Exam 1 Flashcards
What are the 3 major components of a cell?
- cytoplasm
- nucleus
- plasma membrane
Why is cell compartmentalization important?
allows control of concentrations of ions, substates, cofactors, and enzymes
distinct chemical reactions need to take place
What is the difference between cytosol and cytoplasm?
cytosol: gel-like liquid surrounding organelles
cytoplasm: cytosol + organelles (entire inside of cell) NOT NUCLEUS
All cells have a __________
plasma membrane
What is the oldest type of cell?
prokaryotes
What 4 things do eukaryotes and prokaryotes have in common?
- DNA
- ribosomes
- cytoplasm
- plasma membrane
What cells lack organellees?
prokaryotes
what cells are ONLY single celled?
prokaryotes
What is distinct between a Gram negative and positive bacteria?
positive: one membrane (stained)
negative: two membranes
How many membranes does the nucleus have?
2
What organelle is the nucleus membrane continuous with?
ER
What are the 2 exceptions to the nucleus rule for eukaryotes?
red blood cells (no nucleus)
muscle cells (multiple nuclei)
What is the nuclear lamina?
intermediate filaments providing structural support and movement
What is the nucleolus?
compartment where ribosomal DNA is transcribed and ribosomes assemble
What is the function of ribosomes?
protein translation
What organelle has their own ribosomes and DNA?
mitochondria
What is the difference between ribosomes for eukaryotes v. prokaryotes?
eukaryotes have more and larger subunits
___________ is maintained during vesicular transport
topology
What happens in the rough ER?
ribosomes translocate proteins to ER lumen
What happens in the smooth ER?
lipid synthesis
What are muscle cell ER’s called?
sarcoplasmic reticulum
Where does CORE glycosylation occur?
ER
Where does glycosylation occur?
ER and golgi
What is dolichol phosphate?
initial building block for core glycosylation in the ER.
What is the most acidic organelle?
lysosomes
Where does protein sorting occur?
Golgi
What ribosomal unit is common in prokaryotes and eukaryotes?
5S
What do lysosomes do?
break down macromolecules
_________ is the study of inherited traits and their variation and transmission
genetics
___________ is the way genes transmit biochemical, physical, and behavior traits from parent to offspring
heredity
__________ are produced by an interaction between genes and their environment
traits
Mendelian traits are caused by how many genes?
one
What are the 3 components of DNA?
- phosphate
- sugar
- bases
What are exons and introns?
exons: coding region of gene
introns: NONcoding region of gene
____________ are the basic unit of chromosome packaging
nucleosomes
_________ DNA connects nucleosomees
linker
What are the 5 histone proteins for condensing DNA?
H2A
H2B
H3
H4
H1
What are centromeres?
where sister chromatids are connected and spindles attach
What are telomeres?
end caps of chromosomes
essential for pairing homologous chromosomes
How many chromosomes are in diploid (2n) and haploid (1n)?
diploid 2n = 46
haploid 1n=23
What is the p and q arm of the chromosome?
p = short arm
q = long arm
What is the labeling process of 9q21.33 for chromosomes?
9=chromsome
a=arm
2=region
1=band
33=sub band
All cells except _________ contain the entire genome
RBC
What is epigenetics?
heritable changes in gene expression that occurs independently of the DNA sequence
What is an example of epigenetics?
chromatin modification
non-coding RNA
Are germline or somatic mutations inherited?
germline
What is a point mutation?
changes of a single nucleotide in the DNA
What are transition mutations?
pyrimidine to another pyrimidine
purine to another purine
What are transversion mutation?
pyrimidine to purine
purine to pyrimidine
What are the pyrimidines?
C
T
What are the purines?
A
G
What is a silent mutation?
no change in amino acid
What is a nonsense mutation?
stop codon generated
What is a missense mutation?
amino acid change
What is an insertion/deletion mutation?
1 or more nucleotides are inserted or deleted
What is a frameshift mutation?
insertion/deletion alters the codon reading frame so the wrong amino acid
What kind of mutation happens in cystic fibrosis?
point mutation in G551D (codes for wrong amino acid)
What is the Online Mendelian Inheritance in Man (OMIM)?
database that catalogs genes known to cause disorders or traits
What is a gene pool?
sum of all alleles in a population
What is the founders affect?
reduction of genetic variation that results when a new colony is established by small subset from the larger population
What is DNA profiling?
compares DNA sequences among individuals to establish or rule out identity
Why is exome sequencing better?
more sensitive than whole-DNA sequencing
What is precision medicine?
consults DNA information to select drugs that work best for the individual
What gene is affect in sickle cell anemia?
