Chapter 3 Flashcards
a map
Ø Made up of chromosomes
Ø The Human Karyotype has 23
pairs of chromosomes
Karyotype
one half of a duplicated chromosome
chromatid
a molecule composed of two
polynucleotide chains that coil around
each other to form a double helix
Ø The string that comprises the
chromatin fibers
DNA
a sequence of DNA or RNA that
codes for a molecule or a protein
basic unit of heredity
the human body has approximately
20,000 to 25,000 different genes
Gene
organized package of
DNA
chromosomes
consists of a sugar molecule attached
to a phosphate group and a nitrogen containing base
Ø the basic building block of nucleic
acids
Nucleotide
joined together by covalent bonds
between the phosphate group of one
nucleotide and the third carbon atom of
the pentose sugar in the next
nucleotide.
Nucleotide
This produces an alternating backbone
of sugar - phosphate - sugar - phosphate
all along the polynucleotide chain.
Ø 10 pairs of nucleotides in each full turn
of the helix in the DNA molecule
Nucleotide
nucleotides without a phosphate
group
nucleosides
consists of a segment of
DNA wound around eight
histone proteins and
resembles thread wrapped
around a spool
Nucleosomes
What controls the formation of mRNA
gene (DNA)
what spreads throughout the cell to control formation of a specific protein
mRNA
The entire process, from transcription of the genetic code in the nucleus to translation of the RNA code and the formation of proteins in the cell cytoplasm
gene expression
the 4 nitrogenous bases
purines: adenine and guanine
pyrimidines: thymine and cytosine
what consists the nucleotides
(1) phosphoric acid
(2) a sugar called deoxyribose
(3) four nitrogenous bases
purines: adenine and guanine
pyrimidines: thymine and cytosine
first stage in DNA formation
formation of nucleotides
the nucleotides formed using the four bases
deoxyadenylic,
deoxythymidylic, deoxyguanylic, and
deoxycytidylic acids.
combining one molecule of phosphoric acid,
one molecule of deoxyribose, and one of
the four bases forms a _________
acidic nucleotide
what pairs with adenine (purine base)
what pairs with cytosine (pyrimidine)
thymine (pyrimidine base)
guanine (purine base)
Gives the DNA the ability to
control the formation of
proteins
Genetic code
true or false
the purine and pyrimidine bases
projecting to the side of each
DNA strand are exposed after spliting the DNA molecule apart, the genetic code is formed
TRUE
consists of successive “triplets”
of bases—that is, each three
successive bases is a CODE
WORD
genetic code
true or false
The successive triplets of the DNA
control the sequence
of amino acids in a protein
molecule that is to be
synthesized
FALSE, the genetic code instead of DNA
what are the stop codons
UAA, UGA, UAG
what amino acid has CCG as RNA codon
PROLINE
What amino acid has GAA as RNA codon
Glutamic Acid
a process that removes the intervening,
non-coding sequences of genes (INTRONS) from pre-mRNA and joins
the protein-coding sequences (EXONS) in
order to produce a mature mRNA that
can be transported outside the nucleus.
RNA splicing
True or False
Transcription is done when the DNA code from the Cytoplasm is transferred to the RNA Code (Nucleus)
False. DNA - Nucleus
RNA - Cytoplasm
during mRNA synthesis, the two strands of __________ separate temporarily in the nucleus and uses the DNA template
DNA
the resulting complementary code triplets in the mRNA which control the sequence of amino acids in a protein to be synthesized in the cell cytoplasm.
codons
In the RNA synthesis, the building blocks are the same with the DNA except for the sugar deoxyribose replaced with ______ and thymine replaced by another pyrimidine ____________
RIBOSE
URACIL
this activates the RNA Nucleotides
RNA polymerase
TRUE OR FALSE
In the activation of RNA nucleotides,
there is adding of two extra phosphate radicals to each nucleotide to form
triphosphates.
These last two phosphates are
combined with the nucleotide by
high-energy phosphate bonds
derived from carbon
FALSE - derived from ATP
TRUE OR FALSE
small quantities of ATP energy are
made available to each of the
nucleotides.
