Genetics, Multiples and Unusual Births Study Guide Flashcards
What are Genetics?
Genetics is the study of the way animals and plants pass on information to their offspring
What are examples of genetics?
Eye color, hair color, height, body build, blood types, intelligence, gender, etc.
What are Chromosomes? Where can you find them?
Chromosomes are threadlike structures of nucleic acids and protein found in the nucleus of most living cells that carry genetic information in the form of genes
How many chromosomes are you supposed to have?
23 pairs of chromosomes (46 in total) in regular cells; 23 chromosomes in reproductive cells
How many chromosomes are from each parent?
23 from each parent
When does conception occur?
When the ovum/egg and sperm come together; When the ovum/egg is fertilized by the sperm
What is the difference between a dominant vs. recessive gene?
Dominant genes are the more powerful trait in a person while recessive genes are the weaker trait in a person. You need only 1 dominant gene for the trait to be expressed, whereas you need 2 recessive genes for the trait to be expressed.
What is a carrier gene? Give one example.
A carrier gene is a recessive gene that is not visible. One example of a carrier is someone with one cystic fibrosis gene that will not have cystic fibrosis but will give cystic fibrosis to their child if the other parent also has the cystic fibrosis gene.
What is a sex linked gene? Give one example.
A sex-linked gene is when a mother passes a recessive gene down to her son on her X gene. One example of a sex linked gene is when a mom has the gene for color-blindness and passes it on to her son, even though the gene is not expressed for her.
What is the purpose of Genetic Counseling?
The purpose of genetic counseling is to identify the likelihood of passing certain genetic diseases or disorders onto your children. It is done by evaluating family history and medical records, ordering genetic tests, and evaluating the results of the investigation. The best time to see a genetic counselor is before getting pregnant.
Achondroplasia: definition, 2 symptoms, and life expectancy
Definition: A bone growth disorder that causes disproportionate dwarfism
Symptoms: Short in stature, normal sized torso, short limbs
Life expectancy: Can be fatal if the person has homozygous achondroplasia but lifespan is normal for other people with achondroplasia
Cystic fibrosis: definition, 2 symptoms, and life expectancy
Definition: A life-threatening disorder that causes severe damage to the lungs and digestive system
Symptoms: Thick mucus, trouble breathing, more prone to diseases
Life expectancy: Most people with cystic fibrosis live into their 20s-30s but some are living into their 40s-50s
Down syndrome: definition, 2 symptoms, and life expectancy
Definition: A genetic disorder caused when an abnormal cell division results in extra genetic material from Chromosome 21
Symptoms: Distinct facial features, heart problems
Life expectancy: Average life expectancy of someone with down syndrome is 60 years
Hemophilia: definition, 2 symptoms, and life expectancy
Definition: A bleeding disorder that slows the blood clotting process
Symptoms: Uncontrollable bleeding, joint pain, large and frequent bruising
Life expectancy: Life expectancy for men with hemophilia varies depending on the quality of medical care they can receive, but the average life expectancy is about 10 years shorter than it is for the general male population
Progeria: definition, 2 symptoms, and life expectancy
Definition: An extremely rare and progressive genetic disorder that causes children to age rapidly
Symptoms: Slowed growth, hair loss, thinning and wrinkled skin
Life expectancy: The average life expectancy for someone with progeria is about 13-14 years, but some people have been able to live into their 20s
Sickle cell disease: definition, 2 symptoms, and life expectancy
Definition: An inherited disease in which red blood cells are shaped like a sickle or crescent
Symptoms: Anemia, frequent infections, swelling of hands and feet
Life expectancy: The life expectancy of people with sickle cell disease is about 54 years
Tay Sachs: definition, 2 symptoms, and life expectancy
Definition: A rare inherited disorder that progressively destroys nerve cells in the brain and spinal cord
Symptoms: Loss of motor skills, exaggerated startle reaction to loud noises, seizures and paralysis
Life expectancy: Most children with Tay Sachs only live to about 2-4 years old
Turner Syndrome: definition, life expectancy, 2 symptoms
Definition: A genetic condition in which a female does not have the usual pair of two X chromosomes
Symptoms: Short stature, broad chest, widely-spaced nipples
Life expectancy: Life expectancy for women with Turner syndrome is slightly reduced. On average, the life expectancy of people with Turner syndrome is up to 13 years shorter than that of the general population.
What does IVF stand for? What is the process?
IVF stands for In-Vitro Fertilization
The process of IVF is:
- Production of eggs are stimulated by hormone therapy
- Eggs are retrieved from the ovary
- Sperm samples are provided
- Eggs are sperm are combined and fertilized
- Fertilized eggs are reintroduced into uterus
What does ICSI stand for? What is the process?
ICSI stands for Intra-Cytoplasmic Sperm Injection
The process of ICSI is:
- A single sperm is drawn into a micro-needle
- The sperm is directly injected into the mother’s egg
What is a zygote?
A cell that is formed when a sperm fertilizes an egg (ovum)
What is the difference between a monozygote and a dizygote?
Identical vs fraternal
A monozygote is 1 fertilized ovum that split into 2 identical cells while a dizygote is 2 different ovums that were fertilized with 2 different sperm
What is considered a multiple birth?
2+ babies are born at the same time
What are conjoined twins and the two theories on how they occur? What is the difference in the two theories?
Identical twins that are joined in utero (share one or more organs)
The 1st theory is that the fertilized egg split partially and the 2nd theory is that the fertilized egg split completely but adhesive molecules in the 2 eggs attracted each other and fused the eggs together again
