Genetics Exam 1 Flashcards
(277 cards)
1
Q
The theory of pangenesis was first proposed by______.
a. Aristotle
b. Galen
c. Mendel
d. Hippocrates
e. none
A
d. Hippocrates
2
Q
Which of the following is correct regarding the blending theory of inheritance?
a. It believed that heriditary traits blended from one generation to the next
b. It was possible for the blending to change the trait from one generation to the next
c. It was supported by early research by Joseph Kolreuter
d. It was the prevailing theory of inheritance prior to Mendel
e. All the answers are correct
A
e. All the answers are correct
3
Q
Mendel’s work was rediscovered in 1990 by which of the following individual(s)?
a. Carl Correns
b. Erich von Tschemak
c. Hugh de Vries
d. All the answers are correct
A
d. All the answers are correct
4
Q
The stamen represents the ____ portion of the plant, while the ovules represent the ____ portion of the plant.
a. Female; male
b. Male; female
c. Female; female
d. Male; male
A
b. Male; female
5
Q
Which of the following traits was not studied by Mendel?
a. flower color
b. seed color
c. pod color
d. pollen color
e. plant height
A
d. pollen color
6
Q
When studying a genetic cross, the second generation following the initial cross is identified by which of the following?
a. P generation
b. F1 generation
c. F2 generation
d. F3 generation
e. P3 generation
A
c. F2 generation
7
Q
Mendel’s work with monohybrid crosses provided proof of which of the following?
a. Blending theory of inheritance
b. Particulate theory of inheritance
c. Chromosomal theory of inheritance
d. Pangenesis
e. None of the answers are correct
A
b. Particulate theory of inheritance
8
Q
Mendel’s work with single-factor crosses resulted in the development of which of the following?
a. Law of segregation
b. Law of independent assortment
c. Theory of natural selection
d. Law of biological evolution
e. All the answers are correct
A
a. Law of segregation
9
Q
When Mendel crossed two pants that were heterozygous for a single trait, what was the phenotypic ratio of their offspring?
a. 1:2:1
b. 9:3:3:1
c. 3:1
d. 7:4
e. Varied depending on the trait
A
c. 3:1
10
Q
When Mendel crossed two plants that were heterozygous for a single trait, what was the genotypic ratio of their offspring?
a. 1:2:1
b. 9:3:3:1
c. 3:1
d. 1:1
e. Varied depending on the trait
A
a. 1:2:1
11
Q
An individual who has two identical alleles for a trait is said to be _____.
a. Homozygous
b. Heterozygous
c. Isozygous
d. A variant
A
a. Homozygous
12
Q
The genetic composition of an individual is called its ______.
a. Phenotype
b. Genotype
c. Hybrid
d. Dominance
e. None of the answers are correct
A
b. Genotype
13
Q
In a Punnett square diagram, the outside of the box represents the ______.
a. Diploid offspring
b. Haploid offspring
c. Diploid gametes
d. Haploid gametes
A
d. Haploid gametes
14
Q
Mendel’s work with two-factor (dihybrid) crosses led directly to which of the following?
a. Chromosomal theory of inheritance
b. Particulate theory of inheritance
c. Law of segregation
d. Law of independent assortment
e. Theory of biological evolution
A
d. Law of independent assortment
15
Q
In a dihybrid cross using Mendelian inheritance, if both parents are heterozygous for both traits, what will be the phenotypic ratio of their offspring?
a. 3:1
b. 1:2:1
c. 1:1
d. 9:3:3:1
A
d. 9:3:3:1
16
Q
In a dihybrid testcross, the individual being examined is crossed to which of the following?
a. an individual who is homozygous dominant for one trait but not the other
b. self-fertilized
c. an individual who is homozygous for both traits
d. an individual who is heterozygous for both traits
A
c. an individual who is homozygous recessive for both traits
17
Q
In humans, patterns of inheritance are often studied using which of the following?
