Exam 3 Content (pt 1) Flashcards
(108 cards)
1
Q
what causes genetic variation?
A
mutation
2
Q
definition
mutation
A
any inheritable change in a nucleotide sequence
3
Q
genetic mutations must be replicated during DNA replication before they are passed on to offspring
A
true
4
Q
definition
genotype
A
the genetic makeup of a cell of organism
5
Q
definition
polymorphism
A
any nucleotide change in a gene
6
Q
definition
allele
A
these are different versions of the same gene
7
Q
how many alleles are there in one gene?
A
2
8
Q
where is each allele located?
A
on the chromosome
9
Q
a phenotype is the expression of a genotype
A
true
10
Q
what makes each allele different from one another?
A
nucleotide sequences
11
Q
what makes genetic differences harmful?
A
decreases survival or reproduction
12
Q
what influences the rate of mutation?
A
- genome size
- number of cell divisions
13
Q
most arising mutations come from the father (XY)
A
true
14
Q
what are the types of mutations?
A
- germ-line
- somatic
15
Q
which type of mutation is heritable?
A
germ-line
16
Q
small scale mutations only involve the nucleotides
A
true
17
Q
what are the types of small scale mutations?
A
- point mutations
- insertions
- deletions
18
Q
somatic mutations are nonheritable
A
true
19
Q
somatic mutations are only passed off to daughter cells
A
true
20
Q
what is the benefit to HBB gene mutation?
A
protection from malaria
21
Q
what is the harm to HBB gene mutation?
A
causes sickle cell anemia
22
Q
humans have a large genome & undergo many cell divisions
A
true
23
Q
what is the most dangerous type of mutation?
A
protein mutations
24
Q
the rate of mutation within each generation is more important for germ-line mutations
A
true
25
the *rate of mutation* within **DNA replication** is more _important_ for ***somatic mutations***
true
26
what kind of *mutation* do all **daughter cells** inherit?
**somatic mutations**
27
what kind of changes occur in **point mutations**?
**changing out a single nucleotide**
28
**insertions** & **deletions** involve *one or more nucleotides*
true
29
**mutations** occur *spontaneously* & *randomly*
true
30
what do **single point mutations** generate?
**single nucleotide polymorphisms** *(SNP)*
31
what is the type of *genotype change* when there is no change to the **amino acid sequence**?
**silent**
32
**single base pair** mutations can be _nonsynonymous_ or _synonymous_
true
33
what constitutes a **nonsynonymous mutation**?
**changes in amino acid sequences**
34
where do **nonsense mutations** create _premature stop codons_?
in the *coding region* of **mRNA** during *translation*
35
what happens to the **protein** in _nonsense mutations_?
it becomes unstable & truncated
36
what occurs when **deletion** of 1 or 2 base pairs occur?
**frameshift mutation**
| shifting of the **translational reading frame**
37
how many *InDels* of **base pairs** will lead to an *InDel* of an ***amino acid***?
**3**
38
how many **base pairs** makeup one *reading frame*?
**3**
39
what is the name for the factors that cause **mutations**?
**mutagens**
40
what is considered a **true repair** of the _DNA_?
**damage reversal**
41
what is the *most important* _mechanism_ of **DNA polymerase**?
**proofreading DNA sequences**
42
what kind of _error_ does **mismatch repair** correct?
**replication error**
43
**damaged base error** will be *repaired* by which mechanism?
**base excision repair**
44
how many **nucleotides** will be removed in _base excision repair_?
**1**
45
what are the types of **mutations** in _chromosomes_?
* duplication
* deletion
* inversion
* translocation
46
what causes a **translocation mutation**?
**chromosome breaks**
47
what occurs during a **translocation mutation**?
two normal chromosomes will break and exchange this broken fragment
48
which component is ***doubled*** after the _S phase_?
**DNA**
49
**chromosomes** are the same number *before* & *after* _S phase_
true
| GGA v. GGA
50
# definition
**homozygous** _allele_
possession of the same version of alleles in a gene
51
# definition
**heterozygous** _allele_
having two ***different*** versions of the gene
52
what is the *process* that creates a **gamete** that will lead to the creation of a _zygote_?
**meiosis**
53
what is another name for a **zygote**?
**fertilized egg**
54
**zygotes** are _diploid_ cells
true
55
what is the next step for a **zygote** to undergo?
**mitosis**
56
how many cells does one cell further divide into during **mitosis**?
**2**
57
_one cell_ further divides into **4 cells** during _***meiosis***_
true
58
what are the *subphases* included in **M phase**?
* mitosis
* cytokinesis
59
how many *mitotic cell divisions* does **meiosis** undergo?
**2**
60
what happens to _homologous choromosomes_ during **synapsis**?
they pair with each other & lie side by side
61
in which *subphase* of *meiosis* does **cytokinesis** occur?
