Biology Chapter 10

Base sub: Sickle Cell Anemia

One base substitution in a certain location in the gene for hemoglobin causes red blood cells to become abnormally-shaped and clog blood vessels. If someone has two copies of this mutation then they will have the disease

Point mutations

They can cause health disorders because they end up changing the way important proteins work

How can the wrong amino acid be added during translation?

a base substitution mutation in mRNA

Frameshift Mutation

a mutation caused by an insertion or deletion, which causes a shift in the translational reading frame

Insertions

a point mutation in which one or more base pairs is added to a DNA sequence

Deletion

a point mutation in which one or more base pairs is deleted.

Silent mutation

a point mutation that has no overall effect on a protein's function

Nonsense mutation

a point mutation that turns one codon into a stop codon

pyrimidine

a single-ring base, like thymine and cytosine.

What might a nonsense mutation in the mRNA result in?

a truncated copy of the protein Klq is produced

Reading frame

a way of dividing the mRNA into codons and focusing on one codon at a time

DNA polymerase

always double-checks its work to make sure all the nucleotides have been replicated correctly. When it finds an error in the DNA sequence, it quickly stops and fixes it before replication.

Duchenne muscular dystrophy (DMD)

disorder that's caused by a nonsense mutation. Patients suffer from severe muscular weakness that gets worse over time.

Mutagen

environmental agent, chemical or physical, that causes a mutation in an organisms' DNA

UV radiation, chemical, x rays, extreme heat

examples of mutagen

What is an efficient way of causing multiple mutations in a bacterial cell?

exposing the bacteria to UV light

The enzyme affected in Tay-Sachs disease is

hexosaminidase A

when will a frameshift not occur even if there is insertion or deletion?

if an insertion or deletion consists of nucleotides numbering a factor of 3, then a frameshift will not occur.

In Tay-Sachs disease, a frameshift mutation of the hexosaminidase gene causes _____ of the enzyme.

incorrect synthesis

Purine

is a double-ring nitrogenous base, like adenine and guanine.

Tay-Sachs Disease

is a human disorder caused by a frameshift mutation. People may suffer from muscle weakness, seizures, deafness, blindness, or dementia.. Its job is to keep harmful chemicals from building up in our nerve cells.

Missense mutation

is a point mutation that changes a codon to indicate a different amino acid

Hemoglobin

is a protein that helps us carry the oxygen in our bloodstream

Dystrophin

is a structural protein that helps make up our muscle tissue.

Sickle-cell anemia

is one disease that is caused by a missense mutation. The mutation occurs in the hemoglobin gene.It also affects the shape of our red blood cells, which need to be round in order to move smoothly through our blood vessels. trouble circulating oxygen

A mutation in DNA can affect the amino acid sequence because it affects the code found in

mRNA

What causes point mutations?

random mistakes that occur while a DNA sequence is being built. don't usually happen to more than one nucleotide. They generally involve a single nucleotide being added, subtracted, or replaced with a different kind.

Nucleotides

repeating units of a DNA sequence

DNA

the unit of heredity of all organisms

Base substitutions' two types

transitions and transversions.

Transversion

when a purine is switched with a pyrimidine, or vice-versa,

Insertion: Tay Sachs disease

when a short nucleotide sequence is inserted into the hexosaminidase gene. This gene makes a protein important in removing specific toxins from the nervous system. If a mutation occurs in this gene, then nerve cells will start to die

When can a genetic mutation get passed down through successive generations?

when it does not affect the organism's ability to survive and reproduce

Which is an example of a transversion?

5' CCAC 3' is mutated to 5' CCTC 3'

Deletion: Duchenne Muscular dystrophy

A deletion of a certain nitrogenous base in the dystrophin gene causes the disease. This disease is sex-linked and tends to be much more common in males than females. It causes weakened muscles and early death, just by one little base being removed.

Mutation

any change in the nucleotide sequence of an organism's DNA

Transitions

are base substitutions that swap a purine for another purine or a pyrimidine for another pyrimidine.

Point Mutations (smaller mutations)

are changes in the genetic sequence that occur at a specific point along the DNA strand.

Base substitutions

are just what they sound like; they're point mutations in which one nitrogenous base is substituted by a different base.

point mutations' s two basic types

base substitutions and insertions and deletions.

mutations can cause a variety of disorders:

cystic fibrosis, color blindness, Tay-Sachs disease, sickle-cell anemia, and cancer.

Tay-Sachs disease results from a buildup of harmful chemicals in the

nerve cells

mutagen

origin of mutations

gen

origin or creation of something

Genes

sequences of DNA that code for proteins