Test 1 Flashcards
(215 cards)
1
Q
what are the types of genetics
A
population
molecular
transmission
2
Q
what is transmission genetics
A
how mutations are passed from one generation to the next, the basic principles of heredity, focuses on the individual organism, how gametes separate into probable individuals
3
Q
what is a pedigree used for?
A
to figure out how a disease is transmitted
4
Q
what is molecular genetics
A
the chemical nature of the gene, how genetic information is encoded, replicated, and expressed, focuses on the gene and its structure, organization and function
5
Q
what is population genetics
A
the genetic composition of populations, how genetic composition changes geographically and with the passage of time, the focus is the group of genes found in a population, alleles in a population are used to figure out organisms in a population having a phenotype, population is the unit that evolves in biology
6
Q
what is an SNP
A
single nucleotide polymorphism,
7
Q
how can we use SNPs
A
see how populations evolved looking at these SNPs
8
Q
what is genetics
A
the study of heredity and the variation of inherited characteristics, how characteristics are inherited from one generation to another and the mutations within it, it is a broad field
9
Q
how did the study of genetics begin
A
with domestication of plants and animals, ancient jewish writing shows their was understanding of genetics of hemophilia, the ancient greeks had theories of inheritance
10
Q
what were mendels main contributions
A
traits are passed from generation to generation, transmission of genetic information from parents to offspring, his word formed the foundation for genetics, looked at dominate and recessive traits
11
Q
defintion of genetics
A
defined as the branch of biology concerned with the study of heredity and variation
12
Q
how many genomes do we have in our cells
A
2 (one from mom and one from dad)
13
Q
what is the law of segregation
A
during meiosis the 2 genomes segregate
14
Q
what is the law of independent assortment
A
the probability of getting either trait is the same (they are independent of each other, nonhomologous chromosomes assort independently
15
Q
what did mendel orginally term a gene as
A
zellemente - “cell elements”
16
Q
who coined the word gene
A
Johannsen used it to describe mednelian units of heredity
17
Q
what else was johannsen responsible for?
A
distinction between phenotype and genotype
18
Q
what is a phenotype
A
the expression of the trait
19
Q
what is a genotype
A
alleles in the gene that make the phenotype
20
Q
what did sutton study
A
grasshopper meiosis and said that genes were located on chromosomes
21
Q
what did boveri study
A
same as sutton but on sea urchins
22
Q
what did sutton and boveri estabish
A
the chromosomal theory of inheritance
23
Q
what is the chromosomal theory of inheritance
A
individual genes are found at specific locations on particular chromosomes, and that the behavior of chromosomes during meiosis can explain why genes are inherited according to mendels laws
24
Q
what did morgan propose
A
that genes are on chromosomes like beads on a string, first discovered linkage, seperable units but connected on a chromsomes he also pionered drosophilia research
25
what did mendel disocver when showing how traits were passed from parent to offspring
it was not a straightforward way, it is dominance and recessiveness
26
what did the frederick griffith experiment show
bacterial transformation
27
how did the frederick griffith experiment work
when live non virulent strains and dead virulent strains were injected in the same mouse, the mouse died
28
what did Avery, MacLeod, Maclyn, and McCarty disocver and how
that DNA was the genetic mateiral, they injected proteanase and DNAase in mice witht the transforming strains and found that the mice lived when injected with the DNA so the DNA must be making all the instructions
29
what was the orignal but now incorrect term for a gene
one gene codes for one protein
30
why doesnt one gene code for one protien
there can be oberlapping strands that DNA is taken from, alternative splicing, non protein coding genes, different buidling blocks of given mRNA molecule can be located on different chromosomes, transgeneration epigentic inheritance, polycistronic mRNAs, trans splicing, alternatively spliced products with alternate reading frame
31
what is Dscam used for
brain development in drosophilia, can make many genes
32
miRNAs
dont make protein from them, help to irregulate gene expression
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polycistronic mRNA
mRNAs that code for more than one protien
34
trans splicing
exons from 2 different primary RNA trasncripts are joined end to end and are ligated, 2 different genetic regions can make one protein
35
modern definiton of a gene
all of the continuous sequences of a nucleic acid (DNA or RNA) that makes a functional product
36
what must be true of a gene
must be able to aquire mutations, might be the unit of natural selection, regulatory genes are classified as gene associated elements
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how are genes named
they are alwaysitalicized, if capital it is dominant, if lowercase it is recessive
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how are human genes named
the entire gene is capatilized and italicized
39
classical genetics (forward)
If we begin by looking at the phenotype But not we are interested in learning what gene caused the phenotype Classical genetics/ forward
40
reverse genetics
