediate filaments
105
how do microtubules move things
motor proteins (kinesin and dynein) walk along tubules
106
bendable projections of cell membrane, contain microtubules organized into a ring
cilia (lots of small) and flagella (long)
107
structure of microfilimaments
double helix made of actin proteins
108
what is the motor protein of microfilaments
myosin
109
how do things move inside plant cells
cytoplasmic streaming
110
how do prokaryotic cells divide
fission
111
process where DNA is replicated, attach each chromosome to membrane, get separated by cell elongation, new cell wall and membrane made, organized by tubulin like protein
fission
112
DNA replication produces
2 sister chromatids joined by proteins at centromere
113
use of microtubules in mitotic spindle to separate sister chromatids to make separate chromatids, not full cell division
mitosis
114
where do some microtubules attach to chromosome centromeres
kinetochore
115
how are spindle poles organized
by a pair of centrioles
116
protein surrounding centromere, controls movement by shortening and sliding along microtubule using motor proteins
kinetichore
117
subdivision of the cytoplasm into 2 cells
cytokinesis
118
phases of mitosis
prophase, prometaphase, metaphase, anaphase, telophase,
119
stage of mitosis when chromosomes condense, spindle forms, nuclear envelope starts to break down
prophase
120
stage of mitosis when spindle is set up, machine built, chromosomes condensed
prometaphase
121
stage of mitosis when everything is lined up, chromosomes line up in center of cell
metaphase
122
stage of mitosis when sister chromatids detach and move to opposite ends of cell
anaphase
123
phase of mitosis when spindle disappears, nuclear envelope reforms, cell divides
telophase
124
what happens prior to mitosis
chromosomes are duplicated in loose chromatin, nucleus intact
125
animal cells form cleavage furrow that pinches cell into 2, actual division of cell
cytokinesis
126
how do plant cells divide
inside cell wall have turgor pressure, form new membrane from vesicles fusing in middle of cell (cell plate)
127
life cycle of a dividing cell
cell cycle
128
DNA replication
synthesis/S phase
129
division
mitotic/M phase
130
period between M and S phase
G1 gap phase
131
period between S and M phases
G2 phase
132
can block progression through the cell cycle based on size, nutrients, DNA replication, chromosome attachment to spindle
cell cycle checkpoints
133
what is the clock of biology
cyclin protein
134
complex of two proteins, drives cell through G2 checkpoint, regulated by clock
MPF
135
when cyclin binds to the cyclin dependent kinase...
active MP is created
136
what attaches phosphate to target proteins
kinase
137
results in cloning (identical copies)
mitosis
138
how is genetic info passed without cell division
transformation, conjugation (only in prokaryotes)
139
specialized channels take up DNA from outside, gets incorporated into chromosome
transformation
140
long extensions of membrane (pili) pass fragments from chromosomes or small circular plasmids
conjugation
141
when is sexual reproduction and eukaryotic cell fusion
fertilization
142
cells that have a pair of homologous chromosomes (2n)
diploid
143
cells that have only 1 of each homologue (1n)
haploid
144
have same regions coding for same protein types but can have different versions (alleles)
homologous chromosomes
145
cells that have 1 of each chromosome homologue (haploid 1n)
gametes (sperm/egg)
146
cells that have pairs of homologues (diploid)
zygote
147
somatic cells are diploid, gametes are haploid
animal life cycle
148
haploid gametes (sperm and egg) fertilize to create a diploid zygote, which undergoes mitosis and development to result in what
multicellular diploid adult (2n = 46)
149
what do diploid cells have
pair of homologous chromosomes
150
has same genes in the same region coding for the same protein, but has different alleles, not exact copies
homologous chromosomes
151
when a diploid cell undergoes 2 divisions and results in 4 haploid cells
meiosis
152
difference between mitosis and meiosis
mitosis separates exact copies (sister chromatids), while meiosis 1 separates homologous chromosomes
153
difference between haploid and diploid cells
haploid cells have only one chromosome, while diploid cells have 2
154
when parts of homologous chromosomes are recombined at the chiasma in meiosis 1
crossing over
155
when chromosomes are bound/paired together
synapse, forms tetrad
156
what is a chiasma
site of crossing over
157
second division of meiosis, hales the amount of DNA, no DNA rep, sister chromatids separate
meiosis 2
158
experimented with the law of segregation and independent assortment
Mendel in 1865
159
why were peas a good organism to use?
they are true breeding, so they keep their traits unless you allow cross fertilization,
160
when alleles on both homologs are identical (PP, pp)
homozygous
161
when the alleles are different (Pp)
heterozygous
162
law that two alleles in the parent segregate from each other during the formation of gametes
law of segregation
163
Pp parent produces gametes that are either P or p with equal probability
example of the law of segregation
164
RrYy parent makes four different gametes, and how Rr segregates does not change how Yy segregates
example of independent assortment
165
why was Mendel lucky that he used peas?
