Test 2 Flashcards
1
Q
What are sperm and ova called?
A
Gametes
2
Q
Where can a copy of the original genetic material from both parents be found?
A
In every typical body cell, our gametes, and the sex chromosomes
3
Q
How many chromosomes does a typical somatic cell have compared to a gamete?
A
A typical somatic cell has 46 chromosomes, whereas a gamete has 23 chromosomes
4
Q
What is the third period of prenatal development called?
A
The period of the fetus
5
Q
What forms by the 5th day following fertilization?
A
A blastocyst
6
Q
Which part begins to develop first during prenatal development?
A
The head
7
Q
When does the heart begin to beat after conception?
A
The heart begins to beat about the 4th week after conception.
8
Q
What does phenotype refer to?
A
Phenotype refers to the actual expression of characteristics.
9
Q
What is a teratogen?
A
A teratogen is a substance that can cause birth defects.
10
Q
How is the developing fetus nourished?
A
The developing fetus is nourished by nutrients that pass from the mother’s blood through the placental membrane via the umbilical cord to the fetus.
11
Q
What are characteristics that depend on the interaction of multiple genes called?
A
Such characteristics are said to be polygenic.
12
Q
What factor is most responsible for the similarity of MZ twins compared to DZ twins?
A
The factor most responsible for this degree of similarity is considered to be shared genes.
13
Q
What happens to most zygotes with serious genetic problems?
A
They never implant into the uterine lining.
They are also often miscarried after the second or third trimester.
14
Q
What is Phenylketonuria (PU)?
A
It can be detected at birth and treated with a special diet.
It is not caused by a dominant gene or treated with a blood transfusion.
15
Q
What will the mesoderm develop into?
A
The mesoderm will develop into muscles.
It also contributes to the spinal column and lungs.
16
Q
What chromosome pattern does a male with Klinefelter’s syndrome have?
A
The chromosome pattern is XXY.
17
Q
What is the age of viability?
A
It is the age at which an infant stands a good chance of survival if born early.
18
Q
What happens during the last stage of childbirth?
A
The baby is born, and the placenta is delivered.
19
Q
What is the gestation age range for a term baby?
A
37-42 weeks
20
Q
What is considered a premature baby?
A
Born before 37 weeks
21
Q
What is the classification for a baby born after 42 weeks?
A
Postmature
22
Q
What is the average birthweight at 38 weeks?
A
3400 grams (7 lbs)
23
Q
What is the low birthweight threshold?
A
Less than 2500 grams (5 1/2 lbs)
24
Q
What does ‘small for gestational age’ mean?
A
At 90% or less average birthweight
25
Fill in the blank: The average birthweight is _______ grams at 38 weeks.
3400
26
True or False: A baby is classified as premature if born at 36 weeks.
True
27
What percentage of death rate is associated with birthweight under 1000 grams?
50%
28
What happens when the ova ripens?
The ova breaks through the ovary known as the corpus luteum to prepare for fertilization. It sends signals to the brain.
29
What is the corpus luteum?
The corpus luteum is where the egg breaks free.
30
Where does fertilization take place?
Fertilization takes place in the first third of the fallopian tube within the first 24-72 hours.
31
What happens to sperm in the vagina?
1/4 of sperm die initially due to the acidity of the vagina, which stuns them for about 20 minutes.
32
What occurs when a sperm reaches the egg?
When a sperm gets to the egg, a hard shell is formed around it.
33
How many sperm are typically found in an ejaculate?
~360 million sperm
34
How many sperm typically survive to reach the ovum?
Only 300-500
35
How many sperm fertilize the ovum?
Only one
36
What happens to the tail of the sperm during fertilization?
Tail drops
37
Where does fertilization take place?
In the oviduct
38
What is the first part of the fallopian tube where fertilization occurs?
First 1/3 of fallopian tube
39
What is the first stage of prenatal development called?
Zygote Period (Germinal period)
40
What is the second stage of prenatal development?
Embryo Period
41
What is the third stage of prenatal development?
Fetus Period
42
Fill in the blank: The fertilized egg is known as a _______.
Zygote
43
What is the time frame from fertilization to implantation?
Approximately the first 2 weeks
## Footnote
This period includes cell duplication and early development stages.
44
How long does it take for the first cell division to occur after fertilization?
About 30 hours
## Footnote
This marks the beginning of embryonic development.
45
What is the size of the egg at the time of fertilization?
Approximately the size of a period
## Footnote
This highlights the small size of the human egg.
46
What is formed on Day 4 of embryonic development?
Morula
## Footnote
The morula is a solid ball of cells.