Beta globin
What is the acronym for labeling chromosomes?
CARBS
What signal tells cells to divide?
cyclin
Has cell size increases, volume __________
decreases
What happens at G1 in interphase of mitosis?
cell growth
What happens at G0 in interphase of mitosis?
limbo stage
What happens at S phase in interphase of mitosis?
DNA replicates
Spindles synthesized
What happens during Prophase of mitosis?
nuclear membrane break down
DNA coils
microtubules organize into spindles
What are kinetochore?
connects microtubules to centromeres
What happens during metaphase of mitosis?
spindles attach
sister chromatids align
What happens during anaphase of mitosis?
centromeres divide
chromatids separate to poles
What happens in Anaphase A in mitosis?
kinetochore MT pull chromatids to spindle poles
What happens in Anaphase B in mitosis?
astral MT pull chromatids towards cell wall
interpole MT slide past each other
What happens during telophase in mitosis?
spindles fall apart
nuclear membrane reforms
What happens during cytokinesis in mitosis?
seperate into daughter cells
What is the input and output of mitosis?
input: parent cell (2n)
output: 2 identical daughter cells (2n)
What is endoreduplication?
cell cycle without cytokinesis
(causes increase in cell size)
What does Propodium Iodide do?
reveals what stage of the cell cycle the cell is in by looking at the ploidy
During mitosis when is the cell diploid (2n)?
interphase
cytokinesis
During mitosis when is the cell tetraploid (4n)?
prophase
metaphase
anaphase
telophase
What are the 2 main goals of meiosis?
- reduce number of chromosomes in half
- introduce diversity
Meiosis has 2 divisions, what type of division is each?
- reduction division (46–>23) diploid to haploid
- equation division (4 cells from 2 cells in meiosis 1)
What is the overall input and output of meiosis?
input: 2n parent cell
output: 4 identical daughter cells 1n
What cells does mitosis and meiosis occur in?
mitosis: somatic
meiosis: mature germ cells
What are the 5 stages of prophase in Meiosis 1?
- leptotene
- zygotene
- pachytene
- diplotene
- diakinesis
What is the acronym for the 5 stages of prophase in meiosis 1?
Lazy
Zebras
Push
Dipping
Donky
What happens during leptotene in prophase 1?
chromosomes condense and coalesce
What happens during zygotene in prophase 1?
synaptomeal complex forms
What happens during pachytene in prophase 1?
bivalent forms and crossing over occurs
What happens during diplotene in prophase 1?
synaptomeal complex disassociates
What happens during diakinesis in prophase 1?
nucleolus disappears
chromosomes coil
What happens during metaphase I of meiosis I?
homologous pairs align
independent assortment
What happens during anaphase I of meiosis I?
homologous pairs separate
What happens during telophase I of meiosis I?
chromosomes move to opposite poles
nuclear envelope forms
What happens during prophase II of meiosis II?
chromosomes condense
What happens during metaphase II of meiosis II?
chromosomes align
What happens during anaphase II of meiosis II?
centromeres divide
chromosomes move to poles
What happens during telophase II of meiosis II?
nuclear envelope develop
separate into individual cells
What is special about Y chromosome palidromes?
allows Y chromosomes to repair themselves
What are Mendel’s 3 laws?
- law of segregation
- law of independent assortment
- law of dominance
What is the law of segregation?
alleles segregate randomly into gametes
What is the law of independent assortment?
alleles get sorted into gametes independently of one another
Is autosomal dominant or recessive gain of function and give an example?
dominant
toxic form of protein
On a pedigree, what form of inheritance is this…
- doesn’t skip generations
- affects all sexes equally
autosomal dominant
What is an example of an autosomal dominant disease?
polydactyly
On a pedigree, what form of inheritance is this…
- parents are heterozygous
- skips generations
autosomal recessive
What is an example of an autosomal recessive disease?
