Exam 1 Flashcards
(232 cards)
1
Q
Define genetics.
A
the science of dealing with heredity and variation. Seeks to find laws governing similarities and differences in individuals related by descent.
2
Q
what makes up genetics?
A
inheritance, traits, and physical appearance.
in other words, it’s what makes you, you
3
Q
define a gene.
A
blueprint for how the body looks.
4
Q
what two things does heredity influence?
A
trait and character
5
Q
what is selection used for?
A
to move the mean of the population
6
Q
what does genetics measure and why?
A
traits, to improve animals
7
Q
define animal genetics
A
the study of principles of inheritance of animals
8
Q
define animal breeding
A
the application of principles of animal genetics with the goal of improving animals.
9
Q
what is the purpose of animal breeding?
A
to improve the economic efficiency of livestock production, so the animal can reach market mode faster and cheaper.
10
Q
what is the main tool of animal breeding
A
selection
11
Q
what does selection do?
A
determines the parents of the next generation
12
Q
what are the two types of selection
A
natural and artificial
13
Q
what are the characteristics chosen for natural selection
A
strength
size
intelligence
color
defense strategies
flexibility
longevity
14
Q
what animal was domesticated first
A
dog
15
Q
what did domestication help with
A
resources, protection, and hunting
16
Q
what is the domestication order
A
dog
goat
sheep
cattle
pig
llama
horse
camel
cat
chicken
guinea pig
turkey
rabbit
mouse
17
Q
who was Robert Bakewell
A
the father of animal breeding
18
Q
what is Bakewells purebred concept
A
in and in breeding (inbreeding to the max)
19
Q
what is Bakewell’s process
A
set goals
early bull progeny test
record system
20
Q
what does the purebred concept do?
A
increases homozygosity
improves uniformity
21
Q
which sex drives gene improvement and why?
A
male, because they produce more
22
Q
what is a downside of pure breeding
A
undesirable alleles are shown
23
Q
what does the bull progeny test do
A
it rates the performance of offspring as opposed to the parent.
24
Q
describe self domestication
A
select for tameness
strict captivity and limit breeding
intentional breeding
trait standardization
eliminate wild species
25
describe human domestication
control herd movement
eliminate problems
select for tameness
strict captivity and limited breeding
trait standardization
eliminate wild species
26
what three events led to modern genetics
Darwin's "the origin of species"
Mendel's "experiments in plant hybridization" and his two laws of segregation and independent assortment
Miescher isolating nucleic acid from pus cells.
27
who coined the term genetics?
Bateson
28
how many dna bases form a codon
3
29
why is selection used
to utilize fewer animals for the same amount if not more of product.
30
0-0.2 is _____ heredity
0.21-0.4 is _____ heredity
0.41-0.99 is _____ heredity
low
medium
high
31
heredity is not a ______ it is a __________
trait; measure
32
what is cryopreservation
freezing semen to use for AI
33
where is nuclear dna found?
nucleus
34
where does protein synthesis occur?
in the ribosomes
35
what did Miescher find in pus in 1868
nuclein, which is a phosphate-rich chemical from white blood cell nuclei
36
DNA has a ___________ backbone
phosphate
37
Describe Griffiths experiment
He used both smooth streptococcus pneumonia (S) which is virulent, and rough streptococcus pneumonia (R) which is nonvirulent. Injected S-strain (killed mouse), R-strain (mouse lived) heat-killed S-strain (mouse lived), and heat-killed S-strain with R-strain (mouse died).
38
dead S-strain + living R-strain = ?
living S-strain
39
Describe the Avery, MacLeod and McCarty experiment
Proved that over time, living R and dead S create living S. Protase ended in S cells, RNase resulted in S cells, ultracenfiguration results in S cells, but DNase resulted in R cells. Indicates a predominance of DNA. RNA and protein was destroyed.
40
Describe the Hershey and Chase (blender) experiment
Used T2 bacteriophage and bacteria. 32P for DNA and 35S for protein. the phage would attach to bacterium, and inject its genes into a host cell. the phage DNA replicates, and new particles assemble. the cell finally bursts, releasing new phage. Proved DNA was hereditary because DNA was found inside both the host and the cell.
