Section 2 Flashcards
(178 cards)
0
Q
What was the scientific objective of Mendel’s experiments?
A
To study how traits are transmitted over generations
1
Q
In the nineteenth century, what was the dominant theory for how traits were inherited?
A
“blending inheritance”
2
Q
What did Mendel study in Vienna?
A
Botany
3
Q
What was the practical goal of Mendel’s experiments?
A
To learn if crossbreeding could produce a new, profitable form of crop for the monastery and landowners in face of competition from abroad
4
Q
How many times did Mendel fail in getting his teaching certificate?
A
Twice
5
Q
What organism did Mendel choose as the subject of his experiments?
A
Common garden pea
6
Q
What is the scientific name of the common garden pea plant?
A
Pisum sativum
7
Q
What turned out to be the key decision that helped Mendel revolutionize the field of genetics?
A
His decision to use the common garden pea plant
8
Q
What traits of pea plants allowed Mendel to conduct large-scale self- or cross-pollination experiments?
A
1) traits that can be easily described and distinguished
2) easy to cultivate
3) reproduce quickly
4) pollination is easy to manipulate due to their relatively large sized flowers
9
Q
What were the seven traits Mendel chose?
A
1) position of flower
2) color of flower
3) shape of pea pod
4) color of pea pod
5) shape of peas
6) color of peas
7) height of plant
10
Q
What variety of plants did Mendel choose?
A
Several stocks of true-breeding varieties
11
Q
How many traits were available for Mendel to pick from? How many did he pick?
A
34; he chose 7
12
Q
What was significant about the traits Mendel chose?
A
They each had only two distinct variants
13
Q
Mendel crossed and followed individual plants that differed in only ________ trait over several generations.
A
One
14
Q
Between 1854 and 1865, how many plants did Mendel meticulously observe and document?
A
about 30,000
15
Q
Every gene codes for the production of one or more ______.
A
proteins
16
Q
Each ______ determines a particular trait, which is either expressed externally or is manifested internally as a complex network of metabolic reactions.
A
protein
17
Q
All somatic cells in our body are ______.
A
diploid
18
Q
What are chromosomes with the same complement of genes called?
A
homologous chromosomes
19
Q
Homologous chromosomes have the same gene at a given ______.
A
locus
20
Q
How do genes at a given loci compare?
A
they contain the same or a slightly different nucleotide sequence
21
Q
The pairs of genes at a given loci are called?
A
alleles
22
Q
If two alleles nucleotide sequences are virtually the same, they are called?
A
homozygous alleles
23
Q
If alleles have different nucleotide sequences, they are called?
A
heterozygous alleles
24
In general, a ______ allele implies that the gene that codes for the particular trait is mutated in such a way that its protein product is defective.
recessive
25
Chromosomes 1 through 22 are _______ chromosomes.
autosomal
26
The 23rd pair of chromosomes are called the....
sex chromosomes
27
The paternal autosome #1 and the maternal autosome #1 are an example of what?
homologous chromosomes
28
In a test cross, if the hybridization experiment investigates only a single trait, it is called a.....
monohybrid cross
29
Which test cross investigates two traits simultaneously?
a dihybrid cross
30
Mendel was the first person to systematically apply ________ in predicting and analyzing results in the study of genetics.
mathematical principles
31
What were the two rules of probability Mendel used were?
The product (multiplication) rule and the sum (addition) rule
32
The third mathematical rule Mendel used was?
binomial theorem
33
What was the ratio Mendel consistently identified?
3:1
34
What act of Mendel marked the birth of modern population genetics?
he counted the number of plants with each phenotype
35
What did Mendel name his "heritable factor"?
an allele
36
Mendel's observation that in his F1 generation, one allele was responsible for the dominant phenotype and another for the recessive phenotype, came to be known as?
Mendel's law of dominance
37
"The pair of alleles in any combination has to be temporarily separated and then re-combined during fertilization." This observation of Mendel came to be known as?
his law of segregation
38
The law of _______ states, "each pair of alleles for a particular characteristic at a given locus segregates independently of alleles at other loci."
Mendel's law of independent assortment
39
What was the name of the obscure local journal Mendel published his work in, where it received little attention? What year?
Experiments on Plant Hybridization in 1866
40
How many decades passed before Mendel's work was rediscovered?
3 decades
41
What was Mendel's first major contribution?
his rejection of the "blending inheritance" idea
42
What was Mendel's second major contribution?
He realized that each gene that controls a certain trait comes in two forms, called alleles.
43
What was Mendel's third major contribution?
his prediction that one allele may dominate over the other
44
What was Mendel's fourth and most important major contribution?