a. dihybrid testcrosses
b. production of true-breeding lines
c. pedigree analysis
d. self-fertilization
e. none of the answers are correct
A
c. pedigree analysis
18
Q
The chance that a future event will occur is called ____.
a. probability
b. goodness of fit
c. degrees of freedom
d. random selection
e. all answers are correct
A
a. probability
19
Q
A coin is flipped 100 times, with a result of 53 heads and 47 tails. The deviation between the observed numbers and the expected 50-50 results is called ____.
a. probability
b. degrees of freedom
c. goodness of fit
d. random sampling error
e. standard error
A
d. random sampling error
20
Q
Which of the following would be used to determine the probability of three independent events in order?
a. sum rule
b. product rule
c. chi-square test
d. binomial expansion
e. random sampling error
A
b. product rule
21
Q
The probability that one event will occur is based on which of the following?
a. sum rule
b. product rule
c. chi-square test
d. binomial expansion
e. random sampling error
A
a. sum rule
22
Q
In the biological sciences, the hypothesis is usually rejected if the P value is_____.
a. greater than 1
b. less than 0.30
c. less than 0.95
d. less than 0.05
e. less than i
A
d. less than 0.05
23
Q
______ is the belief that seeds are produced by all parts of the body and transmitted to the next generation.
a. hippocrates
b. pangenesis
c. blending
d. particulate theory
e. homunculus
A
b. pangenesis
24
Q
If two individuals with different characteristics are mated, their offspring is called a _____.
a. strain
b. true-breeding line
c. gamete
d. cross
e. hybrid
A
e. hybrid
25
If over several generations a trait does no vary in a group of organisms, that group can be called a _____.
a. dihybrid
b. hybrid
c. true-breeding line
d. variant
e. cross-fertilized line
c. true-breeding line
26
A cross in which a research investigates the patterns of inheritance of a single trait is called a _____.
a. monohybrid cross
b. dihybrid cross
c. two-factor cross
d. cross-fertilization
e. self-fertilization
a. monohybrid cross
27
In a genetic cross, the ____ represents the offspring with genetic combinations that were not found in the parental lines.
a. P generation
b. non-recombinants
c. parentals
d. non-parentals
e. none of the above
d. non-parentals
28
Statistical analysis determines the _______ between observed data and what was expected from the original hypothesis.
a. testcross
b. degrees of freedom
c. P values
d. complete hypothesis
e. goodness of fit
e. goodness of fit
29
Cystic fibrosis is an autosomal recessive disorder that affects lung function in humans. If a couple, who are both unaffected, have an affected chile, what is the probability their next child will be an affected girl?
a. 1/2
b. 1/4
c. 1/8
d. 1/16
c. 1/8
30
The basic unit of heredity is the _____.
a. individual
b. gene
c. macromolecule
d. trait
e. none of the above are correct
b. gene
31
A variation of a gene is called a(n) ____.
a. species
b. morph
c. genome
d. allele
e. proteome
d. allele
32
Which of the following acts to accelerate chemical reactions in a cell?
a. nucleic acids
b. lipids
c. carbohydrates
d. enzymes
e. none of the above are correct
d. enzymes
33
The building blocks of DNA are the _____.
a. amino acids
b. carbohydrates
c. enzymes
d. nucleotides
e. lipids
d. nucleotides
34
The structure of a cell that contains the genetic information is called a _____.
a. nucleotide
b. genetic code
c. chromosome
d. nucleic acids
e. none of the above are correct
c. chromosome
35
RNA is formed by the process of ______.
a. transcription
b. translation
c. both transcription and translation
d. none of the above are correct
a. transcription
36
A characteristic that an organism displays is called____.
a. a gene
b. a chromosome
c. DNA
d. gene expression
e. a trait
e. a trait
37
Variation at the molecular level of a gene is called a(n) _____.
a. nucleotide
b. chromosome
c. allele
d. trait
e. none of the above are correct
c. allele
38
A species that contains two copies of each chromosome is called_____.
a. a genetic mutation
b. a morph
c. haploid
d. diploid
e. alleles
d. diploid
39
A cell that makes up the body structure of an organism and is diploid is ______.