47
What structure is formed on Day 5 of embryonic development?
Blastocyst
## Footnote
The blastocyst is a hollow ball filled with fluid and consists of 60-80 cells.
48
When does implantation begin after fertilization?
Around Day 7
## Footnote
Implantation is not complete until Day 10-12.
49
What protective sac forms that is filled with amniotic fluid?
Amnion
## Footnote
The amnion protects the developing embryo.
50
What begins to form on Day 9 as part of the embryonic development?
Chorion
## Footnote
The chorion is another protective sac that forms around the embryo.
51
What structures form from the chorion and connect to the uterine wall?
Villi
## Footnote
Villi contain blood vessels and develop into the placenta.
52
What is the function of the umbilical cord?
Connects placenta to developing child
## Footnote
It serves as a lifeline for the infant, delivering nutrients and oxygen.
53
What substances are delivered to the developing child through the umbilical cord?
Nutrients and oxygen
## Footnote
Waste products are also carried away from the developing child.
54
True or False: The umbilical cord carries waste products away from the developing child.
True
## Footnote
This is essential for the health of the developing fetus.
55
Who is the inventor of the First endoscope?
Leonarh nesan
56
What are the three main calls in embryonic development?
Ectoderm, Mesoderm, Endoderm
57
At approximately how many weeks does organogenesis occur?
At roughly 8 weeks
58
What is the approximate size and weight of the embryo at 8 weeks?
About 2.5 cm, 2 grams
59
What is organogenesis?
Differentiation of body organs
60
What are the three layers of cells that form from the embryonic disk on Day 16?
* Ectoderm
* Mesoderm
* Endoderm
61
What does the ectoderm develop into?
Nervous system, skin, hair, nails
62
What does the mesoderm develop into?
Muscles, skeleton, circulatory system
63
What does the endoderm develop into?
Digestive system, lungs, liver, glands
64
What significant structure forms from the ectoderm by Day 21?
Neural tube
65
Which part of the embryo develops first?
Head
66
When do arms and leg buds appear during development?
Approximately around Day 36
67
When does the heart begin to form and beat?
Around Day 21
68
What structures appear by Day 36?
Tail and gill arches
69
What developmental milestone occurs by Day 48?
Fingers begin to form, looks more human
70
Fill in the blank: The fastest development stage is called _______.
Organogenesis
71
True or False: The embryo starts to bend around Day 25.
True
72
What significant development occurs on Day 48?
Fingers begin to form, looks more human than fishy.
73
What is the approximate length of an embryo at 8 weeks?
Approximately 2.5 cm long.
74
What is the weight of the embryo at 8 weeks?
Approximately 2 grams.
75
What stages are referred to during the fetus period?
Growth + finishing stages
## Footnote
These stages begin around the 3rd month of pregnancy.
76
At what week can the sex of the child be determined?
12th week
## Footnote
This is typically done through ultrasound.
77
What is the role of anitagen during fetal development?
Determines the development of male or female genitalia
## Footnote
If anitagen is present, it indicates a male; if absent, a female will develop.
78
What is Vernix and its function?
Nature's 'chapstick'; protects the skin and lubricates the body
## Footnote
It helps the baby slip out during birth.
79
What is Lanugo?
Fine hair that helps vernix stick to the skin
## Footnote
Some babies are born with it, while others lose it before birth.
80
What does the Age of Viability refer to?
The stage when a fetus has a good chance of survival if born prematurely
## Footnote
Survival chances improve significantly after this age.
81
What are the consequences of too much oxygen during premature birth?
Can result in blindness
## Footnote
Oxygen levels must be carefully monitored in premature infants.
82
What percentage of conceptions survive to live birth?
Less than 1/4
## Footnote
Most conceptions do not implant successfully.
83
Fill in the blank: Vernix is a _______ that protects the skin.
waxy, cream substance
## Footnote
It acts as a barrier for the fetus.
84
What is a sensitive period in the context of teratogens?
Sensitive periods refer to specific times during development when certain structures are particularly vulnerable to damage from teratogens.
85
What can happen if a damaging agent affects the mother during pregnancy?
Birth defects may occur
## Footnote
Birth defects are physical or functional abnormalities that can arise when a teratogen affects the developing fetus.
86
True or False: The presence of a damaging agent always guarantees that the child will be affected.
False
## Footnote
Not every exposure to a teratogen results in birth defects; it depends on various factors.
87
What happens during the first two weeks of pregnancy regarding teratogen effects?
Nothing can really go wrong because it just won’t implant if it does
## Footnote
This period is critical as the embryo may not implant if severely affected.