albanism
Factors that alter single-gene phenotypic ratio…
death before reproduction
lethal alleles
Factors that alter single-gene phenotypic ratio…
multiple alleles will produce variation in phenotype
multiple alleles
Factors that alter single-gene phenotypic ratio…
intermediate of two phenotypes
incomplete dominance
Factors that alter single-gene phenotypic ratio…
expressing both phenotypes
codominance
Factors that alter single-gene phenotypic ratio…
one gene masks the other phenotype
epistasis
Factors that alter single-gene phenotypic ratio…
genotype does not produce the expected phenotype
penetrance
Factors that alter single-gene phenotypic ratio…
genotype has a phenotype with varying intensities
expressivity
Factors that alter single-gene phenotypic ratio…
one gene controls several functions
pleiotrophy
Factors that alter single-gene phenotypic ratio…
environmental cause but looks inherited
phenocopy
Factors that alter single-gene phenotypic ratio…
different genotypes cause same phenotype
genetic heterogeneity
What is an example of lethal alleles?
achondroplasia
What is an example of multiple alleles?
cystic fibrosis
What is an example of incomplete dominance?
FH (familial)
What is an example of codomiance?
ABO blood group
What is an example of epistasis?
Bombay
What is an example of penetrance?
polydactyly
What is an example of expressivity?
Huntingtons (repeat expansion disease)
What is an example of pleiotrophy?
Marphan
Ataxia
What is an example of phenocopy?
HIV
What is an example of genetic heterogeneity?
ALS
Alzheimers
What are pseudoautosomal regions?
homologous regions on X and Y where genes are shared so crossing over can occur
What does not occur in the MSY region of the Y chromosome?
crossing over
SRY and AZF on the Y chromosome are important for what?
fertility
What is the SRY region on the Y chromosome important for?
male specific genes
What happens if a point mutation occurs on the SRY in the Y chromosome?
XY females
What happens if a translocation mutation occurs on the SRY in the Y chromosome?
XX males
On a pedigree, what form of inheritance is this…
-only in males
- all sons are affected
- daughters of the affected male wont be affected
Y-linked inheritance
Is there crossing over on mitochondria chromosomes?
no
What kind of chromosomes have increased rates of mutation?
mtDNA
On a pedigree, what form of inheritance is this…
- always expressed in males
- females must be “aa” to express
- often skips generations
X-linked recessive
On a pedigree, what form of inheritance is this…
- females mainly affected
- rare
- passed on to daughters
X-linked dominant
What are sex-limited traits?
present only in one sex
What is an example of sex-limited trait?
beard growth
what are sex-influenced traits?
dominant in one sex and recessive in the other
What is an example of sex-influenced trait?
baldness
What is the purpose of X-inactivation?
balances gene expression in females
What is genetic mosacism?
patches of tissue that differ in expression of x-linked genes
ex: cats
When can genetic mosaicism be reversed?
germ cell formation
What is a manifesting heterzygote?
expressive recessive trait even though individual is heterozygous
What are Barr bodies used for?
determine sex (only in females)
In the parent of origin effect, what is genomic imprinting?
a gene is silenced because it is inherited from the male or female parent
What is the molecular mechanism of genomic imprinting?
DNA methylation
genomic imprinting is maintained during ________ but removed during _______
mitosis
meiosis
If a gene is hypomethylated it is _____________
expressed
If a gene is hypermethylated it is _____________
supressed
What is uniparental disomy?
inheritance of 2 chromosomes from the same parent
What two events must occur for uniparent disomy to occur?
- nondisjunction of the same chromosome in both sperm and egg
- trisomy then chromosome loss
What are the 3 types of genetic testing methods?
- Cytogenetic
- Molecular genetic
- Biochemical genetic
What does cytogenetic testing look for?
Large changes in DNA (chromosomes changes)
Can use microscopy
What does molecular genetic testing look for?
Small changes in DNA (mutations)
What does biochemical genetic testing look for?
Changes in gene products (like enzymes)
Used for new born screenings
What is cytogenetics?
Study of chromosomes
What is chromatin?
DNA and histones
When is cytogenetics studying during the cell cycle?
Metaphase
What is CENP-A?
Homolog to H3
What is the metacentric centromere positioning?
Centromere in the middle
What is submetacentric in centromere positioning?
Off center
What is the acrocentric centromere positioning?
Unequal arms
What is the telocentric centromere positioning?
Centromere at the ends
What are subtelomeres?
