CYTO Flashcards
one alternative of a pair or group of genes that could occupy a specific position of
chromosome
Allele
Is the cause of similarities between individuals
Heredity
Is the cause of differences between individuals
Variation
Variant of a gene for a trait
Allele
Linear strand of DNA harboring many genes
Chromosome
molecule in which genetic information is encoded
DNA
- that produces the same phenotypic effect whether inherited heterozygously or homozygously
Dominant Allele
- an allele that “masks” a recessive allele
Dominant Allele
unit of genetic information that occupies a specific position on a chromosome &
comes in multiple version aka the allele
Gene
genetic constitution of an organization
Genotype
having a genotype with two different and distinct alleles for the same trait
Heterozygous
having a genotype with two of the same allele for a trait
Homozygous
the physical observable characteristic of an organism
Phenotype
produces no phenotypic effect when inherited heterozygously and only
affecting the phenotype when inherited homozygously
Recessive Allele
- an allele “masked” by a dominant allele
Recessive Allele
Gregor Mendel was born on _____________________ (place) in ___________ (year)
Czech Republic 1822
Mendel went to the ________________, where he studied botany and learned the Scientific Method
and Worked with pure lines of peas for ______ years
university of Vienna, eight
Prior to Mendel, heredity was regarded as “___________” process and the offspring were
essentially a “_____________” of the different parental characteristics
blending, dilution
3 Principles of Mendelian Genetics
- Law of Dominance
- Law of Segregation
- Law of Independent Assortment
Dominant trait is always expressed in F1, while the recessive trait is masked only to
reappear in F2
Law of Dominance
2 alleles for a heritable character separate or segregate during gamete formation, and end
up in different gametes.
- In the monohybrid cross
- Known as the law of purity of gametes
Law of Segregation
Each pair of allele segregate independently of other pairs of alleles durinn gamete
information
- In the dihybrid cross
- Describes how different genes independently separate from one another when
reproductive cells develop (searched)
Law of Independent Assortment
a genetic mix between 2 individuals who have a homozygous genotypes that have
completely dominant or completely recessive alleles, which results in opposite
phenotypes of certain genetic trait
- parents differ by a single trait
- 3:1 phenotypic ratio
Monohybrid Cross
- has 16 punnett square
- combine randomly
- two different genes that differ in two observable traits
- cross that shows the possible offspring for two traits
- studying the inheritance of two characters simultaneously
- 9:3:3:1 phenotypic ratio
- two characters are inherited independently
Dihybrid Cross
- no trait is dominating
- one allele of a pair is not fully dominant over its partner
- third phenotype appears
ex: white x red = pink
Incomplete Dominance
one allele of a pair is not fully dominant over its partner, so a heterozygous phenotype somewhere in between the two homozygous
phenotypes emerges. An example is the case of snapdragons (starr et al., 160p)
b. When an organism is heterozygous for a trait, it will show a third phenotype; the
third phenotype is a blend of the other two
c. Example: cross between white and red flower the offspring becomes pink
Incomplete Dominance
- pair of non-identical alleles specific to two phenotypes which are both expressed at the
same time in heterozygous
ex: AB blood group
Codominance/Multiple Alleles
- means stopping
- a gene at one locus alters the phenotypic expression of the gene at a second locus
- a circumstance where the expression of one gene is modified by the expression of one or
more other genes (searched)
ex: albinism
Epistasis
pleion = more, greek word
- most genes have multiple phenotypic effects
- the phenomenon of one gene or one mutation affecting multiple traits (searched)
ex: cystic fibrosis & sickle cell disease - its alleles is responsible for the multiple
symptoms happening
. Pleiotropy
classified on an either-or-basis
- called quantitative variations usually indicate polygenic inheritance, an additive effect of
two or more genes on a single trait
ex: skin color
Polygenic Inheritance
segregate into the gametes independently of one another
Unlinked gene
- don’t segregate independently of each other and thus don’t give the phenotypic ratio of the F2 offspring
Linked gene
____________ is the genetic material
while a _________ is the basic physical and functional unit of heredity
DNA, gene
The Human Genome Project has estimated that humans have between ________________________ genes
20,000-25,000
The 3-Dimensional structure of DNA was discovered in 1953 by ____________________ in Cambridge,
using the experimental data of Wilkins and Franklin in London, for which they won a Nobel prize.