a. a gamete
b. a somatic cell
c. an allele
d. rare
e. a sperm cell
b. a somatic cell
40
In many organisms, one set of chromosomes comes from the maternal parent, while the other set comes from the paternal parent. Similar chromosomes in these sets are said to be ______.
a. morphs
b. alleles
c. haploid
d. homologs
e. physiological traits
d. homologs
41
In humans, gametes are different than other cells of the body in that they are ______.
a. diploid
b. haploid
c. genetic mutations
d. morphs
e. none of the above are correct
b. haploid
42
_______ is the use of gene sequence to synthesize a functional protein.
a. Loss-of-function mutation
b. Gene expression
c. The human genome project
d. Proteonomics
e. None of the above
b. Gene expression
43
The differences in inherited traits among individuals in a population are called _____.
a. species variation
b. genetic mutations
c. genetic variation
d. natural selection
e. none of the above
c. genetic variation
44
Genetics is the branch of the biological sciences that deals with both heredity and variation. True/False
True
45
Science is conducted using a process called the scientific method. True/false
true
46
Gene expression involves the process of transcription and translation. True/False
`True
47
Which of the following began with the work of Gregor Mendel in the 19th century?
a. population genetics
b. trasmission genetics
c. molecular genetics
b. trasmission genetics
48
DNA stores the information needed for the synthesis of cellular _______.
a. proteins
b. carbohydrates
c. lipids
a. proteins
49
Both genes and the ______ influence the traits of an organism.
a. genome
b. environment
c. population
b. environment
50
A nitrogenous base that occurs in RNA but not in DNA.
a. deoxyribose
b. ribose
c. pentose
d. cytosine
e. uracil
e. uracil
51
What does the term antiparallel refer to when describing the double helix of DNA?
a. the 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand
b. base pairings create unequal spacing between the two DNA strands
c. one strand contains only purines and the other contains only pyrimidines
d. the twisting nature of DNA creates nonpararllel strands
a. the 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand
52
Liver cells are different physiologically than muscle cells because liver cells contain genes unique to liver cells that are not in muscle cells. True/False
False
53
Identify direction information flows in a biological system.
a. DNA -> protein -> RNA
b. Prophase -> Telophase
c. DNA -> RNA -> protein
d. ATP -> ADP
e. RNA -> DNA -> protein
c. DNA -> RNA -> protein
54
When a bacterial cell takes up foreign DNA, this process is called _______.
a. trasnduction
b. conjugation
c. transformation
d. morphogenesis
e. restriction
c. transformation
55
Why does the DNA double helix have a uniform diameter?
a. deoxyribose sugars pair with ribose sugars
b. purines pair with pyrimidines
c. nucleotides pair with amino acids
d. phosphates pair with nitgrogenous bases
e. nitrogenous bases are found outside of the double helix
b. purines pair with pyrimidines
56
Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will by thymine?
a. 24
b. 12.
c. 31
d. 38
b. 12
57
```
DNA is replicated during this stage of the cell cycle.
a. P
b G0
c. M
d. G2
e. S
```
e. S
58
```
According to Beadle and Tatum's hypothesis, how many genes are necessary for this pathway?
Enzyme A Enzyme B
A----------->B----------->C
a. 1
b. 3
c. 0
d. 2
```
d. 2
59
Humans have how many chromosomes?
a. 92
b. 46
c. 23
d. 32
e. 25
b. 46
60
The primary conformation of a protein refers to:
a. sequence of nucleotides in a gene
b. sequence of amino acids in a polypeptide
c. the number of nucleotides in a gene
b. sequence of amino acids in a polypeptide
61
Which of the following is an organic compound?
a. CO2
b. H2O
c. HCl
d. CH4
d. CH4
62
Regions outside the nucleus of the atom that are occupied by electrons are termed _____.
a. shells
b. loci
c. realms
d. spheres
e. orbitals
a. shells
63
Which of the following is a carbohydrate?