Transition regions between telomeres and the actual chromosome
What is the stain for Q banding?
Quinacrine fluorescence
What glows fluorescent in Q-banding?
A/T
What is the stain for G,R,T, and C-banding?
Giemsa
What is stained dark in G-banding?
A/T
What is stained dark on R-banding?
G/C
What is stained dark in T-banding (telomeres)?
G/C
What is stained dark in C-banding (centromere)?
A/T
What is FISH (fluorescence in situ hybridization)?
Chromosomes are labeled by binding fluorescence to complementary DNA
Can identify chromosome differences
What is the chromosomal abnormality isochromosome?
Identical arms
What is the chromosomal abnormality chromothripisis?
Chromosome shatters
What is the mitotic cause of polyploidy?
Multiple fertilizations OR diploid gamete
What is mitotic cause of aneuploidy?
Nondisjunction
What is euploidy?
Correct number of chromosomes
What happens if nondisjunction occurs in mitosis?
Mosaicism
What happens if nondisjunction occurs in meiosis I?
Both copies of homologous chromosomes in one gamete
What happens if nondisjunction occurs in Meiosis II?
Sister chromatids in one gamete
What syndrome is trisomy 18?
Edwards
What syndrome is trisomy 13?
Patau
What syndrome is trisomy 21?
Down’s syndrome
What syndrome is 45X?
Turners
What syndrome is 47XYY?
Jacob’s
What syndrome is 47XXY?
Klienfelter
What syndrome is 47XXX?
Trisomy X
What is the difference between chromosome inversions PERICENTRIC and PARACENTRIC?
Pericentric: inversion that includes centromere
Paracentric: does not include centromere
Is chromosome duplication inherited?
No
Chromsome duplication is an example of copy _____________
Number variants
What is difference between chromosomal translocation RECIPROCAL and ROBERTSONIAN?
Reciprocal: 2 non-homologous chromosomes exchange parts
Robersonian: 2 non-homologous acrocentric (unequal arms) long arms fuse and short arms lost
What is an isochromsome mutation?
Centromeres divide along the wrong plane causing identical arms
What exposure causes ring chromsomes?
Radiation
What is copy number variance?
Number of copies for a gene on a chromosome is not 2n
What is a CNV disease example?
Charchot-Marie-Tooth Disease
What is Charcot-Marie Disease?
CNV disease
Gene dosage affect (amount of gene affects phenotype)
What is CGH (comparative genomic hybridization)?
Finds duplications/deletions which indicate chromosome rearrangement
What does PCR+restriction enzymes and Allele specific PCR find?
Specific mutations / genes
What is a polymorphism?
Change in DNA that is less rare than mutations
What is gene variant?
Used to describe a mutation or a polymorphism interchangeable
What is a VUS?
Variants with unknown functional affects
What are DNA hot spots and 2 examples?
Areas on DNA that a prone to mutation
1. Short repeats
2. Palindromes
What happens to DNA when exposed to alkylating agents?
Removes bases
What happens when DNA is exposed to acridine agents?
Adds/removes bases
What happens to DNA when exposed to X-rays?
Breaks chromosomes
What happens to DNA when exposed to UV radiation?
Creates thymine dimmer
What is the mutation for PKU (phenylketonuria)?
Loss of enzyme that turns Phe into Tyr
What are 2 treatments for PKU (phenylketonuria)?
- KUVAN
- PALYNZIQ
What are 3 treatment options for spinal muscular atrophy (SMA)?
- Spinraza
- Evrysdi
- Zolgensma
Zolgensma uses __________ SMN to treat spinal muscle atrophy
Exogenous
Spinraza uses ___________ oligonucleotides to treat spinal muscular atrophy?
Antisense
Why types of drugs are used to treat the CFTR gene in CF?
Modular drugs (“—ftor”)
What is special about mtDNA?
Circular
Maternal
Polycistronic transcription
Replication independent of mitosis
What is mitochondrial bottle necking?
During production of oocytes, a select number of mtDNA is transferred to each oocyte
What is heteroplasmy?
Differing number of copies of mutant DNA within a cell/person
What is an example of a heteroplasmy disease?
MERRF
When does independent assortment happen?
Metaphase I
What happens in G2 of interphase of mitosis?
Cell growth
Microtubules assemble
Centrioles form