88
What maternal factor affects prenatal environment?
Maternal emotion
## Footnote
This includes the emotional state of the mother during pregnancy.
89
What was the focus of the study comparing two groups of women?
Women who lost their husband while pregnant vs. those who lost their husband after the baby was born
## Footnote
The study aimed to evaluate the impact of maternal loss during pregnancy on child development.
90
What were the behavioral and psychological outcomes observed in children whose mothers lost their husbands while pregnant?
They had a lot of behavioral and psychological issues
## Footnote
This indicates the potential negative effects of maternal emotional distress during pregnancy on child development.
91
What is the consequence of a mother contracting rubella during the embryonic period?
50% of babies are born deaf, blind, or intellectually impaired.
## Footnote
Rubella can lead to severe congenital defects if contracted in early pregnancy.
92
What are the potential outcomes for babies if a mother contracts rubella after the 4th month of pregnancy?
Likelihood of defects drops significantly.
## Footnote
Timing of maternal infection is crucial for the severity of outcomes.
93
What is toxoplasmosis and how can it affect pregnancy?
A parasite found in feces, undercooked meat, and cats that can cause brain damage in the first 3 months of pregnancy.
## Footnote
Toxoplasmosis can also affect eye development.
94
How is HIV transmitted from mother to child during pregnancy?
Through the placenta and breast milk.
## Footnote
Maternal HIV can lead to significant health issues for the baby.
95
Fill in the blank: If a mother contracts rubella during the embryonic period, _______ of babies are affected.
50%
96
True or False: Toxoplasmosis can result in miscarriage.
True
## Footnote
Toxoplasmosis poses risks not only to brain development but also to the viability of the pregnancy.
97
What types of malformations can rubella cause if contracted during the embryonic period?
Blindness, deafness, heart malformations, intellectual disabilities.
## Footnote
These outcomes highlight the importance of maternal health during early pregnancy.
98
What virus is associated with small head size in babies born in South America?
Zika virus
## Footnote
The Zika virus is linked to microcephaly in newborns.
99
What environmental factor can cause damage to a developing child still in the womb
High temperature hot tubs
## Footnote
Exposure to high temperatures can negatively affect fetal development.
100
What is recommended weight gain during pregnancy?
11-14 kg
## Footnote
This weight gain is advised to ensure proper maternal and fetal health.
101
What is the impact of maternal malnourishment on babies?
Malnourishment during pregnancy can lead to low birth weight.
102
During which trimester may maternal nutrition disrupt spinal cord development?
First trimester
## Footnote
The first three months are critical for neural tube development.
103
What vitamin is crucial for neural tube development?
Folic Acid / Folate
## Footnote
Adequate folic acid intake can prevent conditions like Spina Bifida.
104
Fill in the blank: _______ is crucial for preventing Spina Bifida in developing children.
Folic Acid / Folate
## Footnote
Folic acid is essential for proper neural development.
105
What is the best age for women to have a baby in Canada?
Between 13-35 years
## Footnote
Optimal age is around 20-25 years.
106
At what age does the uterus fully develop?
18 years
## Footnote
Development of the uterus is crucial for pregnancy.
107
What are the risks associated with maternal age over 35?
Increased risk of abnormalities, including Down syndrome
## Footnote
Maternal age is a significant factor in genetic risks.
108
What does parity refer to?
The number of pregnancies a woman has had
## Footnote
Parity can influence health outcomes in pregnancies.
109
How does having a first child compare to having subsequent children in terms of maternal relaxation?
Less relaxed with the first child compared to the second
## Footnote
Experience can lead to more confidence in subsequent pregnancies.
110
What happens if there is a gap of 10 years between births?
It can reset maternal experience
## Footnote
Significant time gaps may affect maternal mindset and readiness.
111
What is often observed about the weight of children born to older mothers?
Typically heavier
## Footnote
Older mothers may have different nutritional and health profiles.
112
What term describes the tendency for first-born children?
They tend to be heavier and more vigorous
## Footnote
First-born children may receive more focused care and resources.
113
What is ultrasound?
Ultrasound uses high frequency sound waves to generate images on a computer screen.
## Footnote
It is used to detect size, position, physical development, and multiple pregnancies, typically performed at 12-16 weeks.
114
What is amniocentesis?
Amniocentesis is a procedure where amniotic fluid is extracted with a needle.
## Footnote
The cells from the fluid are cultured and then examined.
115
What is Chorionic Villus Sampling?
Chorionic Villus Sampling involves using a needle through the abdomen or a tube through the vagina to remove tissue from the end of chorionic villi.