Looking at a gene and seeing what phenotype occurs when you break it reverse genetics
use a nonfunctional version of the gene
41
what is gene knockout
making a target gene non fucntional and observing the outcome
42
good model organisms
easy to grow, short life cycle, produce many offspring, genetic analysis is strightforward, if they have a genome that is helpful
43
what is transgenic organisms
transferring genes between species
44
what is chromatin
complex of DNA (and sometimes RNA) and proteins (histones)
45
how much DNA is in every cell
3 feet
46
how is DNA packaged
histones
47
how many molecuels of DNA are in an unreplicated chromosome
1
48
how many molecules of DNA are in a replicated chromosome
2
49
what is the centromere
made of DNA, has specific ATCG sequences, microtubules stick here so chromosomes can be moved around during mitosis and meiosis, it is not always in the middle
50
what are the arms on a chromosome
p and q arms
51
what is a p arm
smaller
52
what is a q armm
longer
53
metacentric chromosome
centromere location is in the center so no p or q arms
54
submetacentric chromosomes
centromere location is between middle and end
55
acrocentric chromosome
centromere location is very close to the end, very small p arms
56
telocentric chromosome
centromere location at the end, only q arms
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monocentric chromosome
1 centromere, what humans have
58
holocentric chromosome
has multiple centromere attachment sites, the whole chromosome is basically a centromere, what arachnids have
59
somatic cells
body cells
60
germ cells
sperm and egg cells, cells carrying onto the next generation
61
what cells does meiosis take place in
germ cells
62
somatic cells have what types of chromosomes
homologous chromosomes
63
how many chromosomes do humans have
46 chromosomes (23 homologous pairs)
64
homologous chromosomes
same chromosomes, same genes, same length, but 2 copies of the same chromosome one from mom and one from dad, may or may not have the same alleles
65
diploid
2 copies of each chromosome in your cell
66
genome
all the genetic infromation in haploid set
67
how many genomes in a human cell
2 (one from mom, one from dad)
68
how many chromosomes in the human genome
23 chromosomes in the human genome
69
what is each gene site on a chromosome
locus
70
biparental inheritance
inheritance from 2 parents, diploid organism
71
sister chromatid
2 molecules of DNA in one chromosome
72
centrioles
cytoplasmic bodies located in the centrosome, made of tubulin, is a rope to pull the chromosomes apart
73
spindle fibers
Composed of microtubules consisting of polymers of protein tubulin.
Play important role in movement of chromosomes as they separate during cell division.
74
what is a centrosome made of
centrioles
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what are the 2 main parts of the cell cycle
interphase
| m phase
76
mitotic phase
mitosis
| cytokinesis
77
interphase
cell growth and copying of chromosomes in preparation of cell division
78
subphases of interphase
G1, S, G2
79
G1
growth
80
S
synthesis, replicate the chromosomes
81
G2
putting things together for mitosis
82
cyclins
makes decisions on when a cell goes through the stages, molecules that control a cellular clock, control progression of the cell cycle, these are expressed cyclically to initiate different portions of the cell cycle
83
what do cyclins activate
cyclin dependent kinases
84
what do Cdks do
cyclin binds to them causing it to phosphorylate another target
85
which cyclin is always on
D
86
which cyclin turns on to go from G1-S
E
87
which cyclin turns on to go from S-G2
A
88
which cyclin turns on mitosis
B
89
what is the hidden stage of the cell cycle
G0 phase
90
example of a cell in G0
nuernons
91
what is G0 phase
for cells not preparing for mitosis, outside of the replicative cycle
92
quiescent cells
reversible, can leave G0
93
example of quiescent cells
stem cells
94
senescent cells
irreversible, stay in G0, be due to stress or damage, telomere shortening, cell that we keep eve if damaged, don’t want the cell to reproduce but want it to do its job
95
differentiated cells
irreversible, stay in G0 and performs their functions
96
what is interphase characterized by
the absence of visible chromosomes, it is 90% of the cell cycle
97
events during G1
cell growth, preparation of chromosomes for replication, synthesis of histones,
98
what can the cell do after G1
continue onto S phase or stop the cell cycle and go into G0
99
Check point in G1
R point or restriction point
100
what happens at the G1 restriction point
checks the cell to make sure it is good enough to move on in the cell cycle, decides if it is going to go to G0
101
what are mitogens
signaling protein that is needed to induce a cell to undergo mitosis, proteins from other cells that tell the cell to to go through mitosis, how the cells comunicate
102
what controls G1-S
cyclin E
103
What cyclin maintains S phase
cyclin A
104
main thing that happens in S phase
chromosomes replicate
105
what holds the sister chromatids together
cohesin
106
when is cohesin formed
during S phase
107
how does cohesin keep the chromatins together
makes a ladder between the chromatids
108
what happens in G2
check to make sure DNA integrity is there, double stranded breaks are fixed, DNA must be intact before going through m phase
109
how does the cell know to go from G2 to mitosis
high expression of Cyclin B
110
checkpoints in G2
DNA damage checkpoint right before Mitosis
111
DNA damage checkpoint
makes sure the chromosome is okay to go through and then increases Cylcin B alot