a. fat
b. glycogen
c. polynucleotide
d. fatty acid
e. phospholipid
b. glycogen
64
Which of the following is a nucleic acid monomer?
a. H+
b. fat
c. nucleotide
d. DNA
e. deoxyribose
c. nucleotide
65
The basic structural and functional unit of life is the:
a. molecule
b. cell
c. organelle
d. atom
e. cytoplasm
b. cell
66
Prokaryotic cells
a. have no cytoplasm
b. have no nucleus
c. have no cell membrane
d. have no DNA
e. have no ribosomes
b. have no nucleus
67
The nuclear division of cell reproduction is called _____.
a. cytokinesis
b. apoptosis
c. mitosis
d. cell cycle
e. plasmolysis
c. mitosis
68
The universal "energy currency" of cells is the molecule called ________.
a. ATP
b. NADH
c. FADH
a. ATP
69
An atom's atomic mass is the total mass of all its electrons, protons, and neutrons. True/false
False
70
You have some limp carrots. To make them crisp again, which would you soak them in
a. strong salt solution
b. pure water
b. pure water
71
How many chromosomes are in the final cells that are produced in humans during meiosis?
a. 46
b. 92
c. 10
d. 23
d. 23
72
Okazaki fragments are DNA fragments found during:
a. translation
b. transcription
c. DNA replication
c. DNA replication
73
How many replication forks are associated with a replication bubble?
a. 1
b. 2
c. 3
d. 4
b. 2
74
an alternative form of a specific gene
allele
75
a building block of polypeptides and proteins; it contains an amino group, a carboxyl group and a side chain
amino acid
76
the accumulation of genetic changes in a species or population over the course of many generations
biological evolution
77
organic molecules with the general formula C(H2O); an example of a simple carbohydrate is the sugar glucose
carbohydrate
78
Human Genome Project
launched in 1990
3 billion base pairs
accuracy > 99.99%
79
evolution and development; all animals develop same
evodevo
80
formation of embryo
embryogenesis
81
which genes are expressed
differentiation
82
artificial life
synthetic life
83
codes for proteins that we can't live without
essential genes
84
DNA fingerprinting
a technology for identifying a particular individual based on the properties of their DNA
85
Mammalian cloning
experimentally, this refers to the use of somatic cell nuclei and enudeated eggs to create a clone of a mammal
86
Recombinant DNA
describes DNA molecules that are produced by molecular techniques in which segments of DNA are joined to each other in ways that differ from their original arrangement in their native chromosomal sites
87
Gene cloning
the production of many copies of a gene using molecular methods such as PCR or the introduction of a gene into a vector that replicates in a host cell
88
Gene therapy
the introduction of cloned genes into living cells in an attempt to cure or alleviate disease
89
Gene programming
a model of programming which uses the ideas of biological evolution to handle a complex problem
90
Genetics
study of heredity and variation
91
Gene
unit of heredity
92
Macromolecules
Nucleic acids, proteins, carbohydrates, lipids (fats)
93
Polymers
made from smaller molecules that are called monomers
94
Purines
A, G
95
Centromere
holds the 2 DNA molecules together
96
DNA backbone
made up of sugar-phosphate
97
"workhorses" of cells
proteins
98
Tubulin/microtubules
cell shape and movement
99
Metabolism
the totality of an organism's chemical reactions; consisting of catabolic/anabolic pathways which manage the material and energy resources of the organism
100
Myosin
muscle contraction
101
Insulin
regulate blood glucose
102
Enzymes
biological catalysts
103
Delta G
change in free energy
104
Catabolic enzymes
breakdown of large molecules into smaller ones; exergonic
105
Exergonic
releases energy -
106
Endergonic
takes in energy +
107
Anabolic enzymes
involved in synthesis of large molecules from smaller ones; endergonic
108
Genetic material
DNA
109
makes up chromosomes
DNA
110
specific regions of DNA that specify synthesis of proteins
genes
111
DNA found in?
