Quiz 1 - Genetics+Cellular Biology Flashcards
DNA directs creation and sequence of _____.
RNA directs creation and sequence of ______
RNA
Polypeptides
DNA has 4 nitrogenous bases in two categories:
Pyrimidines = Thymine and Cytosine
Purines = Guanine and Adenine.
For the 4 nitrogenous bases of DNA, which can bind together?
A-T
G-C
What is the different nitrogenous base in RNA?
Urasil (Pyramidine)
What types of “spelling errors” (Insertions/deletions) would be symptomatic? Asymptomatic? Which ones affect only the single trinome? Which affect the trinome AND those that come after it?
Symp: Non-conservative missense mutation
Nonsense mutation and frame-shift mutation
Asymptomatic: silent mutation + conservative mutation.
Silent, conservative and non-conservative missense
Nonsense (total stop after)
Frame shift - adds an extra base to shift and change all those coming after.
What is the most common type of allele (spelling sequence) among population?
Wild Type
2 types of cellular mutations
Germline - affects all body cells because it stems from egg and sperm (embryo)
Somatic - affects a certain previously healthy cell line (limited) like cancer. Environmental effects.
What is an SNP? (“Snip”)
Example?
A Single Nucleotide Polymorphism or point mutation (single base pair change) that may or may not have an impact.
certain SNP (8q24) associated w/ prostate cancer.
What’s the difference between a genotype and a phenotype?
Example?
Genotype = genomic sequence
Phenotype = how the individual appears on the outside
Ex: Trisomy 21 = Genotype
Facial features of Down Syndrome = phenotype
2 factors of phenotypes
Expressivity - how a certain genotype is expressed in external features
Penetrance - the % of people with the genotype who express the expected phenotype
What is one of the only known complete penetrance genotype that is very predictable
Huntington’s
What can explain familial diseases not explained by SNPs?
Examples?
Copy Number Variants present on chromosomes
Autism, schizophrenia.
What does it mean to be an interfering RNA?
MiRNA or siRNA
Non-coding
Inhibit RNA translation through degradation
Pros and cons to this
Explain epigenetics
Epigenetics talks about how certain genes are turned on or off through methylation - not all genes are on at once.
Environmental factors can play a huge role in epigenetics
What can abnormal methylation lead to?
Cancer development
What holds the DNA strand apart to prepare for reading?
Proteins
What reads the DNA template strand?
mRNA
What carries the copied info out to the cytoplasm?
MessengerRNA
What carries the activated amino acids to the ribosome?
TransferRNA
What allows for easy ID of absent or extra chromosomes?
Chromosomal Array and Giemsa stain
How many pairs of chromosomes? Categorized as?
46 total
22 pairs of autosomes
1 pair of sex chromosomes
Major Chromosomal aberrations occur 1 in every ______ conceptions.
12
What are the 3 trisomies that are compatible with life?
13, 18 and 21
Viability with no X?
With no Y?
No
Yes
What is Turner Syndrome?
Only 1 X chromosome.
what is the most common single chromosome aberration?
Turner Syndrome (X0)
What is Kleinfelter Syndrome?
XXY or XXXY
1:1000 male births
Male appearance
Sterile with moderate mental impairment
What is Jacob’s Syndrome?
XYY (duplicate Y)
Male
Tall, reduced IQ, increased behavioral issues.
Explain
46, XY, 5p-
Also called?
Normal # of chromosomes, Male, missing the short arm of the 5th chromosome.
Cri-du-chat
What 3 things cause increased breakage of chromosomes?
Ionizing radiation
Chemical exposure
Viral infx
Which are less serious - deletions or duplications?
Duplications are less serious.
Two types of Translocations
Reciprocal and Robertsonian.
If you have a robertsonian translocation, but you are healthy, what is the risk?
To your offspring - increased likelihood of miscarriage, and increased risk for offspring with genetic defects.
What are some examples of Trinucleotide repeats?
Stutters
Huntingoton’s Disease
Spinocerebellar ataxia
Fragile X syndrome
What is the most common inheritable intellectual disability?
Fragile X syndrome.
What are the principles of AD inheritance patterns
Autosomal Dominant
Males and Females equally affected (NOT sex-linked)
No “skipping” generations
Every child has 50% chance of inheriting the disorder
What is an example of incomplete AD mutation pattern?
Retinoblastoma.
What is genomic imprinting?
Embryo “labels” maternal vs paternal chromosomes via methylation
What are 3 characteristics of AR mutations?
Incomplete penetrance
Variable expressivity
Delayed age of onset.
What are some AR principles?
M+F equally affected
Disease seen in siblings not parents
1/4th offspring affected on average.
What are some characteristics of mitochondrial inheritance?
Maternally derived
All children of an affected female are affected.
X-linked genetic disorder principles?
Disease Expressed in males
Not transmitted from father to SON
Father transmits to ALL daughters (as carriers)
Affected will be grand sons.
If you have an affected male and a carrier female, what is the recurrence risk for X-linked genetic disorder?
Affected male and normal female?
Daughters = 50% affected, 50% carriers
Sons = 50% normal, 50% affected
All sons normal
All daughters carriers
Genetic testing locates mutations, not _________
Disease. There is no way to tell what the penetrance of the mutation will be.
What is the goal of CYPs?
To completely biotransform to a polar metabolite for elimination.
What does it mean if someone has 3 copies of CYP?
Ultra-rapid metabolizers - chew through drugs.
Where do most CYP Drug-drug interactions occur?
CYP3A4
Is grapefruit juice an inhibitor or inducer?
Inhibitor