## Footnote
Results are available the next day.
116
What are the risks associated with Chorionic Villus Sampling?
Chorionic Villus Sampling increases the risk of miscarriage and limb abnormalities.
## Footnote
The odds of complications are approximately 1 in 50, and the risk increases with age.
117
What is fetoscopy?
Use small tube with light
## Footnote
Fetoscopy is a procedure used to visualize the fetus in the womb.
118
What is the purpose of fetoscopy?
To check physical development and sample blood
## Footnote
It is often used for diagnostic purposes during pregnancy.
119
What can a maternal blood sample detect?
Baby's cells may enter mother's bloodstream
## Footnote
This process can provide important information about the fetus.
120
What conditions can be detected through maternal blood samples?
Kidney disease, anencephaly, spina bifida
## Footnote
These are serious conditions that can affect fetal development.
121
How many stages are there in childbirth?
Three stages
## Footnote
The stages are: dilation and effacement, pushing, and delivery of the placenta.
122
What is the average duration of the first stage of childbirth?
8-14 hours
## Footnote
This duration can vary, especially for subsequent children, which may take 3-2 hours.
123
What is the primary process that occurs during the first stage of childbirth?
Dilation and effacement of the cervix
## Footnote
The cervix must thin and open to 10cm for the baby to exit.
124
What is the significance of reaching 10cm dilation?
It is necessary to avoid a C-section
## Footnote
10cm dilation indicates peak contractions.
125
What natural urge occurs during the second stage of childbirth?
The urge to push
## Footnote
This stage involves the actual birth of the child.
126
How long does the pushing stage typically last for a first birth?
30-90 minutes
## Footnote
The duration is usually shorter for subsequent births.
127
What is the hardest part of the baby to deliver during childbirth?
The head
## Footnote
The head is typically the most challenging part to get out.
128
What happens during the third stage of childbirth?
Delivery of the placenta
## Footnote
This stage marks the end of the childbirth process.
129
Fill in the blank: The first stage of childbirth involves _______ and effacement of the cervix.
dilation
130
What does the APGAR scale measure?
How well a baby came through the trauma of childbirth
## Footnote
The APGAR scale assesses the adjustment of a newborn after birth.
131
When is the APGAR score given?
1 minute after birth for baseline and then 4 minutes after
## Footnote
This timing helps to evaluate the baby's adjustment over time.
132
What is the scoring for Heart Rate in the APGAR scale?
0-2:
* 0 - Close to 0
* 1 - Less than 100
* 2 - More than 100
## Footnote
Heart Rate is a critical indicator of the baby's immediate health.
133
What criteria are used to assess Respiratory Effort in the APGAR scale?
0-2:
* 0 - No breathing
* 1 - Weak cry
* 2 - Strong cry
## Footnote
Respiratory effort indicates how well the baby is breathing after birth.
134
What is the scoring range for muscle tone?
0-2
## Footnote
Muscle tone can be resilient or flaccid.
135
What does a blue undertone in a baby indicate?
Oxygen not circulating good
## Footnote
A pink or rosy complexion is desired.
136
What scale is referenced in the assessment?
HO scale
## Footnote
The scale helps evaluate the health status of the baby.
137
What is the critical score threshold for a baby?
Anything under 4
## Footnote
A score under 4 indicates the baby is in critical condition.
138
What percentage of babies score under 7?
~10%
## Footnote
90% of babies will score 4 or higher.
139
What is the implication of scoring 4-6?
Need a little help
## Footnote
A score under 4 requires immediate health care.
140
What is considered a good score for a baby?
4 or higher
## Footnote
Scores of 4 or higher indicate better health.
141
Fill in the blank: A score under _____ requires immediate health care.
4
142
True or False: A rosy complexion is an indicator of good oxygen circulation.
True
143
What is the equation that represents the relationship between phenotype, genotype, and environment?
phenotype = genotype + environment
## Footnote
This equation signifies that phenotype is influenced by both genetic makeup and environmental factors.
144
What does 'phenotype' refer to?
What you look like, visible characteristics
## Footnote
Phenotype encompasses all observable traits of an organism.
145
What is meant by 'genotype'?
Written in genetic code
## Footnote
Genotype refers to the genetic constitution of an organism.
146
How do genotype and environment interact to affect phenotype?
What you look like will be a combination of both
## Footnote
The visible traits of an organism result from the interplay between its genetic information and environmental influences.
147
True or False: Phenotype is solely determined by genetics.
False
## Footnote
Environmental factors also play a significant role in shaping phenotype.
148
What is the implication of the statement 'sometimes not about genes + sometimes all about genes'?