primarily in nucleus of cell
- mitochondria of eukaryotes
- chloroplasts of prokaryotes
112
Interprets and carries out instruction for DNA
RNA
113
Human cells
2N= 46 chromosomes
114
human chromosome contains
more than a 100 million nucleotides and 1000-2000 genes
115
Gene expression
occurs in two steps: transcription and translation
116
Transcription
genetic information in DNA copied into a nucleotide sequence of RNA
117
Translation
nucleotide sequence in RNA converted into amino acid sequence of a protein
118
RNA polymerase
an enzyme that synthesizes a strand of RNA using a DNA strand as a template
119
characteristic an organism displays
trait
120
appearance of organism (color of a flower)
morphological traits
121
function of organism (ability to metabolize sugar)
physiological traits
122
the observable traits of an organism
phenotype
123
the genetic composition of an individual especially in terms of the alleles for particular genes
genotype
124
Molecular level
genes expressed
125
Cellular level
proteins function
126
Organismal level
traits observed
127
Populational level
genes/traits within a particular species
128
Microevolution
change in gene and allele function in a population
129
differences in inherited traits among individuals within a population
gene variation
130
contrasting forms within a single species
morphs
131
Genetic variation result of various types of changes at molecular level
1. gene mutations
2. changes in chromosome structure
3. changes in chromosome number
132
who provided foundation for science of genetics
Gregor Mendel
133
sexually reproducing species are haploid or diploid?
diploid
134
two copies of each chromosome, one from each parent
homologues
135
What is the relationship between an allele and a gene?
genes are a sequence of DNA. chromosomes are the structure DNA takes in a cell each cell have 2 version of each gene, and these versions are called alleles
136
What is the advantage of sexual reproduction?
genetic variation
137
What cells are diploid?
somatic cells
138
What cells are haploid?
gametes
139
somatic cells in humans
46 chromosomes, 23 chromosome pairs
140
Gametes
sperm and egg cells
141
genetic makeup of a population can change over time
evolution
142
members of a species compete for essential resources
natural selection (Darwin)
143
neutral mutations
unrelated to survival; genotypic change, not phenotypic change
144
Transmission genetics
study how traits passed from one generation to the next; oldest field of genetics
145
Mendel's particles of inheritance
gene
146
Molecular genetics
study of the gene itself (organization, function, regulated)
147
Population genetics
study of genetic variation and its role in evolution; genetic composition of populations and how it changes over time
148
first to conceive idea of heredity
Hippocrates
149
"seeds" produced by all parts of the body
pangenesis
150
Theory of preformationism
entire organism contained fully developed in one of the sex cells
151
mini human
homunculus
152
Blending theory of inheritance
traits blend together generation after generation; Mendel's ideas and conclusions replaced this
153
Particulate theory of heredity
parents transmit to their offspring discrete inheritable factors
154
Wilhelm Johannsen
genotype/phenotype
155
detectable inheritable feature of an organism
character
156
variant of an inheritable character
trait
157
always producing offspring with same traits as parents when self fertilized
true breeding
158
mating or crossing between two individuals that have different characteristics
hybridization
159
two identical alleles for a given trait PP or pp
homozygous
160
two non identical alleles for a given trait Pp
heterozygous
161
crossed two variants that differ in only one trait
monohybrid cross
162
true-breeding parental plants of a cross
P generation
163
hybrid offspring of P generation
F1 generation
164
progency of cross of F1 generation
F2 generation
165
filial
F
166
Mendels principles of heredity
1. law of segregation
2. law of independent assortment
3. law of dominance
167
sorting of alleles into separate gametes
law of segregation
168
genes sort independently
law of independent assortment
169
a cross in which an experimenter crosses an individual that is heterozygous recessive for two genes to an individual that is homozygous recessive for the same two genes
dihybrid cross
170