Watson & Crick
is polymeric nucleic acid of four monomeric robotids or ribonucleotids.
RNA
Each ____________________ contains a pentose sugar
ribonucleotide
DNA and RNA contains what elements
Carbon, Oxygen, Hydrogen, Nitrogen and Phosphorous.
The information content of DNA is in the form of specific sequences of ________________________
nucleotides
The DNA inherited by an organism leads to specific traits by dictating the synthesis of
______________
proteins
______________ are the links between genotype and phenotype
Proteins
the process by which DNA directs protein synthesis,
Gene Expression
Two stages of Gene Expression
Transcription and Translation
In 1909, British physician ___________________ first suggested that genes dictate phenotypes
through enzymes that catalyze specific chemical reactions
Archibald Garrod
___________________ and ____________ exposed bread mold to X-rays, creating mutants that
were unable to survive on minimal medium as a result of inability to synthesize certain
molecules
George Beadle, Edward Tatum
states that each gene
dictates production of a specific enzyme
one gene–one enzyme hypothesis
Who developed the one gene–one enzyme hypothesis
George Beadle, Edward Tatum
Some proteins aren’t enzymes, so researchers later revised the hypothesis: one gene– one enzyme to _____________________
one gene– one protein
Introduced the Central Dogma of Molecular Biology
Francis Crick
a theory stating that genetic information flows only in one direction, from DNA, to RNA, to protein, or RNA directly to protein
Central Dogma of Molecular Biology
is the intermediate between genes and the proteins for which they code
RNA
is the synthesis of RNA under the direction of DNA
Transcription
is the synthesis of a polypeptide, which occurs under the direction of mRNA
Translation
Transcription produces
messenger RNA (mRNA)
are the sites of translation
Ribosomes
In prokaryotes, mRNA produced by _________________ is immediately _____________ without more
processing
transcription, translated
In a eukaryotic cell, the _________________ separates transcription from translation
nuclear envelope
Eukaryotic RNA transcripts are modified through _______________ to yield finished
mRNA
RNA processing
A ___________________ is the initial RNA transcript from any gene
primary transcript
is the concept that cells are governed by a cellular chain of command:
DNA → RNA → protein
Central Dogma of Molecular Biology
Transcription and translation of Prokaryotic Cell happens in the _________________
Cytoplasm
In Eukaryotic cell the transcription process happens in the ___________ and the Translation process happens in the _____________
Nucleus, Cytoplasm
The Genetic Code has ___ amino acids, but there are only _____ nucleotide bases in DNA
20, four
What are the 4 nucleotide bases
Adenine, Thymine, Cytosine, Guanine
Sequence of Nucleotides
Codons
Codons shall contain ____ nucleotide bases
3
process of DNA to RNA
Transcription
During transcription, one of the two DNA strands called the ___________________ provides a template for ordering the sequence of nucleotides in an RNA transcript
template strand
Each codon specifies the _______________ to be placed at the corresponding position along a polypeptide
amino acid
the first stage of gene expression,
TRANSCRIPTION
RNA synthesis is catalyzed by _________________,
RNA polymerase
Pries the DNA strands apart and hooks
together the RNA nucleotides
RNA polymerase
RNA synthesis follows the same base-pairing rules as DNA, except uracil substitutes for ____________
thymine
The DNA sequence where RNA polymerase attaches is called the ________________; in bacteria, the sequence signaling the end of transcription is called the ______________________
promoter, terminator
The stretch of DNA that is transcribed is called a __________________________
transcription unit
The three stages of transcription:
- Initiation
– Elongation
– Termination
signal the initiation of RNA synthesis
Promoters
____________________ mediate the binding of RNA polymerase and the initiation of transcription
Transcription factors
The completed assembly of transcription factors and RNA polymerase II bound to a promoter is
