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3197 Exam 1
n/a
143
Nursing
Undergraduate 3
08/28/2014

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Term
Define genetics
Definition
inherited traits and their variations
Term
Describe genotype
Definition
chemical trait/code in DNA
Term
DNA is made of long strings of chemicals called _____
Definition
nucleotides
Term
DNA is packaged on ____
Definition
chromosomes
Term
What 3 properties of DNA allow for it to be the basis of life?
Definition
can copy itself (replication), can change (mutation and variation), has info for production of functional organisms (expression)
Term
____ is all the DNA in a cell
Definition
genome
Term
Define gene
Definition
segment of DNA (instructional unit) in a cell; codes for proteins
Term
Genes are expressed into ___
Definition
proteins
Term
Define alleles
Definition
different versions of the same gene
Term
Structures and functions of the body are carried out by ____
Definition
proteins
Term
DNA has the code for ____
Definition
proteins
Term
When a gene instructs the production of a protein we say it is _____
Definition
expressed
Term
Define SNPs
Definition
single nucleotide polymorphisms; sequence differences throughout the DNA
Term
What are the 22 pairs of cells in a chromosome that do not differ between sexes?
Definition
autosomes
Term
Genotype refers to the combination of ____
Definition
alleles
Term
What 3 individuals are responsible for the initial discoveries regarding DNA?
Definition
Roselyn Franklin and Watson and Crick
Term
What are the 3 components of a nucleotide?
Definition
sugar, phosphate, and nitrogenous base
Term
What are the two categories of nucleotides?
Definition
Purines (guanine and adenine) and Pyrimidines (cytosine and thymine)
Term
What is another name for nucleotides?
Definition
bases
Term
Define sequences
Definition
long chains of nucleotides
Term
Sequences are held together by the _____
Definition
sugar-phosphate backbone (bond between sugar and phosphate groups)
Term
What is the term that describes the relationships between two sides of a DNA strand?
Definition
antiparallelism
Term
What is the name of the top end of a DNA strand?
Definition
5'
Term
What is the name of the bottom end of a DNA strand?
Definition
3'
Term
Nitrogen bases (nucleotides) are held together with ___ bonds
Definition
hydrogen
Term
Describe a complementary base pair
Definition
two nucleotides held together by hydrogen bonds
Term
Define histones
Definition
proteins that help keep the DNA helix tight (compress)
Term
Define nucleosome
Definition
clumps of histones
Term
Define chromatin
Definition
combination of DNA and proteins in their condensed form; content of nucleus
Term
How is DNA replication semiconservative?
Definition
DNA parent cell splits in half; parent cell is paired with new DNA cell to make daughter cell
Term
What is the purpose of helicase?
Definition
unwinds double helix of DNA
Term
What is the purpose of binding proteins?
Definition
attach and stabilize halves of DNA; keeps strands apart once seperated
Term
What is the function of primase?
Definition
adds short primer (short stretch of RNA) to template strand
Term
What is the function of DNA polymerase?
Definition
brings in new nucleotides to form new DNA strands
Term
Describe Okazaki fragments
Definition
sides of the new DNA that is replicated discontinuously
Term
Okazaki fragments are sealed by what?
Definition
ligase
Term
DNA replication occurs along a chromosome in ____
Definition
replication bubbles
Term
DNA adds nucleotides in a ___ to ___ direction
Definition
5'; 3'
Term
DNA is ___ to RNA
Definition
transcribed
Term
RNA is ____ to proteins
Definition
translated
Term
___ determine overall phenotype of an organism
Definition
proteins
Term
Describe the Central Dogma of Molecular Biology
Definition
central flow of genetic info is from DNA to RNA to protein
Term
Define polypeptide
Definition
chain of linked AA
Term
____ is the primary unit of DNA
Definition
nucleotide
Term
___ is the primary unit of RNA
Definition
AA
Term
What are 3 functions of proteins?
Definition
cellular structures, transporting molecules and signaling molecules
Term
Describe transcription
Definition
makes RNA copy of DNA gene that is complementary to one strand of DNA helix
Term
What are the RNA nucleotides?
Definition
A U C G
Term
What is the final product of transcription?
Definition
mRNA
Term
___ encodes AA sequences (type of RNA)
Definition
mRNA
Term
Define introns
Definition
intervening sequences in mRNA that don't code proteins but allow for smoother transcription and are spliced at the end
Term
Describe RNA splicing
Definition
removes introns and joins exons to make continuous coding sequence during transcription
Term
Before mRNA leaves the nucleus, what must happen to it?
