Quiz 1 - Genetics+Cellular Biology

Question 1

DNA directs creation and sequence of _____.
RNA directs creation and sequence of ______

Answer 1

RNA
Polypeptides

Question 2

DNA has 4 nitrogenous bases in two categories:

Answer 2

Pyrimidines = Thymine and Cytosine
Purines = Guanine and Adenine.

Question 3

For the 4 nitrogenous bases of DNA, which can bind together?

Answer 3

A-T
G-C

Question 4

What is the different nitrogenous base in RNA?

Answer 4

Urasil (Pyramidine)

Question 5

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?

Answer 5

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.

Question 6

What is the most common type of allele (spelling sequence) among population?

Answer 6

Wild Type

Question 7

2 types of cellular mutations

Answer 7

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.

Question 8

What is an SNP? (“Snip”)
Example?

Answer 8

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.

Question 9

What’s the difference between a genotype and a phenotype?
Example?

Answer 9

Genotype = genomic sequence
Phenotype = how the individual appears on the outside
Ex: Trisomy 21 = Genotype
Facial features of Down Syndrome = phenotype

Question 10

2 factors of phenotypes

Answer 10

Expressivity - how a certain genotype is expressed in external features
Penetrance - the % of people with the genotype who express the expected phenotype

Question 11

What is one of the only known complete penetrance genotype that is very predictable

Answer 11

Huntington’s

Question 12

What can explain familial diseases not explained by SNPs?
Examples?

Answer 12

Copy Number Variants present on chromosomes
Autism, schizophrenia.

Question 13

What does it mean to be an interfering RNA?

Answer 13

MiRNA or siRNA
Non-coding
Inhibit RNA translation through degradation
Pros and cons to this

Question 14

Explain epigenetics

Answer 14

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

Question 15

What can abnormal methylation lead to?

Answer 15

Cancer development

Question 16

What holds the DNA strand apart to prepare for reading?

Answer 16

Proteins

Question 17

What reads the DNA template strand?

Answer 17

mRNA

Question 18

What carries the copied info out to the cytoplasm?

Answer 18

MessengerRNA

Question 19

What carries the activated amino acids to the ribosome?

Answer 19

TransferRNA

Question 20

What allows for easy ID of absent or extra chromosomes?

Answer 20

Chromosomal Array and Giemsa stain

Question 21

How many pairs of chromosomes? Categorized as?

Answer 21

46 total
22 pairs of autosomes
1 pair of sex chromosomes

Question 22

Major Chromosomal aberrations occur 1 in every ______ conceptions.

Answer 22

12

Question 23

What are the 3 trisomies that are compatible with life?

Answer 23

13, 18 and 21

Question 24

Viability with no X?
With no Y?

Answer 24

No
Yes

Question 25

What is Turner Syndrome?

Answer 25

Only 1 X chromosome.

Question 26

what is the most common single chromosome aberration?

Answer 26

Turner Syndrome (X0)

Question 27

What is Kleinfelter Syndrome?

Answer 27

XXY or XXXY 1:1000 male births Male appearance Sterile with moderate mental impairment

Question 28

What is Jacob’s Syndrome?

Answer 28

XYY (duplicate Y) Male Tall, reduced IQ, increased behavioral issues.

Question 29

Explain 46, XY, 5p- Also called?

Answer 29

Normal # of chromosomes, Male, missing the short arm of the 5th chromosome. Cri-du-chat

Question 30

What 3 things cause increased breakage of chromosomes?

Answer 30

Ionizing radiation Chemical exposure Viral infx

Question 31

Which are less serious - deletions or duplications?

Answer 31

Duplications are less serious.

Question 32

Two types of Translocations

Answer 32

Reciprocal and Robertsonian.

Question 33

If you have a robertsonian translocation, but you are healthy, what is the risk?

Answer 33

To your offspring - increased likelihood of miscarriage, and increased risk for offspring with genetic defects.

Question 34

What are some examples of Trinucleotide repeats?

Answer 34

Stutters Huntingoton’s Disease Spinocerebellar ataxia Fragile X syndrome

Question 35

What is the most common inheritable intellectual disability?

Answer 35

Fragile X syndrome.

Question 36

What are the principles of AD inheritance patterns

Answer 36

Autosomal Dominant Males and Females equally affected (NOT sex-linked) No “skipping” generations Every child has 50% chance of inheriting the disorder

Question 37

What is an example of incomplete AD mutation pattern?

Answer 37

Retinoblastoma.

Question 38

What is genomic imprinting?

Answer 38

Embryo “labels” maternal vs paternal chromosomes via methylation

Question 39

What are 3 characteristics of AR mutations?

Answer 39

Incomplete penetrance Variable expressivity Delayed age of onset.

Question 40

What are some AR principles?

Answer 40

M+F equally affected Disease seen in siblings not parents 1/4th offspring affected on average.

Question 41

What are some characteristics of mitochondrial inheritance?

Answer 41

Maternally derived All children of an affected female are affected.

Question 42

X-linked genetic disorder principles?

Answer 42

Disease Expressed in males Not transmitted from father to SON Father transmits to ALL daughters (as carriers) Affected will be grand sons.

Question 43

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?

Answer 43

Daughters = 50% affected, 50% carriers Sons = 50% normal, 50% affected All sons normal All daughters carriers

Question 44

Genetic testing locates mutations, not _________

Answer 44

Disease. There is no way to tell what the penetrance of the mutation will be.

Question 45

What is the goal of CYPs?

Answer 45

To completely biotransform to a polar metabolite for elimination.

Question 46

What does it mean if someone has 3 copies of CYP?

Answer 46

Ultra-rapid metabolizers - chew through drugs.

Question 47

Where do most CYP Drug-drug interactions occur?

Answer 47

CYP3A4

Question 48

Is grapefruit juice an inhibitor or inducer?

Answer 48

Inhibitor