41
what is bacteriophage
a virus
42
what makes up a nucleotide?
nitrogen base
phosphate
5-carbon sugar
43
what did Watson and Crick propose?
that DNA is a double helix
44
what is the diameter of DNA
2nm
45
A and T are _______ bonded, C and G are _________ bonded
double; triple
46
what is DNA
deoxyribonucleic acid
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DNA is the _______________ of life
blue print
48
genes code for ________
protein
49
humans have __ chromosomes
46
50
cattle have __ chromosomes
60
51
sheep have __ chromosomes
54
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goats have __ chromosomes
60
53
dogs have __ chromosomes
78
54
cats have __ chromosomes
38
55
chickens have __ chromosomes
78
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pigs have __ chromosomes
38
57
turkeys have __ chromosomes
80
58
horses have __ chromosomes
64
59
donkeys have __ chromosomes
62
60
mules have __ chromosomes
63
61
camels, llamas, and aplacas __ chromosomes
74
62
rats have __ chromosomes
42
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mouses have __ chromosomes
40
64
rabbits have __ chromosomes
44
65
what are the four DNA bases
adenine, thymine, guanine, cytosine
66
what base are A and G in
purine
67
what base are C and T in
pyrimidine
68
what is dna unzipped by in replication?
helicase
69
where are base pairs assembled
the parent template
70
the new DNA strand is ________ to the old one
complementary
71
what is DNA replication?
semi conservative
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what are produced after DNA is unwound with helices
two daughter helices are produced
73
each strand is a _________
template
74
what does complementary base pairing
it ensures T pairs with A and G pairs with C
75
what are the four steps of replication
1. original double helix
2. stands separate
3. complementary bases align opposite of the template
4. enzymes link sugar-phosphate elements of aligned nucleotides in a continuous new strand
76
true or false: replication occurs at both ends
true
77
where does replication begin
the origin of replication
78
________ have multiple origins
eukaryotes
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what does helicase do?
unwinds DNA and keeps strands from rejoining
80
what does primase do?
primes the DNA to find the beginning; does the majority of the work
81
how is the leading strand read?
5' to 3'
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how is the new strand read?
3' to 5'
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how is the lagging strand read?
3' to 5'
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how is the new strand from the lagging strand read
5' to 3'
85
what stabilize the unwound parental DNA
single-stranded binding proteins
86
the leading strand is continuously ________
synthesized
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the lagging strand is discontinuously ____________
synthesized
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what do primase synthesize?
a short RNA primer, extended by DNA polymerase to form an Okazaki fragment
89
what does DNA ligase do?
it joins the Okazaki fragments to the growing strand
90
what does pol 3 do?
produces new strands of complementary DNA
91
what does pol 1 do?
fills in gaps between synthesized Okazaki fragments
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what does DNA helicase do
unwinds the double helix
93
what do single-stranded binding proteins do?
keeps the helix open
94
what does primase do?
crenate RNA primers to indicate synthesis
95
what does ligase do?
welds together Okazaki fragments
96
what do telomeres do?
ensure the maintenance and accurate replication of the chromosome's end.
97
what causes super coiling
unwinding and replication
98
what does topoisomerase do?
an enzyme that relaxes super coils by nicking strands
99
what is redundancy
the basis for the repair of errors that occur during replication or storage
100
breakage and repair create what?
reciprocal products of recombination
101
precision in exchange prevent __________
mutations
102
DNA is _____________ strands
antiparallel
103
how is RNA similar to DNA
they have repeating subunits and nucleotides
104
how does RNA differ from DNA
it is single-stranded, shorter, and less stable
has uracil instead of thymine
105
what is the central dogma
DNA - transcription - RNA - translation - protein
106
what are the 3 RNA molecules
mRNA, rRNA, tRNA
107
what does mRNA do?
it carries the message about what protein to make from the nucleus to the ribosome
108
what is the promoter sequence
TATA
109
once mRNA is formed, what do enzymes do and where?
they remove introns and leave exons
110
what are introns
noncoding sequences
111
what are exons
coding sequences
112
what 3 things happen during transcription
7-methyl cap
polyadenylation (poly-A tail)
intron splicing
113
what does the 7-methyl cap do
it prevents deflation, facilitates attachment to ribosomes, and improves mRNA stability
114
what does the poly-A tail do
signals the end of transcription
115
how many codons are there
64
116
what are the three stop codons
UAA, UGA, UAG
117
what is the start codon?
AUG
118
how many amino acids are there?