By proposing the law of segregation, he laid the foundation for the understanding of how meiosis works.
45
It is the ______ that dictates the expression of a particular trait.
protein
46
The segregation of homologous chromosomes during gamete formation was not completely understood until shortly before _________, with the work of ___________.
WWI; Thomas Morgan
47
During gamete formation, the sperm/egg becomes ________.
haploid
48
In meiosis, each pair of homologous chromosomes is separated from each other during _________.
Anaphase I
49
A hybridization experiemtn in which two plants being crossed are hybrid for two independent traits is called a ______ cross.
dihybrid cross
50
Mendel's fifth and final major contribution was?
his hypothesis that two distinct traits would be sorted into separate gametes independent of each other (law of independent assortment)
51
The chances that two genes that are not linked will be packaged together during meiosis and transmitted to the offspring is highly _______.
unlikely
52
Mendel focused on one to a maximum of ______ traits at anyone time.
3
53
Mendel was elected to the position of ______ (equivalent to a bishop) in the monastery in 1868 and became heavily burdened with _________.
prelate; administrative duties
54
Mendel indicated he was "convinced it [his work] will be appreciated before by the whole world," prior to his death in ______.
1884
55
How many years after Mendel's death did Hugo de Vries launch a plant-breeding program?
Six years
56
Now, almost _____ years later, the paper that was ignored by most of Mendel's contemporaries is still considered one of a handful of seminal studies that have revolutionized biology.
150 yrs
57
Mendel's results were repeated and confirmed by other scientists using different models and eventually led to the formation of _________.
the theory of genetics
58
Of the seven traits Mendel selected to study, non affected the ________ of the plants.
Survival
59
Earlobe attachment, widow's peak, and hitch-hikers thumb in humans are example of what kind of traits?
single gene controlled traits
60
What year was the human genome project completed?
2003
61
Consensus among scientists working on ___________ has been that "All diseases have a genetic component, whether inherited or resulting from the body's response to environmental stresses like viruses or toxins."
The Human Genome Project
62
When did Archibald Edward Garrod describe the first disease linked to genes? What was the name of this disease?
1902; it was called alkaptonuria
63
What is the alternate name for alkaptonuria?
Black urine disease
64
Alkaptonuria is an autosomal ________ condition in which the gene responsible for the the enzyme involved in the metabolism of an amino acid is mutated, and thus the enzyme becomes defective.
recessive
65
To signify the genetic nature of the disease, Garrod called alkaptonuria an "________________."
inborn error of metabolism
66
Cystic fibrosis is what kind of genetic disease?
homozygous recessive
67
This disease occurs when a gene that codes for a channel (transport) protein located on the surface of most cells is mutated and results in the accumulation of thick and sticky mucous in the breathing passages of the lungs and the lining of the digestive system.
Cystic fibrosis
68
Which disease is the most common genetic disease in the US?
Sickle cell anemia
69
Which genetic disease affects one in four hundred African Americans?
Sickle cell anemia
70
A single _______ substitution results in the wrong amino acid being added to hemoglobin and causes the protein to be folded incorrectly in sickle cell anemia.
nucleotide
71
What shape is a normal red blood cell?
donut shaped
72
What is problematic about a sickle shaped red blood cell?
It is too large to squeeze through the tiny terminal blood vessels called capillaries.
73
Which homozygous recessive disease affects one in 3,500 Ashkenazi Jews?
Tay-Sachs disease
74
Tay-Sachs disease affects the enzyme responsible for _________ metabolism?
Lipid
75
Which disease results in neural impulses not being transmitted correctly and can cause paralysis, blindness, deafness, and a variety of neurological disorders?
Tay-Sachs disease
76
Many of our brain cells are covered by a _________ coat.
Lipid
77
In the context of homozygous recessive diseases, individuals who are heterozygous to this gene are phenotypically normal and are called _________.
carriers
78
How many genes are in a haploid human cell?
22,000
79
How many alleles are in a haploid human cell?
44,000
80
The size of each gene averages about _______ nucleotides.
3,000
81
To construct a __________, the genotypes of the parents must be implicitly or explicitly given.
Punnett square
82
When using a Punnett square for a dihybrid cross, keep in mind that the two genotypes each segregate ________.
independently
83
In genetics, the circumstance in which the phenotype of the heterozygote is completely identical to the phenotype of the dominant homozygote is referred to as?
complete dominance
84
The circumstance which is marked by no single trait being dominant or recessive is known as?
incomplete dominance
85
Incomplete dominance occurs because some traits are dependent on how robust the ________ product is.