Phenotype can be influenced variably by genes and environment
## Footnote
This indicates that the contribution of genetics to phenotype can differ depending on the trait.
149
What does it mean when characteristics are described as 'polygenic'?
Many genes involved
## Footnote
Polygenic traits are influenced by multiple genes, rather than a single gene.
150
How many chromosomes are present in a human cell?
46 chromosomes
## Footnote
This includes 23 homologous pairs.
151
What are homologous chromosomes?
Matching pairs of chromosomes, one from each parent
## Footnote
Each pair consists of one chromosome from the male parent and one from the female parent.
152
What is a karyotype?
A visual representation of the 23 homologous pairs of chromosomes
## Footnote
Karyotypes are used to observe chromosomal abnormalities.
153
What is the primary function of chromosomes?
Contain genetic information
## Footnote
Chromosomes are made of DNA (deoxyribonucleic acid).
154
How do chromosomes appear structurally?
Resemble a twisted ladder
## Footnote
The structure of DNA is often described as a double helix.
155
What can be done to chromosomes to improve visibility under a microscope?
Stain them
## Footnote
Staining makes it easier to see the structure and organization of chromosomes.
156
What are somatic cells?
Body cells, including muscles and bones
## Footnote
Somatic cells make up most of the body's tissues and organs.
157
What are germ cells?
Cells unique to ovaries and testes
## Footnote
Germ cells are responsible for reproduction.
158
What do germ cells produce?
Gametes
## Footnote
Gametes are reproductive cells involved in fertilization.
159
What is the male gamete called?
Sperm
## Footnote
Sperm are produced in the testes.
160
What is the female gamete called?
Ova
## Footnote
Ova are produced in the ovaries.
161
What are somatic cells?
Body cells
## Footnote
Somatic cells make up most of the body tissues and organs.
162
How many pairs of autosomes are there in humans?
22 pairs
## Footnote
Autosomes are non-sex chromosomes that contain most of the genetic information.
163
What is the 23rd pair of chromosomes called?
Sex chromosomes
## Footnote
The sex chromosomes determine biological sex.
164
What chromosome combination represents a female?
XX
## Footnote
Females have two large X chromosomes.
165
What chromosome combination represents a male?
XY
## Footnote
Males have one large X chromosome and one small Y chromosome.
166
How does cell division occur in somatic cells?
Through mitosis
## Footnote
Mitosis results in the duplication of cells.
167
What happens to chromosomes during mitosis?
They duplicate and then separate into daughter cells
## Footnote
Each daughter cell is diploid and identical to the original cell.
168
How many chromosomes do humans have in total?
46 chromosomes
## Footnote
This is comprised of 23 pairs.
169
Fill in the blank: The first 22 pairs of chromosomes are called _______.
autosomes
170
True or False: Mitosis results in daughter cells that are haploid.
False
## Footnote
Mitosis produces diploid daughter cells.
171
What are germ cells?
Cells that occur in ovaries and testes
## Footnote
Germ cells are responsible for producing gametes.
172
What do germ cells produce?
Gametes (sperm and ova)
## Footnote
Gametes are the reproductive cells necessary for sexual reproduction.
173
How do germ cells divide?
Through meiosis
## Footnote
Meiosis is a specialized form of cell division that reduces chromosome number.
174
What is the key difference between meiosis and mitosis?
A second division takes place in meiosis
## Footnote
This second division is essential for reducing the chromosome number in gametes.
175
What is the result of meiosis in terms of gametes?
4 gametes with half the number of chromosomes of the parent cell (haploid)
## Footnote
This reduction is crucial for maintaining chromosome number across generations.
176
What happens during the process of meiosis that contributes to genetic variation?
Crossing over occurs
## Footnote
This process mixes up genetic information between homologous chromosomes.
177
What is the total number of chromosomes in a fertilized egg?
46 chromosomes
## Footnote
This is the result of combining the 23 chromosomes from the sperm and 23 chromosomes from the ovum.
178
What role does chance play in the genetic makeup of sperm and ova?
Chance determines which of the 2 chromosomes end up in each haploid cell, leading to 8 million different genetic combinations
## Footnote
This variation arises from the independent assortment of chromosomes during meiosis.
179
What is the process that adds more variability during the first cell division?
Crossing over
## Footnote
This process involves the swapping of DNA segments between homologous chromosomes.
180
What is the first pattern of genetic expression?
Simple dominant-recessive inheritance.
181
What is the second pattern of genetic expression?
Codominance.
182
What is the third pattern of genetic expression?
Sex-linked inheritance.