20
119
name all twenty amino acids
1. l-alanyl
2. l-arginyl
3. l-asparaginyl
4. l-aspartyl
5. l-cysteinyl
6. l-glutaminyl
7. l-glutamyl
8. glycyl
9. l-histidyl
10. lisoleucyl
11. l-leucyl
12. l-lysyl
13. l-methionyl
14. l-phenylalanyl
15. l-prolyl
16. l-seryl
17. l-threonyl
18. l-tryptophanyl
19. l-tyrosyl
20. l-valyl
120
define translation
synthesis of a protein
121
where does translation occur
in the cytoplasm of a cell
122
what does tRNA do
brings specific amino acids to the ribosome to be assembled as a protein
123
what does rRNA do
joins with a number of protein to form ribosomes
124
how long is tRNA
80 nucleotides long
125
what are the 6 steps in translation
1. mRNA leaves the nucleus and goes to the ribosome
2. mRNA binds to the small ribosomal unit
3. tRNA brings an amino acid to the ribosome
4. amino acids form a polypeptide chain
5. tRNA is released from the ribosome
6. other tRNA bring more amino acids to complete the chain
126
where does protein synthesis occur
cytoplasm
127
_______ determines the protein
order
128
list the five steps of protein synthesis
1. mRNA transcribes from DNA
2. tRNA binds to amino acids
3. amino acids bind to ribosomes
4. peptide chain forms
5. peptide chain is complete
129
define mutation
a change in DNA sequence that may be passed to future generations
130
define point mutation
single based substitution
ie: the cat saw the rat
the cat saw the hat
131
define deletion
a small DNA segment is lost
132
define insertion
a segment of DNA is added
133
define frame-shift mutation
modification of the reading frame after a deletion/insertion, resulting in all codons downstream being different
134
true or false: all mutations are bad
false
135
what can good mutations do
allow an individual to perform better
136
where does life begin
as a single cell
137
describe mitosis
somatic (body) cell division
used for growth
creates identical daughter cells with the same amount of chromosomes
138
define chromatid
identical copies of chromosomes
139
define diploid
one complete set of daughter cells
140
what does mitosis begin with
the parent cell
141
what are the steps of mitosis? describe them
prophase- chromatin condense and nuclear envelope disappears
metaphase- chromosomes align at the equatorial plate
anaphase- sister chromatids separate, and centromeres divide
telophase- chromatin expand and cytoplasm divides
142
describe meiosis
a division of gametes (sex cells)
have half the amount of chromosomes as parents in the end
goes through two divisions
143
define haploid
daughter cells have half the chromosomes of parents
144
describe meiosis 1
diploid to haploid
1 random chromatid is drawn to the opposite side
145
describe meiosis 2
similar to mitosis
results in four daughter cells, all haploid
146
what does meiosis end in for male sex cells
4 functional sperm
147
what does meiosis end in for female sex cells
1 functional ovum and 3 polar bodies
148
what are Mendel's two laws
law of segregation
law of independent assortment
149
describe the law of segregation
states each individual has two factors for each trait
these factors segregate during gamete formation
1 factor/gamete
150
_______ determine characteristics
genes
151
define homologous chromosomes
members of a pair and carry genes for the same traits in the same order
152
define alleles
alternate forms of a gene for the same trait
153
alleles are always found on the same ____
loci
154
define a homologous pair
chromosomes with alleles for the same gene in the same location
155
what does a test cross do
it determines the likely genotype of an individual with the dominant phenotype
156
what must you have for a test cross
a known recessive individual
157
define the law of independent assortment
each pair of favors assort independently without regard to how the others separate
158
define gene action
how the genotype of a particular trait affects expression of a phenotype
159
what are the five types of gene action
non-additive
sex-linked
sex-limited
sex-influenced
additive
160
describe non-additive gene action
made up of qualitative traits (few genes)
161
define qualitative and give examples
influenced by few genes
coat color, horned v polled, disease phenotype
162
define quantitative and give examples
influenced by a lot of genes
milk production, growth trait, carcass traits
163
what are types of non-additive gene action
complete dominance, incomplete dominance, epistasis
164
what are types of epistasis
complete dominance, recessive epistasis, and incomplete dominance
165
describe complete dominance and give an example
one allele masks the expression of the other
coat color in cattle
166
describe incomplete dominance
heterozygotes do not have the same phenotype as homozygotes
167
describe epistasis
interaction between non-allelic genes
the phenotypic effect depends on alleles present at another locus
168
describe complete dominance epistasis and give an example
if a dominant allele is there, it will control the genotype
wool pigmentation in sheep
169
give an example of incomplete dominance
coat color in horses
170
what is the genotype of bay horses
CCB_
171
what is the genotype of buckskin horses
CcB_
172
what is the genotype of cremello horses
cc_ _
173
what is the genotype of palomino horses
Ccbb
174
what is the genotype of chestnut horses
CCbb
175
describe sex linkage genes
and give an example
sex is determined by the inheritance of the entire chromosome
coat color in cats (specifically tortoiseshell and calico)
176
the Y chromosome carries ____ genes
few
177
the X chromosomes carries _____ genes
many
178
genes are controlled by _ or _ chromosomes
X, Y
179
what does tortoiseshell coloration prove?