the traits are caused by a mutation in a single gene
166
the physical trait and individual has
phenotype
167
the genetic info the individual can pass on to offspring
genotype
168
can genetic info in the F1 generation be hidden but still passed on to F2
yes
169
alleles that control the phenotype if present
dominant (P)
170
alleles that control the phenotype only if no dominant alleles are present
recessive (p)
171
helps to determine the genotype of an organism, crossed with recessive genotype, if recessive gene appears, other organism is heterozygous
test cross
172
two heterozygous genes crossed at same time
dihybrid cross
173
increases genetic variation
independent assortment
174
if N is the number of homolog pairs that are heterozygotic, 2N is the possible combinations
true
175
helps to figure out genotypes and dominance
pedigrees
176
what phase does crossing over occur in?
metaphase
177
are sister chromatids identical
yes
178
what are the different protein pathways
excreted out of cell, transmembrane protein binds, protein used by the nucleus, or engulfed to produce energy
178
heterozygote has phenotype that is intermediate between that of homozygote (ex: red, white, or pink flowers)
incomplete dominance
179
idea that different alleles give qualitatively different dominant traits, see both traits in heterozygote (ex: blood types)
co-dominance
180
blood type A
has A carb (IaIa or Iai)
181
blood type B
has B carb (IbIb or Ibi)
182
blood type AB
has A AND B carb (IaIb)
183
blood type O
has no carb (ii)
184
immune response to unfamiliar blood cells
transfusion reaction
185
population that makes up species can carry several different mutant alleles of the same gene with...
mild to complete loss of protein function, increased protein function, or novel protein function
186
when a single mutant may affect many tissues and processes
pleiotropic
187
organs for the production of nutrient filled egg or mitotic sperm
specialization
188
individuals that have both ovaries and testes
hermaphrodites
189
what influences the genetic choice between making sperm or egg
inheritance of sex chromosomes
190
have large X and small y chromosome
animals
191
XX individual
female, has ovaries
192
XY individual
male, has testes
193
non sex chromosomes
autosomes
194
how many pairs of autosomes do humans have
22
195
how many pairs of sex chromosomes do humans have
1
196
what is the SRY gene
a part of the Y chromosome that encodes for a master transcription factors that directs development of the testes, leads to chromosomal male
197
is there an equal probability of creating an XX or XY offspring
yes
198
idea that most genes on the X chromosome are not found on the Y
sex-linked genes
199
can autosomal mutations be sex-influenced?
yes (baldness)
200
if 2 X chromosomes, double X mRNA transcription is bad, so XX mammals randomly inactivate one of the X chromosomes
dosage compensation
201
inactive chromosomes in XX cells, tightly wrapped by histones
Barr Bodies
202
when chromosome separation fails during meiosis
nondisjunction
203
what can nondisjunction lead to
aneuplodies (trisomy or monosomy)
204
what are trisomies and monosomies
instead of one homolog pair, 3 or 1 of the homolog (n+1 or n-1)
205
extra 21 chromsome
down syndrome
206
why are many trisomies and monosomies not observed
most don't survive to birth
207
studies genetics in Drosophilia (flies) and the chromosomal theory of inheritance
Thomas Hunt Morgan (early 1900s)
208
nomenclature for alleles
x+ = normal, x= recessive mutant, b+/b = tells which homolog the allele is on
209
when genes cross over and are recombined, it results in
recombinant (non-parental) chromosomes and genotypes
210
what has to happen to get recombinant non-parental combinations
crossing over must happen on parts of the chromosomes between the two genes of interest
211
a larger distance between linked genes means...
higher chance of recombination between the genes
212
usually there are 1-2 crosses per homolog pair, but
location is largely random
213
where does crossing over commonly occur
between distant genes
214
the percent of offspring with a non-parental genotype helps us to know
distance in centimorgans (map units) between genes
215
what shows that genes are linked on a chromosome
lower rates of non-parentals
216
lower numbers of that type of offspring means they are likely
recombinants
217
if genes are far enough apart the max recombination can be
50%, which looks like unlinked genes
218
if offspring output is equal, it can mean the genes are either on separate chromosomes and unlinked, or 50cm+ apart on the same chromsome
true
219
1 trait that influences several genes
polygenic trait
220
often give more quantitative variance than with a single gene
polygenic control
221
complex interactions between genes and traits
epistasis
222
when a trait occurs in both twins
concordance
223
twins with the same genotype
identical monozygotic twins
224
twins with different genotypes
fraternal dizygotic twins
225
if there is a large difference between fraternal and identical concordance of a trait...
the difference is genetic
226
correlate nucleotide differences in DNA from individuals to occurence or strength of a trait, often see correlation to mutations in several genes
genome wide association studies (GWAS)
227
are GWAS proof of a cause
no, only correlation
228
