Genetics Flashcards
What is the Hayflick Limit
Phenomenon that states the number of possible cell divisions are dependent on the length of the telomeres on the chromosomes
Telomerases synthesizes:
Telomeres
What are the point mutations? (3 types)
Substitution, Insertion and Deletion
What is a silent mutation?
No change occurs to amino acids because of redundancy of genetic code
What is a missense mutation?
Substitution mutation that causes a change in an amino acid that was originally coded
What is a nonsense mutation?
Substitution mutation that causes an amino acid codon to change to a stop codon
What is a frameshift mutation?
A point mutation that leads to the alteration of the reading frame
What are histones?
Positively charge protein complex that DNA wraps around. It was 8 subunits
What are nucleosomes?
DNA-histone complex
What is euchromatin?
Loosely packed which allows for RNA polymerase to transcribe
What is heterochromatin?
Tightly packed which prevents RNA polymerase from transcribing (inhibited gene transcription)
What is transcriptome?
The entire set of expressed mRNA (includes exons and introns)
What is proteome?
The entire set of expressed protein. (More proteins than mRNA sequences because of alternative splicing)
What are two types of method for genome sequencing?
Sanger Sequencing - amplifies DNA and uses fluorescence.
Whole Genome Shotgun Sequencing - clones DNA and cut it apart into different segments.
What is Metagenomics?
Sequencing the DNA of entire communities
What is gene density?
Refers to ratio of number of genes compared to total number of nucleotides. Prokaryotes are more dense than eukaryotes because they do not have introns.
Components of human genome? (6 parts)
Exons, Regulatory, Introns, Non-Coding, Repetitive (telomeres), Transposable Elements
Vast majority are non-coding.
How do transposons work?
“Cut and paste” or “Copy and paste”
How do retro-transposons work?
DNA sequence gets transcribed to RNA, RNA is reverse transcribed to DNA, then transposition occurs
What is a homeotic gene?
It is involved in the structural development of body formation.
Homeobox
Specific DNA sequence found in homeotic genes. Encode for homeodomain proteins and are highly conserved.
What is a hox gene?
Specific homeotic gene that controls body position and anatomical structure placement. It is very specific.
Which of the following best describes the law of segregation?
A. Allele copies are separated, based on the parental origin.
B. Allele copies are independently separated.
C. Allele copies are separated during mitosis for genetic recombination.
D. Allele copies are separated to form haploid gametes.
E. Allele copies are separated to form diploid gametes.
D
Meiosis produces four gametes, two of 24 chromosomes and two with 22 chromosomes, what explains what occurred?
Nondisjunction in meiosis I.
After meiosis, the four gamete cells are karyotype. Two of the gametes have 23 chromosomes one has 22 and the last is 24. Which of the following could have occurred?
Nondisjunction in meiosis II
What is pleiotropy?
When a single gene influences more than one phenotype.
What are the three stop codons used in translation?
UAG, UAA, UGA
What is Turner Syndrome?
Condition present in females caused by aneuploidy. Genotype is XO, meaning they are missing an X chromosome.
This genotype is sterile
What is a transition mutation?
Point mutation where a purine or a pyrimidine is substituted for a purine or pyrimidine nucleotide respectively.
What is a transversion mutation?
Point mutation where a purine is sub’ed for a pyrimidine nucleotide or vice versa.
What is Kleinfelter’s syndome?
Genetic disorder caused from nondisjuntion in sex chromosomes. Affects males and is due to the presence of an extra X chromosome (XXY).
Chromosomal duplication?
Chromosome segment is repeated on the same chromosome. Caused by unequal crossing over.