abnormally high extracellular levels of Cl-
defective ion channels
171
lethal dominant alleles
less common than lethal recessives
172
laws of inheritance
used to predict outcomes of genetic crosses
173
chance that an event will occur in the future
probability
174
predict odds two or more independent events will occur
product rule
175
probability an event can occur in two or more independent ways
sum rule
176
used to determine probability of a particular outcome with specific characteristics
binomial expansion equation
177
how close observed data are to predicted values from a hypothesis
goodness of fit
178
low chi square values
indicate high probability H0 accepted
179
high chi square values
indicate low probability H0 not accepted
180
measure of the number of categories that independent of each other n-1
degrees of freedom (df)
181
provide an organized structure
proteins
182
prokaryotes
bacteria; no nucleus; nucleoid; cell membrane; ribosomes; rigid cell wall; outer membrane; flagella
183
eukaryotes
everyone else; true nucleus; membrane-bound organelles; mitochondria; lysosomes; golgi apparatus
184
Mitochondria
ATP synthesis; DNA
185
Lysosomes
intracellular digestion
186
Golgi apparatus
protein modification/ trafficking
187
microscopic examination of chromosomes
cytogenetics
188
activate signal transduction pathways
mitogens
189
Karyotype
photographic representation of chromosomes
190
multicellular organism derived from single cell; zygote
multicellularity
191
Binary fission
how prokaryotes reproduce; asexually
192
Mitosis
cell division in eukaryotes
193
Cell cycle
eukaryotic cells that divide progress through series of stages
194
Interphase
G1, S, G2; chromosomes decondensed; at end, chromosomes have replicated but the six pairs of sister chromatids are not seen until propahse; centrosome divides
195
G0 phase
postponed making a decision to divide; or made the decision to never divide again
196
G1 phase
cell prepares to divide; reaches restriction point
197
Restriction point
committed on a pathway to cell division
198
S phase
chromosomes replicated; presence of sister chromatids; end of this phase results as twice as many chromatids as there are chromosomes in G1 phase
199
G2 phase
cell makes final preparation for nuclear and cell division
200
M phase
mitosis; distribute replicated chromosomes to daughter cells
201
Mitosis
```
Prophase
Prometaphase
Metaphase
Anaphase
Telophase
```
202
Prophase
Mitotic spindle apparatus formed and nuclear envelope dissociates into smaller vesicles
203
Aster microtubules
- star like
- important for positioning of spindle apparatus
- anchor, holds them in place
204
Polar microtubules
- help to push poles away from each other
| - elongate
205
Kinetochore microtubules
attach to kinetochore which is bound to the centromere of each individual chromosome
206
Prometaphase
spindle factors interact with sister chromatids
207
Metaphase
- middle
- pair of sister chromatids align themselves along a plane= metaphase plate
- each pair of chromatids attached to both poles by kinetochore microtubules
208
Anaphase
- apart
- connection holding sister chromatids together is weakened
- chromosomes move to opposite poles
209
Telophase
- reverse prophase
| - chromosomes reach respective poles and decondense
210
Cytokinesis
formation of cleavage furrow in animals
| formation of cell plate in plants
211
Isogamous
gametes morphologically similar; fungi and algae
212
Heterogamous
gametes morphologically different; sperm cells, egg cells
213
process of crossing over
synapsis
214
prophase I divided into 5 periods
```
leptotena
zygotena (pairing of non sister homologous chromatids)
pachytena (crossing-over occurs; chisma)
diplotena
diakensis
crossing over occurs
```
215
for a diploid organism with 6 chromosomes
- mitosis begins with 12 chromatids joined as 6 pairs of sister chromatids
- meiosis II begins with 6 chromatids joined as 3 pairs of sister chromatids
216
Mitosis vs. Meiosis
-mitosis produces 2 diploid daughter cells
| meiosis produces 4 haploid daughter cells
217
production of sperm
spermatogensis
218
acrosome in head of sperm
contains digestive enzymes
219
production of eggs
oogenesis
220
asymmetric
two haploid cells of unequal sized (secondary oocyte and polar body)
221
gametophyte
haploid
222
sporophyte
diploid
223
spores
haploid cells produced during meiosis
224
Anthers
produce male gametophyte
