Test Prep. #1 Flashcards
What are the three parts make that up a nucleotide?
Sugar, Nitrogen Base, Phosphate Base
Draw a nucleotide.
Phosphate Group = Left Hand Circle
Sugar = Middle Pentagram
Nitrogenous Base = Right Hand Rectangle
In DNA, what bases pair together?
A -> T
C -> G
What describes DNA after replication has taken place?
Each DNA has one parental or “old” strand, and one daughter or “new” strand.
What is the end result of semiconservative replication of DNA?
Two identical molecules.
Define Chargaff’s rule.
DNA from any cell of all organisms should have a 1:1 ratio (Base Pair Rule) of pyrimidine and purine bases.
If a sample of DNA is made up of 15% Thymine, what percentage of Adenine does the DNA sample contain? What about Guanine and Cytosine?
If a DNA sample contains 15% Thymine, it will also contain 15% Adenine, and 35% Guanine and 35% Cytosine.
REFERENCING IMAGE: Identify AND describe the cellular process occurring at point A?
Transcription. (DNA to RNA)
Where does transcription occur?
In the nucleus.
REFERENCING IMAGE: Identify and describe the cellular process occurring at point B?
Translation.
What is translation?
The processes by which a cell makes proteins using the genetic information carried in messenger RNA (mRNA).
What is transcription?
Copying a segment of DNA into RNA. It is also the first step of gene expression.
Where does translation occur?
On ribosomes in the cell cytoplasm.
What is the purpose of mRNA?
Directs the cells to make a protein using its natural machinery.
What is the purpose of tRNA?
To bring amino acids to the ribosome for protein production.
For the DNA sequence TAG what is the mRNA codon? What is the tRNA anticodon?
For the DNA sequence TAG, the mRNA codon is AUC, and the tRNA anticodon is UAG.
What is an anticodon?
A sequence of three nucleotides in a transfer RNA (tRNA) molecule that binds to a complementary codon in a messenger RNA (mRNA) molecule.
What is a DNA mutation?
A permanent change in the sequence of DNA, which can occur when a nucleotide is added, deleted, or swapped for another, potentially altering the function of a gene and impacting the organism’s traits.
Does a DNA mutation always result in a phenotypic change?
No.
What is a phenotypic change?
A change in an organism’s observable traits or characteristics, or phenotype, in response to environmental conditions.
USING your CODON chart, if you changed an mRNA codon from UUA to UUU would
this have an effect on the gene expression? Explain.
Changing an mRNA codon from UUA to UUU would affect gene expression because both codons code for the different amino acids.
What are the types of chromosomal mutations? (Hint- there’s 4!)
Deletion, duplication, inversion, and translocation.
What are the types of gene mutations?
Point mutations (like missense, nonsense, and silent mutations), frameshift mutations, insertion mutations, deletion mutations, duplication mutations, and chromosomal mutations.
Define a heterozygous individual.
Having inherited different versions (alleles) of a genomic marker from each biological parent. Aka a big letter and a small letter.
