Mendel and genetics Flashcards
(149 cards)
1
Q
blending hypothesis
A
idea that genetic material contributed by the two mixes
2
Q
blending hypothesis predicts
A
over many generations a freely mating population will give rise to a uniform population of individuals
3
Q
blending hypothesis fails to explain the
A
reappearance of traits that have skipped generations
4
Q
particulate hypothesis is the
A
gene idea
5
Q
particulate hypothesis
A
parents pass on discrete heritable units (genes)
6
Q
with the gene idea, the genes retain their
A
separate identities in offspring
7
Q
genes can be shuffled and passed
A
along generation after generation
8
Q
Gregor Mendel
A
documented genetics with pea plants
9
Q
Mendel developed his theory before
A
chromosomes were observed with the microscope
10
Q
how did Mendel discover the basic principle of heredity
A
breeding pea plant
11
Q
why did Mendel work with pea plants
A
- short generation time
- large number of offspring
- he could control the mating between plants
- distinct flower colour
12
Q
why was it important Mendel could control mating between plants
A
he could be certain for the parentage
13
Q
character
A
heritable trait that varies among individuals
14
Q
example of a character
A
flower colour
15
Q
trait
A
variant for a character
16
Q
example of a trait
A
having purple or white flowers
17
Q
a pea flower has ______ reproductive organs
A
both
18
Q
male reproduction organ in peas
A
stamen
19
Q
the stamen produces
A
pollen
20
Q
female reproductive organ in peas
A
carpel
21
Q
a pea plant will ______ fertilize
A
self
22
Q
what is the zygote encased in
A
a seed (pea)
23
Q
true breeding
A
over many generations of self pollination, plants produce the same variety as the parent
24
Q
example of true breeding
A
the parent has a purple flower and ALL offspring have purple flowers
25
hybridization
mating or crossing of two true-breeding varieties
26
P generation
true breeding parents
27
F1 generation
the first hybrid offspring
28
F2 generation
second generation
29
the F2 generation arises from the
F1 generation as it self-pollinates
30
law of segregation
Two alleles for a heritable character segregate during gamete formation and end up in different gametes
31
if an organism has identical alleles for a character
the allele is present in all gametes
32
will the offspring look like parents if the organism has identical alleles for character
YES
33
dominant trait
always expressed when the allele is dominant
34
recessive trait
only expressed if both alleles are recessive
35
what happens to a recessive trait if there is only ONE allele
will show dominant phenotype
36
Alternative versions of genes
alleles
37
each parent will have _______ of the traits
one
38
each gene is a
sequence of nucleotides at a specific locus
39
how does an organism inherit two copies of a gene
one from each parent
40
genetic locus is represented ______ in a diploid cell
twice
41
what does it mean if two alleles are at a different locus
one is dominant the other is recessive
42
dominant allele
determines the organism's appearance
43
recessive allele
has no noticeable effect on the organism's appearance
44
punnet square
predicts the allele composition of offspring from a cross between individuals
45
what must be known for a punnet square
the genetic makeup
46
homozygote
organism that has a pair of identical alleles for a gene encoding a character
47
a homozygote is said to be _____ for that gene
homozygous
48
phenotype
observable traits
49
heterozygote
organism that has different alleles for a gene
50
a heterozygote is said to be
heterozygous
51
is true breeding homozygous or heterozugous
homozygous
52
phenotype is both
physiological traits and appearance
53
genotype
genetic makeup
54
testcross
breeding an unknown genotype with a RECESSIVE homozygote
55
what does a testcross reveal
the genotype of the organism
56
law of independent assortment
applies only to genes located on different chromosomes
57
law of independent assortment can happen on the same chromosome IF
the genes are far apart on the chromosome
58
monohybrid
heterozygous for the one particular character being followed in the cross
59
dihybrid
heterozygous for the TWO characters being followed in the cross
60
genes are packaged into gametes in all possible allele combinations AS LONG AS
each gamete has one allele for each gene
61
alleles for one gene segregate into gametes ________ of any other gene
independently
62
what is the key phenotypic ratio
9:3:3:1
63
event that is certain to occur has a probability of
1
64
event that is certain to NOT occur has a probability of
0
65
the probability of a current test is _____ by any previous attempts
unaffected
66
multiplication rule
multiply the probability of ONE event by the probability of the other event
67
each gamete has a ______ chance of carrying the dominant or recessive allele
50/50
68
for any heterozygous F2 plant, the dominant allele can come from
the egg OR the sperm but NEVER both
69
addition rule
add the individual probabilities
70
two ways the inheritance of a character is determined by a single gene DEVIATES from Mendel
1. when a gene has more than two alleles
2. when a single gene produces multiple phenotypes
71
alleles can show different degrees of ______ and ______ in relation to each other
dominance and recessiveness
72
complete dominance
the phenotype of heterozygote and the dominant homozygote are indistinguishable
73
incomplete dominance
neither allele is completely dominant and results in a hybrid phenotype
74
co-dominance
two alleles each affect the phenotype in separate ways and BOTH are shown
75
why is an allele dominant