This energy is used to promote
chemical reactions that add each
new RNA nucleotide at the end of
the developing RNA chain.
FALSE - large instead of small
In the DNA strand immediately ahead of
the gene to be transcribed is a sequence
of nucleotides called the _________
PROMOTER
where does the RNA polymerase (activates RNA nucleotides) attach to initiate the formation of RNA
Promoter
After the RNA polymerase
attaches to the promoter, the
polymerase causes ________ of
about two turns of the DNA helix
and separation of the unwound
portions of the two strands
unwinding
true or false
after the polymerase causing unwinding of
about two turns of the DNA helix
and separation of the unwound
portions of the two strands, the polymerase then moves along the
DNA strand, temporarily unwinding and
separating the two DNA strands at each
stage of its movement.
TRUE
where does the covalent linkage of the remaining phosphate on the nucleotide with the end of the growing RNA chain get energy
when the RNA
polymerase breaks two of the
three phosphate radicals away
from each RNA
nucleotides, it liberates large
amounts of energy from the
broken high-energy phosphate
bonds
When the RNA polymerase reaches the
end of the DNA gene, it encounters a
new sequence of DNA nucleotides called
the _____________ which causes the polymerase and the newly formed RNA chain to break away
from the DNA strand.
chain terminating sequence
can the polymerase be used again
and again to form more new RNA
chains?
YES.
does DNA have a high affinity for
rebonding with its own complementary DNA strand?
YES.
the RNA chain is forced away from the
DNA and is released into the _______.
nucleoplasm
true or false
the code that is present in the DNA
strand is eventually transmitted in complementary
form to the RNA chain.
TRUE
name the types of RNA
- Precursor messenger RNA (pre-mRNA)
- Small nuclear RNA (snRNA)
- Messenger RNA (mRNA)
- Transfer RNA (tRNA)
- Ribosomal RNA
- MicroRNAs (miRNAs)
what type of segment is removed during splicing and which is retained in the final RNA
INTRONS, EXONS
what is the immature, single strand of RNA that is processed in the nucleus to form mature
messenger RNA (mRNA).
precursor-mRNA
which RNA carries the genetic code to the
cytoplasm for controlling the type of
protein formed.
mRNA - the codons
what is the start RNA codon
AUG - bday ni mama
it transports activated amino acids to the ribosomes, it is called the anti-codon
transfer RNA
Serves as the physical link between the mRNA and the activated amino acid sequence of
protein. Each type combines specifically with 1 of the 20 amino acids that are to be
incorporated into proteins.
tRNA
true or false
In the ribosomes, each specific type of tRNA
recognizes a particular codon on the pre-RNA
and thereby delivers the appropriate amino
acid to the appropriate place in the chain.
false. mRNA instead of pre-RNA
what is the appearance of the tRNA?
a folded chain of 80 nucleotides with a
cloverleaf appearance
The specific code in the tRNA that allows
it to recognize a specific codon is a triplet
of nucleotide bases and is called an _____
ANTICODON
true or false
This anticodon is located in the middle of
the tRNA molecule (at the top of the
cloverleaf configuration)
false. bottom of the cloverleaf configuration
this type of RNA constitutes 60% of the ribosome
Ribosomal RNA
true or false.
The remainder of the ribosome is
protein, including about 75 types of
proteins that are both structural
proteins and enzymes needed to
manufacture proteins.
TRUE
the _________ acts as a manufacturing plant in
which the protein molecules are formed.
ribosome
this RNA provides the information necessary
for sequencing the amino acids in proper
order for each specific type of protein to be manufactured.
mRNA
this RNA transports amino acids to the
ribosome for incorporation into the
developing protein,
tRNA
the ribosome always functions in association with these two types of RNA
tRNA, mRNA
true or false
the cellular function requires large amounts of ribosomal RNA, hence the chromosomes located in the nucleus contains many duplicates of the DNA genes for ribosomal RNA
TRUEEE
where does the ribosomal RNA collects as it gets formed? hint: it is aa specialized structure lying adjacent to the chromosomes).
