Genetic Testing and Disorders Overview

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Questions and Answers

What is the primary function of a gene?

To facilitate cell division

To form the structural components of the cell

To provide instructions for building proteins (correct)

To store energy for cellular processes

What is the relationship between chromosomes and DNA?

Chromosomes are a single strand of DNA, uncoiled

Chromosomes are smaller components found inside of DNA.

Chromosomes are tightly coiled structures formed by DNA. (correct)

DNA are made of of multiple chromosomes joined together,

If a person tests positive as a carrier for a genetic illness, what does this indicate?

The person has two copies of the mutated gene.

The person will certainly develop the illness.

The person has one copy of the mutated gene and may pass it on to offspring (correct)

The person is currently affected by the illness.

What does genetic testing of DNA determine?

If someone has a genetic disorder, will develop one, or is a carrier. (B) Signup and view all the answers

How many pairs of autosomes are present in a typical human cell's DNA?

22 pairs (C) Signup and view all the answers

What is the result of DNA being isolated from cells and ‘picked apart’?

Disease revelation (C) Signup and view all the answers

When are chromosomes typically visible in a visual, light microscope?

During cell division (C) Signup and view all the answers

What are the 'workers' of your body and essentially responsible for every trait you have?

Proteins (C) Signup and view all the answers

Which procedure involves testing a single cell from an 8-cell embryo?

Preimplantation Genetic Diagnosis (PGD) (C) Signup and view all the answers

What is a primary function of a genetic counselor?

To interpret family history and educate about genetic diseases. (A) Signup and view all the answers

What is the primary purpose of newborn screening?

To test for genetic conditions shortly after birth. (D) Signup and view all the answers

What concept is NOT typically associated with the role of a genetic counselor?

Performing genetic testing directly in a lab. (A) Signup and view all the answers

Which of the following procedures would typically be first conducted earliest during a pregnancy?

Chorionic villus sampling (B) Signup and view all the answers

What is a consequence of having too many or too few chromosomes?

The potential for the development of a disease. (C) Signup and view all the answers

Which procedure involves extracting cells from the amniotic fluid?

Amniocentesis (D) Signup and view all the answers

What is a potential risk associated with both amniocentesis and chorionic villus sampling?

Miscarriage (B) Signup and view all the answers

Why do many people seek genetic testing?

To determine if they carry a disease or could pass it on to their children. (C) Signup and view all the answers

Besides the number of chromosomes, what else can cause disease?

Inheriting defective DNA/bad genes. (B) Signup and view all the answers

In Preimplantation Genetic Diagnosis (PGD), at what stage of development are embryos usually screened?

When they have developed to the 8-cell stage (A) Signup and view all the answers

What aspect of genetic testing is often addressed by genetic counselors?

The psychosocial and ethical issues associated with test results. (C) Signup and view all the answers

Which of these procedures takes a sample using a needle inserted through the abdomen into the uterus?

Amniocentesis (D) Signup and view all the answers

What is the role of genetic counselors as health care educators?

To serve as educators to patients, physicians, and the public. (B) Signup and view all the answers

What type of sample is typically used in newborn screening?

A blood sample (B) Signup and view all the answers

What type of decisions do genetic counselors help individuals or couples make?

Decisions suitable to their cultural, religious, and moral beliefs. (C) Signup and view all the answers

Which step in PCR involves breaking the hydrogen bonds of DNA?

Denaturation (D) Signup and view all the answers

What is the purpose of the DNA primers in PCR?

To identify the sequence of DNA that needs to be copied (A) Signup and view all the answers

At what temperature does annealing of the DNA occur during PCR?

55 degrees C (B) Signup and view all the answers

Which of the following is NOT a common newborn screening consideration?

Down Syndrome for all groups (C) Signup and view all the answers

What is the role of Taq polymerase in PCR?

To build new DNA strands at the location of the primers (A) Signup and view all the answers

What is the main reason why some parents might opt for newborn screening rather than prenatal testing?

Some parents may not want to risk miscarriage that sometimes occur in prenatal testing. (C) Signup and view all the answers

What is a PCR bead?

A small pellet of Taq polymerase and DNA nucleotides. (A) Signup and view all the answers

Which of these PCR steps is most comparable to the gluing of primers onto DNA?

Annealing (D) Signup and view all the answers

What is the primary role of Taq polymerase during the extension phase of PCR?