183
What is the fourth pattern of genetic expression?
Genetic imprinting.
184
What is the fifth pattern of genetic expression?
Polygenic inheritance.
185
What is the term for different forms a gene can take?
Allele
## Footnote
Each allele represents a variation of a gene.
186
What do you call an individual with two dominant alleles?
Homozygous dominant (BB)
## Footnote
This indicates the presence of two identical dominant genes.
187
What do you call an individual with two recessive alleles?
Homozygous recessive (bb)
## Footnote
This indicates the presence of two identical recessive genes.
188
What is the term for an individual with one dominant and one recessive allele?
Heterozygous (Bb)
## Footnote
This indicates the presence of one dominant and one recessive gene.
189
What is the difference between dominant and recessive alleles?
Dominant alleles mask the effect of recessive alleles
## Footnote
This means that the dominant trait will be expressed in the phenotype.
190
True or False: The specific letters used to represent alleles are important.
False
## Footnote
The case of the letters matters (uppercase for dominant, lowercase for recessive), but the specific letters themselves do not.
191
Fill in the blank: Each different form a gene can take is called an _______.
allele
## Footnote
Alleles contribute to the genetic variation observed in traits.
192
Define homozygous dominant.
An individual with two dominant alleles (BB)
## Footnote
This results in the expression of the dominant trait.
193
Define homozygous recessive.
An individual with two recessive alleles (bb)
## Footnote
This results in the expression of the recessive trait.
194
What is the notation for a dominant allele?
Uppercase letter (e.g., B)
## Footnote
Dominant alleles are typically represented by uppercase letters.
195
What is the notation for a recessive allele?
Lowercase letter (e.g., b)
## Footnote
Recessive alleles are typically represented by lowercase letters.
196
What is the relationship between brown and blue eye color in terms of dominance?
Brown eyes are dominant (DOM), while blue eyes are recessive.
197
What does the genotype BB represent?
BB represents brown eyes, indicating the dominant trait will be expressed.
198
What does the genotype Bb indicate about eye color?
Bb represents brown eyes, indicating the dominant trait will be expressed, but the individual is a carrier for the recessive trait.
199
What does the genotype bb represent?
bb represents blue eyes, indicating the recessive trait will be expressed.
200
What is Phenylketonuria (PKU)?
PKU is a genetic disorder caused by two recessive alleles, affecting 1 in 10,000 individuals.
201
What enzyme is lacking in individuals with PKU?
Individuals with PKU lack the enzyme that breaks down harmful amino acids, specifically phenylalanine.
202
What dietary restriction is necessary for individuals with PKU?
Individuals with PKU must avoid milk to prevent the buildup of harmful amino acids.
203
What happens to individuals with PKU if not treated?
Without treatment, acid builds up in the brain, leading to intellectual disability by age 1.
204
What is Huntington's Chorea?
Huntington's Chorea is a dominant genetic disorder affecting the central nervous system.
205
At what age do symptoms of Huntington's Chorea typically appear?
Symptoms of Huntington's Chorea typically appear around age 35.
206
True or False: Huntington's Chorea is a recessive genetic disorder.
False
207
Where can the origins of Huntington's Chorea be traced back to?
Huntington's Chorea can be traced back to Ireland.
208
What is Codominance?
Both alleles share in expression of phenotype
## Footnote
Codominance occurs when both alleles in a heterozygote are fully expressed, resulting in a phenotype that is neither dominant nor recessive.
209
In Codominance, how do alleles express their phenotypes?
Both alleles show genetic Codominance
## Footnote
This means that neither allele masks the other, and both contribute to the organism's observable traits.
210
What is incomplete dominance?
An allele that is stronger than another but isn't totally dominant; both traits show, but one is more dominant under certain circumstances.
211
Give an example of a condition that illustrates incomplete dominance.
Sickle Cell Anemia
212
What percentage of individuals are affected by Sickle Cell Anemia?
8%
213
What are the genotypes for Sickle Cell Anemia?
* bb: All sickle
* Bb: Sickle
* ss: Homozygous recessive
* Ss: Heterozygous (co-dominant)
214
What shape do blood cells take in Sickle Cell Anemia?
Half moon shape
215
What can cause sickle blood cells to clump together?
Exercise
216
What is the consequence of sickle blood cells clumping together?
They can die
217
What genetic combination causes Sickle Cell Anemia?
Two recessive genes
218
In which population is Sickle Cell Anemia more common?
African individuals
219
What advantage does Sickle Cell Anemia provide in certain environments?
More likely to survive Malaria
220
How can environmental manipulation impact sickle blood cells?