225
Ovaries
produce female gametophyte
226
how transmission of chromosomes account for Mendelian patterns of inheritance, proposed by walter sutton and theodore boveri
chromosome theory of inheritance
227
idiplasm
stuff in nucleus; carl nageli's term
228
germ plasm
DNA; august wesrnan's term
229
heterogametic
males; two different germ cells
230
homogametic
female; one germ cell
231
sex chromosomes in birds Z and W
males are homogametic and females are heterogametic
232
sex chromosomes in bees
```
males= drones; haploid; from unfertilized eggs
females= worker/queen; diploid; from fertilized eggs
```
233
Thomas Hunt Morgan
induced mutations of fruit fly
234
genes physically located on X chromosome
X-linked genes or X-linked alleles
235
reciprocal cross
crosses between different strains in which sexes reversed; reveal if a trait is carried on a sex chromosome or autosome
236
genes found on Y chromosome
holandric genes
237
males have only one copy of X chromosome
hemizygous for X-linked gene
238
`genes found on one of the two types of sex chromosomes
sex-linked or X-linked
239
simple Mendelian inheritance
single gene with two alleles
240
prevalent alleles in a population
wild type
241
altered alleles
mutant alleles
242
simple dominant/ recessive relationship
recessive allele does not affect phenotype of heterozygote
243
How can wild-type phenotype of heterozygote be explained?
- 50% of normal protein is enough to accomplish the protein's cellular function
- Heterozygote produces ore than 50% functional protein
244
absolutely required for survival
essential genes
245
absence of protein
lethal phenotype
246
not absolutely required for survival
nonessential genes
247
has potential to cause death; Huntington disease
lethal alleles
248
lethal under certain environmental conditions; Ts lethals
conditional lethal alleles
249
X-linked recessively inherited disease
Favism
250
kill some individuals in a population but not all
semilethal alleles
251
heterozygote phenotype intermediate between both homozygotes
incomplete dominance
252
coat color in rabbits and ABO blood groups is an example of this
multiple allele system
253
antigen
surface of RBC
| anything that stimulates Ab (antibody) production
254
i allele
encodes defective enzyme; antigen O
255
IA allele
antigen A
256
IB allele
antigen B
257
IA and IB
codominant; expressed in heterozygous
258
What would happen if type O receives blood from type A, type B, or type AB blood?
Ab is universal recipient; O is universal donor; RBC's agglutinate (clump together)
259
Dominant and recessive relationship
depends on amount of functional protein
260
Simple dominant/recessive
50% of protein sufficient for expression of dominant phenotype
261
Incomplete dominance
50% of protein not sufficient
262
heterozygote more vigorous than both homozygotes; heterozygote advantage; sickle-cell anemia, Pku, tay-sachs disease, cystic fibrosis
over dominance
263
3 possible explanations for overdominance at molecular/cellular level
1. disease resistance
2. homodimer formation
3. variation in functional activity
264
homodimers
composed of two different subunits and encoded by two alleles of same gene
265
heterosis
many genes, beneficial effects may be attributed to overdominance in one or more heterozygous genes
266
dominant allele may not be expressed in heterozygote individual; polydactyl
incomplete penetrance
267
degree to which a trait expressed
expressivitiy
268
effects of environment on variation on phenotype
norm of reaction
269
allele dominant in one sex but recessive in other sex; pattern baldness in humans
Sex-influenced traits
270
traits occur in only one sex; beard growth, breast development
Sex-limited traits
271
multiple effects cause by single gene/ defect in CFTR transporter
pleiotropy
272
one allele masks phenotypic effects of alleles of different gene
epistasis
273
both parents express same recessive phenotype and offspring expresses wild type phenotype
complementation
274
allele of one gene modifies phenotype of alleles of second gene
modifying gene
275
loss of function of one gene has no effect
loss of function of two genes has effect
both genes redundant
gene redundancy
276
phenotypic effects of mutation reversed by suppressor mutation of another gene
intergenic supressors
277
second mutation reverses phenotypic effect of first mutation
suppresor mutation
