Ch.2 Genes and genetic disease Flashcards
DNA consists of what three main things?
Deoxyribose, phosphate molecule, and four nitrogenous bases
Proteins are composed of ____ _____. How many?
amino acids; 20
What are the two main steps of DNA replication?
- Untwisting and unzipping of the DNA strand.
2. Complementary base pairing by DNA polymerase (A-T and C-G)
In DNA replication, does the single strand act as a template?
Yes
in DNA replication, what allows for complementary base pairing?
DNA polymerase
A ______ is any inherited alteration of genetic material
mutation
The insertion or deletion of one or more base pairs is which type of mutation?
Frameshift
Which type of mutation causes a change in the entire reading frame?
Frameshift
Which type of mutation occurs in the absence of exposure to known mutagens?
Spontaneous
Areas of chromosomes that have high mutation rates are called?
Mutational hot spots
What is a mutagen?
Agent known to increase the frequency of mutations
List some common chemical mutagens
Nitrogen mustard, vinyl chloride, alkylating agents, formaldehyde, and sodium nitrate
RNA is synthesized from the DNA template. This occurs during _______
transcription
With transcription, DNA polymerase binds to the promoter site. T or F?
False, RNA polymerase binds to promoter site
What is the result after RNA is synthesized from the DNA template and RNA polymerase binds to the promoter site?
Formation of mRNA
after RNA polymerase detaches, where does the mRNA go?
It moves out of the nucleus and into the cytoplasm
Transcription of mRNA synthesis continues until?
Until the termination sequence is reached
T or F: introns are removed and the exons are then spliced together before mRNA migrates to the cytoplasm
True
What is translation?
Process by which RNA directs the synthesis of a polypeptide via interaction with tRNA
During translation, what is the site of protein synthesis?
ribosome
_____ is the process by which RNA directs the synthesis of a polypeptide via interaction with tRNA
translation
tRNA contains a sequence of _______ (anticodon) complementary to the triad of nucleotides on the ____ strand (codon)
nucleotides; mRNA
The ____ moves along the mRNA sequence to translate the amino acid sequence
ribosome
Translation continues until….
termination sequence is reached
After the termination sequence is reached, the polypeptide is released into the ______
cytoplasm
T or F, RNA contains the same bases as DNA
False
T or F, DNA is replicated in the cytoplasm
False; nucleus
T or F, a mutation is an inherited alteration of DNA
True
Diploid cells are ______ and haploid cells are _______
somatic; gametes
Sperm and egg cells are called
gametes
How many chromosomes do gametes contain?
23 (one member of each chromosome pair)
How many chromosomes do somatic cells contain?
46 (23 pairs)
Mitosis is the formation of ____ cells whereas meiosis is the formation of ______ cells from diploid cells
somatic cells; haploid cells
What are autosomes?
The first 22 of the 23 pairs of chromosomes in males and females.
T or F, females have a nonhomologous pair of chromosomes XX
False…XX is homologous (same)
The ordered display of chromosomes is the _____
karotype
____ cells have a multiple of the normal number of chromosomes
Euploid
____ and _____ cells are euploid forms
haploid and euploid
When is a euploid called a polypoid cell?
When a euploid has more than the diploid number
What is a triploidy?
A zygote having three copies of each chromosome (69)
What is a tetraploidy?
four copies of each chromosome (92)
What is the leading cause of miscarriages and intellectual disability?
Chromosomal aberrations
Do triploid or tetraploid fetuses survive?
No
What is an aneuploidy?
A somatic cell that does not contain a multiple of 23 chromosomes
A ______ is a cell containing three copies of one chromosome
trisomic/trisomy
Monosomy is the presence of what?
Presence of only one copy of any chromosome
Monosomy is lethal, but infants can survive with trisomy of certain chromosomes. T or F
True; it is better to have extra than less