**Prophase I**
62
what is the **paired homologs** formed during _synapsis_ called?
**bivalent**
63
what are the kinds of **homologs** in one *bivalent*?
* maternal
* paternal
64
what is the result of **one bivalent** _crossing over_?
**recombinant chromatids**
65
when does **crossover** occur in _Meiosis I_?
**Prophase I**
66
why is there a need for a **crossover** within _bivalents_?
increasing genetic variation by creating novel combinations of alleles
67
what is a **chiasma** that was formed during a _crossover_?
it is the _junction_ where the exchange of genetic material between *homologs* occurred
68
what is the state of **chromosomes** at the end of _Prophase I_?
**condensed**
69
what is the next step after **crossover** in _Prophase I_?
**Prometaphase I**
70
which structure _breaks down_ during *Prometaphase I*?
**nuclear envelope**
71
why is there a need for the **nuclear envelope** to _break down_?
to allow for _mitotic spindles_ to attach to *kinetochores* located on the chromosome
72
in which _phase_ do the *bivalents* move to the center of the nucleus?
**Prometaphase I**
73
_orientation_ of bivalents is **random**
true
| remember: bivalents are mother & father
74
what are the phases that would be considered the **end** of _meiotic division_?
* **anaphase**
* **telophase**
75
_only_ **homologous chromosomes** separated during ***Anaphase I***
true
76
which structures ***do not*** separate during _Anaphase I_?
**sister chromatids**
77
what happens to the **chromosomes** at the end of _Telophase I_ & _cytokinesis_?
they become **haploid** *(reduced in half)*
78
how are **centromeres** impacted during _meiotic cell division_?
they remain **intact**
79
what is another name for **Meiosis II**?
**equational division**
80
why does **DNA synthesis** not occur in _Meiosis II_?
it does not promote **genetic diversity** among the newly divided cells from *Meiosis II*
81
why do the **sister chromatids** separate in both _Anaphase II_ & _Anaphase_ *(mitosis)*?
meiosis evolved from mitosis
82
what are the results of **cytoplasmic division** in _females_?
**1** _oocyte_
**3** _polar bodies_
83
**cytoplasmic division** among _males_ is *equal* among the resulting cells
true
| *they all have the same "amount" of cytoplasm*
84
what is the result of a **haploid oocyte** with a **haploid sperm**?
**diploid zygote** (2n)
85
# definition
**nondisjunction**
failure of a pair of chromosomes or chromatids to separate
86
what is the result of a **first division** _nondisjunction_?
_all four_ gametes wil be affected
87
what is the result of a **second division** *nondisjunction*?
only _two_ gametes will be affected
88
what are the types of **errors** that will occur with _nondisjunction_?
gametes will either have an **extra** number of chromosomes or some would be **missing**
89
what kind of _nondisjunction_ would lead to **Trisomy 21: Down Syndrome**?
**first-division nondisjunction**
90
what are the kinds of **syndromes** that result from _nondisjunction_ in *sex-determining chromosomes*?
* **Klinefelter Syndrome**
* **Turner Syndrome**
91
what are the **chromosomes** associated with _Klinefelter Syndrome_?
**XXY**
(extra X)
92
why does **Turner Syndrome** only have the _X chromosome_?
it is missing an X
93
what is the name for *Mendel's* **first law**?
**Segregation**
94
which of Mendel's law order is **Independent Assortment**?
**second law**
95
why were the **anthers** removed from pea flowers in Mendel's *hybridization experiment*?
to prevent self-fertilization
96
what is the female *reproductive organ* in pea plants?
**stigma**
97
what is the result of *crossbreeding* **true breeding parentals**?
**one dominant trait**
98
what is the **dominant trait** observed in Mendel's experiment?
**yellow seeds**
99
the offsprings in an **F1 generation** have what kind of *parentals*?
**true breeding**
100
what is the **phenotypic ratio** of _F2 offspring_?
**3:1**
101
what kind of **offspring** results in the _F1 generation_ interbreeding?
**F2 generation**
| 3:1 phenotypes
102
how many **alleles** does each _nonreproductive cell_ have?
**2**
103
what kind of **gamete** is produced from *2 diploid homozygotes*?
**heterozygotes**
104
explain **Mendel's First Law (Segregation)**
each **F1 offspring** will become _haploid_ due to the chromosomes from the *diploid parentals* separating, giving the offspring _one allele of each_
105
**fertilization** is a *random* occurrence
true
106
what **method** is used to _predict_ probabilities of an offspring?
**punnett square**
107
what is the purpose of **testcrossing**?
determine the **genotype** of an organism that exhibits a _dominant phenotype_
108
how is **testcrossing** conducted?
the organism in question will be crossed with another who is _known_ to have a ***recessive phenotype***