NUCLEOLUS
When large amounts of ribosomal RNA are
being synthesized, the nucleolus is a large
structure, whereas in cells that synthesize
little protein, the nucleolus may not even be seen
true or false
TRUE
where does the Ribosomal RNA binds with to form granular condensation products that are primordial subunits of ribosomes.
ribosomal proteins
ribosome subunits are released from the
nucleolus and transported through the large
pores of the nuclear envelope to almost all
parts of the cytoplasm.
true or false
TRUE
Where are proteins formed? cytoplasm or nucleus?
Cytoplasm, bc the nucleus does not contain mature ribosomes
single-stranded RNA molecules of 21
to 23 nucleotides that can regulate
gene transcription and translation.
microRNA (miRNA)
are miRNAs translated into proteins? are they coding RNAs?
NO.
The generation of miRNAs involves
special processing of longer primary
precursor RNAs called __________ which are the primary transcripts of the gene
primiRNAs
this RNA act to decrease gene expression.
miRNA
The pri-miRNAs are processed in the
nucleus by the microprocessor complex
to __________
pre-miRNAs
it promotes repression of translation or
degradation of the mRNA before it can
be translated by the ribosome.
it plays an important role in normal
regulation of cell function
miRNA
true or false
alterations in tRNA function have been
associated with diseases such as cancer
and heart disease.
false. miRNA
synthetic miRNAs and can be administered
to silence expression of specific genes.
true or false.
TRUEEE
a type of miRNA that is also called
silencing RNA or short interfering RNA.
Small Interfering RNA
these RNAs are short, double-stranded RNA molecules,
comprised of 20 to 25 nucleotides, that
interfere with expression of specific genes.
Small Interfering RNA (siRNA)
can be
used to block translation of any mRNA and
therefore expression by any gene for which
the nucleotide sequence is known.
Small Interfering RNA (siRNA)
true or false
miRNAs are useful therapeutic tools to silence genes
that contribute to the pathophysiology of
diseases.
FALSE. siRNAs
it is the formation of proteins on the ribosomes
Translation
When a molecule of mRNA comes in
contact with a ribosome, it travels through
the ribosome, beginning at its predetermined
end specified by an appropriate sequence of RNA bases called the
CHAIN INITIATING
CODON or the START
CODON (or the AUG codon)
what process is where while the mRNA travels through the
ribosome, a protein molecule is formed
translation
where is the protein molecule freed into as the ribosome terminates or stops the reading of mRNA codons (production of protein)
cytoplasm
A single mRNA molecule cannot form
protein molecules in several
ribosomes at the same time because
the initial end of the RNA strand cannot
pass to a successive ribosome as it
leaves the first
true or false
FALSE. it can
what do you call a cluster of ribosomes
frequently occurring, with 3 to 10
ribosomes being attached to a single
mRNA at the same time.
polyribosomes
is there a specificity of ribosomes for given types of protein
NO. protein molecule can cause formation in any ribosome
what causes the granular appearance of the portions of the reticulum
ribosomes attaching to endoplasmic reticulum
most proteins synthesized by the ribosomes are
released directly into the cytoplasm instead of into the ER.
true or false
false. cytosol
this is released upon the activation of amino acid in which ATP combines with the amino acid, giving up high-energy
phosphate bonds in the process.
Adenosine monophosphate
what is the enzyme that influences peptide bond formation between successive amino acids
peptidyl transferase
the synthesis of proteins is one of the
most energy-consuming processes of
the cell.
true or false
TRUE
how many total high energy phosphate bonds are needed for each amino acid added to the protein chain
4
In this chemical reaction, a hydroxyl
radical (OH− ) is removed from the
COOH portion of the first amino acid,
and a hydrogen (H+ ) of the NH 2
portion of the other amino acid is
removed.These combine to form water, and the
two reactive sites left on the two
successive amino acids bond with each
other, resulting in a single molecule. What process is this
Peptide Linkage
