PBS: Unit 3 Test (Sickle Cell)

Each amino acid is made up of how many nucleotides?

3 nucleotides make up an amino acid (codons)

How does a change in the DNA code affect the shape of a protein? (3.2)

A change in the DNA sequence eventually brings the wrong amino acid which makes the protein bend the wrong way.

What is a chromosome? (3.3)

A chromosome is a structure of tightly coiled DNA around proteins. Chromosomes get transferred and worked with during cell division and replication.

Can a genetic disease such as sickle cell anemia be diagnosed with a karyotype? Why or why not? (3.3)

A genetic disorder such as sickle cell cannot be diagnosed via karyotype, because sickle cell is due to to a single point mutation which cannot be detected by mass bases put together.

What is a mutation? (3.2)

A mutation is a subtle change within the DNA nucleotides, either substitution or deletion.

Should a person have rights to their own organs and tissues? (3.3)

A person should have rights to their organs and tissues and where they go to. This is because of the person's beliefs and values that cannot be argued with by any court of law or practice of medicine.

Why do all the normal cells in the human body have the same number of chromosomes? (3.3)

All the cells in the body have the same # of chromosomes because they are copied from the same original cell.

How does Anna's hematocrit levels relate to her fingernails being a blue gray color? (3.1)

Anna's low hematocrit levels show that she was not getting enough RBCs, and therefore oxygen, to each part of her body. This lead to the discoloration of the ends (farthest from the heart and lungs) of the body

What is the difference between normal and sickle hemoglobin at the DNA, RNA, and protein (amino acid) level? (3.2)

At DNA level: point mutation At RNA level: transcription of mutation At amino acid level: incorrect protein added due to transcription of mutation

Explain why being able to view chromosomes from an individual is a useful tool for scientists and medical professionals. (3.3)

Being able to view chromosomes is a useful tool for scientists as they can diagnose chromosomal errors in a patient, which is otherwise impossible.

What is the "central dogma of biology"? (flow of DNA) (3.2)

DNA -(transcription - matching of base pairs)-> mRNA -(translation - splitting of mRNA into three bases - codons - to bring appropriate amino acids to make chain)-> proteins transcription: in nucleus of cell translation: ribosome/cytoplasm

What is the DNA code? (3.2)

DNA carries instruction to produce proteins and is responsible for passing traits from generation to next.

DNA and RNA differ mainly because...

DNA contains Thymine, and RNA contains Uracil

How is DNA passed to new cells during cell division? (3.3)

DNA is passed to new cells using mitosis and meiosis (where, essentially, the DNA is replicated and then split into two or four new cells).

Explain how DNA, chromosomes, and genes are related. (3.3)

DNA is quite a wild combination of 4 nucleotides, and chromosomes are tightly wound DNA around histone proteins. Genes are sections of DNA that code for a specific trait.

Describe how the DNA is translated into messenger RNA. (3.2)

DNA is transcribed into mRNA, by matching up the 4 nucleotide bases for DNA (AGCT) with the 4 RNA nucleotide bases (AGCU). This occurs in the nucleus of the cell, and the RNA polymerase performs this.

What is the connection between genes and proteins? (3.2)

Genes code for the amino acid sequence that eventually forms a protein - codes for the functioning protein.

How can doctors and genetic counselors calculate the probability of a child inheriting a disease? (3.4)

Genetic counselors can get records of who, in the family, was affected by the disease which helps figure the genotypes of the parents --> calculates probability of child's genotype.

How many proteins make up 1 hemoglobin molecule? What element is an essential part of the hemoglobin molecule and where is it found in the molecule/ (3.2)

Hemoglobin is made up of 4 subunits of polypeptides. The essential part of hemoglobin molecule, heme, is located with iron to bind or release molecular oxygen.

If Anna had a child with a man with sickle cell anemia, would that child also have sickle cell anemia? (3.4)

Her children would have sickle cell, because two affected parents generate only affected offspring.

Explain why a child can have sickle cell anemia even if neither parent has the disease. (3.3)

If both parents are carriers for the disease, the child could be affected by it.

What might happen if there were more hydrophilic amino acids in a protein? (3.2)

If there were more hydrophilic amino acids in a protein, it would be less clumped, as human blood is largely made up of water, and the amino acid is "water-loving".

Why is it important that the end result of the process of meiosis is sex cells that contain half the amount of DNA than is in body cells? (3.3)

It is important for the end result of meiosis to have half the amount DNA than in body cells, because they must fuse with other sex cells to have the same amount of DNA as in body cells.