112
Prophase
decrease cyclin B and D
chromatin condenses
centrosomes move to opposite poles
formation of mitotic spindle
113
what is a centrosome
collection of 2 centrioles
114
metaphase
middle
chromosomes align on the metaphase plate
kinetechores attack to the to the centromsomes and are equally aligned
115
kinetechore
anchor that attached to centromere
116
what breaks down cohesin so the chromatids can seperate
seperase
117
how do we keep the cohesin that we want protected from seperase
shugoshin protects it
118
how many subphases are there in anaphase and what are they
2
| a and b
119
anaphase a
pushes away to either side of the cell
120
anaphase b
pulled apart at the opposite ends, forced in multiple points
121
telophase
```
effects of prophase are reversed
nuclear envelope reassembled
nucleoli reappear
mitotic spindle chomped up
cyclin destroyed
```
122
what type of division is meiosis
reductional divison
123
how many rounds of cell division in meiosis
2
124
aneuploidy
error in cell division, wrong number of chromosomes
125
what does haploid mean
1, one whole genome
126
interkinesis
stage between meiosis 1 and meiosis 2, resting stage preparing for meiosis 2
127
what happens during interkinesis
the spindle in meiosis 1 disassembles and new microtubules assemble for meiosis 2
128
bivalent
pair of 2 homologous chromosomes in prophase 1
129
tetrad
the four sister chromatids found between them
130
general goal of meiosis 1
seperate homologous chromosomes
131
prophase 1 phases
```
leptotene
zygotene
pachytene
diplotene
diakinesis
```
132
leptotene
the individual duplicated chromosomes condense into long thin threads from diffuse chromatin, telomeres have DNA sequences allowing them to attach to the inside nuclear envelope of the nucleus, anchor to the nucklear membrane wall base pair with homologous chromosomes counter parts so they can find eachother, how the homologous chromosomes find their pair
133
zygotene
the chromosomal pairing stage, chromosomal synapsis occurs here; synaptoenamal complex which allows for synapsis forms,
134
synapsis
interlocking of the base pairs of the 2 chromosomes
135
synaptonemal complex
is a lot of proteins forming a ladder that attaches the 2 homologous chromosomes together
136
pachytene
the bivalent forms, crossing over occurs, swapping strands and DNA, complex between chromosomes from mom and dad
137
diplotene
the synaptonemal complex degrades; homologous chromosomes seperate a little, but are still bound
138
diakinesis
chromosomes are at their most condensed nucleolus disappears, nuclear envelope disappears; centrioles move the equator
139
where are chromosomes at their most condensed
diakinesis
140
metaphase 1
at the end of prophase 1, the centromeres are lined up at the equitorial plate, chromomses are at maximum shortness and thickness, terminak chiasmata holding non sister chormatids together, they are all the way separated,
141
anaphase 1
homologous chromosomes seperate, a balance between puishing and pulling forces on the microtubules
142
how do molecules stay intact during anaphase
cohesin
143
when does disjunction occur
anaphase 1
144
what is disjunction
half of the tetrad is randomly puled to opposite poles
145
what is nondisjucntion
may occur- separation not achieved
146
telophase 1
reappearance of nuckear membrane around dyads, nucleus enters into short interphase period, chromomse do not replicate since they already consists of sister chromatids interkinesis occurs afterwards
147
what happens in meiosis 2
same as mitosis
148
what type of genetics did mendel study
transmission genetics
149
what is a monohybrid cross
cross of only one pair of contrasting traits
150
true breeding
the individuals of the traits are homozygous
151
P1 generation
original parents
152
F1 generation
offspring
153
F2 generation
offspring of F1 generation crossed
154
testcross
detemrines if the individual displaying dominant phenotype is homozygous for heterozygous for that trait, always suses homozygius recessive indivual with unknown genotype individual
155
AA x aa
100% will be Aa
156
Aa x Aa
1:2:1
157
Mendels Initial 3 Postulates
Unit factors in pairs
Dominance/recessivness
Segregation
158
unit factors in pairs
genetic charcters are controlled by unit factors (genes) existing in pairs in individual organisms
159
dominance/recessiveness
pair of 2 unlike unit factors (genes) for single characterisitc in individual one unit factor dominant, the other recessive
160
segregation
paired unit factor (genes) segregate (seperate) randomly during gamete formation
161
dihybrid cross
two factor cross, mendel studied inheritance of 2 traits simultaneously, crossing involing two pairs of contrasting traits --> generates unique F2 ratio
162
YyRr x YyRr
9:3:3:1 phenotypic ratio
163
mendels fourth postulate
independent assortment
164
independent assortment
2 monohybrid crosses with the traits inherited independently
165
when does unit factors in pairs occur
first meiotic prophase
166
when does segregation of unit factors during gamete formation
first meiotic anaphase
167
when does independent assortment of segregating unit factors occur
follows many meiotic events
168
law of segregation is when
anaphase 1
169
what do you do to predict genotypes of multiple hybrid crosses
product law
170
what do you do to preduct phenotypes
sum law
171
what is the longest phase of meiosis
prophase 1
172
primary vs secondary sex determination
primary is the genetic sex that determines the identity of the gonads
secondary is the establishment of testes or ovaries, antlers and beards etc.