Definition
cap is added to 5' end and poly-a tail ( many Adenines) is added to 3' end
Term
What is the function of rRNA?
Definition
associates with proteins to form ribosomes; support and catalyze protein synthesis
Term
What is the purpose of tRNA?
Definition
transports specific AA to the ribosomes for protein synthesis
Term
What are the 3 steps of transcription?
Definition
initiation, elongation, termination
Term
Define promotors
Definition
DNA sequence at the beginning of a gene that act as start sequences for transcription
Term
Define alternative splicing
Definition
leads to mix and match of exons to make different versions of proteins
Term
Describe the initiation step of transcription
Definition
RNA polymerase binds to promotor to unwind double helix
Term
Define transcription factors
Definition
proteins that help turn on transcription
Term
Describe the termination phase of transcription
Definition
RNA polymerase reaches terminator sequence and detaches from template
Term
__ nucleotides in a row= __ codon= __ AA
Definition
3;1;1
Term
AA's are connected through a ___ bond
Definition
peptide
Term
What 3 items are required for translation to occur?
Definition
mRNA, tRNA and rRNA
Term
Describe the makeup of tRNA
Definition
Key between mRNA and AA; one end is anticodon that complimentary base pairs with mRNA, other end is AA
Term
What is always the first AA in translation?
Definition
Met
Term
Describe termination in translation
Definition
ribosome reaches a stop codon and everything disassociates; peptide chain is left intact and is now a protein
Term
What is the purpose of control of gene expression?
Definition
cell differentiation, cell function and cell development
Term
At what 3 times are genes typically transcribing?
Definition
specific cell function, development stage or response to environment
Term
If a protein is unnecessary it will stop at the point of _____
Definition
transcription; most important point of gene regulation
Term
What is the broadest level of gene regulation?
Definition
DNA packaging; limits access to genes so transcription can't begin
Term
What is the name for an inactivated X gene in females?
Definition
Barr body
Term
Describe epigenetic marks
Definition
modifications made to DNA or histones; control access to DNA; the more marks, the less the gene is expressed
Term
How do epigenetic marks work?
Definition
Proteins or chemicals that attach to nucleotides or histone tails to control access to DNA
Term
Define epigenetics
Definition
study of heritable changes in genes that are not due to change in DNA sequence; different phenotype same genotype
Term
Define polymorphism
Definition
regular differences between people that occur in >1% of population; SNP
Term
If the genotype shows a mutation the phenotype will be a ____
Definition
mutant
Term
If a mutant allele appears in the genotype, the phenotype will be a ____
Definition
disease
Term
What are the two general categories of mutations?
Definition
germline and somatic
Term
Describe germline mutations
Definition
inherited; present in DNA of all cells; can be passed to next generation
Term
Describe somatic mutations
Definition
not inherited; DNA acquires all change in one cell then all subsequent cells have the mutation; limited to one part of the body; cancer
Term
Define point mutation
Definition
concern single nucleotide (base) change
Term
What are two types of points mutations?
Definition
transitions and transversion
Term
ID
When purine mutates to another purine
Definition
transition
Term
ID:
when pyrimidine mutates to purine or vice versa
Definition
Transversions
Term
What type of mutation is sickle cell
Definition
point mutation
Term
What are 4 possible outcomes of point mutations?
Definition
missense, nonsense, silent, readthrough
Term
Describe missense mutations
Definition
codes for a different AA than what it should
Term
Describe silent mutation
Definition
no difference in protein made
Term
Describe nonsense mutation
Definition
causes stop codon to appear where it shouldn't; factor 11 deficiency
Term
Describe read through mutation
Definition
occur when normal stop codon is mutated into regular AA; causes long proteins; wilm's tumor
Term
Describe splice site mutations
Definition
occurs where introns/exons meet and disrupts splicing; can result in intron being translated to AA or exon skipping
Term
What are 3 possible results of insertions and deletions?
Definition
frameshift mutation, tandem duplication, expanding triplet repeats
Term
Describe tandem duplication in gene mutation
Definition
when duplications of large regions of genetic sequence are inserted into existing sequence
Term
Describe expanding triplet repeats in gene mutations
Definition
number of repeats increases with each generation; symptoms and severity increase and have earlier onset
Term
Describe spontaneous causes of mutation
Definition
originate during DNA replication at low frequency
Term
Describe a mutational hot spot
Definition
occurs more often in regions and repeats; during replication DNA can pair with itself creating hairpin loop
Term
Describe transposons
Definition
causes insertions jumping genes with small sequences scattered in DNA
Term
What are two types of effects of mutations on proteins?