It can affect their viability (e.g., Olympic man example, died at high altitude)
221
What determines sex-linked inheritance?
Sex chromosomes: 23rd pair
## Footnote
The sex chromosomes are X and Y, with males having XY and females XX.
222
What genetic condition is carried on the sex chromosomes and is associated with blood clotting?
Hemophilia
## Footnote
Hemophilia is a disorder that affects the blood's ability to clot, leading to excessive bleeding.
223
What is the incidence of hemophilia in male births?
1 in 3000 male births
## Footnote
This statistic highlights the rarity of the condition among males.
224
Why is hemophilia rare in females?
Need both recessive genes
## Footnote
Females have two X chromosomes, so they require both to carry the hemophilia trait.
225
What do males inherit regarding hemophilia?
Only from mothers
## Footnote
Males receive their X chromosome from their mother, which may carry the hemophilia gene.
226
What is the genetic imprinting process?
One allele expressed, other silent
## Footnote
Genetic imprinting leads to the expression of one allele while the other allele remains inactive.
227
Which syndrome is an example of genetic imprinting?
Angelman syndrome
## Footnote
Angelman syndrome is a neurodevelopmental disorder caused by the loss of function of a gene on chromosome 15.
228
What is the occurrence rate of Angelman syndrome?
1 in 20,000
## Footnote
This statistic reflects the rarity of Angelman syndrome in the population.
229
Fill in the blank: Hemophilia occurs on the _______ pair of chromosomes.
23rd
## Footnote
The 23rd pair of chromosomes are responsible for determining sex-linked traits.
230
True or False: Daughters can inherit hemophilia from both their mother and father.
True
## Footnote
Daughters inherit one X chromosome from each parent, so they can inherit hemophilia from either.
231
What does the term 'polygenic' refer to?
Multiple alleles are involved
## Footnote
Polygenic traits are influenced by more than one gene.
232
Fill in the blank: Polygenic traits involve _______ gene pairing.
[more than one]
233
What is the purpose of breeding in genetic research?
To assess if findings from animal models are applicable to humans
## Footnote
Breeding allows researchers to study genetic traits in controlled environments.
234
What type of studies are used to assess genetic inheritance in humans?
Twin studies
## Footnote
Twin studies compare similarities and differences between twins to evaluate genetic influence.
235
What are the two types of twins?
* Monozygotic (MZ)
* Dizygotic (DZ)
## Footnote
MZ twins originate from a single ovum, while DZ twins come from two separate ova.
236
What is unique about monozygotic twins?
They arise from a single egg that splits
## Footnote
This results in genetically identical individuals known as 'identical twins'.
237
What is the genetic similarity of dizygotic twins compared to siblings?
Genetically no different than siblings
## Footnote
DZ twins develop from two separate eggs fertilized by different sperm.
238
What is the defining characteristic of monozygotic twins regarding sex?
They can only be the same sex
## Footnote
This is due to their identical genetic makeup from a single fertilized egg.
239
Fill in the blank: Dizygotic twins can or cannot be _______.
[the same sex]
## Footnote
DZ twins can be either the same sex or different sexes.
240
What is the genetic relationship between siblings?
Genetically no different than siblings
## Footnote
Siblings share the same genetic material because they originate from different sperm and egg combinations.
241
How does genetic correlation relate to familial relationships?
The closest one related genetically, higher the correlation
## Footnote
This suggests that as genetic relatedness increases, so does the degree of correlation in traits.
242
What role does the environment play in genetic relationships?
Environment plays part
## Footnote
Environmental factors can influence the expression of genetic traits, contributing to differences even among genetically similar individuals.
243
What is the chromosomal composition of Klinefelter Syndrome?
XXY
## Footnote
Klinefelter Syndrome is characterized by the presence of an extra X chromosome in males.
244
What is the prevalence of Klinefelter Syndrome in males?
1 in 750
## Footnote
This statistic indicates how common Klinefelter Syndrome is among male births.
245
At what stage does Klinefelter Syndrome typically manifest symptoms?
Puberty
## Footnote
Individuals with Klinefelter Syndrome are generally normal until they reach puberty.
246
What are common physical characteristics of individuals with Klinefelter Syndrome?
Underdeveloped testes, taller stature, can develop female characteristics
## Footnote
These traits are associated with the hormonal imbalances due to the syndrome.
247
What is a common cognitive characteristic associated with Klinefelter Syndrome?
Lower verbal IQ
## Footnote
Individuals with Klinefelter Syndrome may experience challenges in verbal skills.
248
What is the fertility status of individuals with Klinefelter Syndrome?