173
how many tubes do embryos start with
2
174
what happens to the duct systems in embryos
the wolfian ducts go away if its a female, and the mullerian ducts go away if its male
175
what chromosome houses the maleness genetic information
Y
176
How to all embryos start out
females
177
when do the gonads begin to differentiate ovaries or testes
5th week
178
what are the bipotential gonads
gonads that turn to either ovaries or testes
179
what does the Y chromosome carry
SRY gene
180
what does the SRY gene do?
organizes the bipotential gonads into testes
181
what are PARs
parts of the sex chromosomes near the telomeres that have genes that are inherited in an autosomal fashion
182
how does dosage compensation help mammals
prevents excessive expression of x linked genes in mammals
183
What are barr bodies
they are inactivated x chromosomes
184
why do we have barr bodies
genetic mechanism that compensates for X chromosomes dosage disparities
185
how can an SRY be on an X chromosome
due to pars it can possibly translocate onto the X chromosome
186
dosage compensation
how we turn off the extra X chromosome
187
what is the XIC
x inactivation center
188
important genes housed on the XIC
xist gene and the Tsix gene
189
how do the xist and tsix gene work together
the x chromosome chosen for inactivation turns on the xist gene and the opposite one turns on tsix
190
how is sex determined in drosophila
x is male, XX is female, if its 3 sets of autosomes to 2 x chromosomes then it is mosaic
191
what is the genetic balance theory
when the threshold of maleness is reached by a 1X:2Autosome ratio
192
what are the sexual phenotypes of c elegans
males and hermaphrodites
193
what distinguishes a male c elegan
one testes, has only one x chromosome no y
194
what distinguishes a hermaphordite c elegan
both testes and ovaries, 2 x chromosomes no Y
195
majority of offspring in c elegans
hermaphorites, less than 1% are male
196
what is the homogametic sex in bird
males who are ZZ
197
what are is the female genotype in birds
ZW
198
in birds what determines if the embryo will be male or female
egg
199
what is weird about platy[usses
5 x and 5 ys
200
what is the system of a platypuss called
monotreme system
201
what is haplodiploid sex determination
the sex is based off if the embryo is fertilized, not fertilized then it is haploid and a male, if it is fertilized then it is diploid and a female
202
what is special about reptile sex detemrination
temperature dependent
203
what is temperature dependent sex determination
certain enzymes are affected by temperature, temperature of the outside environment determines if the developing embryo is male or female
204
what is case 1 for temperature dependent sex determination
low temp=females
| high temp=males
205
what is case 2 for temperature dependent sex determination
low temp=males
| high temp=females
206
what is case 3 for temp dependent sex determination
high and low temp=females
| middle=males
207
what is the critical period of incubation known as when it comes to temp dependent sex determination
thermosensitive period
208
what is the main enzyme that deals with temp dependent sex determination
aromatase
209
what does aromatase do
converts androgens (male hormones) to estrogens at certain temps
210
what is sex limited inheritance
expression of a specific phentpype is limited to one sex, involving genes not on the X or Y chromosomes
211
what is sex influenced inheritance
sex of individual influences expression of phentoype not limited to one sex, involving genes not on the X or Y chromosmes
212
how does the sex limited inheritance in chickens works
feathers in chickens are caused by an autosomal gene, hen feathering controlled by a dominant allele expressed in both sexes, male feathering controlled by recessive allele only expressed in males but the actual expression is modified by the individuals sex hormones, you must have 2 copies of the recessive allele and male to get the cocked feathers
213
sex influenced inheritance with baldness
the allele for baldness behaves as a dominant gene in males and ressive in females, females must be BB to be bald but males can be BB or Bb
214
what is white eye color in drosophila knwon as
x linked and recessive trait
215
what is an x linked trait
it is only carried on the X chromosome and it is recesive so you must have 2 copies to inherit the trait in females, males will only need one copy