that coat color locus is on the X chromosome
180
describe recessive sex-linked gene action
give an example
a characteristic pattern of inheritance
Barr bodies in cats creating calico coloration
181
define lionization
genes are randomly expressed in different sections
182
what does the pie balding effect do
causes white fur
183
define sex-influenced gene action
give an example
a trait with the same genotype, but a different phenotype
Hh would be a horned bull but a polled cow
184
in sex-influenced expression differs between...
males and females
185
define sex-limited and give an example
expression of a gene occurs only in one sex
milk production
186
define cryptorchidism and what type of gene action is it
the non-decent of testicles into the scrotum
sex-limited
187
define pleiotropy
one gene affects more than one trait
188
define variable expressivity and give an example
the existence of more than one grade of a trait
skin color
189
define over dominance
give an example
the heterozygote is superior to both homozygotes
malaria
190
define incomplete penetrance
give an example
not every individual with the genotype exhibits the phenotype
polydactyly
191
define complete penetrance
every individual with the genotype expresses the phenotype
192
define lethal
embryonic death or death shortly after birt h
193
define semi-lethal
death before puberty
194
define detrimental
reduction in some measure of fitness/productivity
195
define gene linkage
a condition where non-allelic genes consistently travel together through meiosis
196
what are examples of genetic correlation
pleiotropy and gene linkage
197
define exception
crossing over/exchange of genetic material
198
define recombination
formation of new combinations of genes on a chromosome due to crossing over
199
define complete linkage
no crossing over occurs
200
define incomplete linkage
crossing over occurs
201
__________ breaks occur at __________ sites on each chromosome
mutual; identical
202
crossing over occurs more often between _________ genes
distant
203
define additive gene action
give an example
involve quantitative traits; expression over a continuous range of values
milk production
204
what is the cumulative effect of all genes
phenotype
205
define polyfactorial
quantitative traits that have economic importance
206
define heritability
the ratio of genetic variance to phenotypic variance
207
what does heritability measure
the strength of the relationship between performance and breeding values for a trait
208
what is h2
the probability an offspring will get a trait
209
h2=?
Vg/Vp[Vg+Ve]
210
Vg=
Vbv+Vgcv
211
what is the mcv based off of?
the pairing of alleles
212
what does broad sense h2=
Vg/Vp
213
narrow sense h2=
Vbv/Vp
214
what are the two HWE equations
1. p+q=1
p^2+2pq+q^2=1
215
HWE is mostly a _____________ population with a lot of ___________
hypothetical; assumption
216
what are the HW principles
genetic drift, mutation, recombination, and selection q
217
define population genetics
mechanisms acting within a population
218
define hardy Weinberg principle
in a large, randomly mating population, gene/allelic and genotypic frequencies will remain constant from generation to generation
219
define genetic drift
random traits that happen by chance
220
define natural selection
the best animals reproduce
221
define mutation
changes in chromosomes/genes
222
define migration
movement
223
define population
a group of individuals within a species that is capable of interbreeding and producing fertile offspring
224
give the HWE requirement and then its violations
large population genetic drift
random mating inbreeding
no mutation mutation
no natural selection natural selection
no migration migration
225
what would p and q equal if AA=320, Aa=160 and aa=20
frequency= 0.64, 0.32, 0.04
doubled, p=0.8, q=0.2
226
what protein is central to both the initiation and elongation of transcription
RNA polymerase
227
___________ _________ determines which strand is transcribed
promoter sequence
228
what does transcription end with
a poly-A tail
229
how does translation end
with a stop codon
230
list five differences between DNA replication and RNA transcription
Replication is for cell multiplication and transcription is for protein synthesis
replication is bi-directional while transcription is unidirectional
replication uses thymine and transcription uses uracil
replication is double-stranded and transcription is single-stranded
replication uses helicase, transcription has no need for helices
231
what are benefits of splicing
it makes mRNA stable
attaches easily to chromosomes
facilitates nuclear export
232
what are the requirements for HWE? what are the violations?
large population size --> genetic drift
random mating --> inbreeding
no mutations --> mutations
no natural selection --> natural selection
no migration --> migration