To add complementary nucleotides to the DNA strand. (D) Signup and view all the answers

At what temperature does the extension phase of PCR occur?

72°C (D) Signup and view all the answers

What is the purpose of centrifugation in the initial steps of genetic testing?

To separate DNA from other cell components. (D) Signup and view all the answers

What is the term used to describe the fluid that is discarded after centrifugation?

Supernatant (C) Signup and view all the answers

What is the primary function of the primer in the PCR process?

To indicate where Taq polymerase should attach to the DNA strand. (B) Signup and view all the answers

What components does the extension phase of PCR require?

Taq polymerase, DNA nucleotides, and a temperature of 72°C. (A) Signup and view all the answers

What is the term used to describe the process where cells are broken open to release their contents, including DNA?

Lysis (B) Signup and view all the answers

What is the function of Chelex in genetic testing?

This function is not described. (C) Signup and view all the answers

What is the primary function of Chelex in the DNA extraction process described?

To separate the DNA from other cellular components. (D) Signup and view all the answers

After the DNA is extracted and isolated, what is the next step described in the procedure?

Amplifying the DNA. (C) Signup and view all the answers

What is the main function of restriction enzymes in the process described?

To identify single nucleotide polymorphisms (SNPs). (D) Signup and view all the answers

What are single nucleotide polymorphisms (SNPs)?

Single nucleotide differences in DNA. (B) Signup and view all the answers

What does 'sticky end' refer to in the context of this text?

The result of DNA being cut by restriction enzymes. (D) Signup and view all the answers

Why are DNA markers, or 'standard fragments of known lengths', added into the gel during gel electrophoresis?

To provide size references for the other DNA fragments. (A) Signup and view all the answers

What is the purpose of adding the DNA containing supernatant into a new tube?

To separate the DNA from the cell debris remaining in the original tube. (D) Signup and view all the answers

If a restriction enzyme cuts one version of a gene but not another, what does this indicate?

The versions have different SNPs. (B) Signup and view all the answers

Study Notes

Genetic Testing and Screening

Genetic testing examines DNA to diagnose diseases before birth
It can identify diseases a person is born with (inherited)
It can determine the likelihood of passing on genetic illnesses to children
It uses molecular methods like DNA sequencing and karyotyping
It examines chromosomes and genes for abnormalities
Genetic testing involves DNA sampling and analysis

Genes, Chromosomes, and DNA

Chromosomes are tightly coiled DNA
Humans have 23 pairs of chromosomes (22 autosomes, 1 sex chromosome)
Genes are coding sections of DNA, providing instructions for building proteins
Proteins are essential for all traits, including hair color, eye color, blood type, and diseases
Too many or too few chromosomes, or defective DNA, can cause problems

Genetic Disorders

Single-gene disorders: mutations in single genes (e.g., sickle cell anemia, cystic fibrosis) - dominant or recessive inheritance
Multifactorial disorders: caused by multiple genes and the environment (e.g., breast cancer)
Chromosomal disorders: caused by errors in the number or structure of chromosomes (e.g., Down syndrome)
Mitochondrial disorders: caused by mutations in mitochondrial DNA, inherited maternally

Genetic Testing Overview

Genetic counselors help individuals and families understand diagnoses and implications of genetic tests
Genetic counselors educate patients, physicians, and the public about genetic disorders
Genetic counselors address psychosocial and ethical issues related to genetic testing
Carrier screening tests prospective parents for inherited diseases
Preimplantation genetic diagnosis (PGD) tests embryos to avoid passing specific traits to children

Genetic Screening Procedures

Amniocentesis: extracting amniotic fluid
Chorionic villus sampling (CVS): sampling chorionic villi
Newborn screening: testing newborns for inherited diseases
Methods used to amplify DNA include polymerase chain reaction (PCR)

DNA Analysis

Restriction enzymes are molecular scissors that recognize and cut specific DNA sequences
Sticky ends: single-stranded ends of DNA created by restriction enzymes
Gel electrophoresis separates DNA fragments based on size
Markers of known lengths are used as a comparison tool for the sizes of other fragments
This process can reveal a person's genotype, which determines phenotype

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Description

This quiz covers essential concepts related to genetic testing, including DNA analysis, the structure of chromosomes, and common genetic disorders. Understand how inherited diseases can be identified and the impact of genetic information on health. Test your knowledge on the mechanisms behind genetic conditions and their inheritance patterns.