Why is it necessary for DNA to replicate as the first step in mitosis? (3.3)

It is necessary for DNA to replicate in mitosis, because the DNA must divide into two, and must maintain the same amount of DNA as the parent cell. In order for the daughter cells to be identical to the parent cell, they must have the same amount of DNA.

Explain why more males are afflicted with hemophilia than females. (3.3)

Males are more afflicted with hemophilia because the disease is autosomal recessive, so the male only needs one recessive gene to have the disorder (for one x). Females need two (for both x's).

What is the purpose of mitosis? What would happen if cells did not undergo mitosis? (3.3)

Mitosis is the process in which the cells replicate. Without this process, cells would not be able to replicate, growing tissue, and the body would not be able to repair itself.

Explain how just one amino acid change has a huge effect on the protein. (3.2)

One amino acid change could have a huge effect on the protein as it causes one bend or flexed portion and that could prevent it from attaching to other proteins to make a chain.

How are pedigrees used to track diseases? (3.4)

Pedigrees are used to track genetic diseases by noting which specific relatives are carriers of/affected by the diseases and how they will be transmitted

You fall down and scrape your hand - describe what each component of blood would be doing at the injury site. (3.1)

Platelets and WBCs: appear to site to clot the blood to lower blood loss and prevent bacteria to enter body through site.

How are proteins produced in a cell? (3.2)

Proteins are produced from a cell by the DNA transcribing into RNA, then combining into codons to bring the correct amino acids.

Why was the use of Henrietta Lacks' cells considered unethical? (3.3)

She nor her family was told of the exploiting of her cells and then were used around the world and helped make great developments.

How is anemia diagnosed? (3.1)

Sickle Cell Anemia is diagnosed via a hematocrit test, which reveals the percentage of RBCs within the blood. A short amount suggests anemia.

What is sickle cell anemia? (3.1)

Sickle Cell Anemia is when the lifespan of the sickled shape cells are drastically reduced, causing a shortage of RBCs.

What is sickle cell disease? (3.1)

Sickle Cell Disease is a genetic disorder that forms sickle shaped Red Blood Cells (RBCs) instead of circular, that are more stiff and adherent.

How does sickle cell disease affect daily life? (3.1)

Sickle Cell restricts daily life due to extreme pain and lack of blood circulation.

Why is sickle cell anemia classified as a recessive disorder? (3.4)

Sickle cell is classified as a recessive disorder because both alleles must be recessive in order for the person to be affected by the disease.

Describe the difference between how sickle cell anemia is inherited versus how Best disease is inherited. What causes this difference? (3.3)

Sickle cell is inherited with recessive alleles, this means both parents MUST provide recessive alleles. However, Best disease is inherited via dominant alleles, which could mean one dominant and one recessive, or both dominant (therefore, easier to acquire)

Why does sickle cell disease run in families, yet is not present in every generation? (3.4)

Sickle cell is not present in every generation due to the fact that it is recessive, and is, therefore, harder to acquire. This is because dominant alleles easily mask over it.

Why does sickle cell cause reduced hematocrit? (3.1)

Sickle cells are much more fragile than normal RBCs, causing it to rupture more easily.

Basic overview of sickle cell (3.1)

Sickled cell patients have fluid accumulate especially in hair and feet, sickled cells can block blood flow, mishapen cells are sticky, not ALL cells are sickled

Why does the sickling of red blood cells cause health problems? (3.1)

Sickling of RBCs causes build ups of these cells in blood vessels and eventually, clots. This affects the normal circulation through the body, causing blood loss in limbs and head.

How might sickle cell disease have been related to Anna's death? (3.1)

Since Anna's hematocrit levels were low, certain parts of her body were not receiving enough oxygen, maybe her brain, leading to aneurysm and brain death.

How does the karyotype notation help to identify what is abnormal with the persons chromosomes? (3.3)

Since the karyotype notes every autosome (by number), any autosomal error is easily diagnosable.

How does the presence of malaria in a region affect the frequencies of normal versus sickle cell alleles? (3.4)

Since those affected with sickle cell are immune to malaria, they survive to pass their genes onto their offspring, who are also now immune to the disease.

Why do you think scientists call a substitution a "point mutation" and a deletion a "frameshift mutation"? (3.2)

Substitution is called a point mutation because it has a mutational effect on that one point. Deletion shifts all of the following bases over by n, and shifts the frame.