its seen in the phenotype
76
when both a dominant and recessive allele coexist, they
do not interact at ALL
77
for any character that observed a dominant/recessive relationship of alleles depends on
the level we examine the phenotype
78
Whether alleles appear to be completely dominant, incompletely dominant or codominant depends on the
level at which the phenotype is analyzed
79
Dominant alleles are NOT always
more frequent than recessive ones
80
ABO blood groups in humans are determined by that person's
two alleles of the blood group gene
81
Three possible alleles for blood
1. IA
2. IB
i
82
what do the blood types refer to
carbohydrates A and B attached to a cell surface molecule on red blood cells
83
type O blood has _____ carbohydrate
neither
84
Pleiotropy
Genes can have multiple phenotypic effects
85
A single gene can affect a number of characteristics
Pleiotropy
86
Dominant relationships, multiple alleles and pleiotropy all have to do with the
effects of a single gene
87
Epistasis
One gene affects the phenotype of another
88
The two gene products interact
Epistasis
89
Polygenic inheritance
Multiple genes independently affect a single trait
90
The phenotypic expression of a gene at one locus alters the phenotypic expression of a gene at a second locus
Epistasis
91
a gene that determines whether or not a trait will be expressed
Epistasis
92
Quantitative characters
Characters that vary in population in gradations along a continuum
93
Usually indicates polygenic inheritance
quantitative characters
94
The phenotype ratio is broader
polygenic inheritance
95
The phenotype for a character depends on
enviroment as well as genotype
96
Multifactorial
Many factors collectively influence phenotype including genetic and enviromental
97
Refers to an organism in its entirety = all aspects of its physical appearance, internal anatomy, physiology and behaviour
phenotype
98
Refers to its alleles for a single genetic locus
genotype
99
Humans _____ a convenient subject for genetic research
aren't
100
Pedigree analysis
A collection of family history for a trait
101
Assembled into a family tree describing the traits of parents and children across the generations
Pedigree analysis
102
More serious when alleles cause disabling or deadly diseases instead of differing heritable traits
Pedigree analysis
103
The recessively inherited disorders will ONLY show up
homozygous individual
104
carriers
Heterozygotes may appear normal, but they can pass along the recessive allele to their offspring
105
Genetic disorders _____ evenly distributed among all groups of people
aren't
106
Inbreeding causes an increase in
autosomal recessive conditions
107
Most common lethal genetic disease in Canada
cystic fibrosis
108
Normal allele for the gene codes for
A membrane protein that functions in the transport of chloride ions between certain cells and extracellular fluid
109
Most common inherited disorder among people of Africa
Sickle-cell disease
110
Sickle-cell disease is a ______ disorder
recessive
111
At the organismal level of sickle cell
Normal allele is incompletely dominant to the sickle-cell allele
112
At the molecular level
Two alleles are codominant
113
The hereditary component is polygenic
multifactorial disorders
114
_____ has an effect on phenotype
lifestyle
115
risk of a genetic disorder can be assessed before
a child is conceived
116
Most children with recessive disorders are born to parents with
normal phenotypes
117
Amino-centesis
Inserting a needle into the uterus and extract about 10 mL of amniotic fluid
118
Chronic Villus Sampling (CVS)
1. Inserts a narrow tube through the cervix into the uterus
2. Suctions out a tiny sample of tissue from the placenta
119
Imagining techniques
Examine a fetus directly for major anatomical abnormalities that might not show up on genetic tests
120
Ultrasound
Reflected sound waves are used to produce an image of the fetus
121
Dominant disorders that are lethal diseases are _____ common than recessive alleles with lethal effects
less
122
A lethal dominant allele will often cause the
death of the individual = allele is not passed on
123
when can alleles for a dominantly inherited disorder be passed on
first seen after reproductive age
124
the pollen grain grows a ____
pollen tube
125
the pollen tube allows the
sperm to travel to the ovary
126
describe the relationship between phenotype and genotype in incomplete dominance
genotype and phenotype ratios are the same
127
what is the phenotype/genotype ratio in incomplete dominance of F2 generation
1:2:1 = 1 dominant, 2 mixed, 1 recessive
128
genotype of dominant
multiplcation rule
129
phenotype of dominant
add the phenotypes that show at least one dominant allele
130
phenotype of recessive
the same as the genotype
131
why does a dihybrid cross have 16 squares
4 traits have a probability of 1/16
132
3 traits have a probability of
1/8 (1/2 times 3)
133
alleles close together on the same chromosome will
segregate together
134
true breeding are _____
homozygous
135
Type O genotype
ii
136
Type A genotype
IA IA or IA i
137
Type B genotype
IB IB or IBi
138
Type AB genotype
IA IB
139
antibodies present in O type
Anti A and Anti B
140
antibodies present in A type
anti B
141
antibodies present in B type
Anti A
142
antibodies present in AB
NONE
143
Type A blood can receive
Type A or O
144
Type B blood can receive
type B or O
145
Type O blood can receive
type O only
146
Type AB blood can receive
all blood types
147
what blood is the universal DONOR
O
148
what blood is the universal RECEIVER
AB
149
norm of reaction
the phenotypic range of a genotype influenced by the environment