called a _____________________
transcription initiation complex
A promoter called a ___________________ is crucial in forming the initiation complex in eukaryotes
TATA box
In ______________, the polymerase stops transcription at the end of the _________________
bacteria, terminator
In____________, the polymerase continues transcription after the pre-mRNA is cleaved from the growing RNA chain; the polymerase eventually falls off the DNA
eukaryotes
The 5′ end receives a modified nucleotide _______
5′ cap
The 3′ end gets a ______________
poly-A tail
Most eukaryotic genes and their RNA transcripts have _________________ stretches of nucleotides
that lie between coding regions
long noncoding
These noncoding regions are called
intervening sequences, or introns
The other regions are called _________ because they are eventually expressed, usually translated
into amino acid sequences
exons
_________________ removes introns and joins exons, creating an mRNA molecule with a continuous
coding sequence
RNA splicing
are catalytic RNA molecules that function as enzymes and can splice RNA
Ribozymes
5’ cap is also known as
7-methylguanosine (m7G) cap
long chain of adenine nucleotides
Poly-A Tail
is the RNA-directed synthesis of a polypeptide
Translation
A cell translates an mRNA message into protein with the help of ___________________
transfer RNA (tRNA)
Location of mRNA binding site
Small Subunit of Ribosome
Location of tRNA binding site
Large Subunit of Ribosome
facilitate specific coupling of tRNA
anticodons with mRNA codons in protein synthesis
Ribosomes
holds the tRNA that carries the
growing polypeptide chain
The P site
holds the tRNA that carries the next amino acid to be added to the chain
The A site
the exit site, where
discharged tRNAs leave the ribosome
The E site
The initiation stage of translation brings together ______, a ______ with the first _______,
and the _______________
mRNA, tRNA , amino acid, two ribosomal subunits
the start codon
AUG (Methionine)
During the _______________, amino acids are added one by one to the preceding amino acid
elongation stage
In Elongation each addition involves proteins called elongation factors and occurs in three steps: _________________, _____________________, and ______________
codon recognition, peptide bond formation, translocation
Termination occurs when a stop codon in the mRNA reaches the _______ of the ribosome
A site
The A site accepts a protein called a ___________
release factor
causes the addition of a water molecule instead of an amino acid
The release factor
A cell that has the ability to continuously divide and differentiate (develop) into various other
kind(s) of cells/tissues
Stem Cells
All of cell types come from a pool of _____________ in the early embryo
stem cells
come from a five to six-day-old embryo. They have the ability to form virtually
any type of cell found in the human body
Embryonic Stem Cells
are derived from the part of a human embryo or fetus that will ultimately
produce eggs or sperm (gametes).
Embryonic Stem Cells
are undifferentiated cells found among specialized or differentiated cells in a
tissue or organ after birth.
Adult Stem Cells
Based on current research they appear to have a more restricted ability to produce different cell types and to self-renew.
Adult Stem Cells
Each cell can develop into a new
individual
Totipotent
Examples of which are cells from early (1-3 days)
embryos
Totipotent
Cells can form any (over 200) cell types
Pluripotent
Examples of which are some cells of blastocyst (5 to
14 days)
Pluripotent
Cells differentiated, but can form a
number of other tissues
Multipotent
Examples of which are fetal tissue, cord blood, and
adult stem cells
Multipotent
Stem cells need to be ________________ to the appropriate cell type(s) before they can be used clinically
differentiated
Recently, abnormalities in chromosome number and structure were found in _____ human ESC lines
three
‘Blank cells’
unspecialized characteristic
Capable of dividing and renewing themselves for long periods of time
proliferation and renewal characteristic
Have the potential to give rise to specialized cell types
differentiation characteristic
