Genetics Flashcards
1
Q
Somatic Cells
A
have pairs of homologous chromosomes
2
Q
Homologous Chromosomes Share:
A
size
Centro-mere location
Gene locations
(identical in every way)
3
Q
Autosomes
A
number 1-22
4
Q
Sex Chromosomes
A
23rd pair
5
Q
Females are…
A
XX
6
Q
Males are…
A
XY
7
Q
X and Y differ in _____ and _______ contents
A
Size; genetic
8
Q
Meiosis
A
cell division resulting in fewer chromosomes per cell
9
Q
diploid cells
A
2N
two homologous sets of chromosomes
somatic cells
10
Q
Haploid Cels
A
(N)
one set of unpaired chromosomes
gametes
11
Q
Feritlization
A
union of sperm (N) and egg (N)
12
Q
Fertilization creates a…..
A
zygote
13
Q
Meiotic cell cycle:
A
Interphase (G1, S, G2)
Meiosis I
Meiosis II
14
Q
Meiosis I
A
separation of homologous chromosomes
15
Q
Meiosis II
A
separation of sister chromatids
16
Q
Meiosis I Phases in order
A
Prophase I, Metaphase I, Anaphase I, Telophase I
17
Q
Prophase I
A
synapsis and crossing over occurs
18
Q
synapsis
A
homologs come together as pairs (tetrads)
19
Q
Crossing Over
A
Non-Sisters exchange genetic material
20
Q
metaphase I
A
Tetrads align at equator
21
Q
Anaphase I
A
Homologous pairs separate to poles
22
Q
Telophase I, Cytokinesis
A
- Duplicated chromosomes have reached the poles
- Nuclei are haploid (sister still attached)
- Cell divides into 2 daughters
23
Q
Meiosis II
A
- prophase II, Metaphase II, Anaphase II, Telophase II
- no DNA replication between I and II
- both daughters from I enter II
24
Q
Events in the nucleus during meiosis II are ____ as mitosis
A
same
25
End result is ____ ____ ____
four haploid daughters (gametes)
26
males
primary sperm cell (2N) produces 4 sperm cells (N)
27
females
primary egg cell (2N) produces 1 egg cell (N) and 3 polar bodies (N)
28
Similarities between meiosis and mitosis
one duplication of chromosomes
29
differences between mitosis and meiosis
mitosis- 1 division
meiosis- 2 divisions
meiosis pairs homologs and crossing over occurs
30
outcome of mitosis
two genetically identical cells, same chromosome number as the original cell (2N -> 2N * 2)
31
outcome of meiosis
four genetically different cells, half the chromosome number of the original cell (2N -> N* * 4)
32
number of chromosomal duplications in mitosis
1
33
number of chromosomal duplications in meiosis
2
34
number of cell divisions in mitosis
1
35
number of cell divisions in meiosis
2
36
number of daughter cells produced in mitosis
2
37
number of daughter cells produced in meiosis
4
38
number of chromosomes in daughter cells; mitosis
diploid
39
number of chromosomes in daughter cells; meiosis
Haploid
40
How chromosomes line up during metaphase; mitosis
single file
41
how chromosomes line up during metaphase; meiosis
Tetrads
42
Genetic relationship of daughter cells to parent cell; mitosis
identical
43
genetic relationship of daughter cells to parent cell; meiosis
different
44
functions performed in the human body; mitosis
somatic cells
45
functions performed in the human body; meiosis
gametes
46
Independent orientation at metaphase I; separation of chromosomes is _______
random
47
Random fertilization
which sperm fertilizes the egg is random
48
Homologous chromosomes are same in size and gene location but may have ________ versions of a gene at the same locus
different
49
Crossing over involves _______ of ______ ______ between homologous chromosomes
exchange; genetic material
50
what does gene locus contribute to?
certain traits being inherited together
51
Genes that are closely located are likely to....?
be inherited together because they are likely to cross over together
52
Genes that are further away from each other are likely to be... ?
separated form each by crossing over
53
karyotype
shows stained and magnified versions of chromosomes
54
doctors use karyotype because...?
to look for chromosomal abnormalities
55
Trisomy 21
inheritance of 3 copies of chromosome 21
ex. down syndrome
increases with the age of the mother
56
Monosomy and trisomy errors lead to
diseases/ disorders
57
caused by nondisjuncrion
failure of chromosomes or chromatids to separate during meiosis
58
Fertilization after nondisjunction yields....?
zygotes with altered numbers of chromosomes
59
Sex chromosome abnormalities tend to be less severe
ex. small size of the Y chromosome
| X-chromosome inactivation
60
deletion
loss of a chromosome segment
61
chromosome structure changes result form breakage and rejoining of ______ _______
chromosome segments
62
duplication
repeat of a chromosome segment
63
Inversion
reversal of a chromosome segment
64
Translocation
attachment of a segment of one chromosome to a nonhomologous chromosome
65
Errors in gametes cause _____ ______
birth defects
66
Errors in somatic cells cause ______
cancer
67
Gregor Mendel
Austrian monk
worked with pea plants
showed that parents pass heritable factors (genes) to offspring
68
Genetics
the study of heredity
69
heredity
how traits are passed on from parents to offspring
70
character
heritable feature that varies from person to person
71
trait
a variant of a character
72
Genes are found in alternative versions called ______
alleles
73
genotype
combination of alleles
74
organisms inherit _ copies of each gene, one from each parent
2
75
homozygous
genotype has identical alleles (BB or bb)
76
heterozygous
genotype has two different alleles (Bb)
77
phenotype
the appearance or expression of a trait
78
law of segreation
allele pairs separate (segregate) from each other during gamete production so a sperm or egg carries only one allele for each gene
79
law of independent assortment
each pair of alleles segregates independently of the other pairs of alleles during gamete formation
80
pedigree
diagram that shows inheritance of a trait in a family through multiple generations
81
Incomplete dominance
neither allele is dominant over the other
82
Heterozygous individuals express a _______ phenotype
blended; (red+white=pink)
83
multiple alleles
more than two alleles are found in the population
84
diploid individual can carry any ___ alleles
two
85
Codominance
neither allele is dominant over the other
86
Pheiotropy
one gene influencing many characteristics
87
Epistasis
the presence of one gene may alter the effects of another gene
88
Polygenic inheritance
many genes influence one trait
89
linked genes
are located close together on the same chromosome
| tend to be inherited together
90
linked alleles can be separated by ______ ______
crossing over
91
increased distance ______ chances of separation
increases
92
Blood type is determined by two sets of genes
ABO
| Rh
93
The _____ gene determines the "letter" of your blood
ABO
94
The ____ gene determines the positive or negative of your blood
Rh
95
3 different ABO genes
I^A
I^B
i
96
_____ determine what antigen is made
genes
97
Gene I^A makes antigen....
A
98
Gene I^B makes antigen....
B
99
Gene i makes ___ antigens
no
100
I^A and I^B are
codominant
101
Two different Rh genes
Rh +
| Rh -
102
_____ determine what antigen (protein) is made
genes
103
- (minus) gene makes __ antigen
no
104
Antibodies
defense proteins that fight foreign antigens
105
Antibodies are _______ to one antigen
specific
106
When antibody and antigen meet .....
clumping occurs
107
Clumping is...
fatal
