Unformatted text preview: lengthen the parent strand using an RNA template during replication so that the lagging daughter
strand may be completed.
What are the different kinds of genetic mutations? (point, deletion, etc.)
Point- A mutation in a gene involving the replacement of a single nucleotide for another.
Deletion- A mutation that results from loss or removal of a segment of a chromosome.
Silent- does not change amino acid sequence
Translocation-A mutation that results from the movement of a piece of one chromosome to another 4 location on another chromosome
Transversion- Substitution mutation of a purine for a pyrimidine or a pyrimidine for a purine.
Transition- Substitution mutation of a purine for a purine or a pyrimidine for a pyrimidine.
Chromosomal mutation- A mutation affecting a large portion of a chromosome involving millions of
Duplication- A mutation that results from a repeated segment of a chromosome.
Frameshift- Gain or loss of a single nucleotide, changing the reading frame of the mRNA transcript.
Inversion- A mutation involving a piece of a chromosome that breaks off and reattaches in reverse
Translocation- A mutation that results from the movement of a piece of one chromosome to another
location on another chromosome.
What are the effects of these mutations? (nonsense, missense, etc)
Nonsense- Alters the codon such that a premature termination occurs.
Missense- Alters the codon to produce an altered amino acid sequence.
Gain-of-function- A mutation that causes an altered gene product with a new and different function
from the original gene product.
Loss-of-function- A mutation that causes a gene to fail at producing a protein.
What is a somatic mutation?
A mutation that occurs in a non-sex cells within the body and are only passed on to the somatic cells
that are produced after the original cell with the mutation divides. ex: a mutated skin cell may divide
into cells that may produce a blemish or growth. Somatic mutations are not inherited by offspring.
What kinds of mutations are most damaging?
Mutations that delete one nucleotide as opposed to all the nucleotides that code for an amino acid
are worst because they cause a nonsense mutation.
Why are mutations not all bad?
Mutations are the driving force behind evolution. Evolutionary fitness is a result of the additive
effects of many mutations, each introducing small changes to the organism.
How is DNA packaged into chromosomes?
Chromosomes are packaged by histone proteins into a condensed structure called chromatin. The
condensed chromatin is folded and tightly coiled, like a coiled telephone cord, around proteins
called histones that support its structure, allowing the cell’s DNA to be packed into the nucleus.
Why do chromosomes in higher organisms occur in pairs? Why are they called
Chromosomes come in pairs as each half is inherited from each parent. Homologous chromosomes
are chromosome pairs of approximately the same length, centromere position, and staining pattern,
with genes for the same characteristics at corresponding loci. One homologous chromosome is
inherited from the organism's mother; the other from the organism's father. They are usually not
View Full Document