Definition
loss of function and gain of function
Term
Describe loss of function in mutations
Definition
more common and caused by all types of mutations; no proteins or damaged ones that don't work properly
Term
Describe gain of function in mutation
Definition
protein produced that behaves differently (interferes with other proteins or has new different function); not as common and caused by framshifts, insertions and expanding triplet repeats
Term
Describe allelic disorder
Definition
same gene different mutations different effects on proteins, different phenotypes
Term
Describe PSEN1
Definition
missense mutation results in gain of functio and alzheimer disease; nonsense and frame shift mutations result in loss of function and sever acne disorder
Term
Mutations drive ___
Definition
genetic diversity; disease resistance
Term
Describe conditional mutations
Definition
effect phenotype only under certain circumstances
Term
Define cytokinesis
Definition
division of cellular contents
Term
What are the two major stages of the cell cycle?
Definition
interphase and mitosis
Term
Describe interphase
Definition
most of the cell's life is in this phase; maintain basic function; replicate DNA and other structures
Term
What are the 4 phases of interphase?
Definition
G1, G0, S and G2
Term
ID phase of interphase:
synthesis of components
Definition
G1
Term
ID phase of interphase:
quiescent phase
Definition
G0
Term
ID phase of interphase:
replicates entire genome; chromosomes duplicate and appear as 2 chromatids
Definition
S
Term
ID phase of interphase:
after DNA has been replicated but before mitosis
Definition
G2
Term
What are the 5 phases of mitosis?
Definition
prophase, metaphase, anaphase, telophase, cytokinesis
Term
ID phase of mitosis:
mitotic spindle forms centrioles in the cell
Definition
prophase
Term
ID phase of mitosis:
chromatids line up
Definition
metaphase
Term
ID phase of mitosis:
sister chromatids are pulled apart from each other
Definition
anaphase
Term
ID phase of mitosis:
spindle dissasembled; envelopes for around cluster of chromosomes
Definition
telophase
Term
ID phase of mitosis:
when the rest of the cell contents are distributed to daughter cells
Definition
cytokinesis
Term
Describe the cell cycle checkpoints
Definition
checks for DNA damage, spindle assembly, and apoptosis; cancer occurs when cycle is out of control
Term
Describe the mitotic clock
Definition
determines how many times a cell has a divided and how many divisions it has left
Term
Describe telomeres
Definition
tips of chromosomes that shorten after each division. Division ceases when telomeres disappear
Term
For meiosis chromosomes are matched in ___
Definition
homologous pairs; same genes at same loci
Term
How many pairs of chromosomes do humans have?
Definition
23
Term
Describe meiosis 1
Definition
reduction division: 1 diploid splits into 2 haploid
Term
In Meiosis when does crossing over occur?
Definition
prophase 1; homologous reombination
Term
Describe synapsis
Definition
homologous pairs line up side by side in prophase 1
Term
What happens in meiosis 2?
Definition
segregation of sister chromatids
Term
Describe single gene inheritance
Definition
caused by genetic mutation in one gene only; rare
Term
Describe the mode of inheritance
Definition
pattern in which mutations affect a family
Term
What type of genetic mutation is CF?
Definition
autosomal recessive
Term
Describe Mendel's Law of Segregation
Definition
reflects what is happening on chromosomal level during gene inheritance
Term
Identical alleles for a gene is ____
Definition
homozygous
Term
Two different alleles is _____
Definition
heterozygous
Term
Define locus
Definition
the position for a gene on a chromosome
Term
Huntington's disease is ____ ____
Definition
autosomal dominant
Term
Describe autosomal dominant
Definition
you only need one dominant gene to cause a condition;stops after one generation where no one is effected
Term
Autosomal dominant diseases usually cause what kind of mutation?
Definition
gain of function
Term
Autosomal recessive diseases usually result in a ___ mutation
Definition
loss of function
Term
Describe autosomal recessive genes
Definition
can skip generations; more likely to occur with incest
Term
Describe the law of independent assortment
Definition
for two genes on different chromosomes the inheritance of one does not influence the inheritance of the other
Term
Describe the product rule under the law of independent assortment
Definition
the chance that two independent events will both occur is the product of the chance that it will occur alone
Term
Describe conditional probability
Definition
chance of having offspring with certain genotype when you are unsure of those of the parents'; use punnett square and pedigree
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