Protein
86
Which pattern of inheritance is similar to the now rejected idea of blending inheritance?
incomplete dominance
87
The pattern of inheritance in which the heterozygote displays phenotypes that show a range of intermediate phenotypes between the two extremes?
incomplete dominance
88
One human disease that illustrates incomplete dominance is a condition called?
familial hypercholesterolemia
89
In FH, abnormally high cholesterol in the blood, which is inherited as an autosomal _______ trait.
dominant
90
In the US, it is estimated that 1 in _____ individuals carries a defective allele that places them among a group at high risk for developing __________, ___________, and ___________ later in life.
500; high cholesterol, hypertension, and cardiovascular disease
91
In what year and where was the fourteen year old familial hypercholesterolemia patient hospitalized?
1970 at the Southwest Medical Center in Dallas
92
What incidence lead doctors to believe the pattern of inheritance may not be limited to simple dominant-recessive relationships?
The appearance and identification of the first case of familial hypercholesterolemia
93
Cholesterol is considered an indispensable component of what?
the plasma membrane
94
What is the raw material used for the synthesis of all sex steroids?
cholesterol
95
What is the name given to our cells ability to synthesize cholesterol on site through an elaborate and energy-consuming process?
de novo (on site, inside the cell)
96
Our cells prefer to acquire cholesterol from where?
our diet
97
Why can cholesterol not be transported in blood by itself?
its a lipid which is not soluble in blood
98
Which organ packages cholesterol molecules inside large proteins for transport and delivery to all cells?
the liver
99
The protein-cholesterol complex produced by the liver is called?
LDL cholesterol
100
What does LDL stand for?
low-density lipoprotein
101
What is the name of a cell's "mailbox" that will recognize and process the macromolecule LDL?
LDL receptor
102
When LDL carries a load of thousands of cholesterol molecules and binds to the LDL receptor, the entire complex clusters into a specific region on the cell surface called what?
coated pits
103
What happens when a mutation occurs in the LDL receptor gene?
The LDL-cholesterol complex stays in the blood and tends to clog up the arteries.
104
ABO blood typing follows a pattern called...
co-dominance
105
The product of the alleles determining blood type is a membrane protein with two different types of sugar molecules attached to the extracellular portion of the protein. This product is called?
a glycoprotein
106
Landsteiner noticed that the red blood cells of some individuals clumped up when mixed with the ______ from another individual.
serum (liquid part of the blood)
107
Landsteiner studied the patterns of _______ and demonstrated that blood could be divided into groups or types.
agglutination (clumping of RBC)
108
________are expressed on the surface of cells, whereas ________ are found in the bloodstream.
antigens; antibodies
109
What are the two antigens that could possibly be found on human RBCs?
A antigen and/or B antigen
110
What are the two antibodies that could possibly be found in human blood?
anti- A antibodies and/or anti-B antibodies
111
Mixing an antigen with its respective antibodies would result in what?
severe anemia that leads to oxygen deficiency and eventually death
112
Which blood type has neither A nor B antigen but has both anti-A and anti-B antibodies?
OO
113
Which blood type has B antigen and anti-A antibodies?
BB or BO
114
Which blood type has A antigen and anti-B antibodies?
AA or AO
115
Which blood type has both A & B antigen but neither anti-A or anti-B antibodies?
AB
116
Which blood type is the universal donor (can donate to any blood type)?
OO
117
Which blood type can only receive transfusions from its own blood type?
OO
118
Before DNA fingerprinting techniques became available in 1984, _______ was the standard scientific method used to identify specific phenotypes in paternity legal cases.
ABO blood typing
119
Rh factor was first identified in which animal?
Rhesus monkey (Rh)
120
Rh is considered another _______ expressed on the surface of RBCs.
antigen
121
Rh is a ______ _________ trait.
simple dominant
122
What is the only one condition in which Rh factor may lead to a life/death situation?
In the second pregancy of an Rh- mother who is giving birth to Rh+ offspring.
This is because during the first pregnancy the placenta pulls away from the endometrium causing bleeding and introducing the mothers immune system to the baby's RBC. The mothers immune system produces anti-RH+ antibodies that would threaten the second pregnancy.