Why would switching the hemoglobin gene's nth amino acid from glutamic acid (strongly hydrophilic) to valine (strongly hydrophobic) would affect the hemoglobin? (3.2)

Switching the hemoglobin gene's nth amino acid will affect the way it folds which changes the gene's function and how it works. This, essentially, affects a fully functioning hemoglobin.

How does the sequence of nucleotides in DNA determine the sequence of amino acids in a protein? (3.2)

The DNA nucleotides bring appropriate mRNA nucleotides that attach the tRNA to the strand which aids in corresponding the amino acid chain.

How is the RNA molecule a "script" for the protein production process? (3.2)

The RNA molecule is a "script" for protein production because as the RNA is paired into codons (three consecutive nucleotide base pairs), it directs the appropriate anticodon (three complementary bases) for the RNA, which then provides the appropriate amino acids. The RNA essentially prescribes which amino acids to link accordingly.

How does the abnormal shape of sickled red blood cells affect its movement through the blood vessels? (3.1)

The abnormal shape of a sickled RBC affects how it moves because it causes the cells to get stuck in the patients blood vessels as more cells stick together.

Why do abnormal shape of sickled red blood cells cause severe pain in joints? (3.1)

The abnormal sickle cell shape depletes movement of the blood through the blood vessels. This causes blood loss/clots in certain areas causing swelling in some, and pain in others.

What is different from Anna's blood to normal blood? (3.1)

The defining feature of sickle cell anemia must cause a lower red blood cell level. Also, Anna's blood will have sickle shaped RBCs, compared the normal blood having circular shaped.

What is the function of hemoglobin in the body? (3.2)

The function of hemoglobin in the body is that it makes up a majority of RBCs. It carries oxygen and CO2 to the cells to energize and revitalize.

Would a mutational effect be greater in a substitution or a deletion? (3.2)

The mutational effect was greater in the deletion because all of the proceeding bases would be switched, requiring random amino acids, which changes the traits in the DNA.

How does sickle cell change lifestyle? (3.1)

The patient can do most things, but must be careful as is more susceptible to fainting and stroke.

What type of mutation is the sickle hemoglobin mutation? (3.2)

The sickle cell mutation is a point mutation, in which a Thymine base is substituted with an Adenine, bringing a Valine instead of a Glutamic Acid.

What determines the shape of a protein? (3.2)

The specific amino acid determines where the protein twists and bends, depending upon if it is hydrophilic/hydrophobic.

How are traits passed through the generations? (3.3)

Traits are passed through generations by them either being dominant or recessive. They get split up and randomly attached to genes coding for similar traits, which are then interpreted, to determine if the traits will be passed down or not.

In transcription: A matches to.... G matches to.... C matches to.... T matches to.... (3.2)

U C G A

Can changing just one nucleotide in a gene change the shape of a protein? (3.2)

Yes, one nucleotide can change the shape of the protein, especially a deletion, but essentially could bring wrong amino acid, and the protein could bend the wrong way.

Is the shape of a protein affected by its surrounding environment? (3.2)

Yes, the shape of a protein does depend on it's surrounding environment. Certain amino acids react differently to hydrophilic and hydrophobic environments, therefore creating the bends of a protein.

What is an erythrocyte? (3.1)

aka: RBC carries oxygen/hemoglobin to tissues, responsible for red color of vertebrate blood

What is a leukocyte? (3.1)

aka: WBC lacks hemoglobin, contains a nucleus, fights infection and disease

What is a thrombocyte? (3.1)

aka: platelets mini WBCs, assists in blood clotting by adhering to other platelets

_____are 3 letter sequences found on mRNA (3.2).

codons

Symptoms of sickle cell (3.1)

cold extremities, increased heart rate, fatigue, pain in joints

Folic acid and antibiotic treatment for sickle cell is true to...(3.1)

folic acid help with RBC production to prevent anemia, children are more prone to infections, antibiotics help prevent infection

Tay Sachs, Diabetes Type I, and Sickle Cell are all examples of

inherited diseases

Where does the translation process take place?

on a ribosome

A blood transfusion for sickle cell is true to... (3.1)

prevent occlusion (clotting), preventing stroke, and maintaining a proper hematocrit

What is the function of the tRNA molecule? (3.2)

to transfer the correct amino acid to the mRNA

mRNA takes the code from DNA in a process called...(3.2)

transcription

Bone marrow transplants for sickle cell is true to...(3.1)

usually be performed in children under 16, there is a possibility of rejection, has an 85% success rate