Sterile
## Footnote
Most individuals with Klinefelter Syndrome are unable to father children due to infertility.
249
What type of treatment may individuals with Klinefelter Syndrome receive?
Hormone treatment
## Footnote
Hormone therapy can help address some of the physical and developmental issues associated with the syndrome.
250
What is XYY syndrome?
A genetic condition with 47 chromosomes
## Footnote
Involves an extra Y chromosome in males, leading to traits such as being taller and having severe acne.
251
What is the prevalence of XYY syndrome in males?
1 in 1000 men
## Footnote
Often referred to as 'supermale' due to the extra Y chromosome.
252
What are some characteristics of males with XYY syndrome?
* Fertile
* Low sperm count
* IQ similar to typical males
* Taller
* Severe acne
## Footnote
These traits can vary among individuals.
253
What is Turner syndrome?
A genetic condition resulting from having only 1 chromosome on the 23rd pair
## Footnote
Typically represented as XO, indicating a missing X chromosome.
254
What is the chromosomal makeup of individuals with Turner syndrome?
45 chromosomes instead of 46
## Footnote
This results in various physical and developmental traits.
255
What is the prevalence of Turner syndrome in females?
1 in 2500 female births
## Footnote
Only about 10% of affected individuals are able to have children.
256
What are common characteristics of individuals with Turner syndrome?
* Look typical
* Reach puberty
* Parents notice something wrong
* Typically do not start a menstrual cycle
## Footnote
These traits may lead to early medical evaluations.
257
What are the reproductive traits of individuals with Turner syndrome?
Sterile
## Footnote
Hormone treatment may be used to aid in development.
258
What are some physical characteristics associated with Turner syndrome?
* Smaller/shorter stature
* Webbing between fingers/toes/neck
* Lower visual-spatial IQ
## Footnote
These characteristics can impact physical appearance and cognitive abilities.
259
What is XXX syndrome?
A genetic condition affecting females
## Footnote
Also known as Triple X syndrome.
260
What is the prevalence of XXX syndrome?
1 in 1000 females
## Footnote
Most individuals are unaware they have this condition.
261
What are the characteristics of females with XXX syndrome?
* Fertile
* Lower IQ scores
* Usually unaware they have it
## Footnote
Genetic counseling may provide additional information.
262
What is Fragile X syndrome?
A genetic condition related to a pinched part of the X chromosome
## Footnote
Typically affects the 23rd pair of chromosomes.
263
What is the prevalence of Fragile X syndrome?
1 in 1000
## Footnote
It affects both males and females, but symptoms can differ.
264
How does Fragile X syndrome affect males compared to females?
Affects males more severely due to having only one X chromosome
## Footnote
Males are more likely to have intellectual disabilities.
265
What are the characteristics of Fragile X syndrome?
* Pinched
* Broken off
* Missing part of the X chromosome
## Footnote
These structural changes can lead to developmental challenges.
266
What is Fragile X Syndrome?
Atypical condition involving a pinched or missing part of the X chromosome
## Footnote
It affects both males and females, with a prevalence of 1 in 1000.
267
How does Fragile X Syndrome primarily affect males?
Males have only one X chromosome, leading to intellectual disabilities when affected
## Footnote
This is due to the pinched or broken part of the X chromosome.
268
What is the chromosomal abnormality associated with Down Syndrome?
Trisomy 21, which involves three chromosomes at the 21st pair
## Footnote
This results in a total of 47 chromosomes.
269
What is the frequency of Down Syndrome births?
1 in 900 births
## Footnote
This frequency increases with maternal age.
270
How does the severity of Down Syndrome vary?
It is based on how much extra genetic information is present
## Footnote
Not everyone with Down Syndrome has a below-average IQ.
271
What physical features might indicate Down Syndrome?
Singular crease on palm, space between toes, smaller oral cavity, wide-set eyes
## Footnote
Other features include tight hair and a specific eye shape.
272
How does maternal age affect the likelihood of having a child with Down Syndrome?
The frequency increases dramatically as a woman ages
## Footnote
Aging Ova Hypothesis explains this phenomenon.
273
At what age does the risk of having a child with Down Syndrome become significant?
At age 35, the risk is 1 in 365
## Footnote
At age 50, the risk increases to 1 in 10.
274
What is the Aging Ova Hypothesis?
It suggests that as women age, their ova also age, increasing the risk of chromosomal abnormalities
## Footnote
Women are born with all the ova they will ever have.
275
Fill in the blank: The frequency of Down Syndrome increases dramatically after age _______.
35
## Footnote
Risk becomes significant around this age.