123
In relation to Rh factor, which is the dominant phenotype? + or - ?
positive (+)
124
What's the treatment for Rh incompatibility?
an injection of anti-Rh antibodies
125
Rh compatibility can be detected with what? Who should have this test done?
a simple blood test; pregnant women
126
The phenomenon in which a single gene contributes to multiple, unrelated phenotypic traits is known as?
pleiotropy
127
Color is the result of the production of certain _________ molecules.
pigment
128
If pigment molecules are not produced, what color will result?
white
129
In what condition is the enzyme responsible for production of the brown pigment molecule melanin defective because its gene has mutated?
albinism
130
What type if inheritance refers to cases where a single phenotype is under control of multiple genes?
polygenic inheritance
131
Height, weight, and skin color are examples of what kind of inheritance?
polygenic
132
Hundreds of genetic variants in at least 180 loci are associated with human ________.
height
133
Polygenic inheritance is seen in the genetic factors of what cancer?
breast cancer
134
What are the two mutated genes associated with high-risk of breast cancer
BCRA1 and BCRA2
135
Less than _____ percent of breast cancer cases are due to mutation of the BCRA1 and BCRA2 genes.
10%
136
BCRA1 and BCRA2 are present in less than ____ percent of the general population.
<1%
137
While the pattern of _______ inheritance is complex, the probability of inheritance for each individual gene and allele still follows the same laws worked out by Mendel.
polygenic
138
Linked genes do not follow the law of?
Independent assortment
139
How many chromosomes did the pea plants that Mendel used have?
Seven
140
Which specific chromosomes did Thomas Morgan link trait inheritance to?
the sex chromosomes
141
In Morgan's fruit flies, which gender had the white colored eyes, which had the red colored eyes
Male- white eyes, Female- red eyes
142
Morgan suspected that the pattern of inheritance of the ____ chromosome was different than that of the autosome.
X chromosome
143
If two genes are very close together than, a crossover is ______ in the region between them.
unlikely
144
Sturtevant produced the first chromosome map from what species?
Drosophila
145
The measurement for the distance between genes is called?
a genetic map unit
146
___________ has been used to identify the location of many genes that cause genetic disease.
Linkage mapping
147
In most cases, sex determination is genetic, but what other factors play a role in some species?
temperature, environmental chemicals, and social structure
148
Which chromosome determines the male sex?
Y
149
Which gene on the Y chromosome is essential in controlling male traits?
SRY (sex reversal Y)
150
The undifferentiated gonad in humans is destined to become ________ unless told otherwise.
the ovary
151
At what point of gestation is sex determination?
Around two months
152
The undifferentiated human embryo has a pair of gonads that will become the ovaries plus both sets (male and female) of what?
reproductive tracts
153
Human eye color is a ________ type of inheritance?
Polygenic
154
Which genes determine the detection of wavelength light spectra in the visible light range?
Opsin genes
155
Mutation in the opsin genes causes what?
Colorblindness
156
What is the most common type of colorblindness?
red-green
157
Inheritance of colorblindness occurs via and ____-linked recessive allele?
X
158
Who is more likely to be colorblind?
Males
159
Why are males more susceptible to colorblindness?
Since males have only one X chromosome, the inheritance of a defective X from either parent will result in colorblindness.
160
At what ratio does colorblindness affect males versus females?
10:1
161
How many genes are located on the Y chromosome
Less than 200, considered small
162
A trait determined by a Y-linked gene is passed down from who to who?
Father to son to grandson, etc.
163
The Y chromosome can be used to trace what?
Male lineage
164
The DNA from which two organelles does not follow Mendelian laws?
Mitochondria and chloroplasts
165
When wanting to trace male lineage, which is the best substance of choice?
mitochondrial DNA
166
Where is mitochondrial DNA from the male located?
in the middle part of the sperm
167
_______ analysis helps genetic counselors identify the carriers of a disease and determine the risk of developing or passing on traits where a single gene is responsible.
Pedigree
168
Where can chromosomal analysis be performed on babies?
in utero
169
What does "in utero" mean?
in the womb
170
The odds of having a baby with chromosomal abnormality is dramatically increased when the mother is over what age?
Over 35
171
The test in which fetal cells are removed?
karyotyping
172
What are the two methods of karyotyping?
amniocentesis and chorionic villus sampling (CVS)
173
In which karyotyping method is a long needle inserted inside the fluid compartment inside the fetal membrane to obtain cells?
amniocentesis
174
Which method of karyotyping involves taking a piece of fetal membrane to be biopsied?
Chorionic villus sampling (CVS)
175
Recently, fetal cells where found in the mother's _______.
Circulation
176
Recently, genetic tests have been conducted before the embryo does what?
Attaches to the uterine wall
177
If one cell is removed from an eight cell embryo and the other seven cells are replaced back into the mother, can this embryo develop into a normal individual?
Yes, the one removed cell can then be used for